Biology · Science General

Cell Biology and Structure

3,221 Questions

Cell biology focuses on the structure and function of cellular organelles. Key topics include cellular respiration, DNA inheritance, and energy production. These fundamental biology concepts are crucial for medical entrance and state service examinations.

Cell organelles functionsCellular respiration sitesDNA and ribosomesAnimal cell structurePlant cell components

Cell Biology and Structure Questions

Multiple choice

The cells which form the permanent tissues, exhibit some special characteristic features. Which among the following features regarding those cells is incorrect?

  1. Absence of ergastic substances.

  2. The cell wall may be either thin or thick.

  3. Every cell has either one or two large and prominent vacuoles.

  4. Granular cytoplasm.

  5. The cells vary in size and shape considerably.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Ergastic substances are almost always present in the form of secretory products, storage products or excretory products.

Multiple choice

Morphallaxis refers to

  1. regeneration of lost parts like limb

  2. regeneration occurs mainly by the remodelling of existing tissues

  3. replacement of epidermal cells of the skin

  4. healing of wound

  5. All of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Regeneration occurs mainly by the remodelling of existing tissues in morphallaxis. It takes place in physiological regeneration.

Multiple choice

Phagocytosis means _____.

  1. cell dying

  2. cell growing

  3. cell feeding

  4. cell generating
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Phagocytosis literally means 'cell eating' or 'cell feeding' - the process by which a cell engulfs solid particles by extending its membrane around them. Amoeba uses this process to capture food particles. 'Phago' comes from Greek meaning 'to eat'.

Multiple choice

The process of obtaining food by amoeba is called _____.

  1. phagocytosis

  2. photolysis

  3. photosynthesis

  4. none of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Amoeba obtains food through phagocytosis, where it extends pseudopodia (false feet) around food particles, engulfing them into food vacuoles. This is different from photosynthesis (making food from light) or photolysis (breaking molecules using light).

Multiple choice

Amoeba ingests food by using its _____.

  1. legs

  2. hands

  3. pseudopodia

  4. none of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Pseudopodia are temporary cytoplasmic extensions of the cell membrane that amoebas use for movement and feeding. When an amoeba encounters food, it extends pseudopodia around the particle and encloses it through phagocytosis. The term literally means 'false feet' in Greek. Options A and B are incorrect because unicellular organisms don't have legs or hands.

Multiple choice

What are centrosomes related to?

  1. Mitochondria

  2. Lysosomes

  3. Animal cell

  4. None of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Centrosomes are organelles found only in animal cells. They contain centrioles and play a crucial role in cell division by organizing microtubules. Plant cells do not have centrosomes - they use different structures for cell division. Mitochondria and lysosomes are organelles found in both plant and animal cells.

Multiple choice

Body cells display uncontrolled growth in

  1. Bullous pemphigoid

  2. Cancer

  3. Castleman's disease

  4. Coeliac disease

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Cancer is a class of diseases in which a group of cells display uncontrolled growth, invasion that intrudes upon and destroys adjacent tissues, and sometimes metastasis, or spreading to other locations in the body via lymph or blood. These three malignant properties of cancers differentiate them from benign tumors, which do not invade or metastasize.

Multiple choice

Extra nuclear DNA is present in

  1. ribosome

  2. chloroplast

  3. golgi body

  4. ER
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Chloroplast is a semi-autonomous cell organelle, which contains its own DNA and protein-synthesising machinery.

Multiple choice

Which of the following statements is true about log-phase growth of bacteria?

  1. During log-phase, nutrients are metabolised at minimum speed.

  2. Log-phase is the first phase of growth and is a period of slow growth.

  3. Log-phase is the third phase of growth and caused by depleted nutrients.

  4. During log-phase, calculations of growth rate and generation time of bacteria are done.

  5. Log-phase is the final phase of growth where the bacteria run out of nutrients and die.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

This is the correct answer. Bacterial growth follows four phases. The log-phase is the second phase and marked by rapid exponential growth. The rate at which cells grow during log-phase is known as the growth rate (k) and the time it takes the cells to double is known as the generation time (g).