BIOCHEM EXAM 3 FA SYNTHESIS & metabolism, Ketone bodies

Which hormone primarily activates hormone-sensitive lipase in adipose tissue?

A. Insulin

B. Glucagon

C. Epinephrine

D. Cortisol

C. Epinephrine

For fatty acid metabolism what is the enzyme used to create trans -▵2- enoyl-ACP from Palmitic acid (C16)?

acyl-CoA dehydrogenase.

For fatty acid metabolism what is the enzyme used to create L-B hydroxyacyl-CoA from trans -▵2- enoyl-ACP?

Enoyl-CoA hydratase

For fatty acid metabolism what is the enzyme used to create B-Ketoacyl- CoA from L-B hydroxyacyl-CoA?

β-Hydroxyacyl-CoA dehydrogenase

For fatty acid metabolism what is the enzyme used to create Acyl- CoA (C14) from B-Ketoacyl- CoA?

thiolase/ acyl-CoA acetyltransferase

What is the role of carnitine in fatty acid metabolism?

A. Synthesis of fatty acids

B. Transport of fatty acids into mitochondria

C. Energy storage

D. Beta-oxidation

B. Transport of fatty acids into mitochondria

Which coenzyme is NOT involved in β-oxidation?

A. FAD

B. NAD+

C. CoA

D. Biotin

D. Biotin

What is the final product of β-oxidation that enters the TCA cycle?

A. Acetyl-CoA

B. Pyruvate

C. Glucose

D. Lactate

A. Acetyl-CoA

Which ketone body is NOT used for energy by the brain during starvation?

A. Acetoacetate

B. β-hydroxybutyrate

C. Acetone

D. All are used

C. Acetone

Hormone-sensitive lipase is activated by insulin. True/False

false

β-oxidation occurs in the mitochondria. True/False

true

Ketone bodies are synthesized in the liver. True/False

true

Carnitine shuttle is required for short-chain fatty acids. True/False

false

Acetyl-CoA can be used to form glucose through gluconeogenesis. True/False

false

The enzyme ______ is responsible for the first step of β-oxidation, introducing a double bond.

acyl-CoA dehydrogenase

Fatty acids must be converted to ______ before they can enter β-oxidation.

acyl-CoA

The main ketone bodies include acetoacetate, β-hydroxybutyrate, and ______.

acetone

During prolonged fasting, the brain relies on ______ for energy.

ketone bodies

Each round of β-oxidation shortens the fatty acid chain by ______ carbon atoms.

2

Which of the following best defines lipids?

A. Polymers of amino acids

B. Hydrophobic molecules that include fats, oils, and steroids

C. Sugars that dissolve easily in water

D. Polymers of nucleotides

Answer: B

Which of the following is not a type of lipid?

A. Triglycerides

B. Phospholipids

C. Proteins

D. Steroids

Answer: C

What is the main function of lipids in the human body?

A. Catalyze metabolic reactions

B. Store genetic information

C. Long-term energy storage

D. Transport oxygen

Answer: C

Where does the majority of lipid digestion occur?

A. Stomach

B. Mouth

C. Small intestine

D. Large intestine

Answer: C

Which enzyme is primarily responsible for lipid digestion in the small intestine?

A. Salivary amylase

B. Gastric lipase

C. Pepsin

D. Lactase

Answer: B

What molecule is crucial for transporting fatty acid intermediates during fatty acid synthesis?

A. Coenzyme A

B. Acetyl-CoA

C. Acyl Carrier Protein (ACP)

D. NADH

Answer: C

Which of the following is not a component of fatty acid synthase?

A. β-Ketoacyl-ACP synthase

B. Citrate lyase

C. Acetyl transferase

D. Enoyl reductase

Answer: B

How many carbon atoms are in palmitic acid?

A. 14

B. 16

C. 18

D. 12

Answer: B

Which of the following is the correct order of the four-step fatty acid biosynthesis cycle?

A. Reduction, condensation, dehydration, reduction

B. Condensation, reduction, dehydration, reduction

C. Dehydration, reduction, oxidation, condensation

D. Reduction, oxidation, condensation, dehydration

B. Condensation, reduction, dehydration, reduction

What cofactor is required in fatty acid biosynthesis for reduction reactions?

A. NADH

B. NADPH

C. FADH2

D. ATP

B. NADPH

TRUE / FALSE QUESTIONS

Lipids are hydrophilic molecules that mix well with water.

False

Phospholipids play a key role in the structure of cell membranes.(t/f)

True

Lipid digestion begins in the large intestine.(t/f)

False

Fatty acid synthase is a multienzyme complex responsible for fatty acid breakdown.

(t/f)

False

Acetyl-CoA is the molecule that initiates fatty acid synthesis.

(t/f)

True

Acyl Carrier Protein (ACP) acts as a scaffold that holds growing fatty acid chains during synthesis.

(t/f)

True

The formation of palmitic acid requires multiple rounds of the fatty acid synthesis cycle.

(t/f)

True

All enzymes involved in fatty acid synthesis are found in the mitochondria.

(t/f)

False

(t/f) Pancreatic lipase acts in the stomach to begin lipid digestion.

False

One of the primary roles of lipids is insulation and protection of organs.

True

✅ FILL IN THE BLANK QUESTIONS

The major site of lipid digestion is the ______

small intestine.

The enzyme ________is responsible for breaking down triglycerides into fatty acids and monoglycerides.

pancreatic lipase

In fatty acid synthesis, __________ is converted into ________ as a preparatory step.

acetyl-CoA, malonyl-CoA

The four steps in the fatty acid synthesis cycle are (list in order).

condensation, reduction 1 , dehydration, and reduction 2

The cofactor ________ is used in the reduction reactions of fatty acid biosynthesis.

NADPH

Fatty acid synthase catalyzes the formation of ___________, ________-carbon fatty acid.

palmitic acid, 16

_______ are lipids with a four-ring carbon structure.

Steroids

Lipid digestion is facilitated by the emulsifying action of _______

bile salts.

The component of fatty acid synthase that transfers the initial acetyl group is called ________.

Acetyl CoA-ACP acetyltransferase.

What enzyme is used in the condensation step of FA synthesis? Select all that apply

A. B-ketoacyl-ACP reductase

B. B-ketoacyl-ACP synthase

C. Acyl Carrier Protein (ACP)

D. Malonyl CoA-ACP transacylase

B. B-ketoacyl-ACP synthase, D. Malonyl CoA-ACP transacylase

What is the intermediate that you will be making in the condensation step of FA synthesis?

A. B - hydroxybutyryl - ACP

B. Butyryl - ACP

C. Trans-▵2-butenoyl-ACP.

D. Acetoacetyl-ACP

E. Palmitic acid

D. Acetoacetyl-ACP

What is released during the condensation step of FA synthesis?

A. Water

B. Hydrogen

C. Carbon dioxide

D. Salt

E. NADPH

C. Carbon dioxide

What enzyme is used in the Reduction #1 step of FA synthesis?

A. B-ketoacyl-ACP reductase

B. B-ketoacyl-ACP synthase

C. Acyl Carrier Protein (ACP)

D. Malonyl CoA-ACP transacylase

A. B-ketoacyl-ACP reductase

What is released during the Reduction #1 step of FA synthesis?

A. Water

B. Hydrogen

C. Carbon dioxide

D. Salt

E. NADP

E. NADP

What is the intermediate that you will be making in the Reduction #1 step of FA synthesis?

A. B - hydroxybutyryl - ACP

B. Butyryl - ACP

C. Trans-▵2-butenoyl-ACP.

D. Acetoacetyl-ACP

E. Palmitic acid

A. B - hydroxybutyryl - ACP

What is the intermediate that you will be making in the Dehydration step of FA synthesis?

A. B - hydroxybutyryl - ACP

B. Butyryl - ACP

C. Trans-▵2-butenoyl-ACP.

D. Acetoacetyl-ACP

E. Palmitic acid

C. Trans-▵2-butenoyl-ACP.

What enzyme is used in the Dehydration step of FA synthesis?

A. B-ketoacyl-ACP reductase

B. B-ketoacyl-ACP synthase

C. B -hydroxyacyl-ACP dehydratase

D. Malonyl CoA-ACP transacylase

C. B -hydroxyacyl-ACP dehydratase

Where is the OH & H being removed in the Dehydration step of FA synthesis? Select all that apply.

A. C1

B. C3

C. C4

D.C2

E. C5

D. C2 and B. C3

What enzyme is used in the Reduction step #2 step of FA synthesis?

A. B-ketoacyl-ACP reductase

B. B-ketoacyl-ACP synthase

C. B -hydroxyacyl-ACP dehydratase

D. enoyl-ACP reductase

d. enoyl-ACP reductase

Trans-▵2-butenoyl-ACP goes through the reduction #2 reaction to create which type of molecule?

A. B - hydroxybutyryl - ACP

B. Butyryl - ACP

C. Trans-▵2-butenoyl-ACP.

D. Acetoacetyl-ACP

E. Palmitic acid

B. Butyryl-ACP