Cell Structure and Division- Prokaryotic Cells and Viruses

Question 1

How are prokaryotic cells different from eukaryotic cells?

Answer 1

They are smaller and simpler

Question 2

What is the cytoplasm of a prokaryotic cell?

Answer 2

Has no membrane-bound organelles and has ribosomes that are smaller than eukaryotic ribosomes

Question 3

What is the plasma membrane in a prokaryotic cell?

Answer 3

Mainly made of lipids and proteins and controls the movement of substances into and out of the cell

Question 4

What is the cell wall in a prokaryotic cell?

Answer 4

Supports the cell and prevents it from changing shape

Question 5

What is the cell wall made from in a prokaryotic cell?

Answer 5

A polymer called murein which is a glycoprotein

Question 6

What is a capsule?

Answer 6

An organelle that some prokaryotic cells have that is made up of secreted slime and helps to protect bacteria from attack by cells of the immune system

Question 7

What are plasmids?

Answer 7

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

Question 8

Why are plasmids important?

Answer 8

They contain genes for things like antibiotic resistance and can be passed between prokaryotes

Question 9

How many plasmids do prokaryotes contain?

Answer 9

They are not always present or some have several

Question 10

Does a prokaryotic cell have a nucleus?

Answer 10

No

Question 11

What do prokaryotic cells have instead of a nucleus?

Answer 11

The DNA floats free in the cytoplasm, it is circular DNA which is one long coiled-up strand that is not attached to any histone proteins

Question 12

What is the flagellum?

Answer 12

A long hair-like structure that rotates to make the prokaryotic cell move

Question 13

Do all prokaryotic cells have a flagellum?

Answer 13

No, and some have more than one

Question 14

What are viruses?

Answer 14

Acellular, they are nucleic acids surrounded by proteins that aren’t alive

Question 15

What is the size of a virus?

Answer 15

Smaller than bacteria

Question 16

How do viruses reproduce?

Answer 16

They invade and reproduce inside of the cells of other organisms known as a host cell

Question 17

How are viruses different to bacteria?

Answer 17

They have no plasma membrane, no cytoplasm and no ribosomes

Question 18

What is the structure of virus?

Answer 18

A core of genetic material (DNA or RNA), a protein coat around the core called the capsid, attachment proteins that stick out from the edge of the capsid that let the virus cling on to a suitable host cell

Question 19

How do prokaryotic cells replicate?

Answer 19

Binary fission

Question 20

What is binary fission?

Answer 20

The cell replicates its genetic material before physically splitting into two daughter cells

Question 21

What is the first step of binary fission?

Answer 21

The circular DNA and plasmid(s) replicate- the main DNA loop is only replicated once but plasmids can be replicated many times

Question 22

What is the second step of binary fission?

Answer 22

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

Question 23

What is the third step of binary fission?

Answer 23

Cytoplasm begins to divide and new cell walls begin to form

Question 24

What is the fourth and final step of binary fission?

Answer 24

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 plasmids

Question 25

How do viruses use their attachment proteins?

Answer 25

To bind to complementary receptor proteins on the surface of the host cell

Question 26

Why can some viruses only infect one type of cell?

Answer 26

Different viruses have different attachment proteins so require different receptor proteins on host cells

Question 27

Do viruses undergo cell division?

Answer 27

No because they’re not alive so instead they inject their DNA or RNA into the host cell which then uses its own ‘machinery’ to replicate the viral particles