Topic 1: Cell Biology

Question 1

Eukaryotic cells

Answer 1

Complex cell - all animal and plant cells

Question 2

Prokaryotic cells

Answer 2

Small and simple cell - bacterial cells

Question 3

Prokaryote

Answer 3

A single-prokaryotic celled organism

Question 4

Mitochondria

Answer 4

Organelle which is the site of aerobic respiration in a cell

Question 5

Ribosomes

Answer 5

Organelle where protein synthesis occurs

Question 6

Structures of a bacterial cell (6)

Answer 6

1) Cell wall
2) Cell membrane
3) Cytoplasm
4) Single, free-floating circular strand of DNA
5) 1 or 2 small rings of DNA (plasmids)
6) Ribosomes

Question 7

Centimetres, millimetres, micrometres, nanometres to metres

Answer 7

1) 1 cm –> 110^-2
2) 1 mm –> 110^-3
3) 1 um –> 110^-6
4) 1 nm –> 110^-9

Question 8

Differentiation

Answer 8

The process by which a cell changes to become specialised for its job by developing different subcellular structures and becoming a different type of cell

Question 9

Mitosis (6)

Answer 9

1) Interphase - DNA uncoiled, floats in nucleus
2) Prophase - DNA replicates and condenses forming X-chromosomes
3) Metaphase - X-chromosomes line up at equator
4) Anaphase - X-chromosomes split by cell fibres, two arms go to opposite ends of cell
5) Telophase - new nucleus forms around the two sets of chromosomes and cell membrane divides
6) Interphase II - DNA uncoils, two new cells made

Question 10

Medical use of adult stem cells

Answer 10

Bone marrow stem cells can replace faulty blood cells

Question 11

Medical use of embryonic stem cells

Answer 11

1) Can replace faulty cells like insulin-producing cells for diabetics
2) Can replace nerve cells for those paralysed

Question 12

Arguments against stem cell research (3)

Answer 12

1) Stem cells = potential human life
2) Science should concentrate on developing other sources of stem cells
3) Banned in some countries

Question 13

Arguments for stem cell research (3)

Answer 13

1) Helps many people
2) Suffering of patients > the rights of the embryo
3) Embryos used are from fertility clinics and unwanted

Question 14

Diffusion

Answer 14

The net movement of particles from an area of high concentration to an area of lower concentration

Question 15

Factors for the rate of diffusion (3)

Answer 15

1) Temperature
2) Concentration gradient
3) Surface area (for membranes)

Question 16

Osmosis

Answer 16

The net movement of water molecules, across a partially permeable membrane, from an area of high water concentration to an area of lower water concentration

Question 17

Active transport

Answer 17

The movement of particles, across a membrane, from an area of lower concentration to an area of higher concentration requiring energy

Question 18

Examples of active transport (2)

Answer 18

1) Root hair cells in plants absorbing minerals from the soil
2) Bloodstream absorbing nutrients from the gut

Question 19

Adaptations of exchange surfaces (3)

Answer 19

1) Thin membranes to reduce the distance to diffuse
2) Large surface area so lots of substances can diffuse
3) Connected by lots of blood vessels to diffuse quickly

Question 20

Alveoli adaptations (4)

Answer 20

1) Thin walls
2) Enormous surface area
3) Good blood supply for quick absorption
4) Moist lining for dissolving gases

Question 21

Villi (in the small intestine) adaptations (3)

Answer 21

1) Single layer of surface cells
2) Enormous surface area
3) Very good blood supply for quick absorption

Question 22

Gills’ adaptations (4)

Answer 22

1) Tin surface layer
2) Gill filaments with lamellae increase surface area
3) Lots of blood capillaries
4) Large concentration gradient between water and blood

Question 23

MICROSCOPY PRACTICAL

Answer 23

-

Question 24

OSMOSIS PRACTICAL

Answer 24

-