Peroxisomes: Structure, Function, and Role in Lipid Metabolism and Detoxification

Question 1

Which of the following enzymes is not involved in beta-oxidation of lipids within peroxisomes?

Accepted Answer

Citrate synthase

Answer

Acetyl-CoA oxidase

Answer

Catalase

Answer

Fatty acyl-CoA oxidase

Question 2

Which of the following is NOT a function of peroxisomes?

Accepted Answer

Glycogen breakdown

Answer

Fatty acid oxidation

Answer

Reactive oxygen species (ROS) detoxification

Answer

Steroid hormone synthesis

Question 3

Which of the following is NOT a structural feature observed in peroxisomes?

Accepted Answer

Contain ribosomes

Answer

Enclosed by a single membrane

Answer

Notably lack DNA

Answer

Contain the enzyme catalase

Question 4

Peroxisomes play a significant role in the metabolism of which type of lipid?

Accepted Answer

Fatty acids

Answer

Steroids

Answer

Phospholipids

Answer

Triglycerides

Question 5

Which peroxisomal enzyme is crucial for metabolizing reactive oxygen species and toxic molecules?

Accepted Answer

Catalase

Answer

Cytochrome P450

Answer

Superoxide dismutase

Answer

Glutathione peroxidase

Question 6

Catalase, an enzyme found in peroxisomes, primarily functions to:

Accepted Answer

Decompose hydrogen peroxide

Answer

Synthesize fatty acids

Answer

Oxidize fatty acyl-CoAs

Answer

Transport metabolites across peroxisomal membranes

Question 7

Which disorder is associated with impaired peroxisomal function?

Accepted Answer

Zellweger syndrome

Answer

Tay-Sachs disease

Answer

Phenylketonuria

Answer

Down syndrome

Question 8

By what mechanism are peroxisomes directed to specific cellular locations or organelles?

Accepted Answer

By peroxisome targeting signals (PTSs)

Answer

By random diffusion

Answer

By microtubule-based transport

Answer

By vesicles

Question 9

Which multi-enzyme system do peroxisomes use to neutralize harmful reactive oxygen species (ROS) and protect against oxidative stress?

Accepted Answer

Superoxide dismutase (SOD) and catalase

Answer

NADPH oxidase and glutathione peroxidase

Answer

Peroxidases

Question 10

Which of the following is the primary function of peroxisomes in cellular lipid metabolism?

Accepted Answer

Beta-oxidation of fatty acids

Answer

Glycolysis

Answer

Gluconeogenesis

Answer

Citric acid cycle

Question 11

What is the main role of catalase enzyme in peroxisomes?

Accepted Answer

Detoxification of reactive oxygen species

Answer

Fatty acid activation

Answer

Coenzyme A synthesis

Answer

Lipid peroxidation

Question 12

Which cofactor is essential for peroxisomal beta-oxidation?

Accepted Answer

FAD

Answer

NAD+

Answer

Thiamine pyrophosphate

Answer

Coenzyme Q

Question 13

In which cell type are peroxisomes typically most abundant?

Accepted Answer

Liver cells

Answer

Muscle cells

Answer

Nerve cells

Answer

Red blood cells

Question 14

Which disorder is associated with a deficiency in peroxisomal function?

Accepted Answer

Zellweger syndrome

Answer

Cystic fibrosis

Answer

Huntington's disease

Answer

Parkinson's disease

Question 15

Which molecule is transported into peroxisomes via the peroxisomal targeting signal (PTS)?

Accepted Answer

Catalase

Answer

Glucose

Answer

ATP

Answer

RNA polymerase

Question 16

What is the significance of the single-membrane structure of peroxisomes?

Accepted Answer

It facilitates selective transport of molecules across the peroxisomal membrane.

Answer

It protects the peroxisome from damage caused by reactive oxygen species.

Answer

It enables peroxisomes to fuse with other organelles.

Answer

It prevents peroxisomes from being degraded.

Question 17

Which of the following is **NOT** a structural characteristic of peroxisomes?

Accepted Answer

Presence of ribosomes

Answer

Abundant in liver cells

Answer

Contain oxidative enzymes

Answer

Enclosed by a single membrane

Question 18

What is the primary function of peroxisomes in lipid metabolism?

Accepted Answer

Beta-oxidation of very-long-chain fatty acids

Answer

Protein synthesis

Answer

Glycolysis

Answer

Krebs cycle

Question 19

How are peroxisomes targeted to specific cellular locations?

Accepted Answer

Via specific peroxisome targeting signals (PTS) on their proteins

Answer

By attaching to the cytoskeleton

Answer

Through vesicular transport from the Golgi apparatus

Answer

Randomly throughout the cell

Question 20

What is the significance of peroxisomes in human health?

Accepted Answer

They play critical roles in lipid metabolism, detoxification, and cellular homeostasis, impacting overall health and disease.

Answer

They are solely responsible for energy production in cells

Question 21

Which of the following is a primary function of peroxisomes?

Accepted Answer

Lipid metabolism, specifically the breakdown of very long-chain fatty acids

Answer

Photosynthesis

Answer

Protein synthesis

Answer

Glycolysis

Question 22

Peroxisomes contain a unique set of enzymes that facilitate which of the following processes?

Accepted Answer

Detoxification reactions, such as the breakdown of reactive oxygen species and xenobiotics

Answer

Hormone production

Answer

Carbohydrate metabolism

Answer

Nucleic acid synthesis

Question 23

Which of the following is a characteristic feature of peroxisome morphology?

Accepted Answer

Single, phospholipid bilayer membrane without ribosomes

Answer

Ribosomes on the surface

Answer

Double membrane

Question 24

What is the primary substrate utilized by peroxisomes in their lipid metabolism functions?

Accepted Answer

Very long-chain fatty acids

Answer

Amino acids

Answer

Sugars

Answer

Nucleotides

Question 25

What is the main function of the PEX proteins in peroxisomal biology?

Accepted Answer

Targeting of proteins to peroxisomes by recognition of specific targeting signals

Answer

Regulation of peroxisome proliferation

Answer

Degradation of peroxisomal proteins

Answer

Synthesis of peroxisomal membrane

Question 26

Which of the following metabolic pathways occurs in both peroxisomes and mitochondria?

Accepted Answer

Fatty acid oxidation, particularly beta-oxidation of fatty acids

Answer

Protein synthesis

Answer

Photosynthesis

Answer

Glycolysis

Question 27

How do peroxisomes contribute to cellular homeostasis?

Accepted Answer

By maintaining redox balance, detoxifying harmful compounds, and participating in lipid metabolism

Answer

By synthesizing essential molecules

Answer

By providing energy for cellular processes