Animal and plant cells

Question 1

What is a Eukaryotic cell

Answer 1

cell which has a nucleus

Question 2

What is a Eukaryote? give an example

Answer 2

organism made of eukaryotic cells eg human

Question 3

What is a prokaryotic cell? give an example

Answer 3

single cells which do not have a nucleus

Question 4

What is a prokaryote? give an example

Answer 4

organisms made of a single prokaryotic cell eg bacteria

Question 5

What are the characteristics of a bacteria cell?

Answer 5

between 1 and 10 micrometers long
has a cell wall
cell membrane
cytoplasm
single DNA loop
plasmid DNA
ribsomes

Question 6

What is a ribosome?

Answer 6

small cell organelle in the cytoplasm in which proteins are made

Question 7

What is an organelle?

Answer 7

small structure which has a specific job in a cell

Question 8

What are plasmids?

Answer 8

small rings of DNA which have many functions and can give bacteria resistance to antibiotics

Question 9

Where is the dNA held in prokaryotes

Answer 9

In a single DNA loop and in plasmids- not arranged as chromosomes.

Question 10

What is a chromosome?

Answer 10

A structure containing DNA found in the nucleus of a eukaryotic cell

Question 11

What are the components of an animal cell?

Answer 11

Cell membrane
Cytoplasm
Ribosome
Nucleus
Mitochondria

Question 12

What is photosynthesis?

Answer 12

chemical reaction occurs in the chloroplasts of plants and algae and stores energy as glucose or starch

Question 13

What does turgid mean?

Answer 13

when a cell has a lot of water in it’s vacuole and the pressure of it on the cell wall keeps the wall rigid not floppy

Question 14

What are the components of a plant cell?

Answer 14

cell wall 
cell membrane
cytoplasm
chloroplast
nucleus
ribosome
mitochondria
vacuole

Question 15

How is a sperm cell specialised?

Answer 15

1. It has a tail to allow it to swim to the egg

2. They contain a large number of mitochondria to provide the energy needed for them to swim.

Question 16

Identify some specialist cells?

Answer 16

1. Sperm cell
2. Nerve cell
3. Muscle cell
4. Root hair cell
5. Xylem cell
6. Phloem cell

Question 17

Describe how a nerve cell is specialised.

Answer 17

1. They are the longest cells in the body.
2. They have long extensions called axons
3. The axons are coated in a myelin sheath which insulates them as the electrical impulse passes along.
4. The cell membrane has extensions which allow it to pick up the signals from the neighbouring cells.

Question 18

Describe how a muscle cell is specialised

Answer 18

1. They can contract which allow them to pull the bones allowing movement.
2. They contain a large number of mitochondria as the muscles need a lot of energy to contract.

Question 19

Describe how a root hair cell is specialised

Answer 19

They have a thin extension which pokes out into the soil, this increases the surface area of the cell in contact with the soil which allows them to absorb more water and minerals for the plant to use.

Question 20

Describe how a xylem cell is specialised

Answer 20

1. Xylem cells carry water and dissolved minerals from the roots along the stems to the leaves and flowers of the plant.
2. This is called transpiration.
3. The tubes are made from a lot of individual cells that have died and have no end wall or contents. This leaves a hollow tube like a pipe.
4. The side walls are reinforced with a substance called lignin which allows it to support the weight of the plant.

Question 21

Describe how a phloem cell is specialised

Answer 21

1. The phloem cells carry glucose made by photosynthesis from the leaves to all of the other parts of the plant.
2. This is called translocation.
3. They have specialist end walls with small holes, called sieve plates which allow sugars to pass through.
4. They have fewer organelles than many other plant cells to help the sugars to pass though more easily.

Question 22

What is the difference between a generalised and a specialist cell.

Answer 22

Generalised cells are formed first, some then become specialised to perform a specific function, this is called cell differentiation.

Question 23

What is cell differentiation?

Answer 23

A generalised cell becoming specialised for a specific function.

Question 24

Describe the parts of a light microscope.

Answer 24

1. The eyepiece- the lens you look through- usually x10 magnification
2. The objective lens- there are usually 3 of them all different magnifications eg x5 x10 and x25
3. Stage- where you clip the sample slide
4. Specimen- placed on a slide, often in water or stain with a glass cover slip
5. Mirror or light source- reflects light through the specimen and up into the eyepiece
6. Coarse focus- moves the stage up and down quickly to bring the sample into focus.
7. Fine focus- moves the stage slowly to allow the image to be made sharp.

Question 25

What is the equation used to calculate magnification

Answer 25

Total magnification = magnification X magnification

of eyepeice lens of objective lens

Question 26

What is an electron microscope?

Answer 26

A microscope which uses electron beams instead of light to give higher magnification.
The wavelength of the electrons are up to 100,000 times smaller than visible light which means that the images can be viewed at significantly higher magnifications.
They also have much greater resolution (the distance between 2 distinct points) up to 2000 times closer than a light microscope at 0.1nm. This means that sub cellular structures can be seen in detail.