Prokaryotic Cells And Viruses

Question 1

What are prokaryotes?

Answer 1

Single-celled organisms

Question 2

Example of a prokaryote?

Answer 2

Bacteria

Question 3

What is the cell-surface membrane made of?

What does it do?

Answer 3

Mainly of lipids and proteins

Controls movement of substances into and out of the cell

Question 4

What is the cell wall in prokaryotes made of?

What does it do?

Answer 4

Supports the cell and stops it changing shape

Polymer called murein

Question 5

What do some prokaryotes have that protects them from attack by cells of the immune system?

Answer 5

Capsule made of secreted slime

Question 6

What are plasmids?

What do they contain?

Answer 6

Small loops of DNA that aren’t part of main circular DNA molecule

Genes

Question 7

What do prokaryotes have instead of a nucleus?

How is it presented?

Answer 7

DNA floats free in cytoplasm

Circular, 1 long coiled-up strand

Question 8

What is the flagellum?

What does it do?

Answer 8

Long hair-like structure

Rotates it make prokaryotic cell move

Question 9

How small are prokaryotic cells?

Answer 9

Extremely

Less than 2 micrometers

Question 10

How do prokaryotic cells replicate?

Answer 10

Binary fission

Question 11

What happens in binary fission?

Answer 11

Cell replicates its genetic material before physically splitting into 2 daughter cells

Question 12

What is step 1 of binary fission?

Answer 12

Circular DNA and plasmids replicate

Main DNA loop only replicates once but plasmids can be replicated many times

Question 13

What is step 2 of binary fission?

Answer 13

Cell gets bigger and DNA loops move to opposite ‘poles’ of the cell

Question 14

What is step 3 of binary fission?

Answer 14

Cytoplasm begins to divide

New cell walls begin to form

Question 15

What is step 4 of binary fission?

Answer 15

Cytoplasm divides and 2 daughter cells are produced

Each daughter cell has 1 copy of circular DNA but can have a variable number of copies of plasmids

Question 16

What are viruses?(not cells)

Answer 16

Acellular

Question 17

What are viruses?

Answer 17

Nucleic acids surrounded by protein

Question 18

2 examples of viruses?

Answer 18

HIV

Influenza

Question 19

What do all viruses do?

Answer 19

Invade and reproduce inside cells of other organisms

Question 20

What are the cells in other organisms that viruses invade called?

Answer 20

Host cells

Question 21

What is the basic structure of a virus?

Answer 21

Protein coat (capsid) with attachment proteins sticking out from it

Question 22

What do the attachment proteins do?

Answer 22

Let virus cling onto suitable host cell

Question 23

How are viral particles replicated?

Answer 23

Inject DNA or RNA into host cell so hijacked cell uses its own ‘machinery’ to replicate them

Question 24

Why can some viruses only infect one type of cell?

Answer 24

Different viruses have different attachment proteins and therefore require different receptor proteins on host cells