THE MUSCULAR SYSTEM THE MUSCULAR SYSTEM The muscular tissue of the body constitutes from one-third to one-half of the body mass of the average vertebrate. Muscular tissue functions in: ï¿½ movement and locomotion, through its direct connection with the skeletal system ï¿½ more subtle movements associated with maintaining posture/vertical position ï¿½ help to generate heat due to catabolic reactions that are associated with muscular activity (such that animals shiver or increase overall movement when body temperature drops) ï¿½ can be modified into other structures, such as electric organs in some fish The general structure of a muscle fiber include (Fig. 10.2, p. 347) myofibrils (chains of repeating subunits) composed of two kinds of filaments: ï¿½ thin filaments (composed of myosin) and thick filaments (composed of actin, tropomyosin and troponin) that interact by binding to produce a sliding movement between the filaments, and that creates tension in the muscle fiber leading to muscle contraction.

There are three generally recognized muscle tissue types: smooth, cardiac and skeletal, each tissue type with a distinct location in the body, cellular organization (histology), and general action of the muscle fibers (physiology) Because of the multiple functions of muscles, criteria for classifying muscles include: 1. Color ï¿½ skeletal - Fig. 10.2, p. 347 ï¿½ cardiac - Fig. 10.3, p. 348 ï¿½ smooth - Fig. 10.4, p. 348 Smooth muscle ï¿½ found lining the walls of blood vessels, visceral organs (such as the digestive tract and uterus) and are also found attached to hairs in the integument. ï¿½ two general types: - unitary smooth muscle has self-initiated or myogenic contraction to aid in sustaining the rhythmic movement of the organ with which it is associated - multiunit smooth muscle has neurogenic contraction, which requires action potentials sent by neurons to regulate its action.

Cardiac muscle ï¿½ are found solely in the musculature of the heart wall ï¿½ in cardiac muscle the branching of the cells increase its overall connectivity and the cells are firmly united with each other through the intercalated disks ï¿½ cardiac muscle does not fatigue readily, which is a desirable trait in the muscles that maintain circulation of blood ï¿½ action of the cardiac muscle fibers shows mixed control, such that the myogenic rhythm of the heart is maintained by neurogenic control and the entire unit of the cardiac muscle acts as a syncytium, or single functional unit Skeletal muscle ï¿½ skeletal muscles are closely associated with the skeleton and are used in locomotion ï¿½ each skeletal muscle fiber is also a syncytium due to the close connection between cellular units ï¿½ fibers are closely associated with connective tissues and are under voluntary control by the nervous system. Histology Fast General Muscle terminology As you are familiar with from lab, many unique terms are associated with the muscular system, ranging from describing how a muscle works to the general shape of the muscle itself.

The term "muscle" has at least two meanings: ï¿½ muscle cell or fiber - the active contractile component: muscle cells and their endomysium ï¿½ muscle organ - the whole organ: muscle cells plus associated connective tissues, nerves, blood supply Action ï¿½ takes place by contraction, which creates tension in the muscle so that it shortens and thus moves what it is attached to (whether it is a bone, hair or the epithelium of an organ) ï¿½ for skeletal muscles, each muscular unit may be described based on a number of factors, such as where the main body of the muscle (belly) is located, such as shoulder muscles, pectoral muscles, gluteal muscles, etc.

Muscle is not attached directly to bone by the contractile muscle fibers - various wrappings of connective tissues extend beyond the ends of the muscle fibers to connect with the periosteum of the bone: ï¿½ tendon - cordlike attachment ï¿½ aponeurosis - thin flat sheet ï¿½ fascia - thin flat sheets of connective tissues that wrap and bind parts of the body together ï¿½ raphe - junction of two muscles at a band of connective tissue to form a line of fusion, such as the linea alba Basis for muscle contraction: ï¿½ a muscle receiving no nervous stimulus is relaxed or in a resting state - soft shape retained by surrounding collagen fibers ï¿½ when nervous stimuli applied beyond muscleï¿½s threshold level, contraction results and tensile force is generated, constituting the active state ï¿½ the attached bone and/or mass that must be moved represents the load - whether a muscle actually contracts depends on the relative balance between the tensile force of contraction and the load to be moved (Fig. 10.6, p.

351) Major contractile characteristics of a muscle include how rapidly it reaches maximum tension and how long it can sustain this tension Tension and strength are directly related to the number of cross-bridges between muscle filaments ï¿½ in the shortest position, filament overlap interferes with cross-bridge formation and tension is low (Fig. 10.6a) ï¿½ in the longest position, filaments overlap very little with few cross-bridge formations and tension low (Fig. 10.6b) ï¿½ intermediate lengths generate maximum cross-bridging (Fig. 10.6c) Tonic fibers: ï¿½ relatively slow contracting and produce low force ï¿½ can sustain contraction for prolonged periods of time ï¿½ comprise most of the axial and appendicular skeleton Twitch (phasic) fibers: ï¿½ generally produce fast contractions so they often make up muscles used for rapid movement ï¿½ slow twitch vs.

fast twitch relative, but slow take ~2X longer to reach maximum forces Origin: the end of a muscle that attaches to the more fixed part of the skeleton, which is the proximal end in limb muscles Insertion: the point of attachment of a muscle that moves the most when the muscle shortens, and is the most distal end of limb muscles For the biceps, the belly lies anterior to the humerus, the origin the coracoid process of the scapula, and the insertion is the radial tuberosity. For the triceps, the origins are the posterior surface of the humerus and the infraglenoid tubercle of the scapula, and the insertion is the olecranon of the ulna.

The action of skeletal muscles can be: ï¿½ antagonistic - oppose or resist the action of another muscle (such as is the case of the biceps and the triceps) ï¿½ synergistic - work together to produce a common effect (such as in the action of making a fist, in which the muscles of the forearm and fingers work together) Other actions of muscles include: Flexor - decreases the angle at a joint Extensor - increases the angle at a joint Abductor - moves a bone away from the midline Adductor - moves a bone closer to the midline Levator - produces an upward movement Depressor - produces a downward movement Supinator - turns the palm upward or anteriorly Pronator - turns the palm downward Sphincter - decreases the size of an opening Tensor - makes a body part more rigid Rotator - moves a bone around its longitudinal axis We can also describe muscles based on shape, such as in the arrangement of the muscle fibers: Strap-shaped muscles - have parallel fibers and broad attachments (teres major) Fusiform muscles - parallel fibers, but narrow tendons for attachments (biceps) Pinnate muscles - diagonally arranged fibers that insert on the side of the muscle into a tendon.

(subscapularis) Or Size: The main muscle groups correspond with the divisions used for the skeletal system: Axial muscles - trunk and tail muscles of fishes and tetrapods Branchiometric muscles - also called visceral muscles, such as those associated with the gills, jaws and hyoid apparatus Appendicular muscles - fin muscles of fishes and limb muscles of tetrapods Muscles arise from three embryonic sources: mesenchyme - dispersed throughout the body giving rise to smooth muscles within the walls of blood vessels and some viscera splanchnic layer of the lateral plate mesoderm - develops into the smooth muscle layers of the digestive tract and into the walls of the heart paraxial mesoderm, or somites, and specifically the myotome layer of the somite - the primary source of skeletal muscles during development - within the head region, the myotome does not become completely segmented, and instead forms seven pairs of somitomeres that will produce the musculature of the head region (Fig. 10.22a, p.

365) - the remainder of the somites in the body develop into the trunk and appendicular muscles Homologies During muscle evolution, some muscles have fused with one another, others have split into distinct new muscles, some have become reduced in prominence, and others have changed their points of attachment and hence their evolution Muscle homology can be determined in three ways: - attachment similarity - functional similarity - nervous innervation, due to conserved relationships between a muscle and its nerve supply Establishing similarity can help compare the different groups of muscles (cranial, axial and appendicular) among the different vertebrate classes Cranial muscles External ocular muscles - six extrinsic ocular muscles which attach to the surface of the eye and are responsible for moving the eye within the orbit (Fig. 10.23, p.

366): Dorsal (superior) oblique Ventral (inferior) oblique Dorsal (superior) rectus Ventral (inferior) rectus Medial rectus Lateral rectus These muscles are innervated by the oculomotor nerve Some tetrapods also have a retractor bulbi, which pulls the eyeball further into the orbit to allow for coverage by the nictitating membrane (lacking in humans) Branchiometric muscles - develop from the myotomes caudal to those that produce the ocular muscles ï¿½ closely associated with the visceral skeleton so they are used in both breathing and feeding. ï¿½ perform the function of operating the jaw, opening and closing the spiracle (which functions in water intake into the gills when the fish is eating) ï¿½ may be subdivided based on what visceral arch they are associated with: Fishes' gill arch - Sternothyroid - draws larynx caudally - these muscles are also used in speech and sound production in tetrapods Homologies between the branchial and hypobranchial muscles of several different vertebrate taxa are shown in Table 10.3.

Trunk/axial muscles The axial musculature associated with the trunk can function either in locomotion or breathing Axial musculature begins as myotomes separated by myosepta which are then further divided into two regions: ï¿½ epaxial muscles - muscles on the dorsal part of the body ï¿½ hypaxial muscles - muscles on the ventral part of the body that are separated by the lateral septum (Fig. 10.26, p.

368) Fishes In fishes, the trunk muscles remain divided into folded muscle segments or myomeres, that are divided into myosepta ï¿½ these muscles contract alternately to produce an undulating motion that propels the fish through the water ï¿½ internally, these muscles remain divided into dorsal (epaxial) and ventral (hypaxial) sections by the lateral septum Tetrapods In tetrapods, the trunk muscles function more in maintenance of posture, head movement, and respiration rather than in locomotion, which has shifted to the appendicular muscles The epaxial muscles of the tetrapod trunk skeleton include: Longissimus dorsi - extends vertebral column Iliocostalis - draws ribs together Multifidus spinae - extends vertebral column Spinalis dorsi - extends vertebral column The hypaxial muscles of the tetrapod trunk skeleton include: Abdominal muscles: Diaphragm - separates the thoracic/abdominal cavities, functions in breathing Intercostals - protract/retract ribs Appendicular muscles Appendicular muscle development originates from the somites as ougrowths of the somite myotome into the limb bud - myotomic buds

 to the appendages As the limb bud grows, the appendicular musculature subdivides into the muscle mass that lies above the appendicular skeleton (dorsal muscles) and the mass that lies below the appendicular skeleton (ventral muscles) These muscle masses later differentiate into multiple muscle groups depending on the type of organism Fishes In general, most of the locomotion of fishes is dependent on the action of the axial musculature, which undergoes alternate contraction and relaxation to produce undulating movements of the body Fins (appendicular appendages) function more in maintaining stability, braking and maneuvering - thus, the range of movement of fins is much more limited than that of tetrapod limbs ï¿½ ventral muscles in fishes go to the formation of the abductor muscle, which pulls the fins ventrally and cranially ï¿½ dorsal muscles go to the formation of the adductor muscle found on the posterodorsal part of the fin and moves the fin dorsally and caudally Tetrapods The tetrapod appendicular musculature is more complex than that of fishes because the limbs function in both support and locomotion In tetrapods the function of the dorsal and ventral muscle groups is reversed from that seen in

 fishes ï¿½ the dorsal muscles, which in fishes were responsible for adduction will instead abduct or extend the appendages ï¿½ the ventral muscles formerly used for abduction are instead used for adduction or flexion Pectoral region Flexors of the digits Locomotion The study of locomotion completes our understanding of the skeletal and muscular systems, because it examines the functional relationship between the two systems as well as between the organism and its environment We will discuss three important categories of locomotion: swimming, terrestrial locomotion, and flight.

Swimming We can first distinguish vertebrates that swim by whether they are primary swimmers (species for which swimming is the sole pattern of locomotion) or secondary swimmers (species which have readapted completely or partially to an aquatic mode of life).

Some general requirements of swimmers are that they must: 1) reduce the resistance that water offers to motions of the moving body 2) propel themselves in a relatively dense medium 3) control vertical position in the water 4) maintain orientation and steer the body In addition, secondary swimmers must also undergo secondary adaptations to their circulatory, respiratory and sensory systems to tolerate the high pressures and exposure to water that swimming entails Primary swimmers are generally undulatory swimmers that use the musculature of the fins only, or the fins in combination with the trunk and tail to propel themselves through the water Characteristics of the primary swimmers are: ï¿½ a fusiform body that is held rigid by strong articulation of the vertebral column ï¿½ segmented myomeres that allow individual muscle units to exert forces over the entire side of the body ï¿½ integument that is attached strongly the underlying musculature by connective tissue to increase the compactness of the body The musculature, skeletal system and integument form an integrated unit that helps to streamline the animal and reduce drag as it moves through the water Secondary swimmers are generally oscillatory swimmers that propel themselves through the water with paddle-like movements of the appendages ï¿

½ appendages may also be modified into webbing or flippers to assist in propulsion ï¿½ generally have well-developed appendicular musculature ï¿½ can reduce pressure drag around the body by temporarily streamlining themselves when moving through water Terrestrial locomotion In terms of terrestrial locomotion, there are many different modes that an animal may use: Cursorial - tetrapods that travel far or fast on the land.

Cursorial animals possess a relatively elongate body, in which the vertebral column acts to increase running stride by stretching out to increase forward propulsion Saltatorial - tetrapods that jump or hop. Saltatorial animals have bodies in which the weight is shifted to the hind legs, the legs are powerful and strongly constructed, and the center of mass is aligned with the sacrum Scansorial - tetrapods adept at climbing. Scansorial animals have strengthened pectoral musculature and appendages, and modified phalanges for clinging to vertical surfaces Fossorial - tetrapods that are adept at digging, and live a somewhat subterranean existence. Fossorial animals have highly flexible vertebral columns, strong pectoral musculature, and modified phalanges for digging Each of these different modes of life requires dramatic modifications in the skeletal system (in terms of the parts of the body that receive the most stress) and the associated musculature Animals with bipedal locomotion or that are scansorial have a foot posture that is more plantigrade, in which the soles of the feet are placed flat on the ground.

In contrast, most cursorial animals have a more digitigrade posture, in which the wrist and ankle are carried off the ground and the animal walks on its digits. Or, the animal may be extremely long legged, and walk only on the tips of the digits such that the terminal end of the digit is modified to form a hoof, and other digits are lost, a posture called unguligrade. Flight Tetrapods that fly can do so in three different ways.

Parachuting - use of limbs and body to increase overall surface area to break an inadvertent fall Gliding - use of broad membranes attached to limbs to increase surface area and travel a greater horizontal distance through the air True flight - use of wings to actively sustain movement through the air Tetrapods that use active flight, such as birds, have pectoral appendages that are reduced to a single digit and highly developed pectoral musculature necessary to sustain active flight In birds, the primary flight muscles originate on the ventral surface of an expanded, keeled sternum: ï¿½ pectoralis - depressor of the wing ï¿½ supracoracoideus - levator of the wing In bats, the flight muscles are associated with movement of the humerus and scapula and are located on the side of the thorax: ï¿½ primary wing depressors: - pectoralis Abductor - moves a bone away from the midline Adductor - moves a bone closer to the midline Antagonistic - condition in which a muscle opposes or resists the action of another muscle Aponeurosis - sheetlike tendon of a muscle Cursorial - tetrapods that travel far or fast on the land Depressor

 - produces a downward movement Digitigrade - posture in which the wrist and ankle are carried off the ground and the animal walks on its digits Epaxial - pertaining to structures that lie above or beside the vertebral axis Extensor - increases the angle at a joint Fascia-sheets of connective tissue that lie beneath the skin or ensheathe groups of muscles Flexor - decreases the angle at a joint Flight - use of wings to actively sustain movement through the air Fossorial - tetrapods that are adept at digging, and live a somewhat subterranean existence Gliding - use of broad membranes attached to limbs to increase surface area and travel a greater horizontal distance through the air Hypaxial - pertaining to structures that lie ventral to the vertebral axis Insertion - the point of attachment of a muscle that moves the most when the muscle shortens, or the most distal end of limb muscles Levator - produces an upward movement Origin - the end of a muscle that attaches to the more fixed part of the skeleton, which is the proximal end in limb muscles Oscillatory swimmers - propel themselves through the water with paddle-like movements of the appendages Parachuting - use of limbs and body to increase overall surface area to break an inadvertent fall

 Plantigrade - posture in which the soles of the feet are placed flat on the ground during locomotion Primary swimmers - species for which swimming is the sole pattern of locomotion Pronator - turns the palm downward Raphe - junction of two muscles at a band of connective tissue to form a line of fusion, such as linea alba Rotator - moves a bone around its longitudinal axis Saltatorial - tetrapods that jump or hop Scansorial - tetrapods adept at climbing Secondary swimmers - species which have readapted completely or partially to an aquatic mode of life from a terrestrial life Sphincter - decreases the size of an opening Supinator - turns the palm upward or anteriorly Synergistic - condition in which the muscles work together to produce a common effect Tensor - makes a body part more rigid Undulatory swimmers - use the musculature of the fins only, or the fins in combination with the trunk and tail, to propel themselves through the water Unguligrade - a locomotory posture used by long legged tetrapods, which walk only on the tips of the digits such that the terminal end of the digit is modified to form a hoof, and other digits are lost Bio Final at East Central College - Study

Blue StudyBlue DNA consists of long strands of repeating subunits called nucleotides the simple sugar in DNA; gives it its name deoxyribose a carbon ring structure that contains one or more atoms of nitrogen nitrogenous base double ringed nitrogenous bases; adenine and guanine purines single ringed nitrogenous bases; thymine and cytosine pyrimidines process by which DNA makes copies of itself DNA replication carries the coded instructions for protein synthesis from the DNA in the nucleus to the ribosomes messenger RNA, mRNA three-base code in DNA or RNA codon brings the amino acids to the ribosome in the correct order so that they can be built into proteins transfer RNA; tRNA process of transferring information from a strand of DNA to a strand of RNA transcription sequences of bases within genes that are not part of a code for a protein introns DNA that actually codes for the protein in short sequences exons the process of coverting the info in a sequence of nitrogenous bases in mRNA into a sequnce of amino acids in protein translation on the other side of the tRNA molecule there are 3 nitrogenous bases that pair up with a mRNA codon during translation anticodon change in the sequence of nucleotides within a gene mutation a change in a

 single base pair in DNA point mutation (base-pair substitution) a mutation in which a single base is added or deleted from DNA frameshift mutation anything in the environment that causes mutations in DNA to occur mutagen How does DNA achieve control of a cell?

by controlling the production of proteins What protein controls all of an organisms actions? enzymes Who discovered evidence to determine that DNA is the genetic material of cells? What did they use in their experiment? Hershey and Chase, used viruses made only of DNA and protein to infect bacteria; radioactivly labeled viruses What are the three parts of a nucleotide? simple sugar, phosphate group, nitrogenous base What is the sugar in DNA? deoxyribose What does DNA stand for? deoxyribonucleic acid What is a phosphate group made of? one atom of phosphorous, surrounded by four oxygen atoms What are the 4 nitrogenous bases in DNA? adenine, guanine, cytosine, thymine Which two bases are double ringed? What are they called? adenine, guanine; purines Which two bases are single ringed? What are they called? thymine, cytosine, pyrimidines Which two parts of a nucleotide form the backbone of the DNA strand? the phosphate group and deoxyribose In DNA, which bases are always equal to each other?

adenine= thymine; guanine= cytosine (Chargaff's rule) Who proposed that DNA was made of two chains of nucleotides? Watson and Crick What type of bond holds the nitrogenous bases together? Are they strong or weak? weak hydrogen bonds Which bases bond with each other in DNA? adenine bonds with thymine, guanine bonds with cytosine (ash tray, garbage can) What is the shape of DNA called? Why? double helix because it is two strands twisted together What forms the unique genetic informationof an organism? What do scientists use this for? the sequence of nucleotides How does DNA replication begin? it unzips and unwinds What bonds nucleotides into chains? DNA polymerase I What are proteins polymers of? How many are there? amino acids, 20 What are the three ways that RNA is different from DNA? single strand, sugar is ribose, uracil instead of thymine What are the three types of RNA? messenger, ribosomal, transfer What does a codon code for in RNA? a particular amino acid What is the ribosome made of? What does this do?

ribosomal RNA What are the steps of transcription? Step 1: section of two DNA strands unwinds and separates Step 2: enzyme DNA polymerasematches the free RNA nucleotides with their complimentary DNA bases Step 3: enzymes link the RNA nucleotides together and a mRNA strand is complete Step 4: mRNA breaks away and leaves the nucleus to move to a ribosome What is the main difference between DNA replication and transcription? transcription results in a single RNA instead of a double strand of DNA How many different codons in RNA are there? 64 Do all codons code for amino acids? Why or why not? no, some signal start and stop What is the start codon? What else does it code for? AUG, methionine How many stop codons are there? What are they? 3, UAA, UAG, UGA Can more than one codon code for one amino acid? yes Can a codon code for more than one amino acid? no Where does translation take place? at the ribosomes in the cytoplasm Where is mRNA made in prokaryotic cells? In eukaryotic cells? nucleus What is the role of tRNA?

bringing the correct amino acids to the ribosome in the correct order How many amino acids does each tRNA molecule carry? one What is attached to each end of the tRNA? amino acid and anticodon Describe what happens during translation. Step 1: ribosome attaches to the first codon if an mRNA molecule Step 2: a tRNA molecule brings the first amino acid, methionine Step 3: a new tRNA molecule carrying an amino acid pairs with the second mRNA strand Step 4: a chain of amino acids is formed until the stop codon is reached on the mRNA strand What type of bond forms between amino acids? peptide bond When a mutation occurs in reproductive cells, is there a chance the embryo will not survive? Can there be a positive effect? yes, yes If a mutation occurs in a body cell, will it be passed on to offspring? only a mutation in a reproductive cell, not body What can happen if a gene is damaged in a body cell? frameshift mutation How many amino acids does a point mutation change? one How many amino acids does a frameshift mutation change? all of the ones after it What is spontaneous mutation? a mutation that happens for no known reason What do mutagens include?

radiation, chemicals, high temperatures What are examples of radiation? What does it do to DNA? What does this result in? What type of mutation is this (point or shift)? x-rays, cosmic rays, ultra violet light, nuclear radiation; damage or breat apart DNA; deletion; frameshift mutation What are examples of chemical mutagens? What type of mutation does this cause (point or frameshift)? dioxins, asbestos, benzene, formaldehyde, tobacco smoke; point mutation the grouping of objects based on similarities classification the branch of biology that groups and names organisms based on studies of their different characteristics systematics two-word naming system to identify individual species binomial nomenclature consists of a group of similar species genus second word in a binomial nomenclature, sometimes describes a characteristic of the organism specific eepithet category into which related organisms are placed taxon the next larger taxon, consists of a group of similar genera family Who was Aristotle? What did he develope? He is considered the first what? greek philosopher, first widely accepted system of biological classification Who developed the classification system we use today? Carolus Linnaeus What do the words of the binomial nomenclature system identify?

the first word identifies the genus and the second is the specific epithet What is the species name of humans? Homo sapiens What language do taxonomists use? Why? Latin, because it is no longer spoken therefore it doesn't change How do you write a scietific name? What about typing one? the first letter of the genus name is uppercase but the first one of the other is lowercase, written underline, type italics What tool can anyone use to identify organisms? Describe it. dichotomous key, made up of sets of numbered statements, each set deals with a single characteristic of an organism What is the smallest taxon? What is the largest taxon? species, domain What are all of the taxa in order from largest to smallest? domain, kingdom, phylum, class, order, family, genus, species What are the two main characteristics that distinguish among the six kingdoms? differences in cellular structures, methods of obtaining energy Which two kingdoms are prokaryotes? Are they unicellular or multicellular? How big are they? Are they heterotrophs or autotrophs? How do the autotrophs obtain energy?

Archaebacteria and Eubacteria, unicellular, microscopic, both, chemosyntheic and photo synthetic Where do archaebacteria live? What types of environments are these? extreme environments, anaerobic Where do eubacteria live? Are all eubacteria harmful? Why or why not? most habitats except extreme ones, some, some cause disease but some are harmless or even helpful What is the kingdom name for protists? Where do protists live? Are they unicelluar or multicellular? Are they heterotrophs or autotrophs? Protista, moist environments, both, both Are fungi heterotrophs or autotrophs? Do they move? Are they unicellular or multicellular? How do they obtain nutrients? What are some examples of fungi? heterotrophs, yes, both, from organic materials in the environment What is the kingdom name for plants? Are they unicellular or multicellular? Heterotrophs or autotrophs? Do they have a nucleus? Do they move? What do plant cells usually have? Plantae, multicellular, autotrophs, yes, no, chloroplasts Are animals multicellular or unicellular?

What don't animal cells have? Are they able to move? Are their cells organized? multicellular, cell wall, yes, yes What is a virus? particle that causes disease in organisms and consists of a core of nucleic acid surrounded by a protein coat Are viruses living? Why or why not? no, cannot carry out respiration, grow, or develope What is the only thing that a virus can do? replicate (only with a host cell) What is a host cell? a cell in which a virus replicates What is a bacteriophage? viruses that only infect bacteria What is the core of a virus made of? nucleic acid protein coat that surrounds nucleic acid core What is an envelope? Which viruses have them? Give an example. made of lipids, proteins and carbohydrates, protective outer layer of virus; larger viruses that infect animals; Human influenza and HIV What two things does the protein arrangement of the capsid determine? shape and cell cell can be infected How many viral shapes are there? 4 Describe each viral shape and give an example of each. rod-shaped- long, narrow, helical shape, ex.

tobacco mosaic virus polyhedral- many sided, resemble small crystals, isocahedron- 20 sides, ex. poliovirus enveloped- capsid is encased with an envelope studded with projections (spikes), common in large viruses that infect animals, ex. human influenza and HIV head with tail- viruses that infect bacteria, consists of polyhedral head attached to a cylindrical tail with leg-like fibers, ex. T4 bacteriophage (infect E. coli) How specific are viruses? species specific and some are cell specific Why is the specificity of viruses important? Give the example we talked about. helps us control the spread of it; eradication of small pox by 1980 How long is a typical lytic cycle? How many new viruses can be produced? 30 minutes, 200 viruses Describe the lytic cycle. List the steps to the lytic cycle.

viral replication process that rapidly kills the host causing to lyse (burst) Step A: attachment- viral protein recognize and attach to the plasma membrane of the host cell Step B: entry- the virus injects its nucleic acid into the host Step C: replication- the viral nucleic acid takes over the metabolism of the host cell and forcing ot to produce viral nucleic acid and protein Steo D: assembly- newly synthesized particles are assembled into new viruses Step E: lysis and release- host cell ruptures and releases new virus particles What is the lysogenic cycle? Does the lysogenic cycle kill the host cell immediately? replication process in which a virus does not immediately kill the host What are the steps to the lysogenic cycle? Step A: virus attaches to host cell and injects DNA Step B: viral nucleic acid becomes part of the host cell's chromosomes Step C: the inactive provirus replicates along with host cell's chromosome and host undergoes normal cell division Steo D: provirus cuts loose from the host cell's chromosome and the lytic cycle begins What is a provirus? viral DNA that is integrated into the host cell's chromosomes How long can the lysogenic cycle last?

many years What are the two main groups of bacteria? Describe each. Archaebacteria- group of bacteria that live in unusually harsh environments Eubacteria- "true bacteria"; all of the organisms traditionally known as bacteria How are arcaebacteria different from other bacteria? What does this allow them to do? Give three examples of where you can find them. cell wall, cell membrane, and rRNA are different; live in extreme environments; acidic hot springs, undersea volcanic vents, and highly salty water What are the four groups of archaebacteria? Describe each. mathanogens- produce methane, swamps thermoacidophiles- hot acidic water, acidic hot springs chemosynthesizers- use in organic compounds as a resource, hydrothermal vents extreme halophiles- extremely salty places, The Dead Sea, sea water evaporating ponds Who developed the Gram-stain technique? Hans Christian Gram Describe the process of Gram-staining. 1. bacteria stained with crystal violet (purple) and iodine 2. rinse with alcohol 3. stain with safranin (red) What determines which dye the bacterium takes up? cell wall What are Gram-positive bacteria? Give examples.

cell wall contains peptidoglycan, ex. scarlet fever, actinomytes, yogurt bacteria What are Gram-negative bacteria? cell wall has an extra lipid layer Why is it important to know if bacteria are Gram-positive or Gram-negative? require different antibiotics for treatment What are cyanobacteria? What else are they called? gram-negative eubacteria that perform plant-like photosynthesis and release oxygen as a byproduct; a.k.a. blue green algae Are bacteria prokaryotic or eukaryotic? prokaryotic What is a capsule? What are bacteria with a capsule more likely to do? some bacteria have a sticky gelatinous covering around the cell wall; cause disease What are flagella? long, whip-like protrusions that help bacteria move What is a plasmid? How many can a bacteria cell have? a few genes located in a small circulare chromosome piece, more than one What are pili and what are they used for? hair-like extensions of plasma membrane that helps bacteria stick to a surface; used as a bridge through or on which two bacteria emerge DNA What happens when bacteria grow in penicillin? Why is this a problem for the bacteria?

causes holes to develope in cell wall, allows bursting in osmosis, dead cell What are three ways to distinguish among bacteria? gram-stain reaction, shape, growth pattern What are the three most common shapes of bacteria? coccus (spheres), bacillus (rods), spirillum (spirals) What are the three prefixes of growing patterns and what does each one mean? diplo- paired arrangement; staphylo- cluster of grapes; strepto- chains of cells Why can't bacteria reproduce by mitosis or meiosis? have no nucleus and have circular chromosome What is binary fission and what happens during it? bacteria reproduces asexually, bacteria copies its chromosomes; copy and original copy become attached to the cell's plasma membrane; cell grows larger and eventually the two chromosomes separate and move to the opposite ends of the cell; a partition forms between the chromosomes separating the cell in two similare cells; cells are genetically identical What is conjugation? one bacterium transfers all or part of its chromosome to another cell through ot on the pilus that connects the two cells What are obligate aerobes? Give an example. require oxygen for respiration; ex.

Mycobacterium tuberculosis What are obligate anaerobes? Give an example. killed by oxygen; ex. Treponema pallidum (syphillis), Clostridium botulinum (botulism) What is an endospore and when do bacteria produce them?

a tiny structure that contains a bacterium's DNA and small amount of cytoplasm encased by a tough outer covering that resists drying out, temperature extremes, and harsh chemicals; in unfavorable conditions obtain their nutrients by digesting and absorbing nutrients from dead organisms saprophytes tiny tubes filled with cytoplasm and nuclei that form the body of the fungus hyphae cross-walls, that divide hyphae into sections septa mass of tangles, interwoven hyphae that form the body of a fungus mycelium symbiotic association between a fungus and a photosynthetic organism lichen mutualistic associations between a fungus and the roots of a plant mycorrhizae parts of the hyphae that anchor a fungus to its source of nutrients rhizoids hyphae that connect groups of rhizoids stolons thick walled spores that can withstand unfavorable conditions zygospores when haploid hyphae fuse they form a structure containing a haploid nucleus gametangium club-shaped hyphae that produce spores basidia spores produced in basidia during reproduction basidiospores the underside of most caps have thin sheets of tissue, contain basidia that produce basidiospores gills when a basidios

pore germinates, it produces a hyphae of either mating strain + or - spore germination when different hyphae meet, they fuse and form a new mycelium containing cells with 2 haploid nuclei hyphae fusion the mycelium forms a compact mass, a button, just below the soil's surface, a button developes into a stalk and cap button formation in the basidia, haploid nuclei fuse, meiosis occurs, producing 4 haploid nuclei that develop into basidiospores spore production sac-like structures in which the sexual spores of the fungi develop ascus sexual spores produced inside the ascus ascopores fungal hyphae grow up from the mycelium and elongate to form conidiophores chains or clusters of asexual spores conidia difference between fungus and plants Cell wall- Chitin, Cellulose What are common characteristics of fungi?

eukaryotic, multicellular, heterotrophs that cannot move by themselves How do fungi get nutrition? all fungi are heterotrophs; most are saprophytes, some are parasites, few are predators What are the four major phyla of fungi? zygomycota, basidiomycota, ascomycota, deuteromycota Describe zygomycota. common monds, bread molds, can grow wherever there is water and nutrients, no septa in their hyphae, reproduce sexually and asexually, ex. Rhizopus stolonifer Describe basidiomycota. club fungi, club-shaped hyphae, complex reproductive cycle, reproduce sexually, ex. mushroom Describe ascomycota. sac fungi, largest phylum, reproduce sexually and asexually, ex. truffles and yeast important ascomycotes- mold growing on decaying food, edible (truffles and morels), yeast (unicellular, rarely produce hyphae, anaerobic fermentors), disease causing (apple scab) Describe deuteromycota. imperfect fungi, no sexual reprocution, ex.

Penicillium, Aspergillus, Athlete's foot, ringworm, fingernail infections, Arthrobotrys (fungal predator that traps and kills small worms) What is one characteristic that is common to all animals? What does this mean? heterotrophic, consume What characteristic disinguishes animals from the other kingdoms? What does this mean? locomotion, move from place to place What does sessile mean? permanately attached to a surface What is one trait that scientists use to classify animals? presence or absence of a backbone, or spine, that protects the main nerve chord What are vertebrae? bones that make up the spine What is a vertebrate? arrangement of body parts around a central axis What is asymmetry? What animals have asymmetry? no symmetry, sponge What is radial symmetry? What other characteristics do animals with this symmetry have? animal has body parts radiating from a central point, like spokes of a wheel; slow moving or sessile and have sense organs located around their bodies, ex. starfish What is bilateral symmetry? What other characteristics do animals with this symmetry have?

animal that has body parts arranged in pairs on either side of a central axis; faster and complex sense organs located on the anterior end, ex. horse, dog What is the ventral surface? What is the dorsal surface? bottom of an animal; top of an animal What is the anterior end? What is the posterior end? front of a bilaterally symmetrical animal; rear of a bilaterally symmetrical animal What is segmentation? bodies of animals are divided into repeating subunits What is cleavage? process that the zygote divides by What is an embryo? organism at an early stage of growth and developement What is a blastula and how is it formed? hallow ball of cells; formed when embryo becomes an increasingly higher number of smaller and smaller cells What is a gastrula? Describe gastrula formation. a structure made up of two layers with an opening at one end, cells on on side of blastula move inward What is the ectoderm? What does the ectoderm form? layer of cells on the outer surface of the astrula; developes into skin and nervous tissue What is the endoderm? What does the endoderm form?

layer of cells lining the inner surface of the gastrula; developes into lining of the animal's digestive tract and into organs asociated with digestion What is the mesoderm? What does it form? third cell layer found in developing embryo between the ectoderm and the endoderm; develops into muscles, circulatory system, excratory system and in some animals the respiratory system Compare protostomes and deuterostomes. Give an example of each. protostome is where the blastopore becomes the mouth, ex snails, earthworms, insects deuterostomes is where the blastopore developes into the anus, ex. fish, snake, bird, starfish, frogs and toads, humans What are body cavities? fluid-filled spaces inside bodies which internal argans are found What are aceolomates? What is an example? Where are organs found? animals that develope from three cell layers but have no body cavities; flatworms; imbedded in tissues What is a pseudocoelomate? What is an example? a fluid-filled cavity partly lined with mesoderm; ex. roundworm What is a coelom? What does the coelom do?

What is an example of a coelomate? a fluid-filled space that is completely surrounded by mesoderm; cushions and protects internal organs; ex. human and earthworm What are the three types of skeletons? Describe each. Give an example of an animal with each. hydrostatic skeleton- skeletal system in which muscles surrounds and are supported by a water-filled cavity; ex. earthworms and roundworms exoskeleton- a hard covering of the outside of the body that provides a framework for support; ex. crabs, crawfish, dragonfly, tarantula, ladybug endoskeleton- rigid framework inside body to which muscles attach; ex. starfish, sharks, rays, humans, reptiles, birds What are the two types of digestive systems? Describe them and list advantages and disadvantages. two-way- single opening, enters and leave through the same opening, digested and undigested food is mixed one-way- in one opening, out the other, more efficient What is the simplest nervous system? Describe it. nerve net- consists of individual nerve cells that form a network throughout the body What is a ganglion? Which animals have them? What do ganglia form in more complex animals?

cluster of nerve cell bodies located at the anterior end; bilaterally symmetrical animals; brain What are the characteristics of reptiles? ectothermic, bilaterally symmetrical vertebrates with scales What are the four orders of reptiles? squamata, testudines, crocodilians, sphenodontia What are the distinguishing characteristics of the order squamata? Give examples of each. snakes- legless, arboreal, terrestrial, aquatic; constrictors- squeeze, ex. boa, python, anaconda, venomous- poison to paralyze or kill, ex. cobra, rattle, vipers, swallowers- swallow prey whole, ex. king, corn, rat lizards- four legs. arboreal, ex. chameleon, terestrial, ex. uromastyx, aquatic, ex. marine iguara What are the distinguishing characteristics of the order testudine? Give examples of each. tortoises- dome-shaped shell, terestrial, ex. sulcatta or box turtle turtles- flatter shells, seaturtles- ocean, ex. green sea turtles, freshwater- amphibians, ex.

red-eared slider What are the distinguishing characteristics of the order crocodilians? Give examples of each. crocodiles- narrow, pointed jaw, found in Austrailia, Africa, and N&S America alligators- broat, short snout, found in China and SE U.S. caimens- broad, short snout, smaller, found in Central America gavials- long, narrow snout that broadens at the end, found in India and Burma What are the distinguishing characteristics of the order sphenodontia? Give examples of each. "spade toothed", ex. tuatara What is the unique characteristic to turtles and tortoises? What are the two parts? Describe each part. shell, carapace- curved top of shell that covers the back, plastron- flat shell that covers the bottom of the turtle What type of fertilization do reptiles use? internal Some reptiles lay eggs. What are they called? oviparous food source for the developing embryo What is the amnion? fluid-filled envelope that cushions the embryo What is the allantois? membrane sac that stores waste and is the site for gas exchange What is the chorion?

provides another layer of protection and helps regulate gas exchange What is the albumin? provides additional food, ions, and water to the embryo Describe a reptilian egg shell. leathery or contains calcium (like a bird egg shell), porous allowing oxygen and carbondioxide to pass through, waterproof Which lizards and snakes give birth to live young? How is this done? What is this called?

live in colder regions and sea snakes; hold eggs in their (females) bodies until they hatch; ovoviviparous fan-shaped membranes that are used for balance, swimming and steering fins located on the dorsal side of the shark and is used to help balance the shark dorsal fin located in the ventral side of the shark towards the posterior and also helps the shark maintain balance pelvic fins located in the posterior end of the shark and provides downward propulsion caudal fin located in the ventral surface close to the anterior end and they counteract the downward propulsion of the tail by providing upward lift pectoral fins sharks have tough leathery skin with placoid scales used to provide oxygenated blood directly to the eye and brain through a separate blood vessel spiracle detects movements in the water lateral line system gas exchange takes place here in fish gills small vesicles and pores that form part of an extensive subcutaneous sensory netwrk system ampullae of lorenzini each set of gills is covered by a protective flap of tissue operculum thin-walled sac in the abdominal cavity filled with gas swim bladder What characteristics are common to all fish?

bilaterally symmetrical, coelomates that have endoskeletons, closed circulatory systems, nervous systems with complex brains and sense organs, and efficient respiratory systems, and live in water What are the four classes of fish? Give an example of each. Chondrichthyes: cartilaginous fishes, ex. sharks, rays, and skates Osteichthyes: bony fish, ex. bass, brim, trout Myxini: hagfish Agnathans: jawless fish, includes myxini and cephalaspidomorphi All fish have a lateral line system except which? Agnathans Who many pairs of gills does a shark have? What about Osteichthyes? five to seven; four All sharks must constantly swim except which shark? nurse shark How do you know if a shark is a boy or a girl? if it has claspers it is a boy What is the difference between Chondrichthyes and Osteichthyes? Skeleton: Cartilage- Bone What is the difference between a frog and a toad's skin?

A frog has smooth moist skin while toads have dry bumpy skin What is the difference between a frog and a toad's body? Frogs have a long, tapered body with long legs. Toads have short, squaty body with short legs. Where do frogs live? They live in or near water. Where do toads live? They live in drier regions because their skin is resistant to drying out. They only return to water to reproduce. Why do amphibians require a moist environment for reproduction? Amphibian eggs have no shell and dry up easily How many living species are there? 4,000 Aquatic larvae have what? What is unique about them? What are they replaced with when they become adults? gills, external, lungs How do species without gills or lungs breath? Exchange gases directly through their skin, similar to earthworms salamanders that stay in water all their lives and retain gills and other larval structures as adults axolotl What were Mrs. Meaux's first amphibians? What were their names? Tiger salamanders; Squirt and Squeegee Are caecilians vertebrates or invertebrates? Vertebrates What do caecilians feed on?

Worms and insects How big do caecilians get? 30 cm (14 in) What do most adult amphibians feed on? Insects on the side of its head; covered by a transparent eyelid eyes What is metamorphosis accompanied by?

A change in habitat Posses fins, gills and a 2-chambered heart; feed ion yolk stored in bodies 1st step of metamorphosis Start to develope hide legs, tail shortens and feed on plants in water 2nd step of metamorphosis froglets, 3-chambered heart, lungs, 4 legs, risidual tail 3rd step of metamorphosis Last (4th) step of metamorphosis animal that maintains a constant body temperature and it is not dependent on environmental factors endotherm group of cells that secrete fluids gland a liquid rich in fats, sugars, proteins, minerals, and vitamins milk sheet of muscle located beneath the lungs that separates the chest cavity from the abdominal cavity where other organs are located diaphragm mammals that lay eggs and have a cloaca into which the urinary, digestive, and reproduction tracts open monotremes mammals that give birth to small underdeveloped young that develop in the mother's external pouch marsupials mammals whose young develop inside the mother's body and are nourished by the mother's body until birth placental mammals structure through which the developing young recieve nourishment from the mother's body placenta cone-like teeth in the front of the mouth, specialized

 for stripping and cutting incisors long, pointed teeth on the sides of the mouth, specialized for piercing and tearing canines broad, flattened teeth in the back of the mouth, specialized for grinding and crushing molars and premolars stomach chamber containing bacteria that digests the cellulose in plant tissues rumen pouch located at the end of the small intestine that contains bacteria that digests plant material cecum two sides of the heart are separated by a thick wall of muscle called the septum organs that regulate water balance and remove cellular waste kidneys each kidney is covered by a coat of connective tissue called the capsule directly inside the capsule, extends toward the center of the kidney cortex inner part of each kidney medulla a dilute fluid compossed of the body's excess water and waste urine the fluid flows into collecting ducts and into, for storage urinary bladder processes information that makes thinking and learning possible cerebrum coordinates movement and balance, which make running, walking, swimming, or flying possible cerebellum regulates body activity, such as heart beat, respiration, and swallowing medulla oblongata the time that the embryo stays inside the mother's body gestation period What are the characteristics of mammals?

Which two are unnique to mammals? hair, milk, respiration and circulation, teeth, modified limbs, and learning, endothermic; hair and milk What are the three types of mammals? What are their disinguishing characteristics? Give examples of each. monotremes- lay eggs, ex. duck-billed platypus and echidnas marsupials- underdeveloped young live in external pouch until old enough, ex. kangaroo, opossum, koala bear placental mammals- baby developed inside mother's body, ex. humans, rodents, rabbits, horses What is in order Monotremata? duck-billed platylus and echidnas What is in order Marsupialia? kangaroo, opossum, koala bear What is in order Rodentia? rats, squirrels, guinea pigs, beavers, and chipmunks; largest- capybara What is in order Chiroptera? bats What is in order Lagomorpha? hares, pikas, and rabbits What is in order Carnivora? cheeta, giant panda, sea lions, otters What is in order Cetacea?

dolphin, killer whale, beluga whale What is in order Sirenia? manatees and dugongs What is in order Artiodactyla? hippos, pigs, camels, deer, cows, giraffes What is in order Perissodactyla? horses, rhinos, zebras What is in order Insectivora? moles, shrews, hedgehogs What is in order Proboscidea? elephants

Question: What six letter word is used to describe a fish's tail fin located at the end of its body and used for propulsion ?
Answer: CAUDAL