CELLS

Question 1

What does the cell nucleus do and what size is it?

Answer 1

controls all the activities of the cell and is surrounded by the nuclear membrane. Contains genes on chromosomes that carry codes to make proteins needed to build new cells. 10micrometers diameter.

Question 2

What is the purpose of the cytoplasm?

Answer 2

a liquid gel in which the organelles (the bits inside cells) are suspended and where most chemical reactions needed for life take place

Question 3

What does the cell membrane do?

Answer 3

The skin around the cell - controls the passage of substances such as glucose and mineral ions into the cell.

Question 4

What role do the mitochondria play in the cell and why is this important?

Answer 4

structures in the cytoplasm where aerobic respiration takes place, releasing energy for the cell. 1-2 micrometers in length

Question 5

What role do the ribosomes play in a cell?

Answer 5

where protein synthesis takes place, making all the proteins needed in the cell.

Question 6

Plant cells - what are chloroplasts?

Answer 6

Found in the green parts of the cell - absorb the light so the plant can make food by photosynthesis. Roots don’t have chloroplasts because they’re underground.

Question 7

Plant cells - what is the permanent vacuole and what does it do?

Answer 7

a space in the cytoplasm filled with cell sap, it is important for keeping the cells rigid to support the plant

Question 8

Plant cells - what is special about chlorophyll?

Answer 8

gives the chloroplasts their green colour

Question 9

What is the cell wall made of and what is it for?

Answer 9

strengthens the cell and gives it support. made of cellulose.

Question 10

What is the difference in size between animal and plant cells?

Answer 10

animal cells - 10 - 30 micrometers

plant cells - 10- 100 micrometers

Question 11

Does an animal cell have a cell wall?

Answer 11

No - only a cell membrane.

Question 12

Why is the nucleus so important in plant and animal cells?

Answer 12

It contains the genetic code the cells need to be able to reproduce - all the genes on the chromosomes

Question 13

Which cells do not have chloroplasts and why?

Answer 13

Root cells and onion cells - root cells are underground so cannot photosynthesise and onion cells do not photosynthesise.

Question 14

What are the common features of eukaryotic cells?

Answer 14

They all have a cell membrane, cytoplasm and genetic material (DNA) inside a nucleus.

Question 15

How many cells do bacteria contain?

Answer 15

One - they are single celled organisms.

Question 16

Where would you culture bacteria?

Answer 16

On an agar plate.

Question 17

Why would you culture a bacterial colony?

Answer 17

Because bacteria are so small they can’t be seen under a microscope - if you culture a colony of millions of bacteria you will be able to see them with the naked eye and study them.

Question 18

What’s the difference between eukaryotic and prokaryotic cells?

Answer 18

Eukaryotic - cell membrane, cytoplasm and a nucleus containing DNA
Prokaryotic - cytoplasm, cell membrane surrounded by cell wall, DNA is a single loop floating around in the cytoplasm, may also contain plasmids

Question 19

What are plasmids and what do they do?

Answer 19

Tiny rings of DNA which code for very specific features e.g. antibiotic resistance

Question 20

What is a flagellum (plural flagella) and what is it for?

Answer 20

It is a long protein strand that lashes around and allows the bacteria to move around.

Question 21

How can plasmids be used in genetic engineering?

Answer 21

To carry new genes into the genetic material of other organisms.

Question 22

What would you use an order of magnitude for?

Answer 22

It allows you to make comparisons between the relative sizes of objects or numbers - useful when comparing cell sizes as there is such variety in cell sizes.

Question 23

How do you show orders of magnitude?

Answer 23

In powers of 10 - if a cell is 10 x bigger than another it is an order of magnitude bigger, if it is 100 x bigger then its two orders of magnitude bigger.