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

Where does the Kreb's cycle occur?

  1. In the cytoplasm

  2. In the plastids

  3. In the mitochondria

  4. In the ribosomes

  5. In endoplasmic reticulum
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The Krebs cycle, also known as citric acid cycle usually occurs in the mitochondrial matrix, which is the internal mitochondrial space. This cycle is the second phase during the oxidation of glucose in a process known as cellular respiration.

Multiple choice

The tapetal cells are

  1. uninucleate

  2. anucleate

  3. multinucletae

  4. dikaryotic

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

Tapetal cells are multinucleate as these contain multiple nuclei in them.

Multiple choice

Which a microtubule motor protein carries membrane enclosed organelles toward the plus end of microtubules?

  1. Cytoplasmic dyneins

  2. Axonemal Dyneins

  3. Kinesin

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

Kinesin are plus end directed microtubule protein that uses a microtubule track along which it tends to walk. They are vital to movement of chromosomes during mitosis and are also responsible for shuttling membrane bound organelles (mitochondria, Golgi bodies, and vesicles within eukaryotic cells. 

Multiple choice

Besides the nucleus, the DNA is also present in the

  1. golgi apparatus

  2. ribosome

  3. mitochondria

  4. vacuole

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

Mitochondria contain their own circular DNA molecule (mtDNA), separate from nuclear DNA. This mitochondrial DNA encodes proteins essential for the organelle's role in ATP production. The other organelles listed (golgi apparatus, ribosomes, vacuoles) do not contain DNA.

Multiple choice

Amitosis usually occurs in

  1. eukaryotic cells

  2. prokaryotic cells

  3. viruses

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

It is the simplest form of cell division without forming chromosomes and is usually seen in bacteria.

Multiple choice

Krebs cycle takes place in

  1. chloroplast

  2. ribosome

  3. mitochondria

  4. endoplasmic reticulum

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

Krebs cycle occurs in the mitochondria.

Multiple choice

Which of the following organelles would you select, if the given statement is considered to be an absolute fact? “More the levels of intracellular IP3 (inositol Triphosphate), more is the efflux of Ca++ from its membranes in the cytoplasm.”

  1. Lysosomes

  2. Mitochondria

  3. Peroxisomes

  4. Endoplasmic reticulum
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The Ca++ channel in the membrane of endoplasmic reticulum is also an IP3 receptor and therefore, an increase in IP3 will enhance the activity of the channel, resulting in increased efflux of ions.

Multiple choice

Typical brush border of cells is seen in

  1. proximal convoluted tubules

  2. loop of Henle

  3. distal convoluted tubules

  4. pelvis

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

Typical brush border of cells is seen in proximal convoluted tubules. The microvilli greatly increase the luminal surface area of the cells, presumably facilitating their resorptive function as well as putative flow sensing within the lumen.