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

A small densely stained barr body appears in a female cell nuclei. What will be the nature of this body?

  1. Constitutive euchromatin

  2. Facultative euchromatin

  3. Constitutive heterochromatin

  4. Facultative heterochromatin
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The regions of DNA packed in facultative heterochromatin will not be consistent between the cell types within a species, and thus is a sequence in one cell that is packed in facultative heterochromatin.

Multiple choice

Which of the following is not a correct statement with reference to peroxisomes?

  1. They are also known as uricosomes.

  2. They help in the storage and transport of lipids in plants.

  3. They carry out photorespiration.

  4. They were first discovered in the liver cells and kidney cells.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

They do not help in the storage and transport of lipids in plants. This function is performed by spherosomes. So, this is not the correct statement. 

Multiple choice

Which of the following is the most suitable statement to justify 'the mesosomes of bacteria are equivalent to the mitochondria of eukaryotes'?

  1. These are double membraned organelles.

  2. These occur freely in the bacterial cytoplasm.

  3. These help in respiration in bacteria.

  4. These are self replicating organelles & can multiply, even when the cell is not dividing.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

 Mesosome is the invagination of the plasma membrane. It has respiratory enzymes, so it helps in bacterial respiration.

Multiple choice

Name the cell organelle which is surrounded by a single unit membrane and contains two major enzymes namely isocitrate lyase and maltase synthetase.

  1. Glyoxysomes

  2. Lomasomes

  3. Spherosomes

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

Glyoxysome is the cell organelle which is surrounded by a single unit membrane and contains two major enzymes namely isocitrate lyase and maltase synthetase. Glyoxysomes were first discovered by Beevers (1961) and later on described in detail by R.W. Briedenbach (1967).

Multiple choice

What concentration of magnesium ions is required for joining of ribosomes to form dimers?

  1. Mg++ ion concentration is 0.001 M

  2. Mg++ ion concentration is 0.01 M

  3. Mg++ ion concentration is less than 0.0001 M

  4. Mg++ ion concentration is more than 0.02 M
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

 At this concentration, the ribosomes combine in pairs, to form dimers, each of which has a sedimentation coefficient of 120 S.(�S� is the sedimentation coefficient & is also known as �Svedberg Unit� ).

Multiple choice

Energy generator is related to

  1. mitochondria

  2. lysosomes

  3. animal cell

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

Mitochondria are known as the powerhouse of the cell because they generate most of the cell's supply of adenosine triphosphate (ATP), which is used as a source of chemical energy.