B2 - Cells

Question 1

What decided what a cell will develop into?

Answer 1

If certain genes were switched on or off

Question 2

What are organelles?

Answer 2

Parts of a cell that have a specific role

Question 3

What do human cells have in common with plant cells?

Answer 3

Cell membrane
Cytoplasm
A few other organelles

Question 4

What does the cell membrane do?

Answer 4

A protective layer around a cell that controls the movement of substances going in and out of the cell

Question 5

What is the cytoplasm?

Answer 5

A liquid medium inside the cell that holds all organelles

All chemical reactions happen in the cytoplasm

Question 6

What do the cytoplasms use to perform chemical reactions?

Answer 6

Enzymes

Question 7

What are mitochondria?

Answer 7

Organelles that release energy through respiration

They became a part of most cells through symbiosis

Question 8

What are ribosomes?

Answer 8

Organelles that perform protein synthesis by following instructions on mRNA

Question 9

Where do the proteins go after being synthesised in the ribosomes?

Answer 9

Cytoplasm

Question 10

What is the nucleus?

Answer 10

Contain the chromosomes which contain genes which specify the proteins to be made

Question 11

What do plant and algae cells have that animals don’t?

Answer 11

A cell wall

Question 12

What is the cell wall made from?

Answer 12

Cellulose

Question 13

What do plant cells need to perform photosynthesis?

Answer 13

Chloroplasts

Question 14

What do chloroplasts contain?

Answer 14

The green pigment chlorophyll

Question 15

What do plant cells have that nothing else has?

Answer 15

Vacuole

Question 16

What is a vacuole?

Answer 16

An organelle that stores cell sap

Question 17

What is yeast?

Answer 17

A single celled organism that only has cells with a cell wall, cell membrane, cytoplasm and nucleus

Question 18

What is bacteria?

Answer 18

A single celled organism that has a cytoplasm and a cell membrane surrounded by a cell wall

The genetic material floats freely in the cytoplasm because there is no nucleus

Question 19

What are plasmids?

Answer 19

Small rings of DNA that can be passed to other bacteria without reproduction taking place

Question 20

What are flagella?

Answer 20

Whip-like structures on the outside of some bacteria to help them move

Question 21

If we want to examine bacteria in close detail, what instrument do we use?

Answer 21

Microscope

Question 22

How does a light microscope work?

Answer 22

A light is shone on the plate with the bacteria on
The light travels up the lens which magnifies the image
The light then hits the eyepiece which magnifies the image further

Question 22

What is an electron microscope?

Answer 22

A microscope that uses electrons instead of light to magnify the image

Question 23

What is cell sap?

Answer 23

A weak solution of sugar and salts

Question 24

In what 3 ways are red blood cells adapted to carry oxygen?

Answer 24

Concave gives a big surface area for absorbing oxygen. This also helps them pass smoothly through capillaries to reach body cells

They are full of haemoglobin which absorbs oxygen

They have no nucleus to leave more room for haemoglobin

Question 25

What are the 4 ways that the different gametes are adapted?

Answer 25

The egg cell contains huge food reserves to nourish the embryo in the early stages

When a sperm fuses with the egg, the egg instantly changes its structure to stop more sperm getting in

Sperm have a long tail and streamlined head to help it swim to the egg. There are also a lot of mitochondria that provides the energy needed

Sperm also carry enzymes in their heads to digest through the cell membrane