Cell Biology and Cell Division MCQs for MDCAT

Correct answer: D. Clones

Clones are genetically identical individuals or cells produced through asexual reproduction, sharing the exact same DNA as their single parent.

Correct answer: B. 27

A centriole is composed of nine triplets of microtubules, giving a total of 27 microtubules arranged in a cylindrical structure.

Correct answer: C. Anaphase

Anaphase is the most critical phase of mitosis, as sister chromatids separate and are pulled to opposite poles, ensuring equal distribution.

Correct answer: A. Smooth Endoplasmic Reticulum

The smooth endoplasmic reticulum in liver cells is rich in detoxifying enzymes that metabolize drugs and other poisons.

Correct answer: D. Parkinson's Disease

Parkinson's disease results from the death of a small population of dopaminergic cells in the basal ganglia, impairing the initiation and control of movement.

Correct answer: C. Cell Mediated Immunity / Response

Cell-mediated immunity is the branch of the immune response in which T-cells directly recognize and attack antigens or infected cells.

Correct answer: B. -35 sequence

This sequence is located about 35 base pairs upstream of the transcription start site and contains the TTGACA sequence, which is recognized by the sigma subunit of RNA polymerase during transcription initiation. It plays a crucial role in positioning RNA polymerase and initiating transcription.

Correct answer: D. Bacteria & Archaea

Bacteria and Archaea are the groups where cell walls may be absent. While many bacteria have cell walls, there are some bacteria such as Mycoplasma species, that lack a rigid cell wall. Archaea also have diverse cell envelope structures, and not all of them have a cell wall.

Correct answer: C. Glycolipids and glycoproteins

Glycolipids and glycoproteins presence are the basic factors for differentiating cells

Correct answer: C. Spirochete

In the context of the endosymbiotic theory, spirochetes are interesting because some scientists hypothesize that certain spirochetes may have played a role in the evolution of eukaryotic cells. This theory suggests that early eukaryotic ancestors may have engulfed spirochete-like bacteria, leading to the development of complex cellular structures. This relationship could have contributed to the evolution of unique cellular processes seen in modern eukaryotes, illustrating the potential impact of these prokaryotic organisms on the evolution of life.

Correct answer: C. Mitochondria

Option C is correct.Mitochondria are regarded as self-replicating organelles. They have their own DNA and can replicate independently of the nucleus. This means that they can divide and reproduce independently, without the assistance of other organelles.Mitochondria are essential for energy production in the cell. They convert food into energy in the form of ATP, which is the cell's energy currency. Mitochondria are also involved in other cellular processes, such as cell signaling and apoptosis (programmed cell death).The endoplasmic reticulum (ER) is not regarded as a self-replicating organelle because it does not have its own DNA. DNA is required for self-replication, as it contains the instructions for building new organelles. The ER is a network of membranes that is involved in the production and transport of proteins and lipids. It is made up of two types of membranes: the rough ER and the smooth ER. The rough ER is covered in ribosomes, which are the organelles that synthesize proteins. The smooth ER is involved in the production of lipids and the detoxification of drugs and toxins. Golgi bodies are also not self-replicating organelles. Golgi bodies are involved in the processing and packaging of proteins and lipids for transport to other parts of the cell. Vacuoles are not self-replicating organelles. Vacuoles are storage organelles that can contain water, salts, and other molecules.

Correct answer: D. Non-capsulated and R-Type

Streptococcus pneumoniae strains are classified into two main types based on their capsule:- S-type (Smooth-type): Capsulated, virulent strains with a smooth colony morphology.- R-type (Rough-type): Non-capsulated, non-virulent strains with a rough colony morphology.The capsule is a layer of polysaccharides surrounding the bacterial cell wall, which helps protect the bacteria from phagocytosis and is a key virulence factor. Non-virulent strains lack this capsule, making them more susceptible to host immune responses.