QCM : Human Cell Structure and Function — 9 questions

Questions et réponses du QCM

1. Which statement best describes the role of the cell membrane in human cell organization?

It assembles ribosomal subunits for protein synthesis
It forms a selectively permeable boundary that regulates entry and exit
It generates most ATP through cellular respiration
It stores genetic material and directs cell division

It forms a selectively permeable boundary that regulates entry and exit

Explication

The cell membrane is selectively permeable and controls what enters and leaves the cell while helping maintain internal conditions. The other options describe the nucleus, nucleolus, ribosomes, or mitochondria.

2. What is the main function of the nucleolus inside the nucleus?

It packages proteins for secretion
It separates the nucleus from the cytoplasm
It converts glucose into ATP for the cell
It produces ribosomal components needed for protein synthesis

It produces ribosomal components needed for protein synthesis

Explication

The nucleolus is the nuclear region involved in producing ribosomal components, which are needed to build ribosomes. It is not the boundary of the nucleus, nor is it involved in ATP production or Golgi packaging.

3. What does translation accomplish in a cell?

It converts mRNA information into an amino-acid chain
It copies DNA into RNA inside the nucleus
It sorts proteins into vesicles for secretion
It breaks down worn organelles for recycling

It converts mRNA information into an amino-acid chain

Explication

Translation uses the mRNA code to assemble amino acids into a protein. DNA copying is transcription, while protein sorting and organelle breakdown are Golgi/lysosome functions.

4. How do rough endoplasmic reticulum and smooth endoplasmic reticulum differ in their main functions?

Rough ER stores DNA, while smooth ER produces ribosomes
Rough ER synthesizes proteins, while smooth ER synthesizes lipids
Rough ER generates ATP, while smooth ER controls cell division
Rough ER packages hormones, while smooth ER digests particles

Rough ER synthesizes proteins, while smooth ER synthesizes lipids

Explication

Rough ER has ribosomes attached and mainly synthesizes proteins, while smooth ER lacks ribosomes and mainly synthesizes lipids such as phospholipids and cholesterol. The other choices describe unrelated organelles or processes.

5. Which function is most closely associated with lysosomes?

Packaging proteins for secretion
Detoxifying compounds with oxidizing chemistry
Producing ATP through electron transport
Digesting unwanted material with hydrolase enzymes

Digesting unwanted material with hydrolase enzymes

Explication

Lysosomes are the cell’s internal digestive system and contain hydrolase enzymes that break down ingested material and damaged structures. Detoxification is a peroxisome function, not a lysosome function.

6. Why are cristae important in mitochondria?

They carry out endocytosis of nutrients
They increase the surface area for ATP-producing reactions
They form the selective barrier of the cell membrane
They store ribosomal RNA for translation

They increase the surface area for ATP-producing reactions

Explication

Cristae are folds of the inner mitochondrial membrane that expand surface area for ATP production. The other options describe unrelated structures or processes.

7. Why do many water-soluble substances such as ions and glucose need membrane proteins to cross the plasma membrane?

Because the cytoskeleton actively digests them
Because they are converted into ATP before crossing
Because the phospholipid bilayer blocks them from diffusing freely
Because peripheral proteins trap them on the membrane surface

Because the phospholipid bilayer blocks them from diffusing freely

Explication

The phospholipid bilayer forms a barrier to many water-soluble substances, so they typically require membrane proteins such as channels or transporters. Fat-soluble substances cross more easily without that assistance.

8. What is autophagy?

The uptake of extracellular fluid into small vesicles
The direct contact signaling between neighboring cells
The engulfment of worn or damaged organelles for lysosomal digestion
The secretion of hormones into the bloodstream

The engulfment of worn or damaged organelles for lysosomal digestion

Explication

Autophagy is intracellular digestion in which damaged or worn organelles are enclosed in autophagosomes and then fused with lysosomes. Uptake of extracellular fluid is pinocytosis, not autophagy.

9. Which type of signaling uses hormones released into the bloodstream to reach distant target cells?

Endocrine signaling
Paracrine signaling
Autocrine signaling
Juxtacrine signaling

Endocrine signaling

Explication

Endocrine signaling carries hormones through the bloodstream to distant targets. Juxtacrine requires direct contact, and paracrine acts locally on nearby cells.

Révisez avec les flashcards

Mémorisez les réponses avec 18 flashcards sur Human Cell Structure and Function.

Cell membrane — role?

Controls entry and maintains internal conditions.

Nucleus — function?

Stores genetic material and controls cell activities.

Nucleolus — role?

Produces ribosomal components for protein synthesis.

Voir les flashcards →

Approfondir avec la fiche

Consultez la fiche de révision complète sur Human Cell Structure and Function.

Voir la fiche →

Cours similaires

Alterations électriques et troubles ioniques cardiaques

Fundamentos de Estafilococos y su Diagnóstico

Organisation et Fonction du Système Nerveux

Anatomie

Correction des troubles de la vision

Maturation folliculaire et ovulation

Fonctionnement et Spécificités des Enzymes

Crée tes propres QCM

Importe ton cours et l'IA génère des QCM avec corrections en 30 secondes.

Générateur de QCM