Biology ยท 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

'Cisternae' (flattened sac like membranous structures) are usually found in

  1. Golgi complex

  2. Mitochondria

  3. Chloroplasts

  4. Nucleolus
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Cisternae are the flattened, disc-like, membrane-bound sacs that comprise the Golgi apparatus (also called Golgi complex or Golgi body). They are stacked together and function in processing, packaging, and modifying proteins and lipids synthesized in the endoplasmic reticulum. The Golgi apparatus is not found in mitochondria (powerhouse of cell), chloroplasts (site of photosynthesis), or nucleolus (site of ribosome synthesis).

Multiple choice

Which of the following statements is not true?

  1. Every organism begins its life as a single cell.

  2. Cell division is performed by only higher multicellular organisms.

  3. About 20 million red blood cells in our body are destroyed every minute.

  4. Repair of injury is done by the process of cell division.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Cell division is performed by all the organisms, be it unicellular or multicellular.

Multiple choice

_______ is/are called the powerhouse of cell.

  1. Mitochondria

  2. Vesicles

  3. Endoplasmic reticulum

  4. Plasma membrane
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Mitochondria is called the powerhouse of a cell.They take in glucose and oxygen and produce energy which they capture and pack as energy-rich molecules of ATP.

Multiple choice

Mammalian erythrocytes have short life span due to absence of

  1. endoplasmic recticulum

  2. mitochondria

  3. nucleus

  4. golgi complex
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Mammalian erythrocytes (red blood cells) lack a nucleus and most organelles, including mitochondria and endoplasmic reticulum. The absence of a nucleus prevents protein synthesis and cellular repair, while the lack of mitochondria means they rely on anaerobic glycolysis. These limitations contribute to their relatively short lifespan of approximately 120 days.

Multiple choice

What are phragmoplasts?

  1. The spindle microtubules formed during cell division which area involved in pulling the chromosomes to the ends of dividing cell.

  2. A set of microtubules formed during cell division to guide the dictyosome vesicles to the site of cell wall formation.

  3. Narrow holds in the cell walls of adjacent cells through which protoplasmic connections are established.

  4. The plastids in ray parenchyma cells of stems that store carbohydrates and other nutrients during dormant periods.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Phragmoplasts are temporary structures formed during telophase of cell division in plant cells. They consist of microtubules and actin filaments that guide vesicles containing cell wall materials to the forming cell plate. This matches option B, which correctly describes them as guiding dictyosome vesicles to the site of cell wall formation. Options A, C, and D describe different cellular structures.

Multiple choice

Callus is defined as

  1. decaying cells

  2. differentiated cells

  3. sterile mass of cells

  4. undifferentiated mass of cells
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

A callus is an unorganized or undifferentiated mass of proliferating plant cells formed when plant tissues are cultured on a nutrient medium containing appropriate growth regulators. It serves as a starting point for plant regeneration in tissue culture.