cell processes

Question 1

photosynthesis definition

Answer 1

photosynthesis is plants using light energy to make chemical energy/sugar/glucose

Question 2

photosynthesis equation

Answer 2

water + carbon dioxide → glucose + oxygen (in the presence of light

Question 3

where does photosynthesis occur

Answer 3

in the chloroplasts of plant cells

Question 4

where does the light dependent phase occur

Answer 4

thylakoid/grana

Question 5

where does the light independent phase occur

Answer 5

stroma

Question 6

what is the light dependent phase

Answer 6

photolysis

Question 7

what is the light independent phase

Answer 7

hydrogen combined with carbon dioxide to make glucose

Question 8

what are 5 factors that affect photosynthesis

Answer 8

temperature, light intensity, number of chloroplasts, chlorophyll concentration, water availability

Question 9

what are the 4 structures adapted for photosynthesis

Answer 9

stroma, chlorophyll, double membrane, chloroplasts

Question 10

how is the stroma adapted for photosynthesis

Answer 10

Stroma has light independent reactions / captures carbon / is clear.

Question 11

how is the chlorophyll adapted for photosynthesis

Answer 11

Chlorophyll / thylakoid membranes / grana absorb light / where light reactions happen.

Question 12

how is the double membrane adapted for photosynthesis

Answer 12

Double membrane (around chloroplast) is clear to allow light through, it also controls what goes in and out of chloroplast.

Question 13

how is the chloroplasts adapted for photosynthesis

Answer 13

Plants in the shade have bigger chloroplasts or more chloroplasts than plants in high light areas.

Question 14

draw a chloroplast

Answer 14

refer to notes

Question 15

respiration definition

Answer 15

the process that releases energy (ATP) from glucose / sugar. It can occur aerobically or anaerobically.

Question 16

what are the two kinds of respiration

Answer 16

anaerobic and aerobic

Question 17

what is anaerobic respiration

Answer 17

Anaerobic respiration takes place in the cytoplasm of an animal / plant cell and does not use oxygen. It makes less ATP than aerobic respiration.

Question 18

what is aerobic respiration

Answer 18

Aerobic respiration takes place in the mitochondria of an animal / plant cell and uses oxygen. It makes more ATP than anaerobic respiration.

Question 19

anaerobic respiration equation

Answer 19

Glucose → lactic acid + (2) ATP (in animals and bacteria)

Glucose → Alcohol + (2) ATP (in fungi and plants)

Question 20

aerobic respiration equation

Answer 20

oxygen + glucose → carbon dioxide + water + (36) ATP (energy)

Question 21

2 advantages of aerobic respiration

Answer 21

lots of energy gained

Can be maintained as long as there is glucose due to minimal waste products.

Question 22

2 advantages of anaerobic respiration

Answer 22

energy in times of less (or no) oxygen

Energy is made faster.

Question 23

2 disadvantages of aerobic respiration

Answer 23

always needs oxygen

takes longer

Question 24

2 disadvantages of anaerobic respiration

Answer 24

Less ATP gained

build-up of toxic waste products.

Question 25

mitochondria drawing

Answer 25

refer to notes

Question 26

enzyme definition

Answer 26

Enzymes are proteins that act as a biological catalyst / speed up biological reactions by lowering the activation energy. They are specific to a reaction and are not used up in the reaction.

Question 27

how do enzymes perform their functions

Answer 27

Lock and key Induced fit Enzymes lower the activation energy required for biological reactions. Enzymes have an optimum (best) temperature and pH where they catalyse reactions the fastest.

Question 28

what is locke and key

Answer 28

enzyme and substrate behave like a lock and key, the enzyme has an active site of a specific shape that fits a specific substrate.

Question 29

what is induced fit

Answer 29

enzymes are able to change their shape so the substrate fits into the active site.

Question 30

enzyme inhibitor definition

Answer 30

they prevent the substrate from binding to the active site of enzymes and slow down (or stop) biological reactions.

Question 31

what can denature enzymes

Answer 31

temperature and pH

Question 32

how does temperature denature enzymes

Answer 32

when the temperature is too high causing the enzymes’ 3D protein structure to change shape and alter the active site permanently (irreversible). Therefore, substrates can no longer ‘fit’ the active site and the biological reaction slows / stops.

Question 33

how does pH denature enzymes

Answer 33

extreme pH levels (very high or very low) causing the enzymes’ 3D protein structure to change shape and alter the active site permanently (irreversible). Therefore, substrates can no longer ‘fit’ the active site and the biological reaction slows / stops.

Question 34

enzyme drawing

Answer 34

refer to notes

Question 35

what is the purpose of DNA replication

Answer 35

to create identical copies of the cell’s DNA so new cells have correct information / correct amount of DNA in each cell. This allows the new cells to carry out their function

Question 36

what is the purpose of mitosis

Answer 36

to create identical cells for growth and repair.

Question 37

steps of DNA replication (before mitosis)

Answer 37

1. DNA uncoils and unzips (an enzyme does this) 2. Bases are added by another enzyme to each unzipped strand according to the base pairing rule (A-T & G-C) 3. The leading strand is copied continuously 4. The lagging strand is copied in parts called Okazaki fragments 5. Two identical strands of DNA are produced.

Question 38

steps of mitosis

Answer 38

1. Chromosome replicate (copy) 2. Replicated chromosomes line up in the middle of the cell 3. Spindle fibres attach to the centromere of the chromosomes 4. Chromosomes are pulled apart to each end of the cell 5. The cell divides into two identical cells.

Question 39

where does mitosis occur

Answer 39

Happens more often in tissue that is replaced/damaged often: Skin, Inside intestines Happens less in tissue that is not replaced often: Brain, Liver, Heart

Question 40

when does mitosis occur

Answer 40

Happens more often in young organisms (they grow faster) | Happens in plants more often during warmer weather (spring/summer)

Question 41

mitosis drawing x2

Answer 41

refer to notes

Question 42

3 types of transport

Answer 42

diffusion, osmosis, active transport

Question 43

diffusion definition

Answer 43

is the net movement of a substance from an area of high concentration to low concentration. Diffusion takes place along a concentration gradient. Diffusion is passive / has no energy requirement.

Question 44

osmosis definition

Answer 44

the movement of water from an area of high water potential to an area of low water potential through a cell/semi-permeable membrane. This is a passive process because no ATP/energy is needed and the water moves along a concentration gradient from high to low.

Question 45

active transport definition

Answer 45

is the movement of materials against a concentration gradient from low to high concentration. It requires the use of ATP (energy) and takes place through protein molecules in the cell membrane.

Question 46

how does the size of cells affect transport (surface area to volume ratio)

Answer 46

Cells can only grow to a certain size before the SA:V ratio becomes too small to support rapid transport of materials throughout the cell. Therefore, after the cell reaches a certain size, it must carry out mitosis to produce two new smaller cells that have a larger SA:V ratio and can transport materials at a fast-enough rate to support cellular function. For example, oxygen must be able to diffuse into the cell fast enough to support respiration (carbon dioxide also needs to be able to diffuse out). Therefore, by keeping cells small enough to have the correct SA:V ratio for transport of materials, mitosis helps each new cell to function better.