Cell Biology

Question 1

What is the job of a nucleus?

Answer 1

Controls cell activities and contains the genetic material

Question 2

What is the function of the cytoplasm?

Answer 2

Where most of the chemical reactions take place.

Question 3

What is the function of the cell membrane?

Answer 3

Controls the passage of substances in and out of the cell.

Question 4

What type of respiration takes place in the mitochondria?

Answer 4

Aerobic respiration takes place in the mitochondria.

Question 5

What is the function of ribosomes?

Answer 5

To synthesize proteins.

Question 6

Why do plant cells have a cell wall?

Answer 6

To strengthen the cell.

Question 7

Why do plant cells contain a vacuole?

Answer 7

To contain cell sap which supports the plant.

Question 8

Why do plants need chloroplast?

Answer 8

To absorb light to make glucose by photosynthesis

Question 9

Which cells are eukaryotic?

Answer 9

Plant, animal and fungal cells

Question 10

Which cells are prokaryotic?

Answer 10

Bacterial cells.

Question 11

What does and what doesn’t a prokaryotic cell contain?

Answer 11

It contains small rings of DNA called plasmids and doesn’t contain mitochondria or chloroplast.

Question 12

What is in a bacterial cell?

Answer 12

Plasmid, cytoplasm, cell wall, chromosomal DNA, Flagella.

Question 13

What do plant cells contain that animal cells do not?

Answer 13

Cell wall, chloroplast, and a vacuole.

Question 14

What are the steps for the required practical: Use a light microscope to observe a section of plant and animal cells?

Answer 14

1) Place a tissue sample on a microscope slide.
2) Add a few drops of sustainable stain.
3) Lower a coverslip onto the tissue.
4) Place the slide on the stage and focus using low power.
5) Change to high power and refocus.
6) Draw any types of cells that can be seen.
7) Add a scale line to the diagram.

Question 15

What is the equation to work out magnification?

Answer 15

Size of image / Size of real object.

Question 16

How many cm, mm, micrometres and nanometres are there in 1 meter?

Answer 16

CM=100
MM=1,000
MICROMETER=1,000,000
NANOMETER=1,000,000,000

Question 17

What is a light microscope?

Answer 17

Developed in the late 16th century and has a greater resolution than the human eye. Also allowed them to see the animal, plant, and bacteria cells.

Question 18

What is an electron microscope?

Answer 18

First used in 1933. Gives more resolution and cells can be seen in finer detail.

Question 19

What type of simple cell division does bacteria use?

Answer 19

Binary fission

Question 20

What type of simple cell division does bacteria use?

Answer 20

Binary fission

Question 21

What is a culture?

Answer 21

Bacteria that can be grown in a nutrient broth or colonies on agar.

Question 22

What is the technique to make uncontaminated cultures?

Answer 22

1) Petri dish and agar are sterilised to kill unwanted microorganisms.
2) An inoculating loop is sterilised by passing it through a flame.
3) The cooled inoculating loop is used to transfer bacteria to the agar.
4) Lid must be quickly removed and replaced with tape to stop it from coming off.
5)Store the dish upside down to stop condensation from dripping on the agar surface.

Question 23

What is the cultures techniques called?

Answer 23

Aseptic technique

Question 24

What does the nucleus of a cell contain?

Answer 24

Chromosomes made of DNA

Question 25

How many pairs of chromosomes do humans have?

Answer 25

23 pairs.

Question 26

What happens during mitosis?

Answer 26

1) One set of chromosomes is pulled to each end of the cell.
2) The nucleus divides.
3) The cytoplasm and cell membranes divide to form 2 identical cells.

Question 27

What is an undifferentiated cell and what is it called?

Answer 27

A cell that has not become specialised yet. It is called a stem cell.

Question 28

Where are stem cells found?

Answer 28

They are found in human embryos, in the umbilical cord of a newborn baby.

Question 29

Where are adult stems found?

Answer 29

In some organs and tissues.

Question 30

What is therapeutic cloning?

Answer 30

When a cloned embryo of the patient is used as a source of stem cells.

Question 31

Why are some people concerned about cloned embryos?

Answer 31

There might be risks or religious and ethical reasons.

Question 32

Where are the stem cells in plants found?

Answer 32

In the meristem.

Question 33

What is diffusion?

Answer 33

Diffusion is the net movement of particles from a high concentration to a low concentration.

Question 34

What diffuses during gas exchange in lungs., gills and plant leaves?

Answer 34

Oxygen and carbon dioxide.

Question 35

What are the factors that affect the rate of diffusion?

Answer 35

The concentration gradient, the temperature and the surface area of the membrane.

Question 36

What is osmosis?

Answer 36

Osmosis is the diffusion of water from a dilute solution to a concentrated solution through a partially permeable membrane.

Question 37

What is the method for the effect of different concentration sugar solutions on plant tissues and what is the result?

Answer 37

1) Cut some cylinders of potato tissue and measure their mass.
2) Place the cylinders in different concentrations of sugar solution.
3) After about 30 minutes remove the cylinders and measure their mass again.
If the cylinder changes in mass they have gained or lost weight via osmosis.

Question 38

What are the IV, DV and CV of the practical : The effect of different concentration sugar solutions on plant tissues

Answer 38

IV= The concentration of sugar solution.
DV= The mass of the potato.
CV= The temperature, the time and the volume of solution.

Question 39

What is Active Transport?

Answer 39

Active Transport moves substances against a concentration gradient, from a low concentration to a high concentration.

Question 40

What does Active Transport allow?

Answer 40

Allows mineral ions to be absorbed into plant root hairs from very dilute solutions in the soil. Also allows sugar molecules to be absorbed from the gut to the blood.