All Free Biology MCQs with Answers
Every Biology question in the bank, across all chapters, each with the correct answer and a written explanation. Free and unlimited, with no account needed.
19844 questions · page 675 of 1985
6741. It is a disease characterized by the accumulation of lipids in the brain cells leading to mental retardation and even death:
- A. Grave's disease
- B. Glycogenesis type II disease
- C. Addison's disease
- D. Tay-Sach's disease
Explanation: Storage diseases are due to the absence of lysosomal enzymes. If a lysosomal enzyme responsible for lipid metabolism is absent, it leads to the accumulation of lipids in brain cells that causes mental retardation and death. Such storage disease is known as Tay-Sach's disease.
Correct answer: Tay-Sach's disease6742. Tay-Sach's disease occurs when cells build upto certain amaount of lipids in cell. Which organelle is responsible for the disease?
- A. Golgi apparatus
- B. Lysosomes
- C. Mitochondria
- D. SER
Explanation: Tay-Sach's disease is a genetic disorder that results in the destruction of nerve cells in the brain and spinal cord. It is due to the deficiency of lipids-digesting enzymes in the body. These enzymes are present in lysosomes. Hence, lysosomes are responsible for such types of storage diseases.
Correct answer: Lysosomes6743. Suicidal bags are:
- A. Peroxisomes
- B. Lysosomes
- C. Mitochondria
- D. Chloroplast
Explanation: Lysosomes are involved in a process called autolysis which is a type of programmed cell death. In this process, lysosomes burst and their enzyme contents are quickly dispersed throughout the cytoplasm. In this way, the cell is disintegrated into fragments that are phagocytosed by other cells. Due to this function, lysosomes are also called suicidal bags.
Correct answer: Lysosomes6744. Which of the following statement is incorrect?
- A. CO2 fixation occurs in stroma.
- B. Chloroplasts are self-replicating.
- C. Inter-granum is photosynthetic.
- D. Chloroplasts have 70S ribosomes.
Explanation: Inter-granum is non-green part that connects two grana. The process of photosynthesis does not occur on inter-granum because of absence of chlorophyll.
Correct answer: Inter-granum is photosynthetic.6745. Among followings which cellular organelle contains clrcular DNA similar to those found in bacteria?
- A. Ribosomes
- B. Chloroplast
- C. Lysosome
- D. Nucleus
Explanation: According to the endosymbiotic hypothesis, chloroplasts are believed to be symbiotically originated from bacteria. They have their own circular DNA and 70S ribosomes, just like bacteria.
Correct answer: Chloroplast6746. Each chloroplast contains_grana.
- A. 10-30
- B. 40-60
- C. 100-130
- D. 150-180
Explanation: It is a fact. There are about 40-60 grana found in each chloroplast.
Correct answer: 40-606747. What is the specific name given to biological membrane that surrounds the vacuoles?
- A. Plasma membrane
- B. Plasmalemma
- C. Endomembrane
- D. Tonoplast
Explanation: The tonoplast is the membrane enclosing the vacuole, also known as the vacuolar membrane. It maintains the turgor pressure of the cell. It controls the movement of molecules between the cytosol and sap.
Correct answer: Tonoplast6748. Which of these is present in plant cell only?
- A. Peroxisomes
- B. Smooth endoplasmic reticulum
- C. Cytoskeleton
- D. Central vacuole
Explanation: Only plant cells have large central vacuole that provide support and turgidity to the plant cells. In other eukaryotes, it is not present in the center.
Correct answer: Central vacuole6749. The membrane separating the vacuole from cytoplasm is called:
- A. Cristae
- B. Tonoplast
- C. Cisternae
- D. Vacuolar membrane
Explanation: Tonoplast is the membrane that separates vacuole from the cytoplasm.
Correct answer: Tonoplast6750. It is the correct location of ATP synthase in mitochondria:
- A. Mitochondrial matrix
- B. Outer mitochondrial membrane
- C. Inner mitochondrial membrane
- D. Inter-membrane space
Explanation: Fact: ATP synthase are present in the inner mitochondrial membrane at cristae.
Correct answer: Inner mitochondrial membrane