4th Biochemistry Lecture Exam (Batch 2025) Flashcards by

The major control point of glycolysis is the reaction catalyzed by:
A. glucokinase
B. pyruvate kinase
C. phosphofructokinase
D. glyceraldehyde 3-phosphate dehydrogenase

C. phosphofructokinase

Regulatory/ Irreversible Steps
(1) Hexokinase/ Glucokinase
(3) Phosphofructokinase-1 (Rate-limiting step)
(10) Pyruvate Kinase

How well did you know this?

Not at all

Perfectly

Which of the following are intermediates of glycolysis that can be used to produce ATP by substrate-level phosphorylation?

A. 3-phosphoglycerate and 2-phosphoglycerate
B. 1,3-bisphosphoglycerate and phosphoenolpyruvate
C. glyceraldehyde 3-phosphate and dihydroxyacetone phosphate
D. glucose 6-phosphate and fructose 6-phosphate

B. 1,3-bisphosphoglycerate and phosphoenolpyruvate

Substate-level phosphorylation = 4 ATP
(7) Phosphoglycerate kinase (1,3-BPG -> 3-PG)
(10) Pyruvate Kinase (PEP->Pyruvate)

How well did you know this?

Not at all

Perfectly

The conversion of pyruvate to lactate in the red blood cells serves:
A. to regenerate NAD+
B. to synthesize additional ATP
C. to complete the oxidation of glucose to CO2 and H2O
D. to prevent accumulation of hydrogen peroxide that can cause hemolysis

A. to regenerate NAD+

Lactic acid fermentation, Anaerobic part of EMP, Major fate of Pyruvate in skeletal muscles and BC involves re-oxidation of NADH, ensures NAD supply.

How well did you know this?

Not at all

Perfectly

True of glucokinase:

A. present in the liver and pancreas
B. has higher affinity for glucose than hexokinase
C. can phosphorylate not only glucose but also fructose, galactose and mannose
D. inhibited allosterically by its product glucose 6-phosphate

A. present in the liver and pancreas

How well did you know this?

Not at all

Perfectly

How many ATP is produced for every glucose molecule oxidized in the muscles during high intensity exercise when supply of oxygen is limited?

A. 32
B. 30
C. 10
D. 2

D. 2

How well did you know this?

Not at all

Perfectly

The enzyme that converts pyruvate to acetyl CoA prior to its entry in the citrc acid cycle:

A. acetyl CoA carboxylase
B. pyruvate carboxylase
C. acetyl CoA synthetase
D. pyruvate dehydrogenase

D. pyruvate dehydrogenase

How well did you know this?

Not at all

Perfectly

Fill up the missing intermediate in the glycolytic pathway
Glyceraldehyde 3-phosphate ➝_______________ ➝ 3-Phosphoglycerate
A. phosphoenolpyruvate
B. 2-phosphoglycerate
C. 1,3 bisphosphoglycerate
D. dihydroxyacetone phosphate

C. 1,3 bisphosphoglycerate

How well did you know this?

Not at all

Perfectly

Glycolytic pathway regulation involves:
A. allosteric stimulation by ADP
B. allosteric inhibition by ATP
C. feedback, or product, inhibition by ATP
D. all of the above

D. all of the above

How well did you know this?

Not at all

Perfectly

Why does the glycolytic pathway continue in the direction of glucose catabolism?
A. There are essentially three irreversible reactions that act as the driving force for the pathway
B. High levels of ATP keep the pathway going in a forward direction
C. The enzymes of glycolysis only function in one direction
D. Glycolysis occurs in either direction

A. There are essentially three irreversible reactions that act as the driving force for the pathway

Regulatory/ Irreversible Steps
(1) Hexokinase/ Glucokinase
(3) Phosphofructokinase-1 (Rate-limiting step)
(10) Pyruvate Kinase

How well did you know this?

Not at all

Perfectly

Which of the following is not true of glycolysis?
A. ADP is phosphorylated to ATP via substrate level phosphorylation
B. The pathway does not require oxygen
C. The pathway oxidizes two moles of NADH to NAD+ for each mole of glucose that enters
D. The pathway requires two moles of ATP to get started catabolizing each mole of glucose

C. The pathway oxidizes two moles of NADH to NAD+ for each mole of glucose that enters

How well did you know this?

Not at all

Perfectly

Cleavage of a hexose bisphosphate:
A. Aldolase
B. Hexokinase
C. Fructose 2,6-bisphosphate
D. Lactate dehydrogenase

A. Aldolase

Hexoses
(Glucose, Galactose, Mannose) : Aldoses
(Fructose) : Ketoses

How well did you know this?

Not at all

Perfectly

Irreversible phosphorylation of glucose:
A. Aldolase
B. Hexokinase
C. Fructose 2,6-bisphosphate
D. Lactate dehydrogenase

B. Hexokinase

Regulatory/ Irreversible Steps
(1) Hexokinase/ Glucokinase
(3) Phosphofructokinase-1 (Rate-limiting step)
(10) Pyruvate Kinase

How well did you know this?

Not at all

Perfectly

Activates the rate-limiting glycolytic enzyme:
A. Lactate dehydrogenase
B. Hexokinase
C. Fructose 2,6 bisphosphate
D. Aldolase

C. Fructose 2,6 bisphosphate

How well did you know this?

Not at all

Perfectly

Reduction of pyruvate:
A. Forward glycolytic reaction with glucose-6-phosphate as substrate
B. Lactate dehydrogenase
C. Hexokinase
D. Fructose 2,6-bisphosphate

D. Fructose 2,6-bisphosphate

Gluconeogenesis (+) : Glucagon
Glycolysis (-) : Insulin

How well did you know this?

Not at all

Perfectly

Forward glycolytic reaction with glucose-6-phosphate as substrate
A. Isomerization
B. Reduction of pyruvate
C. Activates the rate-limiting glycolytic enzyme
D. Irreversible phosphorylation of glucose

A. Isomerization

How well did you know this?

Not at all

Perfectly

Which of the following is not accomplished in glycolysis?
A. Net ATP synthesis
B. Substrate level phosphorylation
C. Oxidative phosphorylation
D. Generation of reducing equivalents

C. Oxidative phosphorylation

Cellular Respiration:
Glycolysis (Catabolic)
Tricarboxylic Acid/ Kreb Cycle
Electron Transport Chain/ Oxidative phosphorylation

How well did you know this?

Not at all

Perfectly

What is the difference between hexokinase and glucokinase?
A. Hexokinase phosphorylates glucose; glucokinase does not
B. Hexokinase is absent in the liver; glucokinase is abundant in the liver
C. Hexokinase is inhibited by glucose-6-phosphate; glucokinase is not
D. Hexokinase has a low affinity for glucose; glucokinase has a high affinity for glucose

C. Hexokinase is inhibited by glucose-6-phosphate; glucokinase is not

How well did you know this?

Not at all

Perfectly

What is the main purpose of the hexokinase reaction?
A. To facilitate the exocytosis glucose from the interior of the cell
B. To activate glucose for glycolysis
C. To convert glucose to a 6-carbon ketose
D. A and B only

B. To activate glucose for glycolysis

Hexokinase/Glucokinase effectively traps glucose inside the cell after being transported by GLUT-2(Liver)/ GLUT-3 (Kidney)

**Hexoses **
(Glucose, Galactose, Mannose) : Aldoses
(Fructose) : Ketoses

How well did you know this?

Not at all

Perfectly

Where does glycolysis take place?

A. Mitochondrial matrix
B. Inner membrane of the mitochondria
C. Outer membrane of the mitochondria
D. Cytoplasm

D. Cytoplasm

How well did you know this?

Not at all

Perfectly

What type of metabolic process is glycolysis?
A. Anabolic
B. Catabolic
C. Amphibolic
D. Anaplerotic

B. Catabolic

Metabolism:
* Catabolism (Break down : produces energy) : -lysis, -oxidation
* Anabolism (Building up : uses energy) : -genesis, -synthesis
* Amphibolic (Both Catabolic and Anabolic)
* Anaplerotic (refill / replenish depleted intermediates in TCA which have been used for biosynthetic reactions; continuous functioning)

How well did you know this?

Not at all

Perfectly

Which of the following reactions are considered as gluconeogenic reactions or pathways?
A. Glycogen ➝ Glucose
B. Alanine ➝ Pyruvate
C. Acetoacetate ➝Glucose
D. Pyruvate ➝ Acetyl-CoA

B. Alanine ➝ Pyruvate

A. Glycogen ➝ Glucose (Glycogenesis)
B. Alanine ➝ Pyruvate (GNG : Glucose-Alanine Cycle)
C. Acetoacetate ➝Glucose (Cholesterol synthesis)
D. Pyruvate ➝ Acetyl-CoA (Transition State)

How well did you know this?

Not at all

Perfectly

Which of the following is not a gluconeogenic enzyme?
A. Glucose-6-phosphatase
B. Glyceraldehyde-3-phosphate dehydrogenase
C. Phosphoglycerate kinase
D. Pyruvate kinase

D. Pyruvate kinase

How well did you know this?

Not at all

Perfectly

What is the role of the enzyme** aldolase in gluconeogenesis?**

A. It synthesizes 2 triose phosphates for gluconeogenesis
B. It condenses 2 triose phosphates to form a 6-carbon compound
C. It converts aldoses to ketoses
D. It delivers adenosine triphosphate to the cytosol as a source of energy for gluconeogenesis

B. It condenses 2 triose phosphates to form a 6-carbon compound

How well did you know this?

Not at all

Perfectly

Why is gluconeogenesis not possible in skeletal muscles?

A. Skeletal muscles do not have the enzyme lactate dehydrogenase to convert lactate to pyruvate
B. Skeletal muscles do not have mitochondria for oxaloacetate synthesis
C. Skeletal muscles do not have the enzyme glucose-6-phosphatase
D. Skeletal muscles are deficient in fructose-1,6-bisphosphatase, the rate-limiting enzyme of gluconeogenesis

C. Skeletal muscles do not have the enzyme glucose-6-phosphatase

Both in cytosol and mitochondria in liver (90%) and renal cortex (10%)

How well did you know this?

Not at all

Perfectly

25. Which of the following can be used as a substrate for gluconeogenesis? A. Acetyl-CoA B. Lactate C. Acetoacetate D. Leucine

B. Lactate ## Footnote FUNCTION OF GNG * maintains blood sugar concentration, * uses lactate and glycerol (end products of glycolysis and glycerol), * excretes excess protons by kidneys during metabolic acidosis, * recycles C skeletons of deaminated AA

26. Which glucose transporter is activated in the presence of insulin? A. GLUT 1 B. GLUT 2 C. GLUT 4 D. SGLT 1

C. GLUT 4

27. Which is the correct sequence of events for the secretion of insulin from the pancreas? A. Increased glucose → increased glycolysis → Increased ATP synthesis → Depolarization of the beta cell→ Exocytosis of insulin B. Decreased serum glucose→ increased pancreatic gluconeogenesis → Increased glycolysis → Depolarization of the beta cell → Insulin secretion C. Increased glycolysis → Elevation of pancreatic glucose → Increased ATP synthesis → Increased free phosphate in pancreas→ Insulin exocytosis D. Decrease of pancreatic glucose → Cell depolarization→ Increased calcium influx to the cell → Increased glycolysis → Insulin secretion

A. Increased glucose → increased glycolysis → Increased ATP synthesis → Depolarization of the beta cell→ Exocytosis of insulin

28. Which enzymes circumvent the glycolytic reaction catalyzed by pyruvate kinase? A. Pyruvate dehydrogenase and Lactate dehydrogenase B. Pyruvate carboxylase and PEP carboxykinase C. Hexokinase and glucokinase D. Fructose-6-phosphate and fructose 1,6-bisphosphate

B. Pyruvate carboxylase and PEP carboxykinase

29. Which of the following substrates are decreased by glucagon? A. Glucose B. Fructose-2,6-bisphosphate C. Fructose D. Cyclic AMP

B. Fructose-2,6-bisphosphate

30. Which portion of an amino acid is used for gluconeogenesis? A. Carbon skeleton B. Amino group C. Carboxyl group D. Peptide linkage

A. Carbon skeleton ## Footnote FUNCTION OF GNG * maintains blood sugar concentration, * uses lactate and glycerol (end products of glycolysis and glycerol), * excretes excess protons by kidneys during metabolic acidosis, * recycles C skeletons of deaminated AA

31. During starvation, which molecule acts as an activator of gluconeogenesis? A. Acetyl-CoA B. Lactate C. ATP D. NADH

A. Acetyl-CoA

32. Which hormone is the primary regulator of gluconeogenesis? A. Epinephrine B. Glucagon C. Insulin D. Incretin

B. Glucagon

33. Which of the following is required by the enzyme PEP carboxykinase? A. Biotin B. GTP C. Pyridoxal phosphate D. NADH

B. GTP

34. How many DHAPs are needed to synthesize 1 molecule of glucose? A. 1 B. 2 C. 3 D. None of the above- DHAP cannot form glucose

A. 1

35. Which fatty acid can synthesize glucose? A. Acetate B. Malate C. Propionate D. Palmitate

C. Propionate ## Footnote Gluconeogenesis: Glucogenic AA (Alanine) : Glucose Alanine Cycle Lactic Acid (RBC) : Cori cycle Glycerol (Propionate): Lipolysis/Beta-oxidation

36. Secretion of insulin from pancreatic B cells: A. GLYCOLYSIS B. GLUCONEOGENESIS

A. GLYCOLYSIS

37. Increased Fructose 2,6-bisphosphate concentration: A. GLYCOLYSIS B. GLUCONEOGENESIS

A. GLYCOLYSIS

38. Increased cyclic AMP synthesis: A. GLYCOLYSIS B. GLUCONEOGENESIS

GLUCONEOGENESIS

39. Increased beta oxidation of fatty acids: A. GLYCOLYSIS B. GLUCONEOGENESIS

B. GLUCONEOGENESIS ## Footnote Gluconeogenesis: Glucogenic AA (Alanine) : Glucose Alanine Cycle Lactic Acid (RBC) : Cori cycle Glycerol (Propionate): Lipolysis/Beta-oxidation

40. Increased catecholamine synthesis: A. GLYCOLYSIS B. GLUCONEOGENESIS

B. GLUCONEOGENESIS ## Footnote Hormonal control * Induction of enzyme synthesis – key GNG enzymes ↑ by glucocorticoids, ↓ by insulin (also induces EMP enzymes) * Covalent modification * Glucagon ↓ pyr kinase by phosphorylation, ↑ F2,6BPase by phosphorylation * Insulin ↓ GNG by ↓cAMP levels = ↓ phosphorylation of F2,6BPase Examples of HORMONES * Glucagon * Catacholamines (EPI/NE) * Cortisol * Thyroid hormones * Growth hormones (GH)

41. Which of the following steps is reversible? A. Glucose → Glucose-6-phosphate B. Glucose-6-phosphate →Fructose-6-phoosphate C. Fructose-6-phosphate → Fructose 1,6-bisphosphate D. Phosphoenolpyruvate → Pyruvate

B. Glucose-6-phosphate →Fructose-6-phoosphate ## Footnote Regulatory/ Irreversible Steps (1) Hexokinase/ Glucokinase (3) Phosphofructokinase-1 (Rate-limiting step) (10) Pyruvate Kinase

42. Why is lactate the final product of glycolysis in red blood cells? A. Red blood cells have an abundance of Lactate dehydrogenase B. Red blood cells are not capable of fermentation C. Red blood cells lack mitochondria for aerobic glycolysis D. Red blood cells are used for gluconeogenesis

C. Red blood cells lack mitochondria for aerobic glycolysis

43. Which product accumulates during ethanol catabolism? A. NADH B. NAD+ C. Glucose-6-phosphate D. Pyruvate

B. NAD+

44. Fluoride inhibits the enzyme enolase. What would be the consequence of this inhibition? A. There will be an increase in the activity of pyruvate kinase B. There will be an accumulation of 2-phosphoglycerate C. There will be an increase in the synthesis of pyruvate D. All of the above

B. There will be an accumulation of 2-phosphoglycerate ## Footnote Glycolysis Step (9) : (2-phosphoglycerate -> Phosphoenolpyruvate) Enzyme: Enolase

45. Which reaction produces ATP? A. Fructose-6-phosphate → Fructose 1,6-bisphosphate B. Phosphoenolpyruvate → pyruvate C. 3-phosphoglyerate → 1,3-bisphosphoglycerate D. All of the above

B. Phosphoenolpyruvate → pyruvate ## Footnote ATP Producing STEPS (7) 1,3BPG -> 3PG : Phosphoglycerate Kinase (10) PEP -> Pyruvate : Pyruvate Kinase

46. The enzyme pyruvate carboxylase produces which of the following products? A. Biotin only B. Oxaloacetate only C. Biotin and oxaloacetate D. Neither Biotin nor oxaloacetate

B. Oxaloacetate only

47. Which of the following would cause hypoglycemia? A. Increased cortisol B. Insulin overdose C. Injection of intramuscular epinephrine D. All of the above

B. Insulin overdose

48. Which enzyme is used for both glycolysis and gluconeogenesis? A. Glucose-6-phosphatase B. 3-phosphoglycerate kinase C. Hexokinase D. PFK-1

B. 3-phosphoglycerate kinase

49. Which of the following statements about gluconeogenesis is FALSE? A. It consists entirely of all the reactions of glycolysis working in the opposite direction B. It requires a high energy phosphate as a source of energy C. It employs the enzyme glucose-6-phosphatase D. It is one of the ways that mammals maintain blood glucose levels between meals

A. It consists entirely of all the reactions of glycolysis working in the opposite direction ## Footnote Not a reverse of glycolysis/EMP; but 8 out of 11 glycolysis steps are reversible and are shared Direct reversal of EMP = ΔG°’ = +20 Kcal/mol = very unfavorable thermodynamically GNG = ΔG°’ = -9 Kcal/mol = feasible (Gibbs Law)

50. In humans, gluconeogenesis: A. Is essential for the conversion of fatty acids to glucose B. Is activated by the hormone insulin C. Helps to reduce blood glucose after a carbohydrate-rich meal D. Can result in the conversion of amino acids to glucose

D. Can result in the conversion of amino acids to glucose ## Footnote Gluconeogenesis: Glucogenic AA (Alanine) : Glucose Alanine Cycle Lactic Acid (RBC) : Cori cycle Glycerol (Propionate): Lipolysis/Beta-oxidation

51. In our diet, 90% of the fats are in this form: A. Triglycerides B. Cholesterol C. Phospholipids D. Glycolipids

A. Triglycerides

52. These fatty acids lower both the plasma LDL and HDL A. ω-6 Fatty Acids B. ω-3 Fatty Acids C. Saturated Fatty Acids D. Monounsaturated Fatty Acids

A. ω-6 Fatty Acids ## Footnote Monounsaturated FA: Lowers total plasma cholesterol and LDL Maintains or Increase HDL ω-6 Fatty Acids Lowers both LDL and HDL ω-3 Fatty Acids Little effect on LDL and HDL

53. Which statement more appropriately defines lipids? A. Lipids are homogeneous group of compounds B. Lipids are essential components of all living organisms C. Lipids are water soluble organic compounds D. Lipids are all hydrophobic compounds

B. Lipids are essential components of all living organisms

54. The essential fatty acids are examples of this class of fatty acids: A. Saturated fats B. Monounsaturated fats C. Polyunsaturated fats D. None of the above

C. Polyunsaturated fats ## Footnote Saturated Fats * Have only single bonds in hydrocarbon chain Double bonds in cis form * 1 Double Bond = monounsaturated * 2 or more Double Bond = polyunsaturated

55. Which of the following statements is FALSE? A. As number of double bonds increases, melting point decreases B. When double bonds are present they are nearly always in the trans configuration C. When double bonds are present they are always spaced at three-carbon intervals D. The introduction of a cis double bond causes the fatty acid to bend at that position

B. When double bonds are present they are nearly always in the trans configuration ## Footnote * In most unsaturated fatty acids, the cis isomer predominates; the trans isomer is rare * Unsaturated fatty acids have lower melting points than their saturated counterparts * The greater the degree of unsaturation (or the more double bonds), the lower the melting point

56. With only a few exceptions, natural fatty acids: A. Contain an even number of carbon atoms B. Arranged in a branched line C. Have a carboxyl group (-COOH) at one end D. Have a methyl group (CH3) at the other end

B. Arranged in a branched line

57. The following statements about fatty acids is **false?** A. As number of carbon chain length increases, melting point also increases B. When double bonds are present, they are always spaced at three-carbon intervals C. When double bonds are present they are nearly always in the cis rather than a trans configuration D. The omega system of naming fatty acids involves numbering the carbon atoms beginning at the carboxyl end

D. The omega system of naming fatty acids involves numbering the carbon atoms beginning at the carboxyl end ## Footnote Carboxyl Group - Polar Head (Hydrophilic): Water-Soluble (Delta) Methyl Group (Hydrophobic): Oil-Soluble (Omega) Two systems in designating location of double bonds; based on lettering system: Δ (delta) system: * Start counting at the carboxylic acid group (COOH) = C1 * The position of the double bond is denoted by the carbon atom of the double bond closest to the carboxylate * Carbon from C1. * C1=carboxylate * C2=α-carbon * C3=β-carbon * LastC=ω-carbon * Remember:delta end is water-soluble n or ω (omega) system * The Methyl group=C1 * methylgroup=ω-carbon * Remember:omega end is oil-soluble

58. The figure below is a representation of Linoleic Acid which has the following abbreviations, except: A. 18:2 (9, 12) B. 18:2 (6, 9) C. 18:2 (ω-6) D. 18:2 (n-6)

B. 18:2 (6, 9) ## Footnote Omega-9 * Oleic Acid (1) Omega-6 * Linoleic Acid (2) * gamma-Linolenic (3) * Arachidonic acid (4) Omega-3 * alpha-Linolenic (3) * Eicosapentanoic Acid (EPA) (5) * Docasahexaenoic Acid (DHA) (6) (#)***Bonds

59. True of geometric isomerism among fatty acids: A. Occurs in saturated fatty acids B. Depends on the orientation of the groups around the axes of the double bonds C. Trans configuration entails acyl chains to be on same side of the double bonds D. Cis configuration entails acyl chains to be on opposite side of the double bonds

B. Depends on the orientation of the groups around the axes of the double bonds

60. Which is a True statement about lipids A. Their fluidity decreases with chain length and increases according to degree of unsaturation B. Melting point decreases with increasing carbon number C. Melting point of a saturated fatty acid is lower than in unsaturated fatty acid with the same number of carbons D. Double bonds increase melting point relative to saturated acid

A. Their fluidity decreases with chain length and increases according to degree of unsaturation ## Footnote * The greater the degree of unsaturation (or the more double bonds), the lower the melting point

61. Which of the following statements **does not** describe Trans fatty acids? A. They are chemically classified as unsaturated fatty acids B. They behave more like a saturated fatty acids in the body C. They elevate serum LDL and HDL D. They increase the risk for coronary heart disease

C. They elevate serum LDL and HDL

62. Which of the following is **not used** in naming fatty acids? A. Carbon atoms are numbered from the carboxyl carbon B. The carboxyl carbon is designated as carbon No. 1 C. Carbon number 1 is also known as the α-carbon D. The terminal methyl carbon is known as the ω- or n-carbon.

C. Carbon number 1 is also known as the α-carbon ## Footnote Carboxyl Group - Polar Head (Hydrophilic): Water-Soluble (Delta) Methyl Group (Hydrophobic): Oil-Soluble (Omega) Two systems in designating location of double bonds; based on lettering system: Δ (delta) system: * Start counting at the carboxylic acid group (COOH) = C1 * The position of the double bond is denoted by the carbon atom of the double bond closest to the carboxylate * Carbon from C1. * C1=carboxylate * C2=α-carbon * C3=β-carbon * LastC=ω-carbon * Remember:delta end is water-soluble n or ω (omega) system * The Methyl group=C1 * methylgroup=ω-carbon * Remember:omega end is oil-soluble

63. Which of the following is a false statement regarding the International Union of Pure and Applied Chemistry (IUPAC) Nomenclature or “Systematic names”? A. Counting begins from the carboxylic acid end B. Double bonds are labeled with cis-/trans-notation C. Systematic names give the least information D. The systematic name tells the number of C in the Fatty Acid chain, the degree of unsaturation, the C=C bond placement in the molecule and its stereochemistry

C. Systematic names give the least information

64. Generation of free radicals from lipids containing polyunsaturated fatty acids, that damage tissues and cause disease results from this process: A. Peroxidation B. Oxidation C. Hydrogenation D. Carboxylation

A. Peroxidation ## Footnote Lecture Notes: * Peroxidation of lipids containing polyunsaturated fatty acids leads to generation of free radicals that damage tissues and cause disease

65. True of essential fatty acids A. Linoleic acid is the precursor of ω-6 arachidonic acid B. α-Linolenic acid is the precursor of ω-3 fatty acids that are important for growth and development C. They are dietary essentials in humans because we lack the enzymes needed to synthesize them D. All of the above

D. All of the above ## Footnote Omega 3 Family (alpha-linolenic): * Eicosapenaenoic Acid (EPA), * Docasahexaenoic Acid (DHA). Omega 6 Family (linoleic): * Gamma-Linolenic Acid (GLA), * Dihomo-Gamma-Linoleic Acid (DGLA), * Arachidonic Acid, * Conjugated Linoleic Acid (CLA). ESSENTIAL FATTY ACID * ɷ-3 Family – From Alpha-Linolenic Acid. * ɷ-6 Family – From Linoleic Acid * Body cannot add double bonds beyond Carbon 9 from delta end (*Essential Fatty Acids are acquired from Diet

66. Which of the following **does not **represent the fatty acid abbreviation 18:1 (9)? A. The fatty acid has 18 Carbons B. The fatty acid has 1 double bond C. Position of the double bond is at Carbon 9 from the methyl end D. This represents Oleic Acid

C. Position of the double bond is at Carbon 9 from the methyl end

67. What are the main storage forms of fatty acids? A. Monoacylglycerols (Monoglycerides) B. Diacylglycerols (Diglycerides) C. Triacylglycerols (Triglycerides) D. All of the Above

C. Triacylglycerols (Triglycerides)

68. These fatty acids are being used to fortify milk formula to promote brain development A. ω-3 Fatty Acids B. ω-6 Fatty Acids C. ω-7 Fatty Acids D. ω-9 Fatty Acids

A. ω-3 Fatty Acids ## Footnote Omega 3 Family (alpha-linolenic): * Eicosapenaenoic Acid (EPA), * Docasahexaenoic Acid (DHA). Omega 6 Family (linoleic): * Gamma-Linolenic Acid (GLA), * Dihomo-Gamma-Linoleic Acid (DGLA), * Arachidonic Acid, * Conjugated Linoleic Acid (CLA).

69. Classify Palmitic acid, a 16-carbon fatty acid that functions as structural lipids, according to their chain length using the choices below: A. Short-chain fatty acids (SCFA) B. Medium-chain fatty acids (MCFA) C. Long-chain fatty acids (LCFA) D. Very long-chain fatty acids (VLCFA)

C. Long-chain fatty acids (LCFA) | APB - CaLaMyPaStAr ## Footnote SCFA: less than 6 MCFA: 6-12 LCFA: 13-21 VLCFA: more than 22 As number of chain length increases, melting point also increases

70. Classify Arachidonic acid, a 20-carbon fatty acid that serves as a precursor of prostaglandins according to their chain length using the choices below: A. Short-chain fatty acids (SCFA) B. Medium-chain fatty acids (MCFA) C. Long-chain fatty acids (LCFA) D. Very long-chain fatty acids (VLCFA)

C. Long-chain fatty acids (LCFA) | POLLA ## Footnote SCFA: less than 6 MCFA: 6-12 LCFA: 13-21 VLCFA: more than 22 As number of chain length increases, melting point also increases

71. Classify Linoleic acid and α-Linolenic acid which are essential fatty acids that have 18 carbons according to their chain length using the choices below: A. Short-chain fatty acids (SCFA) B. Medium-chain fatty acids (MCFA) C. Long-chain fatty acids (LCFA) D. Very long-chain fatty acids (VLCFA)

C. Long-chain fatty acids (LCFA) | POLLA ## Footnote SCFA: less than 6 MCFA: 6-12 LCFA: 13-21 VLCFA: more than 22 As number of chain length increases, melting point also increases

72. Classify Capric acid which is a 10-carbon fatty acid found in significant quantities in milk according to their chain length using the choices below: A. Short-chain fatty acids (SCFA) B. Medium-chain fatty acids (MCFA) C. Long-chain fatty acids (LCFA) D. Very long-chain fatty acids (VLCFA)

B. Medium-chain fatty acids (MCFA) ## Footnote SCFA: less than 6 MCFA: 6-12 LCFA: 13-21 VLCFA: more than 22 As number of chain length increases, melting point also increases

73. Classify Acetic Acid, a 2-carbon atom fatty acid that is a major end product of carbohydrate fermentation by rumen organisms, according to their chain length using the choices below: A. Short-chain fatty acids (SCFA) B. Medium-chain fatty acids (MCFA) C. Long-chain fatty acids (LCFA) D. Very long-chain fatty acids (VLCFA)

A. Short-chain fatty acids (SCFA) ## Footnote SCFA: less than 6 MCFA: 6-12 LCFA: 13-21 VLCFA: more than 22 As number of chain length increases, melting point also increases

74. Which describes the fatty acid below? A. Monoenoic acid B. Dienoic acid C. Trienoic acid D. Tetraenoic acid

D. Tetraenoic acid

75. The classification of the fatty acid above according to its chain length A. Short-chain fatty acids (SCFA) B. Medium-chain fatty acids (MCFA) C. Long-chain fatty acids (LCFA) D. Very long-chain fatty acids (VLCFA)

C. Long-chain fatty acids (LCFA) ## Footnote SCFA: less than 6 MCFA: 6-12 LCFA: 13-21 VLCFA: more than 22 As number of chain length increases, melting point also increases

76. Which of the following best describes phospholipids? A. Main lipid constituent of cell membrane B. Polar ionic compounds made up of an alcohol that is attached to a glycerol or to a sphingosine C. Amphipatic in nature D. All of the above

D. All of the above ## Footnote phospholipids: * Main lipid constituent of cell membrane, * Amphiphatic in nature

77. The following are true of fatty acids, except: A. Transported by serum albumin from their point of origin to their site of consumption B. Exists in the body only in the free or unesterified form C. Oxoidized by the muscle and liver to provide energy D. Serves as the main energy reserve of the body

B. Exists in the body only in the free or unesterified form

78. The following are true of steroids, except: A. Derivatives of cyclopentanoperhydrophenanthrine B. Has four fused rings with carbons numbered in sequence C. Sterols are steroids with 8-10 carbon atoms in the side chain and a fatty acid attached at carbon 3 D. Much of the plasma cholesterol is in the esterified form

A. Derivatives of cyclopentanoperhydrophenanthrine ## Footnote Steroid Nucleus: Cyclopentanoperhydropenanthrene Membrane Ring Complex derivatives of triterpenes

79. What is the chemical formula of a fatty acid at physiologic pH? A. CH3(CH2)nCOO- B. CH2(CH3)n C. CH3(CH2)nCOOH D. CHnCH3CH2

A. CH3(CH2)nCOO-

80. The following is not true of fatty acid chains: A. Saturated fatty acid chains contain at least one double bond B. When double bonds are present, they are nearly always in the cis rather than in the trans configuration C. If the fatty acid has two or more double bonds, they are always spaced at 3 carbon intervals D. The carbon atoms are numbered beginning with the carboxyl carbon as carbon 1

A. Saturated fatty acid chains contain at least one double bond ## Footnote Saturated Fats * Have only single bonds in hydrocarbon chain Double bonds in cis form * 1 Double Bond = monounsaturated * 2 or more Double Bond = polyunsaturated

81. Phospholipids contain: A. Hydrophilic heads and hydrophobic tail B. Long water-soluble carbon chains C. Positively charged functional groups D. Both B and C

A. Hydrophilic heads and hydrophobic tail ## Footnote Carboxyl Group - Polar Head (Hydrophilic): Water-Soluble (Delta) Methyl Group (Hydrophobic): Oil-Soluble (Omega)

82. Arachidonic acid has twenty carbon atoms with: A. Two double bonds B. Three double bonds C. Four double bonds D. Eight double bonds

C. Four double bonds

83. Cholesterol is the precursor of the following, except: A. Steroid hormones B. Vitamin A C. Bile salts D. Sex hormones

B. Vitamin A

84. Palmitic acid has 16 carbon atoms with: A. No double bonds B. Two double bonds C. Four double bonds D. Six double bonds

A. No double bonds | APB- CaLaMyPaStAr ## Footnote Saturated FA: APB- CaLaMyPaStAr Unsaturated FA: POLLA

85. True of the molecular structure of glycerol, except: A. Linear chain of four carbons B. Backbone of many other lipids C. The central carbon is bound to one hydroxyl radical and to one hydrogen atom D. The two other carbons at the ends are bound to a hydroxyl radical and two hydrogen atoms

A. Linear chain of four carbons

86. True of phospholipids: A. Made up of one molecule of glycerol bound to three long molecules of fatty acid B. They are amphipathic in nature C. Non-polar portion is due to a phosphate group D. Polar portion is due to long chain fatty acids

B. They are amphipathic in nature

87. Triacylglycerols are: A. Soluble in water B. Insoluble in water C. Soluble in water at elevated temperature D. Partially soluble in water

B. Insoluble in water ## Footnote Lipids have the common property of being relatively insoluble in water (hydrophobic) but soluble in nonpolar solvents.

88. Which of the following take up cholesterol from the peripheral tissues back to the liver? A. VLDL B. Chylomicron C. LDL D. HDL

D. HDL

89. A primary bile acid: A. Taurocholic acid B. Lithocolic acid C. Glycocholic acid D. Cholic acid

D. Cholic acid ## Footnote Bile Acids – 24-Carbon steroids secreted into the bile to emulsify dietary fats; They have a 5- carbon side chain at position 17 that contains a carboxyl group, making them acidic. **Cholic Acid – Major Human Bile Acid.**

90. What phospholipid make up dipalmitoyl lecithin, the major constituent of lung surfactant? A. Phosphatidyl inositol B. Phosphatidyl serine C. Phosphatidyl ethanolamine D. Phosphatidyl choline

D. Phosphatidyl choline ## Footnote Lecithin (Phosphatidylcholines, Surfactants, Surface-Acting Agents) * Functions to increase pulmonary compliance (Compliance is the ability of lungs and thorax to expand); * To prevent Atelectasis (Collapse of the lung) at the end of expiration; * Play an essential role in reducing surface tension in lung alveoli.

91. Which of the following statements regarding fructose 1,6-bisphosphatase is true? A. It is inhibited by fructose 2,6-bisphosphate B. It is induced in the fed state C. It is inhibited by glucagon D. It is induced by AMP

A. It is inhibited by fructose 2,6-bisphosphate

92. Which of the following gluconeogenic reactions generate NADH as a byproduct? A. Pyruvate → Oxaloacetate B. Pyruvate →Acetyl-CoA C. Lactate → Pyruvate D. Alanine → Pyruvate

C. Lactate → Pyruvate

93. Which of the following tissues/cells contribute to the glucose that is being synthesized through gluconeogenesis? A. Red blood cells B. Neurons C. Liver cells D. Skeletal muscle tissue

C. Liver cells ## Footnote Both in cytosol and mitochondria in liver (90%) and renal cortex (10%)

94. Why is oxaloacetate converted to malate in gluconeogenesis? A. To generate ATP B. To allow oxaloacetate to traverse the mitochondrial membrane C. To synthesize FADH2 D. All of the above

B. To allow oxaloacetate to traverse the mitochondrial membrane

95. What happens when the insulin:glucagon ratio increases? A. Promotion of gluconeogenesis B. Promotion of glycolysis C. Promotion of glycogen breakdown D. Inhibition of fatty acid synthesis

B. Promotion of glycolysis

96. Which of the following is a gluconeogenic precursor? A. Glycerol B. Galactose C. Glycogen D. Glucagon

A. Glycerol ## Footnote GNG: Synthesis of glucose from non-carb sources * Lactate * Pyruvate * Glycerol * Glucogenic AA (Alanine) * Odd-chain FA (Propionate)

97. Which of the following inhibits the rate-limiting step in glycolysis? A. Citrate B. ATP C. Glucagon D. All of the above

D. All of the above

98. Increased concentration of NADH: A. activates pyruvate kinase B. inhibits pyruvate kinase

B. inhibits pyruvate kinase ## Footnote Increase NADH: Glycerol/GNG Decrease NADH: Insulin/Glycolysis

99. Activation of PDH phosphatase: A. activates pyruvate kinase B. inhibits pyruvate kinase

A. activates pyruvate kinase

100. PDH phosphorylation: A. activates pyruvate kinase B. inhibits pyruvate kinase

B. inhibits pyruvate kinase

Brainscape's Knowledge GenomeTM

4th Biochemistry Lecture Exam (Batch 2025) Flashcards

Brainscape's Knowledge Genome^TM