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

Nuclear pyknosis refers to

  1. decrease in the amount of nucleoplasm on ageing

  2. shrinking of nucleus and its staining deeply

  3. degeneration of nuclear membrane

  4. decrease in genetic material inside the nucleus
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The degenerative process in which nucleus becomes shrunken and stains deeply is referred to as nuclear pyknosis.

Multiple choice

Which of the following types of oscillating gene present in plants regulates the expression of CAB?

  1. Toc1 gene

  2. The LHY gene

  3. The CCA1 gene

  4. Kai genes

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

Toc1 gene, also known as Timing of CAB Expression 1 gene, is an oscillating gene found in the plants that is known to control the expression of CAB. It has been shown to affect the period of circadian rhythms through its repression of transcription factors. This was found through mutations of toc1 in plants that had shortened period of CAB expression.

Multiple choice

Which of the following maintains the size and structure of sponge?

  1. Choanocytes

  2. Pinacocytes

  3. Porocytes

  4. Myocytes

  5. Mesohyl
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Pinacocytes are flattened cells containing many granules; capable of contracting. They are involved in the maintenance of the size and structure of sponge. They can expand and contract to slightly alter the size of the sponge and can also produce collagen.

Multiple choice

There are numerous types of cells, which can live and move within the mesohyl of a sponge. Which of the following are the well known totipotent cells capable of removing the wreckage blocking the ostia of the sponges?

  1. Sclerocytes

  2. Spongocytes

  3. Archaeocytes

  4. Grey cells

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

Archaeocytes are amoeba-like cells that are totipotent, in other words each is capable of transformation into any other type of cell. They also have important roles in feeding and in clearing debris that block the ostia.