B4 COPY

Question 1

What is respiration?

Answer 1

Transferring energy from the breakdown of glucose

• animals produce glucose when breaaking down biomass
• plants make glucose by photosynthesis

Question 2

In plants, where does aerobic respiration take place?

Answer 2

In the mitochondria as it contains the enzymes required for aerobic respiration.

Question 3

What is the formula for aerobic respiration?

Answer 3

Glucose+oxygen>carbon dioxide+water

Question 4

What is anaerobic respiration?

Answer 4

Transferring energy without oxygen

-takes place in the cytoplasm

Question 5

What is the formula for anaerobic respiration?

Answer 5

Glucose > Lactic Acid

Some organisms produce ethanol and carbon dioxide

Question 6

What examples of anaerobic respiration are there?

Answer 6

• Human cells respire anaerobically when doing exercise

- some bacteria respire anaerobically to survive

Question 7

What is the job of the cell cycle?

Answer 7

Making new cells for growth and repair

Question 8

What happens at the interphase?

Answer 8

Before the cell divides, it has to grow

It then duplicates its DNA so there is one copy for each new cell.

Question 9

What happens at the mitosis?

Answer 9

Chromosomes line up and are pulled apart by the cell fibres
-arms of each chomosome go to opposite ends of the cell
Membranes form around the chromosmes-become the nuclei of the 2 cells
Then the cytoplasm and membrane then divide, producing daughter cells-idnetical to parent cell

Question 10

What are light microscopes?

Answer 10

Work by passing light through the specimin

-they let us see things like the nuclei and chloroplasts

Question 11

What are electron miscroscopes?

Answer 11

Use electrons rather than light

• higher magnification and resolution than light microscopes
• allow us to see internal structure of things like chloroplasts

Question 12

What is the equation for total magnification?

Answer 12

eyepiece lens magnification x lens magnification

Question 13

What happens during sexual reproduction?

Answer 13

Father and mother gametes pair up to form a zygote

• the zygo undergoes cell division and develops into an embryo
• the embryo inherits characteristics from both parents

Question 14

What happens in division 1 in Meiosis?

Answer 14

Firstly the cell goes through the interphase

• chromosomes line up in pairs
• pairs pulled apart
• some of the father’s chromosomes and mother’s chromosomes go into each new cell
• the chromosome number of each new cell is half that of the original cell

Question 15

What happens in division 2 of meiosis?

Answer 15

Chromosomes line up again

• pulled apart
• you get 4 gametes

Question 16

What makes stem cells different to normal cells?

Answer 16

Cells in an embryo are all embryonic stem cells

• embryonic cells are unspecialised
• humans have stem cells in places like the bone narrow

Question 17

What are meristems?

Answer 17

Tissues found in areas of plants which are growing

• unspecialized so can form any cell type in the plant
• form tissues such as phloem and xylem

Question 18

How can stem cells be used in medicine?

Answer 18

Stem cells can be extracted from embryos and grown to differentiate into different cells.
-stem cells could be used to replace cells which have been damaged.

Question 19

What are the dangers of stem cells?

Answer 19

Stem cells divide very quickly so a tumour could develop.

Stem cells can contain viruses

Question 20

What are auxins?

Answer 20

Plant hormones which determine growth at the tips of shoots and roots.
-promotes growth in shoot but inhbits growth in root

Question 21

What does ‘shoots are positively phototropic’ mean?

Answer 21

They grow towards the light

-when a growth tip is exposed to light, the cells grow faster on that side that’s in the light

Question 22

What does ‘shoots are negatively gravitropic’ mean?

Answer 22

When a tip is growing sideways, it produces an unequal amount of auxin on the lower side
-the shoots bends in the same direction as gravity

Question 23

What does ‘roots are positively gravitropic’ mean?

Answer 23

The roots grow in the opposite direction to gravity.

Question 24

What does ‘roots are negatively phototropic’ mean?

Answer 24

Roots grow away from light.

Question 25

How do photropism and gravitoprism increase a plant’s chance of survival?

Answer 25

Growing towards the light may allow a plant to absorb more sunlight.

Question 26

What do Gibberellins do?

Answer 26

Control Germination and flowering

Question 27

What does ethene do for a plant?

Answer 27

Stimulates shedding of leaves and ripening of fruit.

-ethene is produced by aging leaves -breaks the cells wall causing the leaves to fall off