Biology

1. Plant cells transport sucrose across the vacuole membrane against its concentration gradient by a process known as
A. simple diffusion.
B. passive transport.
C. active transport.
D. cellular respiration.
E. facilitated diffusion.

2. When a photon is absorbed by chlorophyll,
A. ATP is split into ADP, phosphate, and energy.
B. hydrogen ions are released.
C. the chlorophyll becomes “excited,” or energized
D. the chlorophyll molecules fluoresce.
E. a greater number of light wavelengths can be absorbed

3. The chemiosmotic generation of ATP is driven by
A. osmotic movement of water into an area of high solute concentration.
B. the addition of protons to ADP and phosphate via enzymes
C. oxidative phosphorylation.
D. a difference in H+ concentration on both sides of a membrane.
E. None of the above

4. Which of the following statements about the electron transport chain is true?
A. Electrons are received from NADH and FADH2.
B. Electrons are passed from donor to recipient carrier molecules in a series of oxidation-reduction reactions.
C. Usually the terminal electron acceptor is oxygen.
D. Most of the enzymes are part of the inner mitochondrial membrane.
E. All of the above

5. How does the reduction of pyruvate to lactic acid during fermentation allow glycolysis to continue in the absence of oxygen?
A. This reaction is a kinase reaction.
B. This reaction is coupled to the formation of ATP.
C. Water is formed during this reaction.
D. This reaction is coupled to the reduction of NAD+ to NADH
E. This reaction is coupled to the oxidation of NADH to NAD+.

6. When NADH donates two electrons to ubiquinone during respiration, ubiquinone is
A. oxidized.
B. phosphorylated.
C. reduced.
D. aerobic.
E. hydrolyzed.

7. The oxidation of malate to oxaloacetate is coupled to the reduction of NAD+ to NADH + H+. NAD+ is a(n)
A. phosphate ester.
B. oxidizing agent.
C. vitamin.
D. phosphorylating agent.
E. reducing agent.

8. Which of the following is an example of an exergonic reaction?
A. Receptor-mediated endocytosis.
B. The beating cilia of a protozoan
C. Cellular respiration
D. Phagocytosis
e The Na+–K+ pump

9. The net energy outcome of cyclic photophosphorylation is
A. sugar.
B. ATP and NADPH.
C. ATP.
D. ATP and NADH.
E. NADPH.

10. The O2 gas produced during photosynthesis is derived from
A. CO.
B. CO2.
C. bicarbonate ions.
D. glucose.
E. water.

11. Substrate-level phosphorylation is the transfer of a(n)a. phosphate to
a protein.
b. phosphate to a substrate.
c. phosphate to an ADP.
d. ATP to a protein.
e. phosphate from ATP to a substrate

12. Negative feedback in a sequence of chemical reactions involves a chemical that appears _______ in the sequence and _______ reaction.
A. late; inhibits an earlier
B. late; activates an earlier
C. early; inhibits a later
D. late; inhibits a later
E. early; activates a later

13. In noncyclic photophosphorylation, electrons from _______ replenish chlorophyll molecules that have given up electrons.
A. CO2
B. water
C. NADPH + H+
D. O2 gas
E. None of the above

14. How does an ion channel exert its specificity for one ion and not another?
A. It is a simple matter of charge and ionic size.
B. The ion lets go of its water and is attracted to a channel pore protein.
C. The ion channel hydrates ions as they pass through.
D. There are recognition sites in the ion channel.
E. The ion channel makes use of aquaporins.

15. During photorespiration, rubisco uses _______ as a substrate.
A. CO2
B. glyceraldehyde 3-phosphate
C. NADPH
D. 3-phosphoglycerate
E. O2

16. In C4 plants, CO2 is first fixed into a compound called
A. oxaloacetate.
B. ribulose bisphosphate.
C. pyruvate.
D. glucose.
E. 3-phosphoglycerate

17. Photophosphorylation provides the Calvin-Benson cycle with
A. water and photons.
B. CO2 and glucose.
C. ATP and NADPHu
D. light and chlorophyll.
E. protons and electrons.

18. Toxic peroxides that are formed unavoidably as side products of important cellular reactions are collected and neutralized in _______.
A. Peroxisome
B. Mitochondria
C. Golgi complex
D. Lysosome
E. Endoplasmic Reticulum

19. When vesicles from the Golgi apparatus deliver their contents to the exterior of the cell, they add their membranes to the plasma membrane. The plasma membrane does not increase in size, because
a. some vesicles from the Golgi apparatus fuse with the lysosomes.
b. membrane vesicles carry proteins from the endoplasmic reticulum to the Golgi apparatus.
c. membrane is continually being lost from the plasma membrane by endocytosis.
d. new phospholipids are synthesized in the endoplasmic reticulum.
e. the phospholipids become more tightly packed together in the membrane

20. In some prokaryotic organisms the plasma membrane folds to form an internal membrane system that is able to
a. carry on photosynthesis.
b. engulf and phagocytize bacteria.
c. synthesize proteins.
d. propel the cell.
e. hydrolyze carbohydrates to ATP.

21. Proteins from the Golgi are transported to the correct location by means of
A. motor proteins.
B. signals found on the packaged proteins.
C. microtubules
D. the control provided by the nucleus.
E. the direction in which all vesicles travel within the cell.

22. Microtubules are made of
a. actin, and they function in locomotion.
b. tubulin, and they are essential in chromosome distribution during mitosis.
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c. tubulin, and they are found in microvilli.
d. actin, and they function to change cell shape.
e. polysaccharides, and they function in locomotion.(c)97 VeriSign

23. Which of the following represents the correct pathway for the synthesis and secretion of insulin, a protein secreted by the cells of the pancreas?
A. Lysosome; vesicle; plasma membrane
B. Rough ER; Golgi apparatus; vesicle; plasma membrane
C. Golgi apparatus; rough ER; lysosome
D. Plasma membrane; coated vesicle; lysosome
E. Rough ER; cytoplasm; plasma membraneleft

24. What is the purpose of the folds of the inner mitochondrial membrane?
A. They increase the surface area for the exchange of substances across the membrane.
B. The folds have no known purpose
C. They anchor the mitochondrial DNA.
D. They increase the volume of the mitochondrial matrix.
E. They create new membrane-enclosed compartments within the mitochondrion.

25. Lysosomes are important to eukaryotic cells because they contain
A. photosynthetic pigments.
B. their own DNA molecules.
C. digestive enzymes
D. starch molecules for energy storage.
E. the cells waste materials.

26. Which of the following organelles is found at the base of every eukaryotic cilium and flagellum?
A. Basal body
B. Nucleolus
C. Centriole
D. Flagellum
E. Microvillus

27. Which of the following statements is true regarding mitochondria and chloroplasts?
A. Animal cells produce chloroplasts.
B. Mitochondria and chloroplasts may be found in the same cell.
C. Mitochondria and chloroplasts are not found in the same cell.
D. Chloroplasts can revert to mitochondriain certain conditions.
E. All of the above

28. When a severely dehydrated patient is brought to the hospital, an IV of normal saline is started immediately. Distilled water is not used because
A. it would cause blood cells to swell and eventually burst.
B. nutrients are provided by the saline.
C. normal saline is more economical.
D. the distilled water might be contaminated by bacteria.
E. it would cause water to leave the cells and the cells would collapse.

29. If you removed the pili from a bacterial cell, which of the following would you expect to happen?
A. The bacterium would dry out.
B. The bacterium would no longer be able to swim.
C. The shape of the bacterium would change
D. The bacterium would not adhere to other cells as well.
E. The bacterium would no longer be able to regulate the movement of molecules into and out of the cell.

31. Plant and animal cells are similar in appearance. One difference is that
A. only animal cells have mitochondria.
B. only plant cells have peroxisomes.l
C. plant cells have a cell wall instead of the plasma membrane found in animal cells.
D. only animal cells contain centrioles.
E. plant cells lack a cytoskeleton.

30. Osmosis moves water from a region of _______ to a region of _______.
A. high concentration of dissolved material; low concentration of dissolved material
B. hypertonic solution; hypotonic solution
C. low concentration of dissolved material; low concentration of dissolved material
D. low concentration of dissolved material; high concentration of dissolved material
E. low concentration of water; high concentration of water

32. If a shallow pan is filled with water, a drop of red ink is placed in one end of the pan, and a drop of green ink is placed in the other end, which of the following will be true at equilibrium?
A. The red ink will be uniformly distributed in one half of the pan, and the green ink will be uniformly distributed in the other half of the pan.
B. Each ink will move down its concentration gradient.
C. No predictions can be made without knowing the molecular weights of the pigment molecules.
D. The concentration of each ink will be higher at one end of the pan than at the other end.
E. The red and green inks will be uniformly distributed throughout the pan.

33. Which of the following is true of lysosomes?
A. They are the sites where autophagy occurs.
B. They may contain anthocyanins that aid in pollination.
C. They provide turgor in plant cells.
D. They may have arisen through endosymbiosis.
E. They are found only in plants.

34. Which of the following is a function of a plant cell vacuole?
A. Storage of toxic by-products and wastes
B. Support for the cell
C. Containment of animal-attracting pigments that aid in pollination
D. Hydrolysis of seed proteins into plant embryo food
E. All of the above

35. The surface area of the small intestine is greatly increased by
A. myosin.
B. thylakoid membranes.
C. pili.
D. microtubules.
E. microvilli.

36. Which of the following does not affect the rate of diffusion of a substance?
A. Electrical charge of the diffusing material
B. Concentration gradient
C. Temperature of the solution
D. Molecular diameter of the diffusing material
E. Presence of other substances in the solution

37. For each molecule of ATP consumed during active transport of sodium and potassium,
A. two Na+ ions are imported and one K+ ion is exported.
B. two K+ ions are imported and three Na+ ions are exported.
C. two Na+ ions are imported and three K+ ions are exported.
D. three K+ ions are imported and two Na+ ions are exported.
E. one K+ ion is imported and three Na+ ions are exported.

38. Which of the following structures is involved with the movement of organelles within a cell?
A. Intermediate filaments
B. Mitochondria
C. Golgi apparatus
D. Endoplasmic reticulum
E. Microtubules

39. The electric signal for a contraction passes rapidly from one muscle cell to the next by way of
A. freeze-fractures.
B. integral membrane proteins.
C. tight junctions.
D. gap junctions.
E. desmosomes.

40. A concentration gradient of glucose across a membrane means that
A. the glucose molecules are chemically more tightly bonded on one side than on the other.
B. glucose molecules are more crowded on one side of the membrane than on the other.
C. there are more glucose molecules within the membrane than outside the membrane.
D. there is less water on one side of the membrane than on the other.
E. there are more moles of glucose on one side of the membrane than on the other.

41. Which of the following statements most accurately describes the function of plasmodesmata in plant cells or gap junctions in animal cells?
A. Plasmodesmata allow passage of only proteins between adjacent cells.
B. Gap junctions allow passage of only proteins between adjacent cells.
C. Gap junctions allow passage of proteins and small molecules between adjacent cells.
D. Plasmodesmata allow passage of proteins and small molecules between adjacent cells.
E. None of the above

42. The long and complex series of events that occurs when a signal binds to the cell surface and is converted from one form to another is called _____.
A. action potential
B. signal transduction
C. transesterification reaction
D. signal analysisng mat
E. signal cross-wiring

43. How is phosphorylation important in a signal transduction cascade?
A. A hormone will phosphorylate the entire cell, thus causing the cell to be marked for destruction.
B. Phosphorylation will shut down a signal transduction cascade, thus leading to an end of the signal.
C. When the hormone itself becomes phosphorylated, it travels to all nearby cells and activates them to release more hormones of that same type.
D. Phosphorylation will turn an inactive protein into an active one, which triggers another response in the cell.
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e. Phosphorylation will specifically modify the cellular lipids.

44. Which statement best describes what would happen if you treated cells in a developing frog embryo with a molecule that blocked a cadherin observed in muscle tissue?
A. The formation of the middle lamella between adjacent muscle cells would be disrupted.
B. Connections between gap junctions will be disrupted.
C. Adhesion of muscle cells to cells of non-muscle tissues would be disrupted.
D. Connections between the cytoskeleton of muscle cells and the ECM would be disrupted
E. Adhesion of muscle cells to other muscle cells would be disrupted.




45. The most abundant protein found in the extracellular matrix of animal cells is _____.
A. pectin
B. collagen
C. cellulose
D. keratin
E. hemoglobin