Most Important Cell Structure and Function MCQs with Answers

Ribosomes are universal organelles responsible for synthesizing proteins.

Mitochondria are the primary sites of ATP production, making them abundant in high-energy-demand cells.

The Golgi apparatus modifies, sorts, and packages proteins and lipids for secretion or delivery.

Centrosomes, with centrioles, organize microtubules and are crucial in animal cell division.

The plasma membrane serves as the outer boundary of animal cells, regulating transport.

Plants store glucose as starch. Animals store it as glycogen, especially in liver and muscle cells.

The cytoskeleton provides support, maintains cell shape, and helps with movement inside the cell.

The cell wall provides rigidity and protection to plant cells and lies outside the plasma membrane.

These features — cell wall, chloroplasts, and large central vacuole — are characteristic of plant cells.

Eukaryotic cells possess a variety of membrane-bound organelles (like the nucleus, mitochondria, ER, Golgi), which are not found in prokaryotic cells.

Prokaryotic cells lack a true nucleus; their genetic material is located in an irregular region called the nucleoid.

A key distinction is the presence of a membrane-enclosed nucleus in eukaryotic cells, which is absent in prokaryotic cells.

Ribosomes are essential for protein synthesis and are found in both types of cells, though structurally different.

Peptidoglycan is the primary component of the bacterial cell wall, providing structural integrity.

Eukaryotic cells divide through mitosis or meiosis, unlike prokaryotes which divide by binary fission.

Prokaryotic cells are typically much smaller (1–10 µm) than eukaryotic cells (10–100 µm).

The plasma membrane is a universal feature that controls the exchange of substances in all cells.

Eukaryotic cells possess a complex cytoskeleton that supports structure and organelle movement.

Prokaryotes exchange genes using horizontal gene transfer: conjugation, transformation, and transduction.

Prokaryotic cells lack mitochondria and perform respiration using their cell membrane.

Prokaryotic DNA is circular and not associated with histone proteins.

Many prokaryotes move using a simple flagellum that rotates like a propeller.

Eukaryotic cells have their genetic material organized into multiple linear chromosomes, enclosed in a nucleus.

The endomembrane system is a hallmark of eukaryotic cells, allowing compartmentalization and specialized functions.

Eukaryotic membranes contain sterols(CHOLESTROL) that regulate fluidity, which are typically absent in prokaryotic membranes.

Prokaryotic DNA is not associated with histones, unlike eukaryotic DNA which is wrapped around histone proteins.

Prokaryotic DNA is typically a single circular chromosome; eukaryotic DNA consists of multiple linear chromosomes.

Photosynthetic prokaryotes use internal thylakoid membranes in the cytoplasm, not chloroplasts.

Eukaryotic genomes are generally larger and more complex, containing more genes and non-coding regions.

In prokaryotes, these processes occur together in the cytoplasm due to the absence of a nuclear envelope.

Eukaryotic cells have numerous membrane-bound compartments for specialized metabolic processes.

Plasmids, a small, circular, extrachromosomal DNA molecule, are typical in prokaryotes and provide additional traits like antibiotic resistance.

Endoplasmic Reticulum is a eukaryotic-specific organelle not found in prokaryotes.

The nucleus houses the cell's DNA and controls all cellular functions, including gene expression and cell division.

Nuclear pores regulate the transport of macromolecules between the nucleus and cytoplasm.

The nucleolus synthesizes rRNA and assembles ribosomal subunits.

The RER is involved in the synthesis and processing of proteins, particularly those for secretion or membrane insertion.

The SER plays roles in lipid metabolism, detoxification, and calcium storage.

The Golgi apparatus is responsible for processing and packaging proteins and lipids for delivery.

Cisternae are the stacked, membrane-bound structures that make up the Golgi apparatus.

Mitochondria are responsible for most of the cell’s ATP production via aerobic respiration.

Cristae increase the surface area for ATP-producing reactions in the mitochondria.

The mitochondrial matrix houses enzymes and substrates for the Krebs cycle (citric acid cycle).

Ribosomes translate mRNA into polypeptide chains (proteins).

Proteins synthesized on RER ribosomes are destined for membranes, secretion, or specific organelles.

Peroxisomes carry out beta-oxidation of long-chain fatty acids and neutralize toxic compounds.

The nucleoplasm is the substance within the nuclear envelope that contains chromatin and the nucleolus.

Secretory cells have abundant RER and Golgi apparatus for protein production and export.

Mitochondria convert glucose into ATP through the process of cellular respiration.

The nucleoplasm is the semi-fluid substance within the nuclear envelope, suspending the chromatin and nucleolus.

The outer nuclear membrane is connected to the Rough ER, showing their functional continuity.

Ribosomes on the RER synthesize proteins for secretion or membrane integration.

The cis face of the Golgi apparatus is closest to the ER and receives vesicles from it.

The trans face of the Golgi apparatus is the site for final modification and sorting.

The inner membrane’s cristae hold the electron transport chain (ETC) critical for ATP synthesis.

Mitochondrial DNA is circular and inherited from the mother.

Cells with high energy needs contain many mitochondria for ATP production.

The nuclear lamina is made of protein filaments that support the nuclear envelope.

Insulin is synthesized in the RER, processed in the Golgi, then secreted via vesicles.

In this model, Golgi cisternae mature and move from cis to trans while carrying cargo.

Mitochondria release signals that trigger apoptosis (programmed cell death) during cellular stress or damage.

Protein glycosylation primarily occurs in the RER and Golgi, not the SER.

Free ribosomes produce proteins that function in the cytosol.

Nuclear pores regulate selective exchange between nucleus and cytoplasm.

The inner mitochondrial membrane lacks cholesterol and instead maintains efficiency through a high protein-to-lipid ratio.

Vesicles from the trans-Golgi carry processed proteins and lipids to their specific cellular destinations or outside the cell.

Chromatin consists of DNA wound around histone and non-histone proteins, aiding in packaging and gene regulation.

The ER lumen is where proteins fold and undergo initial modifications before transport.

Liver cells have extensive SER to detoxify drugs and metabolize lipids.

Cristae increase surface area for the proteins involved in the electron transport chain and ATP synthesis.

The nucleolus synthesizes rRNA and assembles ribosomal subunits.

Free ribosomes produce proteins that stay in the cytosol, such as metabolic enzymes.

Electron transport drives the proton gradient, powering ATP synthesis during oxidative phosphorylation.

The cis face receives proteins from the ER and begins their modification.

Nuclear pores allow selective transport of RNA, proteins, and small molecules.

Proteins for lysosomal degradation follow the RER → Golgi → lysosome pathway.

The Krebs cycle occurs in the matrix, while oxidative phosphorylation occurs at the inner membrane.

Transport vesicles move cargo from the ER to the Golgi for further processing.

The nucleus controls gene expression and cellular regulation, making it the control center.