Archive for June 2021

The production of antibodies

12:24

The production of antibodies



a. occurs in B cells and is referred to as the humoral immunity response

b. occurs in T cells and is referred to as cellular immunity.

c. occurs in B cells and is referred to as cellular immunity.

d. occurs in T cells and is referred to as humoral immunity.

e. None of the above are correct.



Answer: a. occurs in B cells and is referred to as the humoral immunity response

Which of the following reactions require SAM?

12:23

Which of the following reactions require SAM?



a. Synthesis of dopamine

b. Synthesis of norepinephrine

c. Conversion of tryptophan to serotonin

d. Conversion of norepinephrine to epinephrine

e. None of the above are correct.



Answer: d. Conversion of norepinephrine to epinephrine

The fixation of nitrogen requires _______.

12:18

The fixation of nitrogen requires _______.



a. Fe-Mo protein

b. Fe protein

c. ferredoxin

d. Both A and B are correct.

e. All of the above are correct.



Answer: e. All of the above are correct.

One-carbon carriers in metabolism include

12:15

One-carbon carriers in metabolism include



a. biotin

b. folate

c. SAM

d. Both B and C are correct.

e. All of the above are correct.



Answer: e. All of the above are correct.

SAM is a methyl donor in the synthesis of ______.

12:14

SAM is a methyl donor in the synthesis of ______.



a. melatonin

b. creatine

c. phosphatidylcholine

d. Both A and C are correct.

e. all of the above are correct



Answer: e. all of the above are correct

The tranport of GSH out of cells serves all of the following functions except ______.

12:14

The tranport of GSH out of cells serves all of the following functions except ______.



a. protection of the plasma membrane.

b. amino acid transport.

c. transfer of sulfur atoms out of cells.

d. formation of mercapturic acid derivatives of organic contaminants

e. None of the above are correct



Answer: e. None of the above are correct

The rate limiting step in fatty acid synthesis is

12:11

The rate limiting step in fatty acid synthesis is



A) condensation of acetyl-CoA and malonyl-CoA.

B) formation of acetyl-CoA from acetate.

C) formation of malonyl-CoA from malonate and coenzyme A.

D) the reaction catalyzed by acetyl-CoA carboxylase.

E) the reduction of the acetoacetyl group to a β-hydroxybutyryl group.



Answer: D) the reaction catalyzed by acetyl-CoA carboxylase.

Cholesterol is a precursor of _________.

12:10

Cholesterol is a precursor of _________.



A) Testosterone.

B) Estrogen.

C) Cortisol.

D) Aldosterone.

E) All of the above.



Answer: E) All of the above.

Lipolysis is used to

12:10

Lipolysis is used to



A) Degrade triacylglycerols

B) Prepare triacylglycerols for excretion

C) Remove lipids from membranes

D) Cleave fatty acids into 2 carbon units

E) Convert fatty acids to glucose



Answer: A) Degrade triacylglycerols

Extra Question) Membrane remodeling

12:09

Extra Question) Membrane remodeling



A) Requires phospholipases



B) Requires acyl transferases



C) Occurs only when cells are under stress



D) Both A and B are correct



E) All of the above are correct



Answer: D) Both A and B are correct

_____ is the rate-limiting enzyme in cholesterol synthesis.

12:09

_____ is the rate-limiting enzyme in cholesterol synthesis.



A) HMG-CoA reductase phosphatase

B) HMG-CoA reductase kinase

C) Mevalonate kinase

D) Phosphomevalonate kinase

E) None of the above is correct



Answer: E) None of the above is correct

In animals the function of peroxisomal b-oxidation appears to be

12:07

In animals the function of peroxisomal b-oxidation appears to be



A) energy generation

B) gluconeogenesis

C) synthesis of very long fatty acids

D) degradation of branch chain fatty acids

E) shortening of very long fatty acid chains



Answer:  shortening of very long fatty acid chains

Membranes are rigid when they contain

12:02

Membranes are rigid when they contain



Large amounts of cholesterol

Large amounts of unsaturated fatty acids

Large amounts of saturated fatty acids

Large amounts of water

A and B



Answer: Large amounts of saturated fatty acids

A consequence of replacing dietary fat content with sugars is

12:01

A consequence of replacing dietary fat content with sugars is



No effect on body weight

An increase in body weight

A small loss of body weight

A large decrease in body weight

An initial loss of weight followed by a large increase in body weight



Answer: An increase in body weight

The function of dolichols is to

12:01

The function of dolichols is to



Transport sugars in glycoprotein synthesis

Bind carbohydrate on the cell surface of bacteria

Bind to oxygenated carotenes

Serve as precursors of carotenoids

They are degradation products of steroids



Answer: Transport sugars in glycoprotein synthesis

Membrane receptors are transmembrane molecules or molecular complexes that

11:59

Membrane receptors are transmembrane molecules or molecular complexes that



A) Monitor and respond to changes in the cell's environment.

B) Bind to hormones or neurotransmitters

C) Are involved in embryonic and fetal development

D) Initiate an intracellular response when they bind an appropriate molecule

E) All of the above are correct



Answer: E) All of the above are correct

The function of glucose permease is an example of

11:57

The function of glucose permease is an example of



A) Primary active transport

B) Secondary active trasnport

C) Facilitated diffusion

D) Simple diffusion

E) None of the above are true



Answer: B) Secondary active trasnport

ω-6 Fatty acids

11:57

ω-6 Fatty acids


A) Have a double bond six carbon atoms from the carbonyl end of the chain

B) Have a double bond six carbon atoms from the methyl end of the chain

C) Have six double bonds in the molecule

D) Have three more double bonds than ω-3 fatty acids

E) Contain six trans double bonds in the molecule



Answer: B) Have a double bond six carbon atoms from the methyl end of the chain

In simple diffusion a solute

11:57

In simple diffusion a solute


A) Is propelled by random molecular motion

B) Moves up its concentration gradient

C) Moves across a membrane because of an input of free energy.

D) Both A and B are correct

E) All of the above are correct



Answer: A) Is propelled by random molecular motion

Patients with familial hypercholesterolemia

11:57

Patients with familial hypercholesterolemia


A) Possess depressed levels of plasma cholesterol

B) Have missing or defective LDL receptors

C) Are homozygous or heterozygous for a nonfunctional LDL receptor gene

D) Have very high levels of serum cholesterol

E) B, C and D are correct



Answer: E) B, C and D are correct

Energy requiring transport mechanisms include

11:56

Energy requiring transport mechanisms include



A) Primary active transport

B) Diffusion

C) Facilitated diffusion

D) Both A and B are correct

E) Both A and C are correct



Answer: A) Primary active transport

Which of the following statements is not true?

11:56

Which of the following statements is not true?



A) Membrane potential is an electrical gradient across a membrane.

B) A decrease in membrane potential is referred to as membrane depoalarization.

C) The term repolarization is defined as the reestablishment of the original membrane potential.

D) The diffusion of potassium ions out of a nerve cell make the inside of the membrane negative.

E) The sodium channel in muscle and nerve cells is a voltage-gated channel.



Answer: D) The diffusion of potassium ions out of a nerve cell make the inside of the membrane negative.

In the fluid mosaic model of membrane structure

11:55

In the fluid mosaic model of membrane structure



A) Proteins form an inner layer between two layers of lipid

B) Proteins coat an inner layer of lipids

C) Proteins float in a lipid bilayer

D) Proteins are covalently bonded to the lipid bilayer

E) All of the above are true



Answer: C) Proteins float in a lipid bilayer

Which of the following statements concerning the anion channel protein is not true?

11:55

Which of the following statements concerning the anion channel protein is not true?




A) It plays an important role in carbon dioxide transport in blood

B) It facilitates the chloride shift

C) Bicarbonate and chloride exchange occurs through the anion channel protein

D) The N-terminal methionine residue of the anion channel protein is prenylated

E) All of the above statements are true.



Answer: D) The N-terminal methionine residue of the anion channel protein is prenylated

Which of the following statements concerning carotenoids is not true?

11:54

Which of the following statements concerning carotenoids is not true?



A) Carotenoids are the only examples of the monoterpenes

B) The carotenes are hydrocarbon members of the carotenoids

C) Xanthophylls are oxygenated derivatives of the carotenes

D) Carotenoids are orange-colored pigments

E) None of the above are true



Answer: A) Carotenoids are the only examples of the monoterpenes

The myelin sheath

11:53

The myelin sheath


A) Surrounds nerve cell axons

B) Contains large amounts of cardiolipin

C) Facilitates nerve impulse transmission

D) Both A and B are correct

E) Both A and C are correct



Answer: E) Both A and C are correct

All of the following are glycolipids except _________.

11:53

All of the following are glycolipids except _________.



A) Sulfatides

B) Cerebrosides

C) Gangliosides

D) Both A and B are correct

E) None of the above are correct



Answer: E) None of the above are correct

The role of very low density lipoproteins is

11:53

The role of very low density lipoproteins is



A) Scavenging the cholesterol from cell membranes

B) Transporting of lipids from liver to tissues

C) Transporting of cholesterol esters to the liver

D) Both A and B are correct

E) All of the above are correct



Answer: B) Transporting of lipids from liver to tissues

The functions of fat include

11:43

The functions of fat include


A) Insulation

B) Energy storage

C) Water-repellent properties

D) Both A and B are correct

E) All of the above are correct



Answer: E) All of the above are correct

Phospholipids are

11:43

Phospholipids are


A) Structural components of membranes

B) Surface active agents

C) Rich energy sources

D) Both A and B are correct

E) All of the above are correct


Answer: D) Both A and B are correct

The essential fatty acids are

11:42

The essential fatty acids are



A) Arachidonic acid

B) Linoleic acid

C) Linolenic acid

D) Both A and B are correct

E) Both B and C are correct



Answer: E) Both B and C are correct

Prostaglandins are involved in _________.

11:42

Prostaglandins are involved in _________.



A) Ovulation

B) Inflammation

C) Digestion

D) Both A and B are correct

E) All of the above are correct



Answer: D) Both A and B are correct

I made mention of an awe inspiring molecular precursor of cholesterol in class. I said it's almost there, but just needs some electrons to move around and then it form the steroid nuclease. The name of that molecule is.

11:41

I made mention of an awe inspiring molecular precursor of cholesterol in class. I said it's almost there, but just needs some electrons to move around and then it form the steroid nuclease. The name of that molecule is.



A) Cholyl-CoA

B) Lanosterol

C) Geranylpyrophosphate

D) Squalene

E) Farnesylphyrophosphate



Answer: D) Squalene

According to the solid state model of electron transport electron transfer is efficient because

11:40

According to the solid state model of electron transport electron transfer is efficient because



A) Electron transfer is the result of random collisions

B) There are short diffusion distances between components for mobile electron carriers

C) UQ is abundant

D) Cytochrome c diffuses rapidly

E) Electron carriers are mobile



Answer: B) There are short diffusion distances between components for mobile electron carriers

The statement aerobic organisms use oxygen to generate energy required to maintain metabolic processes yet they risk damage caused by highly reactive oxygen molecules can be referred to as:

11:38

The statement aerobic organisms use oxygen to generate energy required to maintain metabolic processes yet they risk damage caused by highly reactive oxygen molecules can be referred to as:



A) Oxidation

B) Reactive oxygen species

C) Oxygen paradox

D) Metabolic damage

E) Thermodynamic inconsistency



Answer: C) Oxygen paradox

The primary function of catalase is to

11:37

The primary function of catalase is to



A) Detoxify peroxides

B) Reduce the disulfide group

C) Convert hydrogen peroxide to water

D) Generate ROS

E) Oxidize heme



Answer: C) Convert hydrogen peroxide to water

Which of the following is not a step in the ATP synthesizing process?

11:37

Which of the following is not a step in the ATP synthesizing process?



A) ADP + Pi bind to the L site

B) ATP is synthesized as the L conformation converts to the T conformation

C) ATP is released as the T conformation converts to the O confirmation

D) The O conformation binds ADP and Pi

E) All of the above are correct



Answer: D) The O conformation binds ADP and Pi

Carbon monoxide inhibits which of the following?

10:48

Carbon monoxide inhibits which of the following?


A) NADH dehydrogenase

B) Ubiquinone

C) Cytochrome oxidase

D) Succinate dehydrogenase

E) None of above are correct



Answer: C) Cytochrome oxidase

One of the mechanisms by which vitamin C protects membrane is by

10:47

One of the mechanisms by which vitamin C protects membrane is by


A) Regenerating reduced α-tocopherol

B) Reacting with proline

C) Reacting with peroxyl radicals

D) Both A and B are correct

E) Both A and C are correct



Answer: E) Both A and C are correct

Glutathione peroxidase

10:45

Glutathione peroxidase



A) Converts organic peroxides into alcohols

B) Generates GSH from GSSG

C) Reduces H2O2 into H2O

D) Both A and B are correct

E) Both A and C are correct



Answer: E) Both A and C are correct

ROS are generated during

10:44

ROS are generated during




A) Xenobiotic metabolism

B) Respiratory burst

C) Ionizing radiation

D) Both A and B are correct

E) All of the above are correct



Answer: E) All of the above are correct

In the ATP Synthase the Fo factor

10:43

In the ATP Synthase the Fo factor




A) Has three types of subunits

B) Possesses ATPase activity

C) In a transmembrane proton channel

D) Both A and B are correct

E) Both A and C are correct



Answer: E) Both A and C are correct

Examples of uncouplers include ________.

10:43

Examples of uncouplers include ________.



A) DNP

B) Antimycin

C) Gramicidin

D) Both A and B are correct

E) Both A and C are correct



Answer: E) Both A and C are correct

Evidence supporting the chemiosmotic theory inculdes all of the following except

10:43

Evidence supporting the chemiosmotic theory inculdes all of the following except



A) Inhibitors of ATP synthesis have been shown to dissipate the proton gradient

B) Mitochondria with disrupted membranes cannot synthesize ATP

C) ATP synthesis is depressed when mitochondrial swelling occurs as a result of osmotic changes

D) The pH of a weakly buffered suspension of mitochondria rises when O2 added.

E) Actively respiring mitrochondria expel protons



Answer: D) The pH of a weakly buffered suspension of mitochondria rises when O2 added.

Facultative anaerobes

10:40

Facultative anaerobes



Organisms that possess antioxidant molecules that detoxify ROS

Grow only in the absence of oxygen

Can use oxygen when it is available

Require oxygen to grow

Release oxygen



Answer: Can use oxygen when it is available

Obligate anaerobes are

10:40

Obligate anaerobes are



Organisms that possess antioxidant molecules that detoxify ROS

Grow only in the absence of oxygen

Can use oxygen when it is available

Require oxygen to grow

Release oxygen



Answer: Grow only in the absence of oxygen

After the evolution of oxygenic photosynthesis the release of oxygen was not immediately followed by the accumulation of oxygen in the atmosphere. This was true because

10:39

After the evolution of oxygenic photosynthesis the release of oxygen was not immediately followed by the accumulation of oxygen in the atmosphere. This was true because



It was incorporated into organic molecules

It remained dissolved in water

It was consumed by oxidizable materials such as iron and ammonia

A and C

A, B and C



Answer: It was consumed by oxidizable materials such as iron and ammonia

The most pivotal event in the history of life on earth was

10:39

The most pivotal event in the history of life on earth was



The development of DNA

The development of RNA

Emergence of the water splitting complex in Photosystem II

Development of photosynthesis

Adaptation to life on land



Answer: Emergence of the water splitting complex in Photosystem II

Oxygen is useful for energy generation because

10:39

Oxygen is useful for energy generation because



It is soluble in the cell membrane

It is abundant

It is a powerful reducing agent

It is a powerful oxidizing agent

A, B and D


Answer: A, B and D

The citric acid cycle is a component of aerobic respiration. Molecular oxygen

10:08

The citric acid cycle is a component of aerobic respiration. Molecular oxygen



A) Is directly involved in the reactions of the cycle

B) Is only indirectly involved in the reactions of the cycle

C) Is an important substrate for the cycle

D) Both A and C are true

E) None of the above are true.



Answer: B) Is only indirectly involved in the reactions of the cycle

The overall reaction catalyzed by pyruvate dehydrogenase is which of the following?

10:07

The overall reaction catalyzed by pyruvate dehydrogenase is which of the following?



A) CH3COCHO + NAD+ + CoASH 🡪 CH3CHOSCoA + NADH

B) CH3COCOO- + FAD +CoASH 🡪 CH3CHSCoA + NADH

C) CH3COCOO- + NAD+ + CoASH 🡪 CH3COSCoA + NADH

D) CH3CH(OH)COO- + NADH + CoASH 🡪 CH3CH(OH)COSCoA + NAD+

E) None of the above is correct



Answer: C) CH3COCOO- + NAD+ + CoASH 🡪 CH3COSCoA + NADH

What is the reduction potential for the overall reaction?

10:07

Pyruvate + NADH + H+ --🡪 Lactate + NAD+


The half cell reaction ( with their standard reduction potentials ) are

Pyruvate + 2H+ + 2e- 🡪 Lactate (-0.19V)

NAD+ + H+ +2e- 🡪 NADH (-0.32V)



What is the reduction potential for the overall reaction?



A) + 0.00V

B) + 0.03 V

C) + 0.13 V

D) +0.22 V

E) +0.15 V



Answer: C) + 0.13 V

Which of the following reactions requires GDP

10:04

Which of the following reactions requires GDP



A) Fumarate 🡪 Malate

B) SuccinylCoA 🡪 Succinate

C) Malate 🡪 Oxaloacetate

D) Citrate 🡪 Isocitrate

E) α-Ketoglutarate 🡪 Succinyl CoA



Answer: B) SuccinylCoA 🡪 Succinate

The redox reaction in which succinate is converted to fumarate uses FAD rather than NAD+ because

10:04

The redox reaction in which succinate is converted to fumarate uses FAD rather than NAD+ because



A) FAD is a stronger oxidizing agent than NAD+

B) NAD+ is a stronger oxidizing agent than FAD

C) FAD is required for the oxidation of carboxylic acids

D) Only FAD can penetrate into mitochondria

E) NAD is not found in the cytoplasm.



Answer: A) FAD is a stronger oxidizing agent than NAD+

In a redox reaction, an electron acceptor is

10:01

In a redox reaction, an electron acceptor is



A) Oxidized as it accepts one or more electrons

B) The reducing agent

C) Converted to an electron donor with the gain of one or more electons

D) All of the above are correct

E) None of the above are correct



Answer: C) Converted to an electron donor with the gain of one or more electons

In any redox reaction, an electron donor is

10:01

In any redox reaction, an electron donor is




A) The reducing agent

B) The oxidizing agent

C) Reduced as it accepts electrons

D) All of the above are correct

E) None of the above are correct



Answer: A) The reducing agent

Which of the following reactions has an oxidized product?

10:00

Which of the following reactions has an oxidized product?




A) Carboxylic acid 🡪 aldehyde

B) R-SH + RSH 🡪 R-S-S-R

C) Alcohol 🡪 Ketone Wrong answer on the answer key here. this is oxidized.

D) Glutamate 🡪 α-Ketoglutarate

E) None of the above are correct



Answer: E) None of the above are correct

Which of the following reactions is an oxidation reaction?

10:00

Which of the following reactions is an oxidation reaction?



A) NaOH +HCl 🡪 NaCl + H2O

B) CH3COOH 🡪 CH3COO- +H+

C) CH3CHO 🡪 CH3CH2OH

D) CH3CH2OH 🡪 CH3CHO

E) CH2=CH2 + H2O 🡪 CH3CH2OH



Answer: D) CH3CH2OH 🡪 CH3CHO

In order to determine the standard voltage of a reaction

09:59

In order to determine the standard voltage of a reaction



A) The individual reaction reduction potentials must be added

B) The standard cells must be written as they occur in the reaction and the voltages are added.

C) All the reactions must be written as oxidations and the voltages are added.

D) The voltages of the individual reactions at pH = 7 must be calculated and the resultant voltages are added.

E) A standard voltage for a reaction must be determined experimentally.



Answer: B) The standard cells must be written as they occur in the reaction and the voltages are added.

Redox potential is best defined as

09:56

Redox potential is best defined as


A) The tendency of one species to gain electrons

B) The tendency of one species to lose electrons

C) The tendency of a species to gain or lose electrons

D) The entropy of a reaction expressed as a voltage difference

E) None of the above is correct



Answer: C) The tendency of a species to gain or lose electrons

NADH is produced in which of the following reactions?

09:53

NADH is produced in which of the following reactions?



A) Malate 🡪 Fumarate

B) Succinate 🡪 Fumarate

C) α-Ketoglutarate 🡪 SuccinylCoA

D) SuccinylCoA 🡪 Fumarate

E) Oxaloacetate 🡪 Citrate



Answer: C) α-Ketoglutarate 🡪 SuccinylCoA

FADH2 is a product of which of the following reactions?

09:53

FADH2 is a product of which of the following reactions?



A) Pyruvate 🡪 Acetyl CoA

B) Malate 🡪 Oxaloacetate

C) SuccinylCoA 🡪 Succinate

D) Succinate 🡪 Fumarate

E) Succinate 🡪 Malate



Answer: D) Succinate 🡪 Fumarate

Place the following reaction intermediates of the citric acid cycle in chronological order. i. malate, ii fumarate, iii succinylCoA, iv citrate, v α-ketoglutarate.

09:52

Place the following reaction intermediates of the citric acid cycle in chronological order. i. malate, ii fumarate, iii succinylCoA, iv citrate, v α-ketoglutarate.



A), i, ii, iv, v, iii

B) iv, v, iii, i, ii

C) iv, i, v, iii, ii

D) v, iii, i, ii, iv

E) iv, v, iii, ii, i



Answer: E) iv, v, iii, ii, i

A diauxic shift is

09:50

A diauxic shift is



A significant change in gene expression

Shifting from aerobic to anerobic respiration

Shifting from anerobic to aerobic respiration

Change in composition of microbes in a sample

Change in the amount of ATP used to ferment glucose



Answer: A significant change in gene expression

The Pasteur Effect is

09:49

The Pasteur Effect is


Fermentation of glucose

Repression of aerobic metabolism by glucose

Repression of glycolysis by oxygen

Repression of glucose metabolism by ethyl alcohol

Fermentation of ethyl alcohol



Answer: Repression of glycolysis by oxygen

The Crabtree effect in yeast is

09:48

The Crabtree effect in yeast is



Fermentation of glucose

Repression of aerobic metabolism by glucose

Repression of glycolysis by oxygen

Repression of glucose metabolism by ethyl alcohol

Fermentation of ethyl alcohol



Answer: Repression of aerobic metabolism by glucose

Conversion of fructose-6-phosphate to fructose-1,6-bisphosphate has two purposes. One is the commitment of the molecule to glycolysis, the second is

09:47

Conversion of fructose-6-phosphate to fructose-1,6-bisphosphate has two purposes. One is the commitment of the molecule to glycolysis, the second is



A) Raising the free energy of the system

B) Making possible the formation of a second mole of ATP

C) Preventing the cleavage products of the next step from diffusing out of the cell

D) Preventing the reverse reaction

E) Enolization of the product



Answer: C) Preventing the cleavage products of the next step from diffusing out of the cell

The final product of glycolysis is

09:45

The final product of glycolysis is



A) Dihydroxyacetone phosphate

B) Pyruvate

C) Ethanol

D) Acetyl-CoA

E) Acetaldehyde



Answer: B) Pyruvate

Which of the following enzymes is an oxidoreductase?

08:43

Which of the following enzymes is an oxidoreductase?



A) Aldolase

B) Triose phosphate isomerase

C) Glyceraldehyde-3-phosphate dehdyrogenase

D) Phosphofructokinase

E) Phosphoglucoisomerase



Answer: C) Glyceraldehyde-3-phosphate dehdyrogenase

Fructose-2,6-bisphosphate

08:42

Fructose-2,6-bisphosphate



A) Is an indicator of high cellular glucose concentration

B) Is formed by PFK-1

C) Activates aldolase

D) Both A and B are correct

E) All of the above are correct



Answer: A) Is an indicator of high cellular glucose concentration

Cori's disease is caused by

08:39

Cori's disease is caused by


A) Lack of insulin

B) Lack of phospholylase b

C) Lack of glucagons

D) A deficiency of debranching enzyme

E) Deficient chromium receptors on the cell surface



Answer: D) A deficiency of debranching enzyme

Phosphorylase kinase

08:39

Phosphorylase kinase



A) Converts inactive phosphorylase to active phosphorylase

B) Converts active phosphorylase to inactive phosphorylase

C) Phosphorylates glycogen synthase

D) Convets ADP to ATP

E) Both B and C are correct



Answer: A) Converts inactive phosphorylase to active phosphorylase

Under stressful conditions epinephrine is released from the adrenal medulla. The release of epinephrine has which of the following effects on glucose metabolism?

08:39

Under stressful conditions epinephrine is released from the adrenal medulla. The release of epinephrine has which of the following effects on glucose metabolism?




A) Glycogenolysis is stimulated

B) Glycogenesis is inhibited

C) Adenylate cyclase is activated

D) Both A and B are correct

E) All of the above are correct



Answer: E) All of the above are correct

The conversion of glucose-1-phosphate to UDP-glucose has a ΔG0' near zero. Which of the following reactions is coupled with the above reaction to drive it to completion?

08:37

The conversion of glucose-1-phosphate to UDP-glucose has a ΔG0' near zero. Which of the following reactions is coupled with the above reaction to drive it to completion?



A) Hydrolysis of PPi

B) Hydrolysis of ATP

C) Hydrolysis of ADP

D) Hydrolysis of UDP

E) Hydrolysis of UTP



Answer: A) Hydrolysis of PPi

Which of the following statements about starch and glycogen is false?

08:31

Which of the following statements about starch and glycogen is false?



A) Amylose is unbranched; amylopectin and glycogen contain many (α1 → 6) branches.

B) Both are homopolymers of glucose.

C) Both serve primarily as structural elements in cell walls.

D) Both starch and glycogen are stored intracellularly as insoluble granules.

E) Glycogen is more extensively branched than starch.



Answer: C) Both serve primarily as structural elements in cell walls.

Starch and glycogen are both polymers of:

08:31

Starch and glycogen are both polymers of:


A) fructose.

B) glucose1-phosphate.

C) sucrose.

D) α-D-glucose.

E) β-D-glucose.



Answer: D) α-D-glucose.

From the abbreviated name of the compound Gal(β1 → 4)Glc, we know that:

08:31

From the abbreviated name of the compound Gal(β1 → 4)Glc, we know that:



A) C-4 of glucose is joined to C-1 of galactose by a glycosidic bond.

B) the compound is a D-enantiomer.

C) the galactose residue is at the reducing end.

D) the glucose is in its pyranose form.

E) the glucose residue is the β anomer.



Answer: A) C-4 of glucose is joined to C-1 of galactose by a glycosidic bond.

Which of following is an anomeric pair?

08:29

Which of following is an anomeric pair?


A) D-glucose and D-fructose

B) D-glucose and L-fructose

C) D-glucose and L-glucose

D) α-D-glucose and β-D-glucose

E) α-D-glucose and β-L-glucose



Answer: D) α-D-glucose and β-D-glucose

Which of the following is an epimeric pair?

08:29

Which of the following is an epimeric pair?



A) D-glucose and D-glucosamine

B) D-glucose and D-mannose

C) D-glucose and L-glucose

D) D-lactose and D-sucrose

E) L-mannose and L-fructose



Answer: B) D-glucose and D-mannose

When two carbohydrates are epimers:

08:29

When two carbohydrates are epimers:



A) one is a pyranose, the other a furanose.

B) one is an aldose, the other a ketose.

C) they differ in length by one carbon.

D) they differ only in the configuration around one carbon atom.

E) they rotate plane-polarized light in the same direction.



Answer: D) they differ only in the configuration around one carbon atom.

A potassium ion gradient is set up in insect Malpighian tubules through an active transport process. As a result, potassium concentration is higher in the lumen of the tubules than in hemolymph. How would the potassium gradient affect water movement?

12:41

A potassium ion gradient is set up in insect Malpighian tubules through an active transport process. As a result, potassium concentration is higher in the lumen of the tubules than in hemolymph. How would the potassium gradient affect water movement?


A) Water would be forced out of the lumen of the Malpighian tubules through an osmotic gradient.

B) The potassium gradient would have no effect on water movement.

C) There would be a net movement of water into the lumen of the tubules.

D) Water would be conserved, forming a hypertonic solution in the Malpighian tubules.



Answer: C

Why are the renal artery and vein critical to the process of osmoregulation in vertebrates?

12:41

Why are the renal artery and vein critical to the process of osmoregulation in vertebrates?



A) The kidneys require constant and abnormally high oxygen supply to function.

B) The renal artery delivers blood with nitrogenous waste to the kidney and the renal vein brings blood with less nitrogenous wastes away from the kidneys.

C) The kidneys require higher than normal levels of hormones.

D) The renal artery and vein are the main pathways regulating how much is produced by the kidneys.



Answer: B

African lungfish, which are often found in small, stagnant pools of fresh water, produce urea as a nitrogenous waste. What is the advantage of this adaptation?

12:40

African lungfish, which are often found in small, stagnant pools of fresh water, produce urea as a nitrogenous waste. What is the advantage of this adaptation?



A) Urea takes less energy to synthesize than ammonia.

B) Small, stagnant pools do not provide enough water to dilute the toxic ammonia.

C) The highly toxic urea makes the pool uninhabitable to potential competitors.

D) Urea makes lungfish tissue hypoosmotic to the pool.



Answer: B

Which of the following most accurately describes selective permeability?

12:40

Which of the following most accurately describes selective permeability?



A) An input of energy is required for transport.

B) Lipid-soluble molecules pass through a membrane.

C) There must be a concentration gradient for molecules to pass through a membrane.

D) Only certain molecules can cross a cell membrane.



Answer: D

Through studies of insect Malpighian tubules, researchers found that K+ accumulated on the inner face of the tubule, against its concentration gradient. What can you infer about the mechanism of transport?

12:40

Through studies of insect Malpighian tubules, researchers found that K+ accumulated on the inner face of the tubule, against its concentration gradient. What can you infer about the mechanism of transport?



A) Potassium transport is a passive process.

B) Movement of potassium into the lumen of the Malpighian tubules is an energy-requiring process.

C) Potassium moves out of the tubules at a faster rate than it moves into the lumen of the tubules.

D) Sodium ions will follow potassium ions.



Answer: B

Birds secrete uric acid as their nitrogenous waste because uric acid _____.

12:39

Birds secrete uric acid as their nitrogenous waste because uric acid _____.



A) is readily soluble in water

B) is metabolically less expensive to synthesize than other excretory products

C) requires little water for nitrogenous waste disposal, thus reducing body mass

D) can be reused by birds as a protein source



Answer: C

Urea is produced in the _____.

12:38

Urea is produced in the _____.



A) liver from NH3 and carbon dioxide

B) liver from glycogen

C) kidneys from glycerol and fatty acids

D) bladder from uric acid and water



Answer: A

Urea is _____.

12:38

Urea is _____.



A) insoluble in water

B) the primary nitrogenous waste product of humans

C) the primary nitrogenous waste product of most birds

D) the primary nitrogenous waste product of most aquatic invertebrates



Answer: B

Excessive formation of uric acid crystals in humans leads to _____.

12:38

Excessive formation of uric acid crystals in humans leads to _____.



A) a condition called diabetes, where excessive urine formation occurs

B) a condition of insatiable thirst and excessive urine formation

C) gout, a painful inflammatory disease that primarily affects the joints

D) osteoarthritis, an inevitable consequence of aging



Answer: C

One of the waste products that accumulates during cellular functions is carbon dioxide. It is removed via the respiratory system. What is another waste product that accumulates during normal physiological functions in vertebrates?

12:37

One of the waste products that accumulates during cellular functions is carbon dioxide. It is removed via the respiratory system. What is another waste product that accumulates during normal physiological functions in vertebrates?



I) ammonia

II) uric acid

III) urea



A) only I and III

B) only II and III

C) only I and II

D) I, II, and III



Answer: D

A human who has no access to fresh water but is forced to drink seawater instead will _____.

12:36

A human who has no access to fresh water but is forced to drink seawater instead will _____.



A) thrive under such conditions, as long as he has lived at the ocean most of his life

B) excrete more water molecules than taken in, because of the high load of ion ingestion

C) develop structural changes in the kidneys to accommodate the salt overload

D) risk becoming overhydrated within twelve hours



Answer: B

Unlike most bony fishes, sharks maintain body fluids that are isoosmotic to seawater, so they are considered by many to be osmoconformers. Nonetheless, these sharks osmoregulate at least partially by _____.

12:36

Unlike most bony fishes, sharks maintain body fluids that are isoosmotic to seawater, so they are considered by many to be osmoconformers. Nonetheless, these sharks osmoregulate at least partially by _____.



A) using their gills and kidneys to rid themselves of sea salts

B) monitoring dehydration at the cellular level with special gated aquaporins

C) tolerating high urea concentrations that are balanced with internal salt concentrations to seawater osmolarity

D) synthesizing trimethylamine oxide, a chemical that binds and precipitates salts inside cells



Answer: C

The necropsy (postmortem analysis) of a freshwater fish that died after being placed accidentally in saltwater would likely show that _____.

12:36

The necropsy (postmortem analysis) of a freshwater fish that died after being placed accidentally in saltwater would likely show that _____.



A) loss of water by osmosis from cells in vital organs resulted in cell death and organ failure

B) high amounts of salt had diffused into the fish's cells, causing them to swell and lyse

C) the kidneys were not able to keep up with the water removal necessary in this hyperosmotic environment, creating an irrevocable loss of homeostasis

D) the gills became encrusted with salt, resulting in inadequate gas exchange and a resulting asphyxiation



Answer: A

A necropsy (postmortem analysis) of a marine sea star that died after it was mistakenly placed in fresh water would likely show that it died because _____.

12:35

A necropsy (postmortem analysis) of a marine sea star that died after it was mistakenly placed in fresh water would likely show that it died because _____.



A) it was stressed and needed more time to acclimate to the new conditions

B) it was so hypertonic to the fresh water that it could not osmoregulate

C) its contractile vacuoles ruptured

D) its cells dehydrated and lost the ability to metabolize



Answer: B

Tissues of sharks are isotonic to seawater, but their concentrations of sodium ions, potassium ions, and chloride ions in cells and extracellular fluids are similar to those of freshwater fishes. What can you infer about the movement of sodium and chloride in these animals?

12:34

Tissues of sharks are isotonic to seawater, but their concentrations of sodium ions, potassium ions, and chloride ions in cells and extracellular fluids are similar to those of freshwater fishes. What can you infer about the movement of sodium and chloride in these animals?



A) To maintain homeostasis of sodium and chloride levels, the shark must take up additional sodium and chloride from seawater.

B) Sodium and chloride will diffuse into shark gills from seawater down their concentration gradient.

C) Sharks conserve sodium and chloride, limiting excretion.

D) Sodium and chloride must be eliminated through the gills.



Answer: B

What role do chloride cells play in osmoregulation of marine fish with bony skeletons?

12:34

What role do chloride cells play in osmoregulation of marine fish with bony skeletons?



A) They actively transport chloride into the gills.

B) They mediate the movement of salt from seawater through their gills.

C) They are involved in excretion of excess salt.

D) They actively transport salt across the basolateral membrane of the rectal gland.



Answer: C

Salmon eggs hatch in freshwater. The fish then migrate to the ocean (a hypertonic solution) and, after several years of feeding and growing, return to freshwater to breed. How can these organisms make the transition from freshwater to ocean water and back to freshwater?

12:34

Salmon eggs hatch in freshwater. The fish then migrate to the ocean (a hypertonic solution) and, after several years of feeding and growing, return to freshwater to breed. How can these organisms make the transition from freshwater to ocean water and back to freshwater?



A) The rectal gland functions in the ocean water, and chloride cells function in freshwater.

B) Different gill cells are involved in osmoregulation in freshwater than in salt water.

C) Salmon in freshwater excrete dilute urine, and salmon in salt water secrete concentrated urine.

D) Their metabolism changes in salt water to degrade electrolytes.



Answer: B

Single-celled Paramecium live in pond water (a hypotonic environment). They have a structural feature, a contractile vacuole, which enables them to osmoregulate. If you observed them in the following solutions, at which sucrose concentration (in millimolars, mM) would you expect the contractile vacuole to be most active?

12:33

Single-celled Paramecium live in pond water (a hypotonic environment). They have a structural feature, a contractile vacuole, which enables them to osmoregulate. If you observed them in the following solutions, at which sucrose concentration (in millimolars, mM) would you expect the contractile vacuole to be most active?



A) 0.0 mM sucrose

B) 0.05 mM saline

C) 0.08 mM sucrose

D) 1.0 mM saline



Answer: A

Sharks live in seawater. Their tissues are isotonic to seawater, but their concentrations of sodium ions, potassium ions, and chloride ions in cells and extracellular fluids are similar to those of freshwater fishes. How is that possible?

12:33

Sharks live in seawater. Their tissues are isotonic to seawater, but their concentrations of sodium ions, potassium ions, and chloride ions in cells and extracellular fluids are similar to those of freshwater fishes. How is that possible?



A) Urea and trimethylamine oxide contribute to intra- and extracellular osmolarity in shark tissues.

B) Metabolic intermediates of sharks tie up intracellular chloride and potassium ions.

C) Their blood is hypotonic to their tissues.

D) They excrete large quantities of electrolytes.



Answer: A

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