2A - Prokaryotic cells and viruses

Question 1

What are the organelles of a bacterial cell?

Answer 1

Pili
Plasmid
Genetic material in nucleoid region
Capsule
Cell wall
Plasma cell membrane
Flagellum
Ribosomes

Question 2

What is the function of the large DNA strand in bacterial cells?

Answer 2

Contains the genetic info in the cell.

Primary DNA structure.

Question 3

What is the function of the plasmids in bacterial cells?

Answer 3

Secondary genetic info (smaller).

Question 4

What is the function of the capsule in bacterial cells?

Answer 4

Provides protection.

Prevents desiccation and chemical attack.

Question 5

What is the function of the cell wall in bacterial cells?

Answer 5

Made of murein.

Provides structure to the cell.

Question 6

What is the function of the flagella in bacterial cells?

Answer 6

Used in motility of the cell movement.

Question 7

What is the function of the plasma membrane in bacterial cells?

Answer 7

Controls what enters and exits the cell.

Exchange of substances with the environment.

Question 8

What is the function of the ribosomes in bacterial cells?

Answer 8

Site of protein synthesis.

Smaller than eukaryotes (70s).

Question 9

What is the function of the cytoplasm in bacterial cells?

Answer 9

Site of chemical reactions.

Contains enzymes.

Question 10

What is the function of the pili in bacterial cells?

Answer 10

Attachment to surfaces.

Question 11

What is the function of the attachment proteins in virus cells?

Answer 11

Used to attach to host cells.

Question 12

What is the function of the lipid envelope in virus cells?

Answer 12

Derived from host cell membrane.

Question 13

What is the function of the DNA/RNA in virus cells?

Answer 13

Encodes virus proteins.

Question 14

What is the function of the capsids in virus cells?

Answer 14

Protein coat that encapsulates the DNA/RNA.

Question 15

What is the function of the nucleoproteins in virus cells?

Answer 15

Accessory proteins e.g. enzymes.

Question 16

What is the function of the matrix in virus cells?

Answer 16

Protein layer on the inside of the envelope.

Question 17

How do virus’ replicate?

Answer 17

Use their attachment proteins to bind to complementary receptor proteins on the surface of host cells.

• Attach to host cell and injects its DNA material.
• Genetic material used as code to synthesise proteins.
• New virus particles are assembled.
• Virus’ burst out of, and destroy host cell.

Question 18

How big are prokaryotic cells?

Answer 18

less than 10 um

Question 19

What does prokaryote mean and why?

Answer 19

‘before the nucleus’ because they lack a membrane bound nucleus (or any other membrane bound organelles).

Question 20

What are bigger: bacteria or virus’?

Answer 20

Bacteria are bigger.

Question 21

How do prokaryotic cells replicate?

Answer 21

Binary fission.

Question 22

Describe binary fission:

Answer 22

1. The circular DNA and plasmid(s) replicate. The main DNA loop is only replicated once, but plasmids can be replicated loads of times.
2. The cell gets bigger and the DNA loops move to opposite ‘poles’ (ends) of the cell.
3. The cytoplasm begins to divide (and the new cell walls begin to form).
4. The cytoplasm divides and two daughter cells are produced. Each daughter cell has one copy of the circular DNA, but can have a variable number of copies of the plasmid(s).