Biochem final

... is the major substrate for gluconeogenesis

Alanine

... is a central amino acid in both N and C metabolism.

Alanine (so is glutamate); Alanine metabolic disorder is not heard of. it would be lethal

Which of the following statements concerning the nicotinic acetyl choline receptor is (are) true? Answers 1, 2, and 3 are correct Answers 2 and 4 are correct Answers 1 and 3 are correct Only answer 4 is correct All answers are correct Voltage-gated ion channels are involved The flow of Na+ ions into the cell requires energy Acetyl choline activates a plasma membrane ion channel The signal generated is long lived

Answers 1 and 3 are correct

Brown fat thermogenesis works through ______ and is for ______ thermogenesis. a. Uncoupling; Shivering b. Coupling; Shivering c. Uncoupling; Non-shivering d. Coupling; Non-shivering

Answer: C. Uncoupling; Non-shivering

The starting molecule in the TCA cycle has _________ carbons and the ending molecule has _________ carbons. A. 6:6 B. 5:5 C. 4:4 D. 6:4 E. 4:6

Answer: D - 6:4

Which of the following best describes thermogenesis? A. Energy expended for the purpose of conserving heat equal to that expended for ATP production B. Energy expended for the purpose of conserving heat in addition to that expended for ATP production C. Energy expended for the purpose of generating heat equal to that expended for ATP production D. Energy expended for the purpose of generating heat in addition to that expended for ATP production.

Answer: D . Energy expended for the purpose of generating heat in addition to that expended for ATP production

Which of the following is associated with Fe++ reduction (only) as electrons are accepted during the ETC? a. NADH dehydrogenase b. Succinate dehydrogenase c. Coenzyme Q d. Cytochrome b C1 complex e. Cytochrome c oxidase

Answer: D. Cytochrome b C1 complex

What is the function of Complex III?

Answer: To act as a proton pump.

What is then net energy yield of oxidative phosphorylation, in ATP equivalents, per each mole of FA2H oxidized? a. 1.5 b. 2.5 c. 4 d. 5 e. 10

Answer: a. 1.5

Which of the following are characteristics of mitochondria? Answers 1, 2, and 3 are correct Answers 2 and 4 are correct Answers 1 and 3 are correct Only answer 4 is correct All answers are correct 1.Has double membrane structure 2. Contain DNA that codes for all mitochondrial proteins 3. Major cellular site for ATP generation 4. Function effectively under aerobic and anaerobic conditions

Answers 1 and 3 are correct

Clinical relevance: Metabolic orotic aciduria is caused by OTC deficiency in urea cycle (Session 25). Hereditary orotic aciduria is caused by deficiency in one or two of the downstream enzymes; as a result, orotic acid is is excreted in the urine. Normal growth is impaired for lack of ...

-pyrimidines -Oral administration of uridine is used to treat this condition.

How much dietary protein is required for a healthy human to maintain a nitrogen balance?

0.8 g of protein per kg of desirable body weight Approximately 56 g for an adult man Approximately 44 g for an adult woman Much greater need by infants and children

Which of the following are features of the nucleolus? Answers 1, 2, and 3 are correct Answers 2 and 4 are correct Answers 1 and 3 are correct Only answer 4 is correct All answers are correct 1.Contains chromatin 2.Contains ribosomal RNA genes 3. Site of RNA transcription 4. Site of ribosome assembly

Answers 1, 2, and 3 are correct

Which of the following statements about chemical messengers is (are) true? Answers 1, 2, and 3 are correct Answers 2 and 4 are correct Answers 1 and 3 are correct Only answer 4 is correct All answers are correct They are secreted from cells in response to a stimulus The are transported through body fluids They cause a transient change in their target cells They almost always bind to intracellular receptors

Answers 1, 2, and 3 are correct

Which of the following would be expected for a patient with an OXPHOS disease? A. A high ATP:ADP ratio in the mitochondria B. A high NADH:NAD_ ratio in the mitochondria C. A deletion on the X chromosome D. A high activity of complex II of the electrontransport chain E. A defect in the integrity of the inner mitochondrial Membrane

B. A high NADH:NAD_ ratio in the mitochondria

Prion diseases are caused by RNA viruses DNA viruses Defects in protein folding Mutated oncogenes abnormal levels of heat shock proteins

Defects in protein folding

On average how many protons are required to make one molecule of ATP? a. 1 b. 2 c. 3 d. 4 e. 5

d. 4

The conversion of lactate to glucose occurs in: a. Mitochondria b. Cytoplasm c. Golgi complex d. Both A and B e. Both B and C

d. Both A and B***

Which of the following amino acids when present in internal residues of proteins will contribute a negative charge to the protein at physiological pH? a. Glutamic acid b. Aspartic acid c. Glutamine d. Both a and b e. All of the above

d. Both a and b

What would be the net charge per mole on the R group of an aspartic acid residue in a peptide at a pH of 4.9? (pKa=3.9) a. +1.0 b. +0.5 c. 0.0 d. -0.5 e. -1.0

e. -1.0

Clinical relevance: -Tyrosinemia II:

TAT deficiency; excessive amount of Tyr leads to lesions of the eye and skin as well as neurologic problems.

Which of the following vitamins or enzymes is unable to protect against free radical damage? a. B-Carotene b. Glutathione peroxidase c. Superoxide dismutase d. Vitamin B6 e. Vitamin C f. Vitamin E

Vitamin B6

Which of the following nutrients would be expected to be enriched in a high fat meal? Folate Vitamin E Niacin Vitamin C Vitamin B6

Vitamin E

Clinical relevance: Lesch-Nyhan syndrome is caused by

a deficiency of hypoxanthine-guanine phosphoribosyltransferase (HGPRT). Purine salvage is restricted. Degradation of purine bases forms excessive amount of uric acid, which impairs mental development. Patients are also prone to self-mutilation. Excessive uric acid also results in kidney stone and Gout by forming uric acid crystals in the joints or soft tissues, such as the big toe. Allopurinol reduces the production of uric acid.

Which of the following are characteristics of globular proteins? a. Charged polar amino acid side chains tend to be located on the surface b. Hydrophobic side chains tend to be on the protein interior c. Uncharged polar amino acid side chains can be found in both interior and surface regions d. a and b are correct e. a, b, and c are correct

a, b, and c are correct

Proton motive force across the inner mitochondria membrane consists of a. A membrane potential b. An intact electron transport chain c. A proton gradient d. An ATP synthase

a. A membrane potential c. A proton gradient

1. Know that the major storage form of energy in human is

adipose tissue triglycerides.

Ammonia (NH3) or ammonia ion (NH4+) is toxic; it is transported between tissues as ... The final destiny of ammonia is in the urine as urea or uric acid.

alanine or glutamine

Oxidative phosphorylation (OXPHOS) malfunctioning can be the results of a. Mitochondrial gene deletion b. Nuclear gene deletion c. Chemical inhibition of electron transfer d. Uncoupling of electron transfer with proton transport

all

Which of the following statements about long-chain fatty acid metabolism is true? a. Chylomicrons transports fatty acids from digested food to adipose tissue b. Albumin transports fatty acids released from adipose tissue to liver through blood stream c. Fatty acid-binding proteins transport fatty acids across plasma membrane from interstitial space into cytosol d. Carnitine transports activated fatty acyl groups across the inner mitochondria membrane

all

The TCA cycle requires which of the following cofactors? a. Coenzyme A b. FAD c. FMN d. NAD+ e. Thiamine

all of the above

Type III hyperlipidemia is caused by deficiency of .... Analysis of the serium of patients with this disorder would exhibit which of the following? -Elevated triglyceride levels

apoprotein E

common fats acids palmate: stearate: oleate: linoleate:

palmate: 16:0 stearate: 18:0 oleate: 18:1 linoleate: 18:2

High levels of HDL are protective against atherosclerosis/coronary heart disease because of their participation in ...

reverse cholesterol transport.

Clinical relevance: Purine nucleoside phosphorylase deficiency and adenosine deaminase (A -> I) deficiency lead to

severe combined immunodeficiency disease (SCID), also known as "bubble boy disease". Patients lose both T- and B-cell function, and are prone to infections. Gene therapies had been successful.

Which of the following drugs act by forming covalent bonds with their target enzyme? a. Answers 1, 2, and 3 are correct b. Answers 2 and 4 are correct c. Answers 1 and 3 are correct d. Only answer 4 is correct e. All answers are correct 1. Penicillin 2. Aspirin 3. Allopurinol 4. Diisopropylfluorophosphate

e. All answers are correct

Which of the following are typical features of tyrosine kinase receptors? a. Many growth factor receptors are of this type b. ATP is required for action c. Receptor dimerization is a feature of activation d. They often activate protein kinase cascades e. All are correct

e. All are correct****

The presence of intra‐chain hydrogen (H) bonding is a characteristic of a. Alpha (a) helix regions of a protein chain b. Beta (b) sheet regions of a protein chain c. Beta (b) turn regions of a protein chain d. Both a and b are correct e. Both a and c are correct

e. Both a and c are correct

Hemoglobin A1c (HbA1c) a.Represents a stable enzyme catalyzed modification of hemoglobin b. Represents a stable non enzymatic reaction product of hemoglobin c. Reflects a recent history of blood glucose d. Both a and c are correct e. Both b and c are correct

e. Both b and c are correct

Which of the following statements about transmembrane proteins is (are) true? a. Membrane spanning regions of the protein are rich in polar amino acid side chains b. Many transmembrane proteins are cell surface receptor proteins that bind extracellular ligands c. Many cell receptors contain 7 transmembrane regions d. Both a and b are true e. Both b and c are true

e. Both b and c are true

Glucagon release does not alter muscle metabolism because of which of the following? a. Muscle cells lack adenylate cyclase b. Muscle cells lack protein kinase A c. Muscle cells lack G proteins d. Muscle cells lack guanosine triphosphate (GTP) e. Muscle cells lack the glucagon receptor

e. Muscle cells lack the glucagon receptor****

7. Know that the difference in oxygen binding property between myoglobin and hemoglobin is that

hemoglobin has a quaternary structure (hyperbolic vs. sigmoidal)

Regulation: hexokinase= PFK-1=

hexokinase= by G6P PFK-1= by substrate and ATP (AMP activates it)

PNP deficiency?

loss of T-cell function (bubble boy)

Two of the essential amino acids (...) are strictly ketogenic. They do not produce glucose, only acetoacetate and acetyl-CoA.

lysine and leucine

Beta oxidation inhibited by

malonyl coA

A folate deficiency (whether functional or actual) leads to

megaloblastic anemia caused by an inability of blood cell precursors to synthesize DNA and, therefore, to divide.

Kwashiorkor

muscle wasting>fatty liver excessive protein degradation environmental

5. Under what states would red blood cells use ketone bodies as a source of energy?

never

An individual in sepsis will display which of the following metabolic patterns? nitrogen balance: gluconeogenesis: Fatty acid oxidation:

nitrogen balance: negative gluconeogenesis: up Fatty acid oxidation: up

• By which age do most people lose a tolerance for lactose?

o 5-7

• What are the main glycosidic linkages found between monomers of starches

o A,1-4 and a,1-6

• What does a-amylase hydrozyle

o A1,4 bonds randomly

• Which bonds in starch will a-amylase not digest?

o A1,6 bonds and a1,4 bonds at the non reducing end of the chain

• Which short chain fatty acids are formed by bacterial digestion of fiber in the colon?

o Acetic Acid o Propionic Acid o Butyric Acid

• What environmental situation is detrimental to a-amylase?

o Acids (HCl). Bicarbonate makes it able to function in the duodenum

• What is another way to call lactose intolerance?

o Adult hypolactasia

• What enzyme digests starch

o Alpha amylase

• What enzyme digests high fructose corn syrup

o Amylase (corn syrup is an isomer of starch)

• Why is the Km for GLUT2 on the liver high? (i.e. lower affinity)

o Because we only want the liver to convert glucose into other forms of energy if there is too much/a lot

• What enzyme digest lactose?

o Beta galactosidase and lactase

•What is responsible for lightheadedness during hypoglycemic responses?

o Blood sugar is between 18-54 mg/dL and is too low to make it through the blood-brain barrier. This bariier is therefore responsible for lightheadedness during periods of low BS

• What are the three types of insoluble fibers?

o Cellulose o Hemicellulose o Lignins

• Does GLUT5 have a higher affinity for glucose or fructose?

o Fructose

• Which glucose transporter is associated with the liver?

o GLUT2

• What glucose transporter is found in the SI?

o GLUT2 and GLUT5

• Which transporter transports galactose?

o GLUT2 and GLUT5 (on the basal side)

• Which transporter transports fructose?

o GLUT5 (on the apical side)

• What are the four types of glycosidases

o Glucoamylase o Sucrose-maltase complex o Trehalase o Lactase-glucosylceramidase

• Which enzyme complete the digestion of starch after amylase has done all it can do?

o Glucoamylase and sucrose-isomaltase

• What is another word for disaccharidase?

o Glycosidase

• What types of bonds are hydrolyzed during the digestion of sugars

o Glycosidic bonds

• What does glucoamylase do?

o Hydrolyzes a1,4 bonds of starches that amylase could not digest (i.e at the nonreducing end)

• Where does the digestion of starch begin?

o In the mouth via a-amylase

• How does insulin stimulate transport into muscle and adipose cells?

o Increases transporters on their membranes

• Where are disaccharidases located?

o Intestinal brush border

• What enzyme is ineffective in a person with lactose intolerance

o Lactase

• What type of transporters should we associate the transport of glucose with?

o Na+ dependent co transporters

• What enzyme digests cellulose?

o None

• Which type of fiber do bacterial flora in the gut prefer to digest?

o Soluble Fiber

• What does the sucrose-maltase complex do?

o Splits sucrose, maltose, and maltotrisose (hydrolyzes most of the a1,6 bonds)

• What enzyme digests sucrose?

o Sucrase

• What is the glycemic index of a food?

o The ability of a food to raise blood sugar o Index is based on white bread which has a score of 100

• Which sugar is found in insects, fungi and algae?

o Trehalose

A large number of overlapping transport systems exist for amino acids in cells. Some systems contain facilitative transporters, whereas others express ..., which allow the active transport of amino acids into cells. Defects in amino acid transport can lead to disease.

sodium-linked transporters

Ammonia is toxic to

the brain and CNS

Sickle cell anemia: mutation of glutamate to...

valine

Tetrahydrofolate. Tetrahydrofolate, which is produced from the vitamin folate, is the primary This vitamin obtains one-carbon units from ...

one-carbon carrier in the body. serine, glycine, histidine, formaldehyde, and formate

High levels of ammonia and glutamine lead to brain swelling, due to ...

osmotic imbalance

... is a ketogenic amino acid that can form acetyl CoA and acetoacetyl CoA in the liver and extra hepatic tissues.

Leucine

A protein has one transmembrane domain composed entirely of a helical secondary structure. Which of the following amino acids would you expect to find in the transmembrane domain? Proline Glutamate Lysine Leucine

Leucine

*Amino acids are the major source of blood glucose: Fed State Short term fasted state Long term fasted state or starvation More than one of the above states None of the above states

Long term fasted state or starvation

What if one ingest not enough protein?

Malnutrition; muscle wasting (Kwashiorkor Syn.)

What prevents futile cycle, inhibits degradation of fatty acid, used in fatty acid synthesis?

Malonyl CoA

Which of the following is involved in the synthesis of tracylglycerols in adipose tissue?

-Fatty acid obtained from chylomicrons and VLDL

The conversion of nascent chylomicrons to mature chylomicrons requires which of the following?

-HDL (High density lipoprotein)

What is the sequence that places lipoproteins from most dense to least dense

-HDL/LDL/VLDL/chylomicrons

What type of receptor is associated with glucagon?

-Heptahelical/g-protein -> cAMP/phosphorylation cascade -> activation of glycogen breakdown

What is the from of glucose that can be used in the synthesis of glycogen?

-UDP-glucose (Uridine diphosphate)

Propionyl CoA can be converted to succinyl CoA to go to TCA, Where can Propionyl CoA come from?

Amino acids and odd numbered fatty acid chains

What is the main goal of the pentose phosphate path?

-Forms NADPH and pentose phosphate that become nucleotides

What are some examples of plasma membrane receptors/signal transducers?

-G Protein coupled receptors -Tyrosine kinases (ras/raf, MAPK) -PIP2, DAG signaling

What kind of receptor transduces signals from glucagon?

-G coupled receptors (activation of cAMP pathway and eventually PKA)

The facilitative transporter that is most responsible for transporting fructose from the blood into the cells is what?

-GLUT 5

Intracellular Protein Degradation: (2)

Autophagy-lysosome pathway: Ubiquitin-proteasome pathway (requires ATP)

A newborn is diagnosed with neonatal jaundice, in this patient, the bilirubin lacks which of the following carbohydrates?

-Glucuronate

What is the toxic/excreted form of UDP Glucose?

-Glucuronides+toxin

The nitrogen donor for the formation of amino sugars is which of the following?

-Glutamine

What molecule combines with phosphoenolpyruvate to make G6P via gluconeogenesis?

-Glycerol 3 Phosphate

What four processes does the release of insulin stimulate?

-Glycogen synthesis, FA synthesis, Triglyceride synthesis, liver glycolysis

What protein anchors glycogen?

-Glycogenin

What three processes does the release of glucagon stimulate?

-Glycogenolysis, Gluconeogenesis, Lipolysis (down regulates liver glycolysis)

Vitamin B12 is involved in two reactions in the body.

- the rearrangement of the methyl group of L-methylmalonyl coenzyme A (L-methylmalonyl-CoA) to form succinyl-CoA, -and it transfers a methyl group, obtained from FH4, to homocysteine, forming methionine.

If a cell were to contain 100% nonfunctional mitochondria, what would be the net ATP yield that would be produced from 1 mole of glucose.

-2 moles

What main things (up)regulate glycogen degradation in muscle?

-AMP, Ca, and epinephrine

Is phosphorylated glycogen phosphorylase activated or deactivated?

-Activated

A patient presented with a bacterial infection that produced endotoxin that inhibits phosphoenolpyruvate carboxykinase (PEPCK). In this patient, then, under these conditions, glucose production from which of the following precursors would be inhibited?

-Alanine

What is the main route of alcohol metabolism? What is the alternate route?

-Alcohol dehydrogenase (ADH) oxidizes alcohol into acetaldehyde (toxic) which is reduced by acetaldehyde dehydrogenase to from acetate (nontoxic). -The other route is by microsomal ethanol oxidizing system (MEOS) involving cytochrome P450 to reduce alcohol to acetaldehyde.

Complex III is inhibited by?

-Antimycin A

Which one of the following apoproteins acts as a cofactor activator of the enzyme lipoprotein lipase (LPL)

-ApoCII

In humans prostaglandins are derived primarily from which of the following?

-Arachidonic acid

Aspirin will inhibit which pathway?

-Arachidonic acid ->thromboxanes

Pyrimidine bases are first synthesized as the free base and then converted to a nucleotide. ... form all components of the pyrimidine ring. Ribose 5-phosphate, which is converted to ..., is required to donate the sugar phosphate to form a nucleotide. The first pyrimidine nucleotide produced is ...

-Aspartate and carbamoyl phosphate -phosphoribosyl pyrophosphate (PRPP) -orotate monophosphate (OMP). The OMP is converted to uridine monophosphate (UMP), which becomes the precursor for both cytidine triphosphate (CTP) and deoxythymidine monophosphate (dTMP) production.

Why is insulin considered to be the regulator of glycogen synthesis and degradation?

-Because its levels in the blood change far more drastically than does glucagon

Intravenous fructose feeding can lead to lactic acidosis caused by which of the following?

-Bypassing the regulated phosphofructokinase 1 (PFK-1) step

Mitochondrial protein synthesis can be inhibited by?

-Chloramphenicol

What causes the gallbladder to release bile acids and pancreas to release digestive enzymes?

-Cholecystokinin

ROS are constantly being formed in the cell. Which of the following is a major site of superoxide generation?

-Coenzyme Q

Where does fatty acid synthesis occur in the cell?

-Cytosol

Is phosphorylated glycogen synthase activated or deactivated?

-Deactivated

Which enzyme breaks down glycogen close to branching points?

-Debranching enzyme

Mitochondrial myopathies could be caused by?

-Defect in carnitine acetyl transferase; defect in b-oxidation, defect in coupling of respiration and oxidative phosphorylation; defect in respiratory chain.

G6P has many pathway choices, what are they?

-Glycolysis, pentose phosphate pathway, glycogen synthesis, and others

... is derived from methionine metabolism and can be converted back into methionine by using both methyl-FH4 and vitamin B12. This is the only reaction in which methyl-FH4 can donate the methyl group. If the enzyme that catalyzes this reaction is defective, or if vitamin B12 or FH4 levels are insufficient, ...

-Homocysteine -homocysteine will accumulate. Elevated homocysteine levels have been linked to cardiovascular and neurologic disease. (uses cobalamins)

Mitochondrial DNA mutations could cause each of the following OXPHOS deficiencies

-Liebers hereditary optic neuropathy (LHON), mitochondrial encephalomyopathy, degenerative diseases such as Parkinsons, MELAS syndrome

Does UDP-glucose participate in synthesis and degraedation of glycogen?

-No, only in synthesis

What are the open ends of glycogen branches called?

-Non-reducing ends

Clinical relevance: -Classic PKU (phenylketonuria): Restrictive dietary therapy is partially effective.

-PAH deficiency; excessive amount of Phe (hyperphenylalaninemia) leads to mental retardation. All newborns in the US are required to have a PKU test at birth.

Where are very long chain fatty acids (24-26 Carbons) oxidized in chain shortening pathways that use FAD containing oxidase to allow for beta oxidation?

-Peroxisomes

How is insulin produced?

-Proinsulin is made by beta cells, cleaved in vesicles to insulin, and secreted in the presence of high blood sugar

What kind of receptor does insulin bind to?

-RTK receptor

What happens to bile salts farther down the intestinal tract?

-Reabsorbed/returned to the liver

What AA residue does PKA stimulated by glucagon phosphorylate?

-Serine (activates some enzymes and inhibits other)

How does glucagon counter the effects of insulin?

-Stimulates cAMP which phosphorylates the enzymes that insulin dephosphorylated

What enzyme does the liver lack so that it cannot consume/metabolize ketone bodies?

-Succinal CoA Acetoacetate CoA transferase

What is a characteristic of sphingosine?

-Synthesized from palmitoyl-CoA and serine

Bile salts must reach a particular concentration within the intestinal lumen before they are effective agents for lipid digestion. This is because of lack of which of the following?

-The bile salt solubility in the lumen is a critical factor.

What ratio causes damage to the liver? How can ethanol cause ketoacidosis? What about lactic acidosis?

-The high NADH/NAD+ ratio generated from ethanol oxidation inhibits oxidation of fatty acids, which accumulate in the liver, and stimulates glycolysis and hyperlipidemia. -High NADH/NAD ratio shifts the pathway for ketone body synthesis instead of the TCA cycle. -High NADH/NAD ratio shifts the lactate dehydrogenase equilibrium to lactate, so that pyruvate formed from alanine is converted to lactate and cannot enter gluconeogenesis.

Which of the following steps in the biosynthesis of cholesterol is the committed rate limiting step?

-The reduction of HMG-CoA to mevalonate

Mitochondrial DNA is more susceptible than nuclear DNA to oxidative damage because?

-There are no mitochondrial histones, there are no DNA repair mechanisms in mitochondria, mitochondria DNA is exposed to larger amounts of free oxygen radicals than nuclear DNA; there are "hot spots" in mitochondria DNA that are subject to oxidative damage.

The apoproteins B-48 and B-100 are similar with respect to which of the following?

-They are synthesized from the same gene.

What are the main two functions of DEB branching enzyme?

-Tranferase removes 3 glucose residues and adds them to a longer chain -Hydrolase breaks the remaining a1,6 branching bond

Newly synthesized fatty acids are not immediately degraded because of which of the following?

-Transport of fatty acids into mitochondria is inhibited under conditions in which fatty acids are being synthesized.

Majority of mass of a lipoprotein is made up of

-Triglycerides

The most abundant component of chylomicrons is which of the following?

-Triglycerides

Further cleavage of the oligopeptides to amino acids is accomplished by enzymes produced by the intestinal epithelial cells. These enzymes include ... located on the brush border and other peptidases located within the cells. Ultimately, the amino acids produced by protein digestion are absorbed through ...

-aminopeptidases -the intestinal epithelial cells and enter the blood.

Urea is formed in the urea cycle from NH4 +, bicarbonate, and the nitrogen of ... (see Fig. 38.1). Initially, NH4 +, bicarbonate, and adenosine triphosphate (ATP) react to produce... , which reacts with ornithine to form .... Aspartate then reacts with citrulline to form argininosuccinate, which releases fumarate, forming ....

-aspartate -carbamoyl phosphate -citrulline -arginine

Nutritional facts: Vitamin B12 is a dietary requirement; only ...can synthesize it. Vitamin B12 in food sources, such as meat, eggs, dairy products, was obtained by animals from their food chain.

-bacteria Vitamin B12 stored in the liver of a healthy person is usually enough for years of use, so vitamin B12 deficiency is uncommon.

SAM biosynthesis and uses: norepinephrine guanidinoacetate nucleotides phosphatidylethanolamine acetylserotonin

-epinephrine -creatine -methylated nucleotides -phosphatidylcholine -melatonin

-Glutamine to glutamate by ... glutamate to glutamine by ... Clinical relevance:

-glutaminase -glutamine synthase (w/ATP). Recall the disorder of urea cycle: urea cycle defect > hyperammonemia > glutamate down−> glutamine up > osmotic imbalance > mitochondria & brain swelling > CNS damage > mental retardation ...

High levels of ... alter mitochondria permeability, leading to cell death -Lower levels of glutamate causes

-glutamine -brain dysfunction, because glutamate is a neurotransmitter. Symptoms include reduced nervous system alertness such as lethargy and disorientation.

Which enzyme breaks down longer chains of glycogen?

-glycogen phosphorylase

Roles of glutamine in the brain. -Brain is a net glutamine ... -Glutamine serves as a precursor for the synthesis of many kinds of neurotransmitter, such as (5) -Glutamine also transports excessive ...

-producer -glutamate, dopamine, epinephrine, serotonin, γ-amino butyric acid - GABA, in the neurons. -NH4+ from the brain into the blood.

Urea cycle: arginase cleaves arginine to .... The cycle is regulated in a feed-forward manner, such that when amino acid degradation is occurring, the rate of the cycle is ....

-release urea and regenerate ornithine -increased

Cytoplasmic proteins targeted for turnover are covalently linked to the small protein ..., which then interacts with a large protein complex, the ..., to degrade the protein in an adenosine triphosphate (ATP)-dependent process.

-ubiquitin -proteasome

Which of the following describe heterotrimeric G proteins? Answers 1, 2, and 3 are correct Answers 2 and 4 are correct Answers 1 and 3 are correct Only answer 4 is correct All answers are correct They bind GDP in the inactive state They can result in activation of adenylyl kinase They contain GTPase activity They can result in the inhibition of adennylyl kinase

...All answers are correct

Which of the following best describes a characteristic of most allosteric enzymes? a. In the absence of effectors, they generally follow Michaelis-Menton kinetics b. They have allosteric activators that bind in the active site c. They have irreversible allosteric inhibitors that bind at allosteric sites d. They are composed of single subunits e. They show cooperativity in substrate binding

...c. They have irreversible allosteric inhibitors that bind at allosteric sites

Which metabolic pathway plays a dominant role under different physiologic states in kidney? 1. Normal state? 2. Acidosis state? 3. Fasted/starvation state?

1. > Anaerobic glycolysis 2. > Amino acid / glutamine oxidation 3. Fatty acid oxidation

how many protons needed to make ATP?

4

4 Steps of long chain fatty oxidation:

1. cross plasma membrane 2. fatty acyl coA synthase activates acyl-coA 3. carnitine transports into mitochondria (reversible) 4. B-oxidation generates NADH and FAD2H and acetyl CoA 5. Acetyl CoA converted to ketone bodies (in liver)

The carbon skeletons of how many nonessential amino acids are derived from glucose?

10

A cell contains two enzymes that catalyze the same reaction, using the same substrate. Enzyme 1 has a Vmax of 5 units/mg enzyme and a Km of 0.1 mM. Enzyme 2 has a Vmax of 50 units/mg and a Km of 5.0 mM. At a concentration of 20 mM substrate, what is the ratio of the rate of product formation of enzyme 1 compared to enzyme 2? 1:4 1:2 1:1 1:16 1:8

1:8

Waste treatment and disposal (ammonium ion, etc.) consumes a lot of energy: kidney uses about

24 g ATP / g tissue per day

Na+/glucose co-transport; K+-Na+ATP pump used to maintain concentration gradient so this is ...

2ndary active transport b/c it uses ATP indirectly

Cholesterol biosynthesis from acetate req's how many steps/how many ATP?

33 steps and 18 ATP

What amino acids are transported to the liver? Why to transport?

> Alanine and glutamine Amino acid degradation occurs in many tissues, but the last step of nitrogen disposal in the form of urea takes place principally in the liver. > Gluconeogenesis occurs only in the liver.

Why is there more alanine and glutamine released from human forearm than their average composition of protein?

> Alanine and glutamine are being synthesized in the skeletal muscle

Why is there less BCAAs released from human forearm than their average composition of protein?

> BCAAs are being catabolized (degraded, oxidized) in the skeletal muscle

Where does amino acid degradation occur?

> In many tissues such as liver, muscle, brain, kidney, etc. > Liver is the only tissue that can do both biosynthesis and degradation of AAs.

Where does amino acid synthesis occur?

> In the liver

Skeletal muscle is a major site of protein synthesis and degradation in human. Metabolism of the carbon skeletons of branched-chain amino acids (BCAAs) occurs mainly in skeletal muscle. Why can't liver oxidize BCAAs?

> Liver does not have significant level of BCAA transaminase (TA).

Serine metabolic disorder is not heard of. Possibly why?

> Serine is the precursor of several other AAs. Metabolic disorder of serine would be lethal.

Both 5-fluorouracil (5-FU) and methotrexate (MTX) are widely used antitumor drugs. What is their MOA (mode of action)?

> They structurally mimic dUMP and FH2, respectively; act as suicide inhibitors. Called as "antimetabolic agents".

Which of the following are sources for the synthesis of glucose in the liver? 1.Pyruvate 2.Alanine 3.Lactate 4.Glycerol 5.AcetylCo-A A. Answers 1, 2, 3, and 4 B. Answers 2 and 4 C. Answers 1 and 3 D. Only answer 4 is correct E. All answers are correct

A. Answers 1, 2, 3, and 4****

Succinate dehydrogenase differs from all other enzymes in the TCA cycle in that it is the only enzyme that displays which of the following characteristics? A. It is embedded in the inner mitochondrial membrane. B. It is inhibited by NADH. C. It contains bound FAD. D. It contains Fe-S centers. E. It is regulated by a kinase.

A. It is embedded in the inner mitochondrial membrane.

The fate of acetate, the product of ethanol metabolism, is which of the following? A. It is taken up by other tissues and activated to acetyl- CoA. B. It is toxic to the tissues of the body and can lead to hepatic necrosis. C. It is excreted in bile. D. It enters the TCA cycle directly to be oxidized. E. It is converted into NADH by ADH.

A. It is taken up by other tissues and activated to acetyl- CoA.

Regulation of ATP homeostasis by

ADP/ATP and NAD+/NADH ratios

What moves ATP out of mitochondria?

ANT adenine nucleotide translocase (ADP antiport)

Which of the following are associated with the cell cytoskeleton? Answers 1, 2, and 3 are correct Answers 2 and 4 are correct Answers 1 and 3 are correct Only answer 4 is correct All answers are correct 1.a tubulin 2. Kinesin 3. b tubulin 4. G-actin

All answers are correct

Which of the following groups can be phosphorylated in plasma membrane cell signaling systems? Answers 1, 2, and 3 are correct Answers 2 and 4 are correct Answers 1 and 3 are correct Only answer 4 is correct All answers are correct Protein tyrosine residues Protein serine residues Protein threonine residues Phosphatidylinositol inositol residues

All answers are correct

For the question below, please use the following keys Answers 1) and 3) are true Answers 2) and 4) are true Answers 1), 2) and 3) are true Only answer 4) is true All answers are true Why is constant protein turnover (degradation, recycling) necessary? Clean up damaged proteins Get rid of unnecessary proteins Synthesize proteins to meet new needs Generate glucose, intermediates and ATPs

All answers are true

Which of the following are typical features of tyrosine kinase receptors? Many growth factor receptors are of this type ATP is required for action Receptor dimerization is a feature of activation The often activate protein kinase cascades All are correct

All are correct

Which of the following are functions of lysosomes? Digestion of foreign substances Have a much lower pH than the cytosolic compartment Contain a wide variety of hyrolic enzymes Digestion of intracellular organelles

All of above

The tertiary structure of a protein can be stabilized by Hydrogen bonds Ionic bonds Hydrophobic interactions Disulfide bonds All of the above

All of the above

Muscle cells contain glycogen phosphorylase that catalyzes the conversion of glucose residues in glycogen to glucose 1-phosphate. Glycogen phosphorylase is activated by AMP and cAMP. This reflects The ability of muscle to generate glucose for energy production when intracellular energy is low The ability of muscle to respond to external stimuli that dictate a need for muscle contraction Regulation of glycogen phosphorylase by both non covalent and covalent mechanisms All of the above (a-c) are true None of the above are true

All of the above (a-c) are true

Which of the following statements about tertiary structure of proteins is (are) true? It can create binding sites for small molecule ligands It can be flexible and dynamic It can contain more than one type of secondary structure All of the above (a‐c) are true None of the above are true

All of the above (a‐c) are true

Which of the following statements about amino acid biosynthesis and degradation are true? 1. The biosynthesis pathways are generally distinct from the degradation pathways 2. Both the biosynthetic pathways and the degradation pathways involve intermediates from the glycolysis pathway and the TCA cycle 3. The degradation fate of carbon atoms of amino acids parallels that of glucose and fatty acids 4. The degradation fate of nitrogen atoms of amino acids is mostly urea For the question below, please use the following keys Statements 1) and 3) are true Statements 2) and 4) are true Statements 1), 2) and 3) are true Only statement 4) is true All statements are true

All statements are true

1. The oxidation of fatty acids is best described by which of the following sets of reactions? A. Oxidation, hydration, oxidation, carbon-carbon bond breaking B. Oxidation, dehydration, oxidation, carbon-carbon bond breaking C. Oxidation, hydration, reduction, carbon-carbon bond breaking D. Oxidation, dehydration, reduction, oxidation, carbon-carbon bond breaking E. Reduction, hydration, oxidation, carbon-carbon bond breaking

Answer A. Oxidation, hydration, oxidation, carbon-carbon bond breaking. Fatty acid oxidation is initiated by the acyl-CoA dehydrogenase (an oxidation step), followed by hydration of the double bond formed in the first step, followed by the hydroxyacyl-CoA dehydrogenase step (another oxidation), and then attack of the B-carbonyl by CoA, breaking a carbon-carbon bond (thiolase step)

Which of the following correctly describes an aspect of glycolysis? a. ATP is formed by oxidative phosphorylation b. 2 ATP are used in the beginning of the pathway c. Pyruvate kinase is the rate limiting step d. 1 pyruvate and 3 CO2 are formed from the oxidation of 1 glucose molecule e. The reaction takes place in the matrix of the mitochondria

Answer B - 2 ATP are used in the beginning (investment phase)

How many net ATPs are produced in anaerobic glycolysis? a. 1 b. 2 c. 4 d. 8 e. 12

Answer B. 2

1) Consider the following experiment. Carefully isolated liver mitochondria are incubated in the presence of a limiting amount of malate. Three minutes after adding the substrate, cyanide is added, and the reaction is allowed to proceed for another 7 minutes. At this point, which of the following components of the elctron transfer chain will be in an oxidized state? A. Complex I B. Complex II C. Complex III D. Coenzyme Q E. Coenzyme C

Answer B. For a component to be in the oxidized state, it must have donated, or never received, electrons. Complex II will metabolize succinate to produce fumarate (generating FAD(2H)) but no succinate is available in this experiment.

An accumulation of hydrogen peroxide in a cellular compartment an be converted to dangerous radical forms in the presence of which metal? a. Selenium b. Iron c. Manganese d. Magnesium e. Molybdenum

Answer B. Iron. The fenton reaction is the nonenzymatic donation of an electron from Fe+2 to H202 to produce Fe+3, the hydroxyl radical, and hydroxide ion. Only Fe+2 or Cu+ can be used in this reaction, thus the other answers are not correct.

Superoxide dismutase catalyzes which of the following reactions? a. O2- + e- + 2H+ H2O2 b. 2O2- + 2H+ -> H2O2 +O2 c. O2- + HO + H+ CO2 + H2O d. H2O2 + O2 4H2O e. O2- + H2O2 + H+ 2H2O + O2

Answer B. Superoxide dismutase combines to superoxide radicals to produce hydrogen peroxide and molecular oxygen. None of the other reactions are correct.

Which of the following compounds does NOT contain a high energy bond? A. 1,3-Biphosphoglycerate B. Phophenolypyruvate C. Creatine Phosphate D. AMP E. Acetyl CoA

Answer D - AMP ***(Also Acetyl Co-A and GDP contain high energy bonds)

1. Starting with glyceraldehyde 3-Phosphate and synthesizing one molecule of pyruvate, the net yield of ATP and NADH would be which of the following?

Answer D, 2 ATP, 1 NADH. By starting with glyceraldehyde 3 phosphate, the energy requiring steps of glycolysis are bypassed. Thus as glyceraldehyde 3 phosphate is converted to pyruvate, two molecules of ATP will be produced and one molecule of NADH will be produced.

Which of the following describe heterotrimeric G proteins? 1. They bind GDP in the inactive state** 2. They can result in activation of adenylyl cyclase** 3. They contain GTPase activity** 4. They can result in the inhibition of adenylyl cyclase**

Answer E. All.

Which of the following groups can be phosphorylated in plasma membrane cell signaling systems? 1. Protein tyrosine residues** 2. Protein serine residues** 3. Protein Threonine residues** 4. Phosphatidylinositol inositol residues**

Answer E. All.

Which of the following describes the anaerobic fates of pyruvate and NADH as they differ from aerobic glycolysis? a. Pyruvate is reduced to lactate in the cytosol, thereby using the reducing equivalents in NADH b. Pyruvate is reduced to lactate in the cytosol and the reducing equivalents of NADH enter mitochondria via a shuttle system. c. Pyruvate enters mitochondria and is oxidized to CO2 and H20 thereby using the reducing equivalents in NADH d. Pyruvate enters mitochondria and is oxidized to CO2 and H20 and the reducing equivalents of NADH enter mitochondria via a shuttle system

Answer. A. Pyruvate is reduced to lactate in the cytosol, thereby using the reducing equivalents in NADH

A patient, Mr. Perkines, has just suffered a heart attack. As a consequence, his heart would display which of the following changes? A. An increased intracellular O2 concentration. B. An increased intracellular ATP concentration. C. An increased intracellular H+ concentration. D. A decreased intracellular Ca+2 concentration E. A decreased intracellular Na+ concentration.

Answer. C. An increased intracellular H+ concentration.

Which of the following coenzymes is unique to alpha-ketoacid dehydrogenase complexes? A NAD+ B. FAD C. GDP D. H20 E. Lipoic Acid

Answer. E-Lipoic Acid

Succinate dehydrogenase differs from all other enzymes in the TCA cycle in that it is the only enzyme that displays which of the following characteristics? A. It is embedded in the inner mitochondrial membrane B. It is inhibited by NADH C. It contains bound FAD D. It contains Fe-S centers E. It is regulated by a kinase

Answer: A - it is embedded in the inner mitochondrial membrane.

The fate of acetate, the product of ethanol metabolism is which of the following? a. It is taken up by other tissues and activated to acetyl CoA b. It is toxic to the tissues of the body and can lead to hepatic necrosis c. It is excreted in the bile d. It enters the TCA cycle directly to be oxidized. e. It is converted into NADH by ADH

Answer: A. It is taken up by other tissues and activated to acetyl CoA. Acetate is converted to acetyl-CoA by other tissues so that it can enter the TCA cycle to generate ATP. Acetaldehyde, not acetate, is toxic to cells, so B is wrong. C is wrong bc acetate is excreted by the lung and kidney, not bile. Acetate cannot enter the TCA cycle direcly. Must be converted to acetyl CoA first.

Which of the following have Fe-S centers to transfer electrons? a. NADH dehydrogenase and succinate dehydrogenase b. Succinate dehydrogenase and coenzyme Q c. Coenzyme Q and cytochrome b C1 complex d. Cytochrome b C1 complex and cytochrome C oxidase e. Cytochrome C oxidase and NADH dehydrogenase

Answer: A. NADH dehydrogenase and succinate dehydrogenase

Caffeine is an inhibitor of the enzyme cAMP phosphodiesterase. Which of the following consequences would you expect to occur in the liver after drinking two cups of strong espresso? a. A prolonged response to insulin b. A prolonged response to glucagon c. An inhibition of protein kinase A d. An enhancement of glycolytic activity e. A reduced rate of glucose export to the circulation

Answer: B

Which compound follows after isocitrate in the TCA cycle? A. Citrate B. Alpha-Ketoglutarate C. Succinyl Co-A D. Succinate E. Fumerate

Answer: B - Alpha - Ketoglutarte

A patient is diagnosed with thiamine deficiency exhibited fatigue and muscle cramps. The muscle cramps have been related to an accumulation of metabolic acids. Which of the following metabolic acids is most likely to accumulate in a thiamine deficiency? A. Isocitric Acid B. Pyruvic Acid C. Succinic Acid D. Malic Acid E. Oxaloacetic Acid

Answer: B - Pyruvic Acid

Which of the following summarized the Cori Cycle? a. Gluconeogenisis in the kidney Glucose Muscle use Lactate production Lactate converted to glucose in the kidney b. Gluconeogensis in liver Glucose Muscle use Lactate production lactate converted to glucose in the liver c. Glycolysis in liver Glucose muscle use lactate production lactate converted to glycogen in liver d. Glycolysis in liver Glycogen Muscle use Lactate production Lactate converted to glucose in liver e. Gluconeogensis in liver lactate muscle use glucose production glucose converted to glycogen in liver

Answer: B Gluconeogensis in liver Glucose Muscle use Lactate production lactate converted to g

Which of the following would be expected for a patient with an OXPHOS disease? A. A high ATP:ADP ratio in the mitochondria B. A high NADH/NAD+ ratio in the mitochondria C. A deletion on the chromosome D. A high activity of complex II of the ETC E. A defect in the integrity of the inner mitochondrial membrane

Answer: B. NADH would not be reoxidized as efficiently by the ETC and the NADH/NAD+ ratio would increase.

Which of the following statements about the TCA cycle is NOT true? A. TCA cycle accounts for more than 2/3 of the ATP generated from oxidation B- All the enzymes required for the TCA cycle are in the mitochondria C- All the enzymes required for the TCA cycle are encoded by mitochondrial DNA D- Acetyl CoA is the direct substrate of the TCA cycle E - The TCA cycle is regulated by the "demand and supply" of energy

Answer: C

Which of the following statements correctly describes reduction of one of the electron carriers, NAD+ or FAD? A. NAD+ accepts two electrons as hydrogen atoms to form NADH2 B. NAD+ accepts two electrons that are each donated from a separate atom of the substrate C. NAD+ accepts two electrons as a hybrid ion to from NADH D. FAD releases a proton as it accepts two electrons E. FAD must accept two electrons at a time

Answer: C

Which of the following is the only compound of the ETC that is NOT protein bound? a. NADH dehydrogenase b. Succinate dehydrogenase c. Coenzyme Q d. Cytochrome b-C1 complex e. Cytochrome c oxidase

Answer: C - Coenzyme Q

Cyanide poisoning inhibits cytochrome oxidation at which of the following locations in the electron transport chain? a. Complex I b. Complex III c. Complex IV d. Complex Q e. Cytochrome C

Answer: C - Complex IV

NADH is produced between which steps of glycolysis? a. D-Glucose and glucose 6 phosphate b. Fructose 6 phosphate and fructose 1,6 biphosphate c. Glyceraldehyde 3 phosphate and 1,3 biphosphophoglycerate d. 1,3 bisphosphoglycerate e. 1,3 biphosphoglycerate and 3 phosphoglycerate

Answer: C Glyceraldehyde 3 phosphate and 1,3 biphoosphoglycerate

1. The ATP yield from the complete oxidation of 1 mole of C18:0 fatty acid to carbon dioxide and water would be closest to which of the following? A. 105 B. 115 C. 120 D. 125 E. 130

Answer: C. 120. An 18 carbon saturated fatty acid would require eight spirals of fatty acid oxidation, which yields 8 NADH, 8 FAD(2H), 9 acyl-CoA. As each NADH gives rise to 2.5 ATP and each FAD(2H) yields 1.5 ATP, the reduced cofactors will give rise to 32 ATP. Each acyl-COA gives rise to 10 ATP, for a total of 90 ATP. This yield 122 ATP, but we must subtract 2 for the activation.

The inner mitochondrial membrane forms a tight permeability barrier to all polar molecules, including ATP, AP, Pi, anions such as pyruvate and cations such as Ca++, H+, and K+. ATP-ADP translocase helps transport: a. ATP and ADP out of the mitochondria b. ATP and ADP into the mitochondria c. ATP out of the mitochondria and ADP into the mitochondria d. ADP out of the mitochondria and ATP into the mitochondria

Answer: C. ATP out of the mitochondria and ADP into the mitochondria

Which of the following enzymes is NOT associated with ATP use or ATP gain? a. Hexokinase b. Phosphofructokinase-1 c. Glyceraldehyde 3 phosphate dehydrogenase d. Phosphoglycerate kinase e. Pyruvate kinase

Answer: C. Glyceraldehyde 3 phosphate dehydrogenase

Dinitrophenol acts as an uncoupler of oxidative phosphorylation by which of the following mechanisms? A. Activating the H+-ATPase B. Activating Coenzyme Q C. Blocking proton transport across the inner mitochondrial membrane D. Allowing for proton exchanges across the inner mitochondria membrane E. Enhancing oxygen transport across the inner mitochondrial membrane

Answer: D. Dinitrophenol equilibrates the proton concentration across the inner mitochondrial membrane, theeby destroying proton motor forces.

Coenzyme A is synthesized from which of the following vitamins? A. Niacin B. Riboflavin C. Vitamin A D. Pantothenate E. Vitamin C

Answer: D. Pantothenate

What types of DNA or RNA are attacked by OXPHOS disease? a. mRNA and tRNA b. mRNA and rRNA c. mtDNA and mRNA d. nDNA and mtDNA e. nDNA and tRNA

Answer: D. nDNA and mtDNA

Dinitrophenol acts as an uncoupler of oxidative phosphorylation by which of the following mechanisms? a. Activating the H+ ATPase b. Activating coenzyme Q c. Blocking proton transport across the inner mitochondrial membrane d. Allowing for proton exchange across the inner mitochondrial membrane e. The proton motive force will be decreased to a value less than zero

Answer: D.Allowing protons for exchange across the inner mitochondrial membrane.

Our cells spend ATP very rapidly and thus ATP needs to be replenished. Which of the following (electron carrying) allows for this replenishing to get more ATP for the electron transport chain? A. cAMP B. FAD C. ADP D. Enzymes E. Coenzymes

Answer: E - Coenzymes

Which of the following describes the products of the TCA cycle? A. 2CO2 + 4NADH + FADH2 + GTP B. 3CO2 + 4NAH + FADH2 + 2GTP C. 2C02 + 2NADH + FADH2 + GTP D. CO2 + 3NADH + FADH2 + GTP E. 2CO2 + 3NADH + FADH2 + GTP

Answer: E. 2CO2 + 3NADH + FADH2 + GTP

Which of the following involved Cu+ ions facilitating the collection of four electrons and the reduction of O2 in the ETC? a. NADH dehydrogenase b. Succiante dehydrogenase c. Coenzyme Q d. Cytochrome b C1 complex e. Cytochrome C oxidase

Answer: E. Cytochrome C oxidase

During exercise, stimulation of the tricarboxylic acid cycle results principally from which of the following? A. Allosteric activation of isocitrate dehydrogenase by increased NADH B. Allosteric activation of fumarase by increased ADP C. A rapid decrease in the concentration of four carbon intermediates D. Product inhibition of citrate synthase E. Stimulation of the flux through a number of enzymes by a decreased NADH/NAD+ ratio

Answer: E. Stimulation of the flux through a number of enzymes by a decreased NADH/NAD+ ratio

Following a meal at the IHOP with extra syrup on a tall stack, which of the following statements is (are) true? The levels of glucose in the blood will increase The levels of glucagon in the blood will increase Glucose will be transported into muscle cells Answers a and c are correct Answers b and c are correct

Answers a and c are correct

Clinical relevance: Leukemic cells require large amount of asparagine for their growth. ... has been used as an antitumor agent to treat acute leukemia.

Asparaginase It reduces the amount of asparagine in the blood available for tumor cell growth.

Which of the following amino acids when present in proteins will contribute a negative charge to the protein at physiological pH Arginine Aspartate Glutamine All of the above (a‐c) None of the above

Aspartate

During fasting, amino acids are released from muscle protein, and enter into various tissues to be metabolized, eventually into CO2, H2O, NH4+, urea, etc. Which of the following amino acids is particularly important for those processes as both a nitrogen donor and a carbon donor? A.Glycine B. Alanine C. Methionine D. Lysine E. Cysteine

B. Alanine

Consider the following experiment. Carefully isolated liver mitochondria are incubated in the presence of a limiting amount of malate. Three minutes after adding the substrate, cyanide is added, and the reaction is allowed to proceed for another 7 minutes. At this point, which of the following components of the electron-transfer chain will be in an oxidized state? A. Complex I B. Complex II C. Complex III D. Coenzyme Q E. Cytochrome C

B. Complex II

Fatty acid derived acetyl-CoA is a source for gluconeogenesis A. True B. False

B. False****

Which of the following would be expected to occur after acute alcohol ingestion? A. The activation of fatty acid oxidation B. Lactic acidosis C. The inhibition of ketogenesis D. An increase in the NAD_ /NADH ratio E. An increase in gluconeogenesis

B. Lactic acidosis

The presence of inter-chain hydrogen(H)bonding is a characteristic of Alpha (α) helix regions of a protein chain Beta (β) sheet regions of a protein chain Beta (β) turn regions of a protein chain Both a and b are correct Both a and c are correct

Beta (β) sheet regions of a protein chain

Which of the following are typical of central nervous system messengers? Biogenic amines Steroid molecules Small peptides Both a and b Both a and c

Both a and c

Under starvation conditions, the largest change in fuel source occurs in Brain Muscle Adipose tissue Red Blood Cells Liver

Brain

The biosynthesis of which of the following nonessential amino acids requires an essential amino acid? A. Alanine B. Arginine C. Cysteine D. Glutamine E. Glycine

C. Cysteine

Besides a small portion of nucleotides being recycled in human body, the vast majority of nucleotides are synthesized de novo. What is the best reason for minimal uptake of nucleotides from diet? A. Nucleotides in the diet are different from nucleotides used in human body B. Minimal nucleotides exist in the diet C. Most nucleotides in the diet are degraded before being absorbed D. Lack of nucleotide uptake transporters in intestinal epithelial cells

C. Most nucleotides in the diet are degraded before being absorbed

AcetylCoA+H2O+NAD+, + FAD + GDP + Pi enter TCA cycle. What comes out?

CO2 + NADH + H+ +FAD(2H) + GTP + CoASH

Aspirin will also lead to covalent modification and inactivation of both the ...

COX-1 and COX-2 enzymes.

Similarities between carbamoyl phosphate synthetase I (CPSI, in urea cycle) and carbamoyl phosphate synthetase II (CPSII, in pyrimidine biosynthesis) include one of the following? Nitrogen source Carbon source Intracellular location Regulation by N-acetyl glutamate Regulation by UTP

Carbon source

Which of the following amino acids when present in proteins could form disulfide linkages? Methionine Cysteine Serine All of the above (a‐c) None of the above

Cysteine

Which of the following are typical chemical messengers of the immune system? Biogenic amines Cytokines Eicosanoids Growth factors All of the above

Cytokines

For a healthy individual with adequate food intake, intensive exercise usually results in the increase of A- Water content in the body B- Number and size of cells in the body C- Fatty acid/adipose mass in the body D- Number and size of mitochondria in muscle cells E- Number and size of neural cells in the central nervous system

D- Number and size of mitochondria in muscle cells

A lack of the enzyme ETF-QO oxidoreductase leads to death. This is caused by which of the following reasons? A. The energy yield from glucose use is dramatically reduced. B. The energy yield from alcohol use is dramatically reduced. C. The energy yield from ketone body use is dramatically reduced. D. The energy yield from fatty acid use is dramatically reduced. E. The energy

D. The energy yield from fatty acid use is dramatically reduced.

How do hormones change after an overnight fast?

Decrease of insulin; > Increase of glucagon and glucocorticoid

Can you identify a few features about purine biosynthesis?

Diverse element donors Energy intensive process Parallel AxP/GxP biosynthesis Reciprocal GTP/ATP energy supply ATP/GTP first (for RNA synthesis), dATP/dGTP second (for DNA synthesis

Induction of CYP2E1 would result in which of the following? A. A decreased clearance of ethanol from the blood B. A decrease in the rate of acetaldehyde production C. A low possibility of the generation of free radicals D. Protection from hepatic damage E. An increase of one's alcohol tolerance level

E. An increase of one's alcohol tolerance level

The conversion of IMP to AMP then to ADP/ATP requires energy from GTP; reciprocally, the conversion of IMP to GMP then to GDP/GTP requires energy from ATP. What is the metabolic benefit of this reciprocity? A. Each reaction requires different amount of energy B. ATP is a favorable energy molecule in purine biosynthesis C. GTP is a favorable energy molecule in purine biosynthesis D. Maintain a balanced energy pool E. Maintain a balanced pool of purine nucleotides

E. Maintain a balanced pool of purine nucleotides

During exercise, stimulation of the TCA cycle results principally from which of the following? A. Allosteric activation of isocitrate dehydrogenase by increased NADH B. Allosteric activation of fumarase by increased ADP C. A rapid decrease in the concentration of four-carbon intermediates D. Product inhibition of citrate synthase E. Stimulation of the flux through a number of enzymes by a decreased NADH/NAD_ ratio

E. Stimulation of the flux through a number of enzymes by a decreased NADH/NAD_ ratio

The degradation of amino acids can be classified into families, which are named after the end product of the degradation pathway. Which of the following is such an end product? A. Citrate B. Fructose 6-phosphate C. Glyceraldehyde 3-phosphate D. Malate E. Succinyl-CoA

E. Succinyl-CoA

Haptic inflammation caused by viral infection often results in leakage of cellular enzymes, such as alanine transaminase (ALT) and aspartate transaminase (AST), into the blood. What are the signs?

Elevation of serum levels of ALT (normal range: 5 to 30 U) and AST (normal range: 10 to 30 U) is a clinical evidence of inflammation. Elevation of serum levels of bilirubin (the degradation product of heme from heamoglobin) during liver viral infection is due to the inability or reduced capacity of the infected liver to conjugate bilirubin for excretion

Clinical relevance: Tyrosinemia I (Tyrosinosis):

FAH deficiency, toxic intermediates may cause liver failure and early death.

The uptake of glucose by muscle tissue in the fed state is an example of what kind of membrane transport? Simple diffusion A ligand gated channel Facilitative transport Active transport Vesicular transport

Facilitative transport

Glucose transporters are present in high concentrations on adipocyte membranes in which of the following metabolic states? Short term fasted state Fed state Long term fasted state or starvation Both A and B Both B and C

Fed state

The fate of the carbons of AAs parallels that of glucose and fatty acids - depending on the fed or fasting state. Glucognenic: Ketogenic:

Glucognenic: TCA cycle Ketogenic: Acetyl CoA, HMG-CoA

Glucose trapping reaction results in which of the following products? Glycogen Glucose‐1‐phosphate Glucose‐6‐Phospate UDP‐glucose Glucose 1,6‐diphosphate

Glucose‐6‐Phospate

... Plays a Pivotal Role in Amino Acid Metabolism

Glutamate

... is a preferred fuel for kidney during metabolic acidosis. Ammonium ion (proton) excretion helps to buffer systemic pH.

Glutamine

1. Consider a person with type 1 diabetes who has neglected to take insulin for the past 72 hours and has not eaten as well. Which of the following best describes the activity level of hepatic enzymes involved in glycogen metabolism under these conditions

Glycogen Synthase: Inactive, PHosphorylase Kinase: Active, Glycogen phosphorylase: Active

Which of the following is typically involved in paracrine signaling Biogenic amines Cytokines Eicosanoids Growth factors All of the above

Growth factors

The buffer system in the blood with the highest buffering capacity is H2PO4-/HPO4-2 H2SO4/SO4-2 Acetoacetic acid/Acetoacetate H2CO3/HCO3- HCO3-/CO3-2

H2CO3/HCO3-

Arginine not req'd by adults, why?

Humans can synthesize arginine but it is confined in the urea cycle; kids need extra amount of arginine for growth.

Compare: Digestion of carbohydrates and lipids begins in which organ? By what enzyme(s)?

In the mouth, by saliva α-amylase and lipase

Digestion of protein begins in which organ? By what enzyme?

In the stomach, by pepsin

What if one ingest too much protein?

Increase of metabolism; weight gain > obesity

...is the branching point of purine nucleotide biosynthesis

Inosine monophosphate (IMP)

Degradation of tryptophan Clinical relevance: Amino acid supplement is effective

Insufficient ingest of tryptophan may result in pellagra symptoms, such as dermatitis, diarrhea, dementia, and even death.

histidine gets degraded to ...

N10-Formyl-FH4

The major cations and anions in the blood are: Na+ and phosphate Na+ and Cl- K+ and Cl- K+ and HC03- Ca2+ and Cl-

Na+ and Cl-

Which of the following molecules are involved in the active transport of molecules across the plasma membrane? Na+, K+-ATPase Facilitative glucose transporter Na+-glucose co-transporter Both a and b Both b and c

Na+, K+-ATPase

Red blood cells use ketone bodies as a source of energy in which of the following states? Fed State Short term fasted state Prolonged fasting state or starvation More than one of the above states None of the above states

None of the above states

The most common urea-cycle defect is

OTC (ornithine transcarbamoylase) deficiency, which is an X-linked disorder has a frequency of 1 in 20,000 to 80,000 live births.

Which of the following represents a direct source of metabolic reducing power? Answers 1, 2, and 3 are correct Answers 2 and 4 are correct Answers 1 and 3 are correct Only answer 4 is correct All answers are correct Glucose UDP‐glucose Pyruvate NADPH

Only answer 4 is correct NADPH

Glycine to glyoxylate to oxalate (and ketone bodies) Clinical relevance:

Oxalate is sparingly soluble in water and can react with calcium to form calcium oxalate precipitate as kidney stone. Excessive accumulation of kidney stones can result in renal failure.

in transamination rxns, what moves amine group from aspartate to glutamate?

PLP

Endopeptidases: (4) Exopeptidases: (2)

Pepsin Trypsin Chymotrypsin Elastase Aminopeptidases Carboxypeptidases

A component of the plasma membrane that can serve as a precursor of a potent cellular signaling molecule is Sphinogomyelin Esterified cholesterol Unesterified cholesterol Phosphatidylinositol Phosphatidylcholine

Phosphatidylinositol

How many types of transport mechanisms are involved in amino acid absorption?

Primary active transport to build up Na+ and K+ gradients > Secondary active transport via Na+-amino acid co-transporter Facilitated transport

...is the quintessential coenzyme of amino acid metabolism. In degradation, it is involved in the removal of amino groups, principally through transamination reactions

Pyridoxal phosphate (derived from vitamin B6)

What is the MOA of allopurinol?

Suicide inhibitor of xanthine oxidase

... is a cofactor that is required for ring hydroxylation reactions (e.g., phenylalanine to tyrosine).

Tetrahydrobiopterin (BH4)

The mechanism of Vitamin E as an antioxidant is best described by which of the following? a. Vitamin E binds to free radicals and sequesters them from the contents of the cell b. Vitamin E participates in the oxidation of radicals c. Vitamin E participates in the reduction of radicals d. Vitamin E forms a covalent bond with the radicals thereby stabilizing the radical state. e. Vitamin E inhibits enzymes that produce free radicals.

The answer is C. Vitamin E participates in the reduction of radicals. Vitamin E donates an electron and proton to the radical, thereby converting the radical to a stable form (LOO LOOH). The vitamin thus prevents the free radical from oxidizing another compound by extracting an H from that compound and propagating a free radical chain reaction. The radical from to Vitamin E generated is relatively stable and actually donates another electron and proton to a second free radical, forming oxidized Vitamin E.

Children with Kwashiorkor usually have a fatty liver. This is due to which of the following? -The high-carbohydrate content of their diet -The high-fat content of their diet -The high-protein content of their diet -The lack of substrates for glycogen synthesis in the liver -The lack of substrates for protein synthesis in the liver

The lack of substrates for protein synthesis in the liver

The term secondary structure as it refers to proteins is defined as The structure present over a short, localized region of the protein The interaction of two different regions of a protein molecule The interaction of two different protein chains All of the above (a‐c) are correct None of the above are correct

The structure present over a short, localized region of the protein

Three separate mechanisms are available for the regulation of HMG-CoA reductase activity.

Transcriptional control. Regulation by proteolysis. Regulation by phosphorylation.

Which enzyme appears to play a central role in protein digestion? Why? Pepsin Trypsin Chymotrypsin Elastase Carboxypeptidase

Trypsin These protein-digestive enzymes can chew each other! So it is important to be activated within a short span of time.

The release of insulin from the β-cells of the pancreas requires Ca2+ influx through a channel that is activated by a change in the membrane potential across the plasma membrane. The movement of Ca2+ is an example of which of the following? Voltage-gated channel Passive diffusion Active transport Ligand-gated channel Phosphorylation-gated channel

Voltage-gated channel

Vitamin thiamine pyrophosphate (TPP) is a coenzyme of several enzymes including pyruvate dehydrogenase and α-ketoglutarate dehydrogenase. Thiamine deficiency can result in Beriberi symptom, lactate acidosis and cardiomyopathy (congestive heart failure). Which of the following is a major cause of thiamine deficiency besides inherited genetic mutation? a. Alcoholism b. Excessive exercise c. Nicotine addiction d. Obesity e. Vegetarianism

a. Alcoholism

Which of the following statements about the active site of enzymes is (are) true? a. Answers 1, 2, and 3 are correct b. Answers 2 and 4 are correct c. Answers 1 and 3 are correct d. Only answer 4 is correct e. All answers are correct 1. The active site typically represents a small fraction of the enzyme surface 2. Functional groups involved in catalysis can include both amino acid R groups and bound cofactors 3. The active site is the location of the transition state of the reaction 4. The active site is capable of only catalyzing the reaction in one direction

a. Answers 1, 2, and 3 are correct

Which of the following statements about the plasma membrane is (are) true? a. Answers 1, 2, and 3 are correct b. Answers 2 and 4 are correct c. Answers 1 and 3 are correct d. Only answer 4 is correct e. All answers are correct 1. It represents a physical barrier to polar compounds 2. Cholesterol is involved in maintaining membrane fluidity 3. Phospholipids are a major component 4. Carbohydrate modifications of proteins tend to be on the inner surface

a. Answers 1, 2, and 3 are correct

Which of the following electron transport chain components is NOT a protein or protein complex? a. CoQ (coenzyme Q) b. Cytochrome c c. Electron transport complex I d. Electron transport complex III e. Electron transport complex IV

a. CoQ (coenzyme Q)

In the fed state, what would be the relative levels of glucokinase in the liver of a normal individual compared to an individual with type 1 diabetes mellitus? a. Higher b. Lower c. No difference

a. Higher*******

Aside from generating NADPH, PPP can also generate...? a. Ribose 5 phosphate b. Mannose 7 phosphate c. Ribose 7 phosphate d. Mannose 6 phosphate

a. Ribose 5 phosphate***

KEY CONCEPT:De Novo cholesterol synthesis requires

acetyl CoA- as a precursor, which is initially converted to hydroxymethyl-glutaryl CoA (HMG-CoA).

Which of the following would be expected if a patient with an OXPHOS disease? a. A high ATP:ADP ratio in the mitochondria b. A high NADH:NAD+ ratio in the mitochondria c. A deletion on the X chromosome d. A high activity of complex II of the electronic transport chain e. A defect in the integrity of the inner mitochondria membrane

b. A high NADH:NAD+ ratio in the mitochondria

Which of the following are typical messengers found in the immune system? a. Biogenic amines b. Cytokines c. Eicosanoids d. Growth factors

b. Cytokines*****

Which of the Following is NOT a causal factor of Leigh disease? a. Deficiency of pyruvate dehydrogenase complex b. Deficiency of thiamine c. Deficiency of pyruvate carboxylase d. Deficiency of acetyl CoA e. Buildup of lactate

b. Deficiency of thiamine

Complete oxidation of an unsaturated fatty acid produces more ATP than complete oxidation of an equal carbon-number of saturated fatty acid a. True b. False (energy is lost because of prepping step with unsaturated fatty acids)

b. False (energy is lost because of prepping step with unsaturated fatty acids)

Substrate binding to the active site of an enzyme most often involves which one of the following types of interactions? a. Disulfide bonds b. Hydrogen bonds c. Ester formation d. Thioester formation e. Van der Waals interaction

b. Hydrogen bonds

What would be the rate of gluconeogenesis in the liver in the fed state of a normal individual compared to an individual with type 1 diabetes mellitus? a. Higher b. Lower c. No Difference

b. Lower********

Coenzyme Q (CoQ) has a 50-carbon long tail; What is the function of this tail? a. Makes CoQ hydrophilic so to move freely within the mitochondria matrix b. Makes CoQ hydrophobic so to move freely within the inner mitochondria membrane c. For transferring electrons d. For pumping protons e. For interacting with other electron transport components

b. Makes CoQ hydrophobic so to move freely within the inner mitochondria membrane

Which of the following statements about the acetyl CoA entering the TCA cycle is true? a. One carbon atom and the electrons associated with it leave the TCA cycle as CO2, NADH or FAD(2H) within the first turn of the cycle b. One carbon atom and the electrons associated with it leave the TCA cycle as CO2, NADH or FAD(2H) within the second turn of the cycle c. Two carbon atoms and the electrons associated with them leave the TCA cycle as CO2, NADH or FAD(2H) within the first turn of the cycle d. Two carbon atoms and the electrons associated with them leave the TCA cycle as CO2, NADH or FAD(2H) within the second turn of the cycle None of the above

b. One carbon atom and the electrons associated with it leave the TCA cycle as CO2, NADH or FAD(2H) within the second turn of the cycle

The first part of PPP consists of.. a. Reductive reactions b. Oxidative reactions

b. Oxidative reactions ****

The TCA cycle is regulated mainly by which of the following factors to achieve an ATP homeostasis? a. The ratio of [ATP]/[NAD+] b. The ratio of [ADP]/[ATP] c. The ratio of [ADP]/[Ca2+] d. The ratio of [NADH]/[NAD+] e. The ratio of [ATP]/[NADH]

b. The ratio of [ADP]/[ATP] and d. The ratio of [NADH]/[NAD+]

Water-soluble end products of pyrimidine degradation. (2)

beta alanine, beta-aminoisobutyrate

Cystic fibrosis:

blockage of pancreatic duct; genetic > In addition to buildup of mucus in the lung ... > Pancreatic zymogens can't enter the intestine

How many ATPs can be generated from complete oxidation of one mole of glucose to CO2 through the aerobic glycolysis pathway and TCA cycle? a. 10-12 b. 20-22 c. 30-32 d. 40-42 e. 50-52

c. 30-32

Which of the following functional groups are often involved in enzyme catalysis? a. Answers 1, 2, and 3 are correct b. Answers 2 and 4 are correct c. Answers 1 and 3 are correct d. Only answer 4 is correct e. All answers are correct 1. Cysteine 2. Leucine 3. Serine 4. Alanine

c. Answers 1 and 3 are correct

Which of the following statements about enzymes is (are) true? a. Answers 1, 2, and 3 are correct b. Answers 2 and 4 are correct c. Answers 1 and 3 are correct d. Only answer 4 is correct e. All answers are correct 1. Enzymes reduce the energy of activation of a reaction 2. Enzymes reduce the net energy change for the reaction 3. Enzymes typically catalyze a specific reaction 4. Nonpolar amino acid R groups are often involved in catalysis

c. Answers 1 and 3 are correct

Which of the following statements about integral membrane proteins is (are) true? a. Answers 1, 2, and 3 are correct b. Answers 2 and 4 are correct c. Answers 1 and 3 are correct d. Only answer 4 is correct e. All answers are correct 1. They can function as ion channels 2. They often function as transporters for hydrophobic molecules 3. They can function as hormone receptors 4. They are typically considered lipid-anchored proteins

c. Answers 1 and 3 are correct

The cofactor for pyruvate carboxylase catalyzing pyruvate to oxaloacetate is: a. NAD+ b. NADP+ c. Biotin d. UDP-Glucose

c. Biotin**

Which of the followings is NOT a component of the electron transport chain? a. Complex I b. CoQ c. Complex II d. Complex III e. Complex IV

c. Complex II

Proteins destined to be located on the extracellular surface of the plasma membranes are typically transiently associated with the a. Nucleus b. Smooth endoplasmic reticulum c. Golgi Complex d. Mitochondria e. Peroxisomes

c. Golgi Complex****

Which of the following isn't a direct product leaving the TCA cycle? a. CO2 b. FAD(2H) c. H2O d. GTP e. NADH

c. H2O

Which cellular component is most vulnerable to free radical damage? a. DNA b. Endoplasmic reticulum c. Plasma membrane (this is the first barrier encountered by external free radicals) d. Mitochondria e. Peroxisome

c. Plasma membrane (this is the first barrier encountered by external free radicals)

NADH is oxidized in mitochondria through oxidative phosphorylation process to generate ATP. How is the NADH generated in cytosol by glycolysis transported to mitochondria? a. through passive diffusion across mitochondria membrane b. through specific NADH transporter on mitochondria membrane c. through specific metabolic shuttle systems d. through adenine nucleotide translocase (ANT)

c. through specific metabolic shuttle systems

Pyrimidine synthesis is regulated at the first committed step, which is the synthesis of cytoplasmic carbamoyl phosphate, by the enzyme ...

carbamoyl phosphate synthetase II (CPSII).

Liver glycogen is a more rapid source of glucose than synthesis of glucose from amino acids because? a. The degradation of glycogen occurs in both fed and fasted states b. The liver has a long term supply of glycogen that can be used c. Glucose synthesis depends upon induction of glucokinase d. Glucose synthesis depends upon induction of phosphoenolpyruvate carboxykinase e. Glucose synthesis in muscle is slower than the breakdown of glycogen

d. Glucose synthesis depends upon induction of phosphoenolpyruvate carboxykinase*****

Myoglobin becomes half saturated with O2 at an oxygen partial pressure of 2.8 mm Hg while hemoglobin is half saturated at 26 mm Hg. This difference is due to differences in a. Primary structure b. Secondary structure c. Tertiary structure d. Quaternary Structure e. the nature of the heme group

d. Quaternary Structure

bacteria does what to bile salts in the intestine?

deconjugate and dehydroxylate

familial hypercholesterolemia type2 caused by

defect in LDL receptor leading to higher cholesterol levels

SER is where...? RER is where...?

drugs are metabolized (P450) proteins are modified post-translation

4. Under what conditions would brain cells utilize ketone bodies as an energy source?

during fasting, strenuous exercise, low carbohydrate, ketogenic diet

Hexokinase I found in red blood cells and glucokinase found in the liver catalyze the same reaction, the formation of glucose 6-phosphate. Hexokinase I has a Km for glucose of 0.05 mM and glucokinase has a Km for glucose of 5 mM. The fasting concentration of blood glucose is approximately 5 mM and raises following a meal containing carbohydrate. The significance of this difference explains a. The ability of red blood cells to use glucose for energy in the fasted state b. The ability of red blood cells to store excess glucose as glycogen c. The ability of red blood cells to convert glucose to fatty acids d. The ability of the liver to synthesize glucose in the fasted state e. The ability of the liver to take up excess glucose in the fed state

e. The ability of the liver to take up excess glucose in the fed state

MELAS is a mitochondrial disorder characterized by

encephalopathy, lactic acidosis, and stroke-like episodes.

Purines, when degraded, cannot generate energy, nor can the purine ring be substantially modified. The end product of purine ring degradation is uric acid, which is ...

excreted in the urine.

2. Know that the food source with the highest caloric content per gram is

fat (not carbohydrates or proteins).

9. Under what state would glucose transporters be present in high concentrations on adipocyte?

fed state

Regulation of the biosynthesis of individual amino acids can be quite complex, but the overriding feature is that the pathways are

feedback-regulated such that as the concentration of free amino acid increases, a key biosynthetic enzyme is allosterically or transcriptionally inhibited.

Cystinuria

genetic, doesn't transport basic amino acids in intestine and kidney, > Renal colic (sharp pain), leads to kidney stones

Metabolic changes resulting from insulin resistance: glycogenolysis: VLDL gluconeogenesis Free fatty acids lipolysis lipogenesis:

glycogenolysis: up VLDL: up gluconeogenesis: up Free fatty acids: up lipolysis: up lipogenesis: down

Four amino acids (serine, glycine, cysteine, and alanine) are produced from glucose through components of the ...

glycolytic pathway.

measure ...for diabetes. why?

glycosated hemoglobin b/c it doesn't fluctuate like BG levels.

Which amino acid acts as a buffer?

histidine

Clinical relevance: Alcaptonuria:

homogentisate oxidase deficiency; a dark pigment appears in urine and may result in arthritic joint pain over time.

alpha helix, R's outside are hydro... and what inside.

hydrophilic outside, hydrophobic inside

hartnup disease

hyperaminoaciduria genetic, mutation doesn't transport neutral amino acids lack of tryptophan the vitamin niacin; both are required for the synthesis of NAD and NADP+.

Defect in the urea cycle leads to elevated ammonia in the blood -

hyperammonemia

Human pancreas secrets bicarbonate (HCO3-) into the small intestine. What are the functions of HCO3- ? i. Neutralize HCl from the stomach ii. Continue to denature dietary proteins iii. Raise the pH to activate digestive enzyme(s) iv. Continue to kill microorganisms in ingested food i and ii are true i and iii are true i, ii and iii are true Only iv is true None is true

i and iii are true

Human stomach secretes HCl to maintain a very acidic environment (pH 2-3). What are the functions of this acidity? Denature dietary proteins Kill microorganisms in ingested food Activate digestive enzyme(s) Neutralize bicarbonate (HCO3-) i. Denature dietary proteins ii. Kill microorganisms in ingested food iii. Activate digestive enzyme(s) iv. Neutralize bicarbonate (HCO3-) i and ii are true i and iii are true i, ii and iii are true Only iv is true All are true

i, ii and iii are true Pepsinogen and pepsin can withstand the strong acidity! Other protein-digestive enzymes can't.

Adipose tissue secretions lead to ...

inflammation by activating macrophages

Hyperprolinemia is due to the genetic defect of ... Hyperprolinemia causes cognitive dysfunction.

proline oxidase (3).

> Glucocorticoits induce ...

protein degradation in skeletal muscle. Elevated level of glucocorticoits also induces de novo synthesis of enzymes involved in amino acid metabolism.

Lysosomal proteases (cathepsins) degrade ...

proteins that enter lysosomes.

of pyrimidine synthesis and regulation (mainly in ...). CPS-II, carbamoyl phosphate synthetase II.

the liver and brain

Glutamine is oxidized by various tissues, including ...

the lymphocytes, gut, and kidney, which convert some of the carbons and nitrogen to alanine.

DNA synthesis uses deoxyribonucleotides (dNTPs). Reduction of the ribose to deoxyribose catalyzed by ribonucleotide reductase (RR) occurs at ...

the nucleotide diphosphate (NDP) level. using ribonucleotide reductase (to thioredoxin)

High levels of ammonia drives ...

the synthesis of glutamine from glutamate

Branched-chain amino acids are direct fuel oxidized similarly as fatty acids mainly in skeletal muscle. Clinical relevance: Deficiency in branched-chain α-keto acid dehydrogenases leads

to maple syrup urine disease and associated neurologic complications such as mental retardation. Difficult to treat because those amino acid are essential. (valine, isoleucine, leucine)

S-adenosylmethionine. SAM, produced from methionine and adenosine triphosphate (ATP), does what?

transfers the methyl group to precursors that form several compounds, including creatine, phosphatidylcholine, epinephrine, melatonin, methylated nucleotides, and methylated DNA.