exam 2

A20

20) In the absence of oxygen, fermentation: A) Generates NAD+ from the reduction of pyruvate B) Generates NAD+ from the oxidation of pyruvate C) Generates ATP from the oxidation of pyruvate D) Generates ATP from the reduction of pyruvate E) None of the answer options is correct

A21

21) The active maintenance of a constant environment is referred to as: A) Homeostasis B) Equilibrium C) Ability D) Symmetry E) Balance

C23

23) ATP is made at the inner mitochondrial membrane using energy supplied by _____. A) A proton concentration gradient B) NAD+ C) ADP D) O2 E) Lactic acid

C24

24) Which of the following most accurately describes the path traveled a new protein synthesized and released from the cell? A) Plasma membrane; ER, transport vesicle; golgi; cytosol; external environment B) Cytosol; golgi; ER; transport vesicle; plasma membrane; external environment C) Cytosol; ER; golgi; plasma membrane, external environment D) SER; RER; golgi, plasma membrane; external environment E) RER; cytosol; golgi; plasma membrane; external environment

C25

25) Starch and glycogen are different in that A) Only one is a polymer of glucose B) Only one contains ribose C) One has more branching and is less dense than the other D) Only one is an energy storing molecule E) Only one can be digested by humans

E26

26) Protein synthesis A) Occurs in the Golgi B) Occurs on the ER C) Is performed by ribosomes D) Occurs in the nucleus E) Two of the above are correct

D27

27) Which one of the following molecules would most likely require a transport protein to cross the plasma membrane of a red blood cell? A) CO2 B) H2O C) O2 D) C6H12O6 E) A steroid lipid

A28

28) The sodium potassium pump is an example of A) Primary active transport B) Secondary active transport C) Passive transport D) Facilitated transport E) A symporter

A29

29) Which type of inhibitor can be overcome completely by the addition of more substrate? A) Irreversible B) Noncompetitive C) Competitive D) Allosteric E) isotomic

B3

3) Most of the ATP produced during cellular respiration is generated through A) Substrate level phosphorylation B) ATP synthase C) Reduction of NAD+ D) Reduction of FAD E) Oxidation of pyruvate

B30

30) The chemical modification of proteins that are destined to leave the cell ... A) Cytosol B) Golgi Apparatus C) Nucleus D) Glycoplast E) Ribosome

A31

31) Defects in which of the following structures are responsible for a condition called "exercise intolerance," where individuals suffer extreme fatigue from minimal exertion? A) Mitochondrion B) Ribosome C) ER D) Golgi E) Lysosome

C32

32) The energy of activation of a reaction is A) The net change in free energy B) The difference in energy between substrate and product C) The energy input needed to reach the transition state D) The difference in energy between the transition state and the product E) Equivalent to the Delta G of ATP hydrolysis

C33

33) Trypsin and elastase are both enzymes that catalyze hydrolysis of peptide bonds. But trypsin only cuts next to lysine and elastase only cuts next to alanine. Why? A) Trypsin is a protein, and ekactase is not B) Delta G for the two reactions is different C) The shape of the active site for the two enzymes is different D) One of the reactions is endergonic, the other is exergonic E) Hydrolysis of lysine bonds requires water, hydrolysis of alanine bonds don't

A7

7) When a protein is assembled from individual amino acids the entropy _________ A) Increases B) Decreases C) Does not change D) Is absorbed E) There is not enough information to answer the question

A8

8) Animals breathe in air containing oxygen and breathe out air with less oxygen. The oxygen is used: A) The citric acid cycle B) The glycolysis pathway C) The conversion of pyruvate to acetyl Co-A D) Photosynthesis E) As an electron acceptor in the electron transport chain

A9

9) Which of the following are true regarding redox reactions? A) Oxidizing agents accept electrons B) The molecule donates electrons, it has been reduced C) Redox reactions may involve the transfer of hydrogen ions (H+) D) The molecule that has gained H atoms is said to be oxidized E) Reducing agents accept H atoms.

E34

34) Enzymatic reactions can become saturated as substrate concentration increases because A) Enzymes have the maximum possible number of hydrogen atoms attached to them B) The concentration of substrate reaches a point at which it cannot increase any further C) Substrates are inhibitors of enzymes D) The activation energy of the reaction reaches a point at which it cannot be lowered E) There are a limited number of the enzyme molecules present

C1

1) The difference between osmosis and diffusion is that A) Diffusion is passive transport whereas osmosis is active transport B) Only in diffusion do molecules move from areas of high concentration to low concentration C) Osmosis refers specifically to the movement of water, whereas diffusion refers to many types of molecules D) Only diffusion refers to the movement of materials across a semipermeable membrane E) The process of osmosis varies according to the kinds of particles present

B10

10) When glucose from your blood is being used up in the bloodstream, what is the next source of energy used in your body? A) Protein from the muscles B) Fat C) Glucose from the brain D) Glycogen from the liver E) Carbohydrates from chloroplasts

C11

11) Which of the following is not typically associated with an animal cells plasma membrane A) Protein B) Carbohydrate C) Nucleic acid D) phospholipid E) all of the above are associated with the plasma membrane

C12

12) If Delta G of a chemical reaction is negative and the change in entropy is that the reaction A) Requires energy B) Is endergonic C) Is exergonic D) Will not reach equilibrium E) Decreases the disorder in the system

E13

13) Which one of the following would most likely be a product of a catabolic reaction? A) A complex carbohydrate like cellulose B) A nucleic acid like RNA C) A motor protein like myosin D) A lipid like cholesterol E) An amino acid like tryptophan

C14

14) Following the citric acid cycle but before the electron transport chain and oxidative phosphorylation, most of the energy comes from the original glucose molecule is in the form of A) Acetyl Co-A B) CO2 C) Pyruvate D) NADH E) ATP

B15

15) The potential energy in a molecule of ATP is held in the A) Carbon binding bonds of the sugar B) Repulsion of the phosphate groups from each other C) The carbon nitrogen bonds of the base D) The carbon oxygen bonds of the sugar E) Repulsion of the sugar and the base

E16

16) Which of these equations is most likely to demonstrate energetic coupling in a cell? A) -7 and -14.8 B) -14.8 and +3.3 C) +3.3 and +7 D) -7 and +7 E) -7 and +3.3

B17

17) Which of the following organelles were once independent prokaryote organisms? A) Mitochondria and lysosomes B) Mitochondria and chloroplasts C) Chloroplasts and golgi apparatus D) Golgi apparatus and ribosomes E) Ribosomes and lysosomes

A18

18) When a mouse cell and a human cell are fused, the membrane proteins uniformly distributed over the surface of the hybrid cell. This occurs because A) Many proteins can move around in the bilayer B) All proteins are anchored within the membrane C) Proteins are asymmetrically distributed within the membrane D) All proteins in the plasma membrane are peripheral E) Different membranes contain different proteins

E19

19) Which of the following would be found in the interior of a lipid bilayer? A) Glycerol B) Phospholipid fatty acids C) Phospholipid phosphate groups D) Hydrophilic membrane proteins E) Two of the above are correct

A2

2) Binding of substrate to the active site of an enzyme is A) Reversible B) Irreversible C) Noncompetitive D) Coupled E) Allosteric

E35

36) The electrical component of an electrochemical gradient is due to A) The use of ATP as an energy source to drive primary transport B) A greater concentration of positive charges on the side of the membrane with the lowest concentration of protons C) A higher pH on the side of the membrane with the highest concentration of protons D) A higher pH on the side of the membrane with the lowest concentration of protons E) A greater concentration of positive charges on the side of the membrane with the highest concentration of protons

B36

37) In eukaryotic cells fermentation occurs in the _______. A) Mitochondria B) Cytosol C) Nucleus D) Vacuoles E) Fermentation does not occur in eukaryotic cells

D37

38) Some bacteria undergo ________ in ________. A) Cellular respiration; mitochondria B) Cellular respiration; chloroplasts C) Photosynthesis; chloroplasts D) Photosynthesis; infolded sections of plasma membrane E) Two of the above are correct

B38

39) The first law of thermodynamics states that ________. A) Combustion engines are 100% efficient B) Energy cannot be created nor destroyed. C) Only eukaryotic cells can produce ATP D) There is an increase of disorder in the universe over time E) The universe becomes more orderly over time.

E4

4) What is the signal recognition particle used for? A) Bringing partially synthesized proteins to the ER B) Guiding proteins to the plasma membrane C) Directing proteins to the Golgi D) Pausing translation E) Two of the above are correct

B39

40) In a chemical reaction, transition-state intermediates have free energies that are A) Lower than either the reactants or the products B) Higher than either the reactants or the products C) Lower than the reactants, but higher than the products D) Higher than the reactants, but lower than the products E) Lower than the reactants, but the same as the products

A5

5) Isocitrate dehydrogenase is a key allosteric enzyme in the citric acid cycle. What kind of effect do you think a high level of NAD+ has on this enzyme? A) Enzymatic activity would increase B) Enzymatic activity would decrease C) Enzymatic activity would not change D) The enzyme would change the Delta G of the reaction E) Two of the above answers are correct.

B6

6) The plasma membrane of animals contains carbohydrates A) On the inner side of the membrane, facing the cytosol B) On the outer side of the membrane, protruding into the environment C) On both sides of the membrane D) In the core of the membrane E) There is no carbohydrate associated with the plasma membrane

A22

Some diseases, such as Tay-Sachs, are caused by the defective breakdown of cellular components. Which of the following organelles is defective? A) Lysosomes B) Ribosomes C) Endoplasmic reticulum D) Golgi apparatus E) Plasma membrane