Biochemistry slido questions

From all chapters

Glutamate is metabolically converted to α-ketoglutarate and NH4+ by a process described as:

oxidative deamination

The coenzyme involved in a transaminase (or aminotransferase) reactions requires which vitamin?

pyridoxine (vitamin B6)

The –NH2 from skeletal muscle is transported to liver in the form of:

alanine

The first NH4+ in the urea cycle comes from:

carbamoyl phosphate

The production of one urea molecule consumes _____ATP molecules.

4

Tetrahydrofolate (THF) and its derivatives shuttle ______between different substrates.

Methyl groups

The metabolism of branched chain amino acids occurs primarily in the:

muscle

Which of the following is not required in the synthesis of fatty acids?

NADH

Which of the following is not true of the fatty acid synthase and the fatty acid b-oxidation systems?

The processes both occur in the mitochondrial matrix

Which of these statements about triacylglycerol synthesis is correct?

Insulin stimulates conversion of dietary carbohydrate into TAGs.

The synthesis of both glycerophospholipids and triacylglycerols involves:

phosphatidic acid.

The rate-limiting step in fatty acid synthesis is

The reaction catalyzed by acetyl-CoA carboxylase

Very-low density lipoproteins are rich in:

Endogenous triacylglycerol

Which of the following is not a step in the uptake of cholesterol from the bloodstream into cells?

The internalized receptor is degraded.

The primary storage form of lipid is ____ and it is normally stored in the ____.

triacylglycerols; adipocytes

Bile salts are important in the initial digestion of triacylglycerols in the intestine because they:

Emulsify the triacylglycerol globules to produce greater surface area which will increase the activity

Transport of fatty acids from the cytoplasm to the mitochondrial matrix requires:

ATP, carnitine and coenzyme A

What is the correct order of function of the following enzymes of b-oxidation? 1. b-Hydroxyacyl-CoA dehydrogenase 2. Thiolase 3. Enoyl-CoA hydratase 4. Acyl-CoA dehydrogenase

4,3,1,2

If the 16-carbon SFA, palmitate is oxidized completely to CO2 and H2O (via the β-oxidation and TCA), and all of the energy-conserving products are used to drive ATP synthesis in the mitochondrion, the the net yield of ATP per molecule of palmitate is:

106

In the disease sprue, B12 is poorly absorbed in the intestine, resulting in B12 deficiency. If each of the following FAs were in the diet, for which one would the process of FA oxidation be most affected in a patient with sprue?

CH3(CH2)11COOH

TRUE OR FALSE: The formation of ketone bodies results from depleted oxaloacetate concentrations in the citric acid cycle.

TRUE

What are the three most common ketone bodies?

Acetone, β-hydroxybutyrate and acetoacetate

Almost all of the oxygen (O2) one consumes in breathing is converted to:

water

TRUE OR FALSE:Mitochondrial cristae decrease the surface area of the inner membrane and are more densely packed in cells with high metabolic activity.

FALSE

Which of the following is not a type of electron carrying molecule associated with the electron transport chain?

Ubiquinone

Cytochrome

Fe-S proteins

Flavoproteins

All of the above are electron carriers

Which of the following enzymes plays a dual role in cells by transferring electrons from the citric acid cycle directly to the electron transfer chain?

Succinate dehydrogenase

Electrons are transferred through the respiratory chain from reduced NADH or FADH2 to oxygen in small steps with each step in the pathway associated with a slightly more ________ reduction potential.

positive

Which of the following is not true of the proton motive force (pmf)?

One component of the pmf is the chemical gradient of protons.

One component of the pmf is the charge gradient of protons.

Generation of the pmf in mitochondria requires succinate.

The pmf is generated by the electron transport chain in mitochondria.

The pmf drives ATP synthesis in mitochondria.

During oxidative phosphorylation, the proton motive force that is generated by electron transport is used to:

Induce a conformational change in ATP Synthase

TRUE OR FALSE: The ATP yield from NADH transported across the mitochondrial inner membrane by the glycerol phosphate shuttle is the same as if the malate/aspartate shuttle were used

FALSE; malate yields more atp

Which combination of cofactors is involved in the conversion of pyruvate to acetyl-CoA?

TPP, lipoic acid, and NAD+

Which enzyme of the citric acid cycle can donate iron when cellular concentrations are low?

aconitase

TRUE OR FALSE: The two carbon atoms that are lost as CO2 in the third and fourth steps of the citric acid cycle are the same as the two carbon atoms of acetyl CoA

FALSE

Taking one molecule of glucose through glycolysis and the citric acid cycle generates:

6C02, 10 NADH/H+, 2FADH2 and 4 ATP

Entry of acetyl-CoA into the citric acid cycle is decreased when:

the ratio of [ATP]/[ADP] is high

TRUE OR FALSE: Humans can convert fatty acids to sugars

FALSE

An enzyme used in both glycolysis and gluconeogenesis is:

3-phosphoglycerate kinase.

All of the following are true regarding fructose 2,6 bisphosphate except

It is a negative allosteric regulator of PFK-1.

The two primary products of the pentose phosphate pathway are:

NADPH and ribose-5-phosphate

The major product from the action of glycogen phosphorylase and the debranching enzyme is ________.

Glucose-1-phosphate

Glycogenin:

is the protein on which new glycogen chains are initiated

Which of the following hormones stimulates glycogen breakdown in the hepatocytes?

Epinephrine and glucagon

TRUE OR FALSE: Glucose yields a good amount of energy upon reduction

FALSE

Which of the following is not a use of Glucose

Gluconeogenesis

Under normal conditions, Glucose is the sole energy source for

CNS and erythrocytes only

Which of the following reactions in glycolysis requires ATP as substrate?

HEXOKINASE

The step that commits glucose to glycolysis is:

Phosphofructokinase-1

The steps of glycolysis between glyceraldehyde 3-phosphate and 3-phosphoglycerate involve all of the following except:

oxidation of NADH to NAD+.

TRUE OR FALSE: Fermentation regenerates NADH for further glycolysis under anaerobic conditions

FALSE

How are glycolysis, ethanol fermentation, and lactate fermentation all related?

All can proceed in the absence of oxygen.

Fructose in the diet or fructose from sucrose in the diet can be a source of calories for fat synthesis in the liver because:

Fructose enters glycolysis after the primary regulation point, PFK-1

Glycerol from hydrolysis of triacylglycerols enters glycolysis at:

Dihydroxyacetone phosphate.

TRUE OR FALSE: Anabolic processes involve degradation of complex molecules into simpler molecules with the net release of chemical energy.

FALSE

TRUE OR FALSE: The anabolic and catabolic processes of cellular metabolism can be coupled by ATP.

TRUE

TRUE OR FALSE: Reactions in metabolic pathways that are subject to regulation are those that are displaced near/at equilibrium

FALSE

An increase in the ratio of [AMP]:[ATP] during exercise causes an increase in the following physiological responses except:

FATTY ACID SYNTHESIS

Which of the following does not contribute to the regulation of enzymatic activity?

DNA stability

An integral membrane protein can be extracted with:

a solution containing detergent.

The fluidity of the lipid side chains in the interior of a biolayer is generally increased by:

An increase in the number of double bonds in fatty acids

When a bacterium such as E. coli is shifted from a warmer growth temperature to a cooler growth temperature, it compensates by:

Putting more unsaturated fatty acids into its membranes

Facilitated diffusion through a biological membrane is

driven by a difference of solute concentration

The type of membrane transport that uses ion gradients as the energy source is:

Secondary active transport.

In one catalytic cycle, the Na+/K+ ATPase transporter transports:

3 Na+ out, 2 K+ in, and converts 1 ATP to ADP + Pi

The Na+-Glucose cotransport system is an example of:

secondary transport

Which of the following fatty acids is 16:0?

Palmitic acid

The desaturation and elongation of alpha-linolenic acid can produce which of the following:

EPA and DHA

Which of the following molecules or substances contain, or are derived from, fatty acids?

Prostaglandins

Sphingolipids

Triacylglycerols

Glycerophospholipids

All of the above contain or are derived from fatty acids.

Biological waxes are all:

esters of single fatty acids with long-chain alcohols.

True or False, the precursor to eicosanoids are essential fatty acids?

TRUE

Non-steroidal anti-inflammatory drugs (NSAIDS) like aspirin and ibuprofen act by blocking production of:

prostaglandins

What chemical feature determines if a sugar is an aldose or a ketose?

The position of the carbonyl carbon

What name is given to monosaccharides that differ in configuration around one carbon atom?

Epimers

Which of the following is not true about cyclization of monosaccharides?

Monosaccharides with 4C or more often form a ring structure in aqueous solutions

Hemoglobin glycation is a process where _________ is __________ attached to hemoglobin

Glucose; non-enzymatically

TRUE OR FALSE: Reducing disaccharides (sugars) do not have a free hydroxyl group at the anomeric carbon while non-reducing sugars do

TRUE

Amylose and amylopectin are the principle storage polysaccharides of:

PLANTS

There are ________ reducing end(s) and _________ non-reducing end(s) found in glycogen and starch

one, many