the processes of life

Question 1

what is anaerobic respiration?

Answer 1

obtaining energy when oxygen is in low concentration

Question 2

where does anaerobic respiration occur?

Answer 2

• vigorous exercise
• plant roots in waterlogged soil
• bacteria in deep puncture wounds

Question 3

what is the equation for anaerobic respiration in bacteria and animal cells?

Answer 3

glucose —> lactic acid + energy

Question 4

what is the equation for anaerobic respiration in yeast and plants?

Answer 4

glucose —> ethanol + carbon dioxide + energy

Question 5

what is respiration?

Answer 5

releasing energy by breaking down large food molecules

Question 6

what is aerobic respiration?

Answer 6

respiration using oxygen

Question 7

what is the word equation for aerobic respiration?

Answer 7

glucose + oxygen —> carbon dioxide + water + energy released

Question 8

what are the factors that limit the rate of photosynthesis?

Answer 8

temperature, carbon dioxide and light intensity

Question 9

what is the cell membrane?

Answer 9

controls what enters and leaves cells

allows gases and water to pass in and out freely

Question 10

what is the cytoplasm?

Answer 10

where most chemical reactions in the cell occur

including anaerobic + production of enzymes

Question 11

what is the nucleus?

Answer 11

contains dna which stores genetic code for making enzymes

Question 12

what is the mitochondria?

Answer 12

contain enzymes required for the release of energy by aerobic respiration

Question 13

what is photosynthesis?

Answer 13

use energy from sunlight to build up large food molecules in plant cells and some microorganisms eg phytoplankton

Question 14

what is the word equation for photosynthesis?

Answer 14

carbon dioxide + water —> glucose + oxygen + energy released

Question 15

what is osmosis?

Answer 15

overall movement of water from dilute solution to a concentrated solution through partially permeable membrane

allows passage of water but not solute molecules

Question 16

what is diffusion?

Answer 16

movement of chemicals from a high concentration to a low

it is:
- passive

Question 17

what happens in photosynthesis?

Answer 17

1) water taken up by plant roots
2) carbon dioxide enters plants, leaves by diffusion
3) oxygen leaves, plant leaves by diffusion

Question 18

whats the optimum temperature of most enzymes?

Answer 18

37 C

Question 19

what do ecologists need to do to investigate the effects of light intensity on plant growth?

Answer 19

• measure how common the plants are
• light meter to measure light intensity
• identification key to identify plants found

Question 20

how is a quadrat put on the ground?

Answer 20

• at random

- a number of times so an average is taken

Question 21

how do ecologists investigate the abundance and distribution of plants?

Answer 21

• in diff areas + make comparison

- diff locations in area + make comparison

Question 22

what is a quadrat?

Answer 22

anything with a defined area which is placed at intervals along transect to sample the area

Question 23

what is a transect?

Answer 23

a line which is used to measure distances by the quadrat if theres an obvious change in the plants in the area

Question 24

what are enzymes?

Answer 24

chemicals that speed up the rate of reaction

Question 25

when do enzymes stop working?

Answer 25

if the pH is inappropriate or the temperature is too higher

enzymes need a specific temperature and pH to work at their optimum

Question 26

which type of respiration releases more energy per molecule of glucose?

Answer 26

aerobic

Question 27

what is the product of photosynthesis?

give 3 answers

Answer 27

• converted into starch for storage
• used in respiration
• converted to chemicals 4 plants growth eg cellulose, chlorophyll, protein

Question 28

what are the possible fates of glucose made by photosynthesis?
(give 6 examples)

Answer 28

• cellulose for cell walls
• protein for growth
• starch for energy storage
• oil for energy storage
• make chlorophyll
• respire to give energy

Question 29

what is active transport?

Answer 29

uses energy from respiration to transport chemicals across a cell membrane

Question 30

what is the role of minerals taken up by plant roots in active transport?

Answer 30

used to make chemicals essential to cells

eg nitrogen taken up as nitrates used to make proteins

Question 31

why cant root cells take up nitrates by diffusion?

Answer 31

nitrates are in a higher concentration in plant cells than the soil

Question 32

what are the uses of anaerobic respiration?

Answer 32

• in yeast used for baking, releasing co2 which makes dough rise
• more energy to cells when necessary

Question 33

what is the energy released in by respiration used in?

Answer 33

• movement:
  contraction of muscles
• synthesis of large molecules from smaller ones:
  chlorophyll from glucose
• active transport

Question 34

what is the active site?

Answer 34

place where substrate fits in enzyme

Question 35

how can the shape of the active site be changed?

Answer 35

• heating enzyme above certain temp
• altering pH level

meaning molecule no longer fits + reaction cant take place
if change is permanent, enzyme = denatured

Question 36

how does photosynthesis take place?

give 3 stages

Answer 36

• light energy absorbed by chlorophyll
• light energy used to rearrange atoms of co2 and h2o to produce glucose
• oxygen = waste

Question 37

what substances move in and out of cells by diffusion?

3 answers

Answer 37

• oxygen
• dissolved food
• carbon dioxide

Question 38

what is a cell wall?

Answer 38

made of cellulose to strengthen cell

Question 39

what is a permanent vacuole?

Answer 39

helps support the cell

Question 40

what are chloroplasts?

Answer 40

contain chlorophyll and some enzymes for photosynthesis

Question 41

what does a rise in temperature in photosynthesis do?

Answer 41

rise in temp increases rate of photosynthesis to certain point, the rate then decreases bc of effect of temp on enzyme activity

Question 42

what does a rise in carbon dioxide and light intensity in photosynthesis do?

Answer 42

if increased, rate of photosynthesis increases + levels off

Question 43

what do plants use the food produced by photosynthesis for?

Answer 43

• respiration
• active transport

excess glucose stored as starch