All Free Biology MCQs with Answers

• A. Plasma cells have RER in abundance
• B. RBCs lack both RER and SER
• C. SER is more than RER in adipose tissue
• D. Hepatocytes have both RER and SER
• E. None

Explanation: The correct answer is Option E: 'None', which signifies that all the other statements regarding endoplasmic reticulum are correct. Each of the other options accurately describes characteristics of the rough and smooth endoplasmic reticulum in different cell types.Option A is correct because plasma cells indeed have a high abundance of rough endoplasmic reticulum due to their role in antibody production.Option B is also correct, as red blood cells lack both types of endoplasmic reticulum after maturation.Option C is correct because adipose tissue contains more smooth endoplasmic reticulum than rough endoplasmic reticulum, reflecting its function in lipid metabolism.Finally, Option D is correct because hepatocytes contain both types of endoplasmic reticulum to support their diverse metabolic functions. Thus, the only incorrect statement is 'None'.

• A. Calcium storage
• B. Steroid synthesis
• C. Enzyme synthesis
• D. Mechanical support

Explanation: Smooth endoplasmic reticulum (SER) is not involved in enzyme synthesis. Enzymes are proteins, and proteins are synthesized in the rough endoplasmic reticulum (RER). The RER is studded with ribosomes, which are the protein factories of the cell. The SER, on the other hand, is not studded with ribosomes, so it does not synthesize proteins. The SER is involved in a different set of functions, including:Lipid synthesis: The SER is the site of lipid synthesis in eukaryotic cells. Lipids are a diverse group of molecules that play important roles in cell structure, energy storage, and signaling.Detoxification: The SER is involved in the detoxification of harmful substances, such as drugs and toxins.Storage: The SER can store calcium ions, which are important for muscle contraction and other cellular processes.Mechanical support is, however, related to both SER and RER.

• A. Mitochondria
• B. Endoplasmic Reticulum
• C. Nucleus
• D. Chloroplast

Explanation: The organelle associated with a single membrane is the endoplasmic reticulum (ER). The endoplasmic reticulum is a complex network of membranes involved in various cellular processes, including protein synthesis, lipid metabolism, and calcium storage.

• A. Ribosomes
• B. Chloroplast
• C. Nucleus
• D. Mitochondria

Explanation: The correct answer is Ribosomes because they do not contain DNA. Ribosomes are the sites of protein synthesis, made up of ribosomal RNA (rRNA) and proteins, and do not have their own genetic material. In contrast, Chloroplasts and Mitochondria contain their own DNA, resembling that of prokaryotes, and are capable of self-replication. The Nucleus also contains DNA, specifically the genomic DNA that encodes the majority of the cell's genetic information.

• A. Endoplasmic reticulum
• B. Ribosome
• C. Nucleus
• D. Chloroplast

Explanation: Explanation:Endoplasmic reticulum is a single membranous organelle while nucleus and chloroplast are bounded by the double membrane. Ribosomes, however, are membrane-less organelles found in both prokaryotic and eukaryotic cells.

• A. Mitochondria
• B. Rough endoplasmic reticulum
• C. Smooth endoplasmic reticulum
• D. Golgi apparatus

Explanation: The Golgi apparatus is essential for the post-translational modification of proteins and lipids, specifically converting them into glycoproteins and glycolipids, which are vital for cell recognition and signaling. The rough endoplasmic reticulum is primarily responsible for synthesizing proteins, while the smooth endoplasmic reticulum specializes in lipid synthesis. Mitochondria, on the other hand, are involved in energy production through cellular respiration and do not participate in protein or lipid modifications.

• A. Glyoxysomes
• B. Lysosomes
• C. Microbodies
• D. Ribosomes

Explanation: Lysosomes contain digestive enzymes that digest the phagocytosed food. Hence, they are most abundant in those cells which are specialized for phagocylic activities, for example neutrophils.

• A. Vacuole
• B. Golgi apparatus
• C. Endoplasmic reticulum
• D. Cytoskeleton

Explanation: Vacuoles provide support for the individual plant cell and contribute to the turgidity of the leaves and younger parts of the plants

• A. 2,2
• B. 2,4
• C. 4,4
• D. 4,2

Explanation: Number of centrioles after completion of the G2 phase and during the metaphase of mitosis is 4 and 4 respectively. During S phase of the cell cycle, the centrosomes replicate. Each centrosome contains 2 centrioles. Since now there are 2 centrosomes, the total number of centrioles will be 4. G2 phase comes right after the S phase and during metaphase cytokinesis has not occured as a result, the cell contains 4 centrioles in both of these stages.

• A. Endoplasmic reticulum
• B. Mitochondria
• C. Ribosomes
• D. Golgi apparatus

Explanation: Due to large size of mitochondria as compared to endoplasmic reticulum, Golgi apparatus and ribosomes, it can be visualized easily with the help of light microscope. Under the light microscope, it appears to be rods or vesicles.