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

Which of the following is not a function of nuclear membrane?

  1. It separates the nucleus from cytoplasm.

  2. It provides flexibility to the cell.

  3. It allows the movement of material between the nucleus and cytoplasm.

  4. It contains the genetic material present inside the chromosomes.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Nuclear membrane is the outer membrane of the nucleus that allows the movement of materials between the nucleus and cytoplasm. It does not provide flexibility to the cell.

Multiple choice

In humans, the structure of cells varies from one organ to another. Which of the following cells in the human body have elongated and branched structures?

  1. Muscle cells

  2. Red blood cells

  3. White blood cells

  4. Nerve cells
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Nerve cells have elongated and branched structures. These are specialised cells that are designed to stimulate other cells in the body in order to communicate. Neurons are excitable, which means they function by using electrical stimulation. Through this electrical message, known as an action potential, neurons are able to initiate action in the cells they target.

Multiple choice

Lysosomes are called as the suicidal bags of a cell because they

  1. digest foreign materials entering the cell

  2. contain powerful digestive enzymes

  3. burst and their enzymes digest their own cells

  4. digest the old organelles of their own cells
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Lysosomes are called the suicidal bags of a cell because during accidental injuries, if their own cell gets ruptured or injured, these lysosomes burst out and release their hydrolytic enzymes into the cell. These enzymes digest the worn out cell.

Multiple choice

Iron uptake is problematic owing to the insolubility of the Fe 3 + ion (usually in the form of hydroxides). Microbes overcome this difficulty by secreting special high-affinity, iron-binding molecules termed as __________.

  1. siderophores

  2. permeases

  3. methionine

  4. vitamins

  5. phosphoenolpyruvate
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

This is true. Microbes have built up specialized transport systems called siderophores. After the molecule is transported in, it gives up the iron ion which is then reduced to the ferrous form (Fe 2+). These siderophores are recycled.

Multiple choice

“Amongst the eukaryotes, fungi and plants are found to have plasmids, but not animals. ”Which of the following are true for the eukaryotic plasmids?

  1. In case of filamentous fungi, plasmids are frequently found in isolates of natural populations.

  2. One strain of fungi always contain a single type of plasmid only.

  3. Plasmids are inherited paternally in crosses.

  4. Circular plasmids are absent in Neurospora sp.

  5. Circular plasmids have two open reading frames (ORF).
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

This is true for filamentous fungi. Here the plasmids are frequently found in isolates of natural populations.

Multiple choice

Whenever bacteria are inoculated into a fresh culture medium, they show characteristic growth curve having four distinct phases. Indicate the phase wherein all the nutrients in the culture medium are used up and the inhibitory end products of metabolism get accumulated.

  1. Lag phase

  2. Log phase

  3. Stationary phase

  4. Death phase

  5. Intermediary phase
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

During the stationary phase, the nutrients in the culture medium are used up and the inhibitory end products of metabolism get accumulated.

Multiple choice

Which of the following statements is/are correct about epidermis?

a. The epidermis is usually made of a single layer of cells. b. Epidermal cells on the aerial parts of the plant often secrete a waxy, water-resistant layer on their outer surface. c. Epidermal cells are flat and have lots of intercellular spaces.

  1. a, b and c

  2. a only

  3. b only

  4. c only

  5. a and b
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

This is the correct answer as both statements are correct. The epidermis is usually made of a single layer of cells. Epidermal cells on the aerial parts of the plant often secrete a waxy, water-resistant layer on their outer surface.