Rutgers Murphy Biochem Exam 2

Membrane remodeling

Requires phospholipases

Requires acyl transferases

Occurs only when cells are under stress

Correct! Both A and B are correct

All of the above are correct

Both A and B are correct

In simple diffusion a solute

Is propelled by random molecular motion

Moves up its concentration gradient

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

Both A and B are correct

All of the above are correct

Is propelled by random molecular motion

The recycling rate of triacylglycerols to fatty acids is inhibited by

Epinephrine

Norepinephrine

Insulin

Lypase

A and B

Insulin

The benzene ring of the aromatic amino acids is formed by the

Dehydrogenation of cyclohexane

Deamination of dietary phenylalanine

Shikimate pathway

Dehydroxylation of tyrosine

Transamination of a-keto-b-methylvalerate

Shikimate pathway

Energy requiring transport mechanisms include

Primary active transport

Diffusion

Facilitated diffusion

Both A and B are correct

Both A and C are correct

Primary active transport

Prostaglandins are involved in _________.

Ovulation

Inflammation

Digestion

Both A and B are correct

All of the above are correct

All of the above are correct

Inorganic nitrogen is initially assimilated into which of the following amino acids

Glycine

Alanine

Serine

Glutamine

Leucine

Glutamine

Why do most naturally occurring fatty acids have cis double bonds in them?

The cis double bond introduces a kink in the chain.

The cis double bond remains results in relatively no change in the fatty acid direction.

The double bond results in a bend in the molecule elevating the melting point of the molecule.

The double bond results in a bend in the molecule lowering the melting point of the molecule.

none of the above

The double bond results in a bend in the molecule lowering the melting point of the molecule.

How many FADH2 molecules would be produced in the oxidation of palmitic acid (16:0 carbons)?

1

3

5

7

9

7

The basic structure of biological membranes is a consequence of the physical properties of _______.

Proteins

Phospholipids

Cholesterol

Water

None of the above are correct

Phospholipids

The pathway in which lipoproteins are transported from the liver to cells is referred to

Endogenous pathway

Exogenous pathway

Apolipoprotein pathway

Chylomycorn distribution pathway

Triacylglycerol absorption pathway

Endogenous pathway

Glycerol from the hydrolysis of triacylglycerols is transported by the blood to the ____

Intestine

Stomach

Liver

Pancreas

A and B

Liver

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

Energy generation

Gluconeogenesis

Synthesis of very long fatty acids

Degradation of branch chain fatty acids

Shortening of very long chain fatty acids

Shortening of very long chain fatty acids

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

Large amounts of saturated fatty acids

Lipolysis is used to

Degrade triacylglycerols

Prepare triacylglycerols for excretion

Remove lipid from membrane

Cleave fatty acids into two carbon units

Convert fatty acids to glucose

Degrade triacylglycerols

The fixation of nitrogen requires _______.

Fe-Mo protein

Fe protein

Ferredoxin

Both A and B are correct

All of the above are correct

All of the above are correct

The conversion of acetyl-CoA to malonyl-CoA is inhibited by ________.

Glucagon

Epinephrine

Palmitoyl-CoA

All of the above are correct

None of the above are correct.

All of the above are correct

Which of the following molecules is not a lipid?

Fatty acids

Steroids

Isoprenoids

Waxes

All of the above are lipids

All of the above are lipids

_________, a product of the oxidation of odd-chain fatty acids, is converted to succinyl-CoA.

Malonyl-CoA

Propionyl-CoA

Acetyl-CoA

Oxaloacetate

Acyl carnitine

Propionyl-CoA

w-6 Fatty acids

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

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

Have six double bonds in the molecule

Have three more double bonds than w-3 fatty acids

Contain six trans double bonds in the molecule

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

The rate limiting step in fatty acid synthesis is

Acetyl-CoA carboxylation

Reduction of a cis double bond

Conversion of the trans double bond to a cis double bond

Reduction of the ketoester to the hydroxyester

Desaturation of the fatty acid to form trans double bonds

Acetyl-CoA carboxylation

Depending on an animal's metabolic needs, fatty acids may be converted to triacylglycerols, energy or __________.

Converted to glycerol

Stored as terpenes

Used in membrane synthesis

Both B and C are correct

Stored as fatty acids

Used in membrane synthesis

_________ are the principal transporters of cholesteryl esters to tissues.

Chylomicrons

Very low density lipoprotein

Intermediate density lipoprotein

Low density lipoprotein

All of the above are true

Low density lipoprotein

What is the major mechanistic difference in purine and pyrimidine biosynthesis?

Purines are much simpler than pyrimidines

Pyrimidines utilize amino acids during synthesis

Purines are synthesized on the ring of ribose

IMP is formed in both pathways

Pyrimidine synthesis is performed before purine

Purines are synthesized on the ring of ribose

Membrane proteins are linked to anchor molecules through a ___________ link

Ether

Ester

Amide

Amino

Plasma

Ether

Neutral fats belong to which of the following?

Phospholipids

Glycolipids

Prostaglandins

Triacylglycerols

Free fatty acids

Triacylglycerols

SAM is a methyl donor in the synthesis of ______.

Methionine

Creatine

Phosphatidylcholine

Both A and C are correct

All of the above are correct

All of the above are correct

Which of the following is not one of the ketone bodies?

Acetoacetate

b-Hydroxybutyrate

b-Methylglutarate

Acetone

None of the above are correct

b-Methylglutarate

___________ is used to transport fatty acids into the mitochondria.

Carrone

Phytate

Creatine

Carnitine

Acyl carrier protein

Carnitine

The fixation of nitrogen requires _______.

Fe-Mo protein

Fe protein

Ferredoxin

Both A and B are correct

All of the above are correct

All of the above are correct

In glycolysis ________ moles of NADH are produced per mole of glucose consumed

1

2

3

4

5

2

The one with the photo

FeS1, cyta, HemeB4, FADH2, cyt1A1, FeS2, UQ, cytb, O2

FeS1, cyta, HemeB4, FADH2, cyt1A1, O2,, FeS2, UQ, cytb

FeS1, cytb, HemeB4, FADH2, cyt1A1, FeS2, UQ, cyta, O2

FeS1, cyta, FADH2, cyt1A1, FeS2, UQ, cytb, O2, HemeB4

FeS1, cyta, HemeB4, FADH2, cyt1A1, FeS2, UQ, cytb, O2

In glycoproteins carbohydrate is most often linked to threonine, asparagine or __________.

Serine

Lysine

Valine

Aspartic acid

Tyrosine

Serine

The three most common homoglycans found in nature are cellulose, starch and __________.

Amylose

Lactose

Fructose

Glycogen

Sucrose

Glycogen

Which of the following yields N-acetyl-D-glucosamine on hydrolysis.

Cellulose

Heparin

Chitin

Amylopectin

Amylose

Chitin

The binding of insulin to receptors on the surface of muscle cells stimulates which of the following processes

Glycogenolysis

Glycogenesis

Release of ATP

Formation of cyclic AMP

Release of glucagon

Glycogenesis

The accumulation of AGEs is linked to which of the following diseases?

Atherosclerosis

Arthritis

Diabetes

Both A and B are correct

All of the above are correct

All of the above are correct

The presence of which of the following molecules indicates that the cell has sufficient energy reserves?

ATP

Citrate

ADP

Fructose-1,6-biphosphate

Both A and B are correct

Both A and B are correct

Which of the following is not a homoglycan?

Cellulose

Glycogen

Starch

Heparin

Amylose

Heparin

Glycoproteins lack which of the following groups typically found in proteoglycans?

Uronic acids

Sulfate groups

N-Glycosidic linkages

Both A and B are correct

All of the above are correct

Both A and B are correct

An enzyme family called the _________ catalyzes the phosphorylation of hexoses in the body.

Hexolysases

Phosphorolysases

Hexokinases

Glucokinases

Phosphofructokinases

Hexokinases

Glycogen is:

Main energy storage molecule of animals

Main carbohydrate reserve of animals

Main carbohydrate found in seeds

A form of plant starch

Both C and D are correct

Main carbohydrate reserve of animals

Glycoconjugates result from the covalent linkage of carbohydrate to proteins or _________

Amino acids

Lipids

Nucleotides

Both A and B are correct

None of the above are correct

Lipids

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

Glycogenolysis is stimulated

Glycogenesis is inhibited

Adenylate cyclase is activated

Both A and B are correct

All of the above are correct

All of the above are correct

Which of the following is required for the conversion of UDP-glucose to glycogen?

Glycogen synthase

Branching enzyme

Glucose phosphorlyase

Debranching enzyme

Both A and B are correct

Both A and B are correct

Fructose-2,6-bisphosphate

Is an indicator of high cellular glucose concentration

Is formed by PFK-1

Activates aldolase

Both A and B are correct

All of the above are correct

Is an indicator of high cellular glucose concentration

Cellulose is indigestible to most animals because:

Cellulose is not soluble in water

Animals lack the enzymes required to hydrolyse the b links of the cellulose

Cellulose has no food value and therefore cannot be digested

Both A and B are correct

None of the above are correct.

Animals lack the enzymes required to hydrolyse the b links of the cellulose

Which of the following carbohydrates is a nonreducing sugar?

Glucose

Fructose

Lactose

Sucrose

Ribose

Sucrose

Which of the following sugars contains a b-1,4-linkage?

Cellulose

Glucose

Amylose

Sucrose

Maltose

Cellulose

Both glycogenesis and glycogenolysis are controlled primarily by the interplay between the two hormones insulin and ________.

Glycogen synthetase

Glucagon

Fructose kinase

Glucose hydrolyase

Pentose kinase

Glucagon

Carbohydrate is thought to enhance the stability of protein molecules by:

Changing the protein's shape to better resist denaturation.

Protecting the underlying protein from the action of proteolytic enzymes

Using hydrogen bonding to increase the stability of the protein

Both A and B are correct

All of the above are correct

Protecting the underlying protein from the action of proteolytic enzymes

Reaction of an amino acid with C1 of a cyclic aldose produces which of the following linkages?

Ester

Amide

Glycosidic

Imine

Schiff base

Glycosidic

Lactose intolerance arises from

Bacteria in the intestine that produce toxic metabolites

The inability of intestinal enzymes to cleave the lactose

A sensitivity to galactose

A sensitivity to glucose

An allergic reaction to glucose

The inability of intestinal enzymes to cleave the lactose

The preferred energy source of the brain is __________.

Fructose

Glucose

Arabinose

Maltose

Sucrose

Glucose

The most abundant organic substance on earth is ______.

Starch

Cellulose

Sucrose

Glucose

None of the above

Cellulose

Which of the following polysaccharides can bind exceptionally large amounts of water?

Cellulose

Glycogen

Starch

Heparin

Amylose

Heparin

How many stereoisomers are possible for an aldohexose

4

8

12

16

32

16

A glycosidic link is chemically an _____.

Ether

Ester

Amide

Aldehyde

Ketone

Ether

All of the following statements regarding folic acid are true except:

N5,N10-methylene THF is a product of the cleavage of glycine

Vitamin B12 is required for the N5-methyl THF-dependent conversion of homocysteine to methionine

N10-formyl THF, CO2, and aspartate are precursors in the synthesis of hypoxanthine

Folic acid is a B vitamin

Folic acid requires intrinsic factor for its absorption in the intestine

Folic acid requires intrinsic factor for its absorption in the intestine

Which of the following is not one of the ketone bodies?

Acetoacetate

b-Hydroxybutyrate

b-Methylglutarate

Acetone

None of the above are correct

b-Methylglutarate

Covalently bound chains with _____________ or more ubiquitin monomers are required to transfer a protein to the proteosome

1

2

3

4

5

4

Which of the following is an alpha-keto acid/alpha-amino acid pair used in transamination?

Pyruvate/leucine

Oxaloacetate/aspartate

Oxaloacetate/glutamate

a-ketoglutarate/aspartate

aa-keto-b-hydroxybutyrate/phenylalanine

Oxaloacetate/aspartate

Saturated fatty acids containing up to 16 carbon atoms are assembled in _______

Mitochondria

Rough ER

Smooth ER

Peroxisomes

Cytoplasm

Cytoplasm

The principal means of producing glycerol in the body

The triacylglycerol cycle

Glyceronerogenesis

Gluconeogenesis

Lipolysis

Liponeogenesis

Glyceroneogenesis

Glycerol from the hydolysis of triacylglycerols is transported from the blood to the _________

Intestine

Stomach

Liver

Pancreas

A and B

Liver

Which of the following is not a function of phspholipases?

Membrane remodeling

Signal transduction

Energy storage

Digestion

Toxic Phospholipases

Energy storage

The intermediates in fatty acid synthesis are linked through a _______ linkage to ACP

Thgioester

Amide

Ester

Acetal

Ether

Thioester

The double bonds in naturally occurring fatty acids are usually ______ isomers

Cis

Oxidation of the carbon farthest from the carbonyl group of a fatty acid is called

w-oxidation

Neutral fats belong to which of the following?

Triacylglycerols

The myelin sheath

Surrounds nerve cell axons

Contains large amounts of cardiolipin

Facilitates nerve impulse transmission

Both A and B are correct

Both A and C are correct

Both A and C are correct

Fatty acid synthesis begins with the carboxylation of acetyl CoA to form _________

Malonyl-CoA

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

Energy generation

Gluconeogenesis

Synthesis of very long fatty acids

Degradation of branch chain fatty acids

Shortening of very long chain fatty acids

Shortening of very long chain fatty acids

Depending on an animal's metabolic needs, fatty acids may be converted to triacylglycerols, energy or __________

Used in membrane synthesis

Patients with familial hypercholesterolemia

Possess depressed levels of plasma cholesterol

Have missing or defective LDL receptors

Are homozygous or heterozygous for a nonfunctional LDL receptor gene

Have very high levels of serum cholesterol

B, C, and D are correct

B, C, and D are correct