Question

As a degree nurse on the ward you explained to a diploma student nurse, that in human,
all vital processes occur in a single cell. If she cares to know more, how would you answer
the questions below to her understanding?
a. What is a cell (1 mark)
b. With a well labeled diagram describe the human cell
c. Explain four functions of the human cell membrane
(Total Marks:

Answer 1

Answer a. A cell is a structural and basic unit of life. For example, a neuron. This is the cell of nervous system in our body, that helps in sensing the stimulus and responding to it in coordination with other cells of the same type.

Answer b.

A typical animal somewhat looks like this. It has organelles numbered as :

1. Lysosomes- these are known as the suicidal bags of the cells. It contains various hydrolytic enzymes for phagocytosis of the antigens.

2. Golgi body- they help in the post translational modification.

3. Centriole- they help in forming the spindle fiber during the cell division process.

4. Cytoplasm- it is the jelly like substance present between the plasma membrane and the nucleus and contains various cell organelles.

5. Nucleolus- it forms the ribosomal RNA.

6. Nucleoplasm- it forms the base substance of the nucleus and contains enzymes for the some phenomenon s of the gene expression pathways.

7. Nucleus- it is the control center of a cell, it contains the genetic material and helps in replication of DNA, and transcription of RNA.

8. Vacuole- this helps in providing osmoregulation to a cell.

9. Plasma membrane- it helps in protection and giving shape to a cell.

11. Mitochondria- they are the powerhouse of the cell as they help in forming the ATP.

10. Smooth endoplasmic reticulum- These are the stacked structures that do not have ribosomes on its surface.

12. Ribosomes- these are the protein factories. In eukaryotic cell they are of 80S type.

13. Rough endoplasmic reticulum- it is a stacked structure close to the nucleus has ribosomes on its surface.

Answer c.

• The plasma membrane forms the outermost layer of the animal cell and helps it in providing a definite shape. It is an intact layer made up of proteins and lipids. Lipids are arranged as bilayer.
• The surface antigens present on the plasma membrane of the red blood cells, makes them of specific blood group, like the individual with blood group A has RBCs with A antigen on them, with B blood group has B antigen on the surface, with AB blood group has both A and B antigens on the surface. O blood group lacks both the antigens.
• It helps in the diffusion of gases along the concentration gradient means from high concentration to the low concentration.
• It has transmembrane proteins that acts as channels and helps in the passage of ions from across the membrane.