Answer the following question given this paragraph: 16 Gregor Mendel and biological inheritance Charles Darwin1 , for all he contributed to the science of biology, never knew about the mechanism by which living things inherit traits from previous generations, or how new traits arise. As any schoolchild can tell you, this mechanism of interitance has since been found to be DNA2 , or deoxyribonucleic acid. DNA allows for stable inheritance of traits: the code in each strand of DNA is replicated precisely through the pairing of basic units along each strand. The error rate in this replication is amazingly low; not even one base pair in a million matches out of sequence. However, when even one base pair is added to a new strain of DNA in an order differently than in the parent chain, it can be the basis of a mutation. These changes in DNA sequences are the microscopic origin of changes in traits of all studied living things. Even the smallest difference in a strand of DNA can result in a change in traits that can cost the life of the organism. Mutations can produce proteins with a new or altered function. In humans, the example of Sickle cell anemia3 is commonly given as its origin is a difference of only one base pair in a section of DNA that encodes red blood cells. Individual sequences of DNA that encode for specific proteins are called genes and are the units of heredity. Each one has a set nucleotide4 , and together all of the genes (and some sequence of DNA that apparently do not code for any biologically important functions) together make up the entire chromosome5. Q: What mechanism is used by living organisms to pass along genes? Choices: - protein - digestion - chlorophyll - dna A:
dna
Answer the following question given this paragraph: Chapter 9 1 Figure 9.10 Ligase, as this enzyme joins together Okazaki fragments. 2 A 4 B 6 A 8 C 10 D 12 The DNA is wound around proteins called histones. The histones then stack together in a compact form that creates a fiber that is 30-nm thick. The fiber is further coiled for greater compactness. During metaphase of mitosis, the chromosome is at its most compact to facilitate chromosome movement. During interphase, there are denser areas of chromatin, called heterochromatin, that contain DNA that is not expressed, and less dense euchromatin that contains DNA that is expressed. 14 Telomerase has an inbuilt RNA template. Q: The dna is wound around proteins called what? Choices: - leptons - nucleotides - pepsins - histones A:
histones
Q: Answer the following question given this paragraph: Sex-linked traits are located on genes on the sex chromosomes. Q: Sex-linked traits are located on genes on what chromosomes? Choices: - reactive - neural - dna - sex A:
A: sex
Question: Answer the following question given this paragraph: Stereoisomers Molecules with the same connectivity but different arrangements of the atoms in space are called stereoisomers. There are two types of stereoisomers: geometric and optical. Geometric isomers differ in the relative position(s) of substituents in a rigid molecule. (For more information on stereoisomers, see Chapter 23 "The ", Section 23.4 "Coordination Compounds". ) Simple rotation about a CC bond in an alkene, for example, cannot occur because of the presence of the bond. The substituents are therefore rigidly locked into a particular spatial arrangement (part (a) in Figure 2.16 "Some Simple (a) Alkenes, (b) Alkynes, and (c) Cyclic Hydrocarbons"). Thus a carboncarbon multiple bond, or in some cases a ring, prevents one geometric isomer from being readily converted to the other. The members of an isomeric pair are identified as either cis or trans, and interconversion between the two forms requires breaking and reforming one or more bonds. Because their structural difference causes them to have different physical and chemical properties, cis and trans isomers are actually two distinct chemical compounds. Q: What is required for interconversion between the two forms of an isomeric pair? Choices: - couple and reforming - fixing and reforming - turn and reforming - breaking and reforming A:
Answer: breaking and reforming
*Question*
Answer the following question given this paragraph: Q: What are changes in membrane potential that vary continuously with the strength of a stimulus are known as? Choices: - reverse potentials - variable potentials - kinetic energy - graded potentials A:
**Answer**
graded potentials
Q: Answer the following question given this paragraph: objects such as furniture or floors). The first widely used antiseptic was phenol. Joseph Lister used it for antiseptic surgery in 1867. Phenol is toxic to humans, however, and can cause severe burns when applied to the skin. In the bloodstream, it is a systemic poisonthat is, one that is carried to and affects all parts of the body. Its severe side effects led to searches for safer antiseptics, a number of which have been found. One safer phenolic antiseptic is 4-hexylresorcinol (4-hexyl-1,3-dihydroxybenzene; resorcinol is the common name for 1,3-dihydroxybenzene, and 4-hexylresorcinol has a hexyl group on the fourth carbon atom of the resorcinol ring). It is much more powerful than phenol as a germicide and has fewer undesirable side effects. Indeed, it is safe enough to be used as the active ingredient in some mouthwashes and throat lozenges. Q: What was the first antiseptic called? Choices: - acid - gasoline - chlorine - phenol A:
A: phenol