B1- Cell Biology

Question 1

What are the two types of cells?

Answer 1

• Eukaryotic (plant and animal)
• Prokaryotic (bacteria)

Question 2

What are the differences between eukaryotic and prokaryotic cells?

Answer 2

Prokaryotic cells are much smaller than eukaryotic cells.
- the genetic material is not enclosed in a nucleus. It is a single DNA loop and there may be one or more small rings of DNA called plasmids.
- they have cytoplasm and a cell membrane surrounded by a cell wall
Eukaryotic cells are animal and plant cells
- have a cell membrane
- cytoplasm
- genetic material enclosed in a nucleus

Question 3

How is genetic information stored in a prokaryotic cell?

Answer 3

Found free within the cytoplasm as:
- chromosomal DNA (single large loop of circular DNA)
-Plasmid DNA

Question 4

What are plasmids?

Answer 4

• Small, circular loops of DNA found free in the cytoplasm and separate from the main DNA
• Carry genes that provide genetic advantages
  e.g antibiotic resistance

Question 5

what are the order of magnitude (sizes)?

Answer 5

centimeter(cm)= 1 x10 ^-2 metres
millimetre(mm)= 1x10^-3 metres
micrometre= 1 x 10^-6 metres
nanometre(nm)= 1 x 10 ^-9 metres

Question 6

List the components of both plant and animal cells (5)

Answer 6

• Nucleus
• Cytoplasm
• Cell membrane
• Mitochondria
• Ribosomes

Question 7

List the additional cell components found in plant cells (3)

Answer 7

• Chloroplasts
• Permanent vacuole
• Cell wall

Question 8

What is the function of the nucleus?

Answer 8

to enclose the genetic material and control cellular activities

Question 9

What is the function and structure of the cytoplasm?

Answer 9

They cytoplasm is a watery solution where chemical reactions take place (eg the first stage of respiration)

Question 10

What is the function of the cell membrane?

Answer 10

to control the molecules that can enter and leave the cell

Question 11

what is the function of the mitochondria?

Answer 11

Mitochondria is where aerobic respiration takes place and provides energy for the cell

Question 12

What is the function of ribosomes?

Answer 12

Ribosomes are the sites of protein synthesis

Question 13

What is the function of chloroplasts?

Answer 13

chloroplasts contain chlorophyll and are the sites of photosynthesis

Question 14

What is the function of the cell wall?

Answer 14

The cell wall is made from cellulose. This strengthens the cell

Question 15

What is the function of the vacuole?

Answer 15

The vacuole is filled with a fluid called cell sap. The vacuole helps give the plant cell its shape

Question 16

REQUIRED PRACTICAL 1: MICROSCOPES ( what a microscope contains)

Answer 16

MICROSCOPE HAS:
- STAGE: where we place the microscope slide, the stage has clips to hold the slide in place
- LAMP: Light from the lamp passes up through the microscope slide
- MIRROR: is used to reflect light up through the microscope slide
- OBJECTIVE LENSES: Have a magnification of 4x, 10x or 40x
- EYEPIECE: where u look through. has a magnification of 10x
- COARSE FOCUSSING DIAL &
FINE FOCUSSING DIAL

Question 17

REQUIRED PRACTICAL 1: MICROSCOPE

Answer 17

1. First, we place the slide onto the stage and use the clips to hold the slide in place.
2. Then select the lowest power objective lens (4x)
3. Need to position the objective lens so it almost touches the microscope slide. to do this, we slowly turn the coarse focussing dial
4. when the objective lens almost touches the slide, we stop turning the dial
5. At this stage look down through the eyepiece and slowly turn the coarse focussing dial. This increases the distance between the objective lens and the slide.
6. We do this until the cells come into focus
7. Need to adjust the fine focussing dial to bring the cells back into focus
8. You should be able to draw the cell under the microscope.
9. On your drawing you should also include a magnification scale. To do this, we place a clear plastic ruler over the stage
10. measure the diameter of the field of view in millimetres. then show this on our drawing using a scale bar and write the magnification