TOPIC 2A - CELL STRUCTURE AND DIVISION

Question 1

Draw and label an animal cell.

Answer 1

(see page 24 in the revision guide)

Question 2

Draw and label a plant cell.

Answer 2

(see page 24 in the revision guide)

Question 3

Draw and label an algal cell.

Answer 3

(see page 24 in the revision guide)

Question 4

Draw and label a fungal cell.

Answer 4

(see page 24 in the revision guide)

Question 5

Draw and describe the function of the cell-surface (plasma) membrane.

Answer 5

(see page 25 in the revision guide)

Question 6

Draw and describe the function of the nucleus.

Answer 6

(see page 25 in the revision guide)

Question 7

Draw and describe the function of the mitochondria.

Answer 7

(see page 25 in the revision guide)

Question 8

Draw and describe the function of the chloroplast.

Answer 8

(see page 25 in the revision guide)

Question 9

Draw and describe the function of the Golgi apparatus.

Answer 9

(see page 25 in the revision guide)

Question 10

Draw and describe the function of the Golgi vesicle.

Answer 10

(see page 26 in the revision guide)

Question 11

Draw and describe the function of a lysosome.

Answer 11

(see page 26 in the revision guide)

Question 12

Draw and describe the function of the ribosome.

Answer 12

(see page 26 in the revision guide)

Question 13

Draw and describe the function of the rough endoplasmic reticulum (RER).

Answer 13

(see page 26 in the revision guide)

Question 14

Draw and describe the function of the smooth endoplasmic reticulum (SER).

Answer 14

(see page 26 in the revision guide)

Question 15

Draw and describe the function of the cell wall.

Answer 15

(see page 26 in the revision guide)

Question 16

Draw and describe the function of the cell vacuole.

Answer 16

(see page 26 in the revision guide)

Question 17

Draw and label a prokaryotic cell.

Answer 17

(see page 28 in the revision guide)

Question 18

Draw and label a virus.

Answer 18

(see page 28 in the revision guide)

Question 19

Describe binary fission.

Answer 19

Prokaryotic cells replicate by Binary Fission.
1) The circular DNA and plasmid(s) replicate. The main DNA loop is only replicated once but the plasmids may be replicated more than once.
2) The cell gets bigger and the DNA loops move to opposite ends of the cell.
3) The cytoplasm begins to divide, and new cell walls begin to form.
4) The cytoplasm divides and two daughter cells are produced. each daughter cell has one copy of the circular DNA but may have a variable number of copies of the plasmid(s).
(see page 29 in the revision guide for a diagram)

Question 20

How do viruses use host cells to replicate themselves?

Answer 20

1) Viruses use their attachment proteins to bind to complimentary receptor proteins on the surface of host cells.
2) Different viruses have different attachment proteins and therefore require different receptor proteins on the host cells. So, some viruses can only infect one type of cell.
3) Viruses are not alive, so do not undergo cell division. Instead, they inject their DNA or RNA into the host cell. The host cell then replicates the viral particles.

Question 21

What does acellular mean?

Answer 21

Not cells. (Not alive)

Question 22

How do you calculate magnification?

Answer 22

magnification = size of image / size of real object

Question 23

What is magnification?

Answer 23

Magnification is how much bigger the image is than the specimen.

Question 24

What is resolution?

Answer 24

Resolution is how detailed the image is. More specifically, it’s how well a microscope distinguishes between two points that are close together.

Question 25

What is the magnification and resolution of an optical microscope?

Answer 25

(see page 30 in the revision guide)

Question 26

What is the magnification and resolution of an electron microscope?

Answer 26

(see page 30 in the revision guide)

Question 27

Describe the differences between a TEM and a SEM.

Answer 27

(see page 30 in the revision guide)

Question 28

How do you prepare a ‘temporary mount’ of a specimen on a slide?

Answer 28

(see page 30 in the revision guide)

Question 29

What is homogenisation in cell fractionation?

Answer 29

Breaking up the cells.

see page 31 in the revision guide

Question 30

What is filtration in cell fractionation?

Answer 30

Getting rid of the large parts.

see page 31 in the revision guide

Question 31

What is ultracentrifugation in cell fractionation?

Answer 31

Separating the organelles.

see page 31 in the revision guide

Question 32

What is the order of the mass of organelles from largest to smallest?

Answer 32

• Nuclei
• Mitochondria and chloroplasts
• Lysosomes
• Endoplasmic reticulum
• Ribosomes

Question 33

What is mitosis used for?

Answer 33

Mitosis is needed for the growth of the multicellular organisms and for repairing damaged tissues.

Question 34

Describe the interphase of mitosis.

Answer 34

(see page 32 in the revision guide)

Question 35

Describe the prophase of mitosis.

Answer 35

(see page 32 in the revision guide)

Question 36

Describe the metaphase of mitosis.

Answer 36

(see page 32 in the revision guide)

Question 37

Describe the anaphase of mitosis.

Answer 37

(see page 32 in the revision guide)

Question 38

Describe the telophase of mitosis.

Answer 38

(see page 32 in the revision guide)

Question 39

What causes cancer?

Answer 39

Uncontrolled cell division. If there is a mutation in a gene that controls cell division, the cells can grow out of control.
- Cancer is a tumour that invades surrounding tissue.

Question 40

Give two examples of cell cycle targets of cancer treatment.

Answer 40

(see page 33 in the revision guide)

Question 41

How do you prepare and stain the root tip in order to observe the stages of mitosis?

Answer 41

(see page 34 in the revision guide)

Question 42

How do you used an optical microscope to observe some prepared root tip cells?

Answer 42

(see page 34 in the revision guide)

Question 43

How do you calculate the mitotic index of a cell?

Answer 43

mitotic index = number of cells with visible chromosomes / total number of cells observed
- The mitotic index is the proportion of cells undergoing mitosis.

Question 44

What is an artefact when using a microscope?

Answer 44

Artefacts are things that you can see down the microscope that aren’t part of the cell or specimen that you’re looking at.

• They can be anything from bits of duct, air bubbles and fingerprints to inaccuracies caused by squashing and staining your sample.
• Artefacts are usually made during the preparation of your slides, you don’t want them.