Y7 Biology Revision

Question 1

How do you prepare a slide?

Answer 1

Cut a specimen into thin layer use tweezers to place it onto slide.Add the stain.Add a cover slip-avoiding air bubbles

Question 2

How do you use a microscope?

Answer 2

1. Clip side onto Stage.
2. Use lowest powered objective lens.
3. Look through eyepiece
4. Use coarse focus dial to get a focused image.
5. Use fine focus dial to get an even sharper image.
6. Change onto higher powered objective lens and refocus.

Question 3

What is the equation for magnification?

Answer 3

Magnification = image size/actual size

Question 4

What is the equation for image size?

Answer 4

Image size = actual size x magnification

Question 5

Name the parts in an animal cell

Answer 5

Cell membrane
Nucleus
Mitochondria
cytoplasm

Question 6

Name the parts in a plant cell?

Answer 6

Nucleus
cell wall
cytoplasm
cell membrane
chloroplasts
vacuole
mitochondria

Question 7

What is the function of the sperm cell?

Answer 7

To carry the father’s genetic information (DNA) to fertilise the egg.

Question 8

What are the adaptions in a sperm cell|?

Answer 8

A long flagellum (tail) which whips from side to side to allow the sperm to move.
The small cytoplasm makes the head streamlined to reduced drag when moving.
The acrosome contains digestive enzymes to break down the outer layers of the egg.
The large nucleus contain genetic information.

Question 9

What is the function of a red blood cell?

Answer 9

To carry oxygen around the body.

Question 10

What are the adaptions in a red blood cell?

Answer 10

Biconcave shape gives a larger surface area to volume ratio to increase diffusion of oxygen in and out of the cell.
Haemoglobin (the red pigment) binds to oxygen to form oxy-haemoglobin so oxygen can be transported. In tissues, this reaction is reversed so oxygen is released.
No nucleus to make more space for haemoglobin.

Question 11

What is the function in a white blood cell?

Answer 11

To defend the body against pathogens.

Question 12

What are the adaptions in a white blood cell?

Answer 12

Lymphocytes make and release antibodies which can destroy pathogens.
Lymphocytes can also make antitoxins against any toxins made by pathogens.
Phagocytes engulf (surround) and digest pathogens.

Question 13

What is the function in a nerve cell?

Answer 13

To carry electrical signals around the body.

Question 14

What are the adaptions in a nerve cell?

Answer 14

Lots of dendrites to make connections with other cells.
A long axon to carry electrical signals over larger distances.
Nerve endings pass chemical signals to other nerve cells. They have lots of mitochondria to provide energy to make chemical transmitters.

Question 15

What is the function in a Muscle Cell?

Answer 15

To contract and relax.
Striated muscles bring about movement.
Smooth muscle squeeze food through the gut.

Question 16

What are the adaptions in a Muscle Cell?

Answer 16

Proteins that slide over each other to make the fibres contract.
Lots of mitochondria to provide energy needed for the chemical reactions that make the cells contract and relax.
Store glycogen, a chemical that can be broken down and then used in respiration by the mitochondria.

Question 17

what is the function in a root hair cell?

Answer 17

To absorb water and minerals from the soil.