Đề 2 – Bài tập, đề thi trắc nghiệm online Hóa sinh lipid

1. Adipose tissue primarily functions in:

A. Protein synthesis

B. Glycogen storage

C. Triglyceride storage and release

D. Detoxification of harmful substances

2. Acyl-CoA synthetase is an enzyme involved in fatty acid activation. It catalyzes the reaction of fatty acids with:

A. Glycerol

B. Coenzyme A (CoA)

C. Phosphate

D. Carnitine

3. In contrast to LDL, which lipoprotein is involved in reverse cholesterol transport, carrying cholesterol from peripheral tissues back to the liver for excretion?

A. VLDL (Very-Low-Density Lipoprotein)

B. Chylomicrons

C. HDL (High-Density Lipoprotein)

D. IDL (Intermediate-Density Lipoprotein)

4. What is the role of bile salts in lipid digestion?

A. To break down triglycerides into fatty acids and glycerol

B. To emulsify dietary fats, increasing their surface area for enzyme action

C. To transport fatty acids into intestinal cells

D. To synthesize triglycerides in the intestines

5. Which of the following is NOT a primary function of lipids in biological systems?

A. Long-term energy storage

B. Structural component of cell membranes

C. Catalysis of biochemical reactions

D. Signaling molecules

6. Which enzyme is the primary target of statin drugs, used to lower cholesterol levels?

A. Lipoprotein lipase

B. HMG-CoA reductase

C. Acyl-CoA dehydrogenase

D. Phospholipase A2

7. Sphingolipids are a class of lipids found in cell membranes, particularly abundant in:

A. Mitochondrial inner membrane

B. Plant cell walls

C. Nerve tissue and myelin sheath

D. Bacterial cell membranes

8. Carnitine shuttle is crucial for fatty acid metabolism because it:

A. Transports fatty acids from the cytoplasm into mitochondria for beta-oxidation

B. Transports acetyl-CoA from mitochondria to the cytoplasm for fatty acid synthesis

C. Synthesizes carnitine from fatty acids

D. Breaks down carnitine into fatty acids

9. Leptin is a hormone produced by adipose tissue that primarily functions to:

A. Promote glucose uptake by cells

B. Increase appetite and food intake

C. Decrease appetite and increase energy expenditure

D. Stimulate insulin secretion

10. Triglycerides, the most abundant type of lipid, are composed of:

A. Two fatty acids and a glycerol molecule

B. Three fatty acids and a phosphate group

C. Three fatty acids and a glycerol molecule

D. Two fatty acids, a glycerol molecule, and a phosphate group

11. What is the function of lipid rafts in cell membranes?

A. To increase membrane permeability to water

B. To provide structural rigidity to the entire membrane

C. To organize membrane proteins and facilitate cell signaling

D. To synthesize membrane lipids

12. Beta-oxidation is a metabolic process in which:

A. Glucose is broken down to produce energy

B. Fatty acids are synthesized from acetyl-CoA

C. Fatty acids are broken down to produce acetyl-CoA

D. Cholesterol is synthesized from fatty acids

13. Glycerophospholipids and sphingolipids both contain:

A. Glycerol backbone

B. Ceramide backbone

C. Fatty acid chains

D. Phosphate group

14. Individuals with a deficiency in lipoprotein lipase (LPL) may exhibit:

A. Lowered LDL cholesterol levels

B. Elevated HDL cholesterol levels

C. Hypertriglyceridemia (high levels of triglycerides in the blood)

D. Hypocholesterolemia (low levels of cholesterol in the blood)

15. Chylomicrons are lipoprotein particles that are formed in:

A. Liver

B. Adipose tissue

C. Intestinal epithelial cells

D. Bloodstream

16. Lipids are a diverse group of biomolecules, largely defined by their:

A. Solubility in water

B. Solubility in nonpolar solvents

C. Presence of phosphate groups

D. Polymeric structure

17. In the context of lipid metabolism, `de novo` synthesis refers to:

A. Breakdown of lipids obtained from diet

B. Synthesis of lipids from non-lipid precursors, like carbohydrates

C. Modification of existing lipid molecules

D. Transport of lipids between tissues

18. How do omega-3 and omega-6 fatty acids differ structurally?

A. Omega-3 fatty acids are saturated, while omega-6 are unsaturated

B. Omega-3 fatty acids have the first double bond at the 3rd carbon from the omega end, while omega-6 have it at the 6th carbon

C. Omega-3 fatty acids are shorter chain than omega-6 fatty acids

D. Omega-3 fatty acids contain nitrogen, while omega-6 do not

19. Which lipoprotein is primarily responsible for transporting cholesterol from the liver to peripheral tissues, and is often referred to as `bad cholesterol` when elevated?

A. HDL (High-Density Lipoprotein)

B. LDL (Low-Density Lipoprotein)

C. VLDL (Very-Low-Density Lipoprotein)

D. Chylomicrons

20. Lipogenesis, the synthesis of fatty acids, primarily occurs in the:

A. Mitochondria

B. Lysosomes

C. Endoplasmic reticulum and cytoplasm

D. Nucleus

21. Pancreatic lipase is essential for digestion of dietary triglycerides. It hydrolyzes triglycerides into:

A. Glycerol and free fatty acids

B. Monoglycerides and free fatty acids

C. Diglycerides and free fatty acids

D. Cholesterol and fatty acids

22. Ketogenesis is the process of producing ketone bodies from:

A. Glucose

B. Fatty acids

C. Amino acids

D. Cholesterol

23. Cholesterol, a steroid lipid, plays a vital role in animal cells by:

A. Providing quick energy

B. Increasing membrane fluidity at high temperatures

C. Decreasing membrane fluidity at low temperatures

D. Modulating membrane fluidity across a range of temperatures

24. Saturated fatty acids differ from unsaturated fatty acids in that saturated fatty acids:

A. Contain one or more carbon-carbon double bonds

B. Have a lower melting point

C. Are typically liquid at room temperature

D. Contain only single carbon-carbon bonds

25. Lipoproteins are essential for the transport of lipids in the bloodstream because:

A. Lipids are highly soluble in blood

B. Lipids are insoluble in blood and need to be carried in protein оболочках

C. Lipoproteins are enzymes that break down lipids in blood

D. Lipoproteins synthesize lipids for transport

26. Phospholipids are amphipathic molecules, meaning they have:

A. Only hydrophobic regions

B. Only hydrophilic regions

C. Both hydrophobic and hydrophilic regions

D. Neither hydrophobic nor hydrophilic regions

27. Eicosanoids, such as prostaglandins and leukotrienes, are signaling lipids derived from:

A. Cholesterol

B. Sphingolipids

C. Arachidonic acid

D. Glycerol

28. Which of the following is a precursor for the synthesis of steroid hormones?

A. Glucose

B. Fatty acids

C. Cholesterol

D. Amino acids

29. What is the role of phospholipases in lipid metabolism?

A. To synthesize phospholipids from fatty acids

B. To break down phospholipids, releasing fatty acids and other products

C. To transport phospholipids in the bloodstream

D. To incorporate phospholipids into cell membranes

30. Peroxisomes play a role in lipid metabolism, specifically in the:

A. Synthesis of all fatty acids

B. Beta-oxidation of very long-chain fatty acids

C. Synthesis of cholesterol

D. Breakdown of cholesterol