Answer the following question given this paragraph: Skeletal Muscle Fiber Structure Each skeletal muscle fiber is a skeletal muscle cell. These cells are incredibly large, with diameters of up to 100 m and lengths of up to 30 cm. The plasma membrane of a skeletal muscle fiber is called the sarcolemma. The sarcolemma is the site of action potential conduction, which triggers muscle contraction. Within each muscle fiber are myofibrilslong cylindrical structures that lie parallel to the muscle fiber. Myofibrils run the entire length of the muscle fiber, and because they are only approximately 1.2 m in diameter, hundreds to thousands can be found inside one muscle fiber. They attach to the sarcolemma at their ends, so that as myofibrils shorten, the entire muscle cell contracts (Figure 38.34). Q: The plasma membrane of a skeletal muscle fiber is called the what? Choices: - sheath - annulata - soleus - sarcolemma A:
sarcolemma
Answer the following question given this paragraph: Q: What regulates the passage of blood into capillary beds? Choices: - bicellular sphincters - diocesan sphincters - cell membrane - precapillary sphincters A:
precapillary sphincters
Q: Answer the following question given this paragraph: Scientists measure the gases that escape from a volcano to predict eruptions. Gases like sulfur dioxide (SO 2 ), carbon dioxide (CO 2 ), hydrochloric acid (HCl), and water vapor can be measured at the site. Gases may also be measured from satellites. The amounts of gases and the ratios of gases are calculated to help predict eruptions. Q: Scientists measure the gases that escape from a volcano to predict what? Choices: - storms - floods - snowfall - eruptions A:
A: eruptions
Question: Answer the following question given this paragraph: Two separate membranes form the mitochondrion. The inner membrane folds into cristae which divide the organelle into three compartments: the intermembrane space (between outer and inner membranes), cristae space (formed by infoldings of the inner membrane), and the matrix (within the inner membrane). The Krebs Cycle takes place within the matrix. The compartments are critical for the electron transport chain structure and function. Glycolysis occurs in the cytoplasm of the cell, with the products of glycolysis entering the mitochondria to continue cellular respiration. Q: How many membranes form the mitochondrion structure of a cell? Choices: - one - five - three - two A:
Answer: two
*Question*
Answer the following question given this paragraph: Mirrors and lenses are used in optical instruments to reflect and refract light. Optical instruments include microscopes, telescopes, cameras, and lasers. Q: Mirrors and lenses are used in optical instruments to reflect and refract what? Choices: - gravity - mass - electricity - light A:
**Answer**
light
Q: Answer the following question given this paragraph: Carl Woese and the Phylogenetic Tree In the past, biologists grouped living organisms into five kingdoms: animals, plants, fungi, protists, and bacteria. The organizational scheme was based mainly on physical features, as opposed to physiology, biochemistry, or molecular biology, all of which are used by modern systematics. The pioneering work of American microbiologist Carl Woese in the early 1970s has shown, however, that life on Earth has evolved along three lineages, now called domainsBacteria, Archaea, and Eukarya. The first two are prokaryotic cells with microbes that lack membrane-enclosed nuclei and organelles. The third domain contains the eukaryotes and includes unicellular microorganisms together with the four original kingdoms (excluding bacteria). Woese defined Archaea as a new domain, and this resulted in a new taxonomic tree (Figure 1.17). Many organisms belonging to the Archaea domain live under extreme conditions and are called extremophiles. To construct his tree, Woese used genetic relationships rather than similarities based on morphology (shape). Woese's tree was constructed from comparative sequencing of the genes that are universally distributed, present in every organism, and conserved (meaning that these genes have remained essentially unchanged throughout evolution). Woese's approach was revolutionary because comparisons of physical features are insufficient to differentiate between the prokaryotes that appear fairly similar in spite of their tremendous biochemical diversity and genetic variability (Figure 1.18). The comparison of homologous DNA and RNA sequences provided Woese with a sensitive device that revealed the extensive variability of prokaryotes, and which justified the separation of the prokaryotes into two domains: bacteria and archaea. Q: In the past, biologists grouped living organisms into five kingdoms: animals, plants, fungi, protists, and what? Choices: - trees - pathogens - lizards - bacteria A:
A: bacteria