Prokaryotic cells and viruses

Question 1

1. Compare the sizes of eukaryotic and prokaryotic cells.

Answer 1

Prokaryotic cells are much smaller than eukaryotic cells.

Question 2

2. Compare and contrast the structure of a
   human cell and a bacterial cell.

Answer 2

Bacterial cell is much smaller than a human cell; Bacterial cell has a cell wall but human cell does not; Bacterial cell lacks a nucleus but human cell has a nucleus; Bacterial cell lacks membrane-bound organelles but human cell has membrane-bound organelles; Bacterial have 70S ribosomes whereas humans have 80S ribosomes; Bacterial DNA is circular but human DNA is linear; Bacterial DNA is not associated with histones whereas human DNA is bound to proteins called histones. Bacterial cells and human cells have similar cell membranes.

Question 3

3. Describe the structure of a prokaryotic cell.

Answer 3

A prokaryote has a murein/peptidoglycan (glycoprotein) cell wall, the cytoplasm contains no membrane bound organelles. DNA is not inside a nucleus, it is a single circular DNA molecule that is free in the cytoplasm and has no associated proteins. Many prokaryotes will also have one or more plasmid. A capsule of slime surrounding the cell. One or more flagella. Ribosomes that are 70s

Question 4

5. Give the functions of organelles in a
   prokaryote.

Answer 4

Cell membrane controls what enters and exits the cell. Glycoprotein cell wall provides strength and rigidity. Flagellum make them motile. Capsules help them hide from immune systems and protects against drying out. Circular DNA is the cells genetic material. Plasmids contain genes and may be swapped between bacteria. 70s ribosomes are for protein synthesis.

Question 5

7. Describe a virus.

Answer 5

Viruses are acellular (not a cell) and non-living. The structure of virus particles include genetic material (DNA or RNA), a capsid and attachment proteins.