Topic 2 - Life Processes

Question 1

Define Respiration.

Answer 1

Respiration is the process of breaking down glucose to release energy which goes into every living cell.

Question 2

Define aerobic respiration.

Answer 2

respiration using oxygen. it is the most efficient way to release energy from glucose.

Question 3

Word equation for aerobic respiration ?

Answer 3

glucose + oxygen = Carbon dioxide + water +(energy)

Question 4

How do cells get what they need for aerobic respiration ?

Answer 4

Capillaries are nearby all cells so they can supply them with glucose ( from breaking down food ) and oxygen ( from air breathed into the lungs) and they take away the waste carbon dioxide. The substances move between cells and capillaries by diffusion.

Question 5

Define Diffusion.

Answer 5

Diffusion is the movement of particles from an area of higher concentration to an area of lower concentration

Question 6

Describe the concentration of oxygen, glucose and co2 in and out of cells and capillaries ?

Answer 6

cells respire and use up oxygen and glucose so the concentration of these is low inside the cell. the concentration of these substances is high in the blood in the capillaries so they diffuse from the capillaries into the cell. When cells respire they produce alot of co2 s the concentration is high in the cell but this means the co2 diffuses into the blood where the concentration is lower.
The bigger the difference in concentration , the faster the rate of diffusion.

Question 7

Equation for cardiac output.

Answer 7

Cardiac output ( cm3 per minute) = heart rate (bmp) x stroke volume ( cm3)

Question 8

Word equation for anaerobic respiration ?

Answer 8

glucose= lactic acid + (energy )

Question 9

define anaerobic respiration ?

Answer 9

respiration without oxygen. It is useful in emergencies but doesn’t release as much energy as aerobic respiration does.

Question 10

What effect does exercise have on your breathing and heart rate when you aerobically respire ?

Answer 10

1. when you exercise , your muscles contract more frequently than normal so you need more energy which comes from increased respiration
2. increased respiration means you need more oxygen in your cells.
3. breathing rate increases to get more oxygen in the blood and to get this oxygenated blood around your body , your heart rate increases which removes co2 more quickly too.
4. to deal with this demand, the rate of diffusion of co2 and oxygen at the lung surface and in muscle cells increases.

Question 11

What effect does exercise have on you when you anaerobically respire ?

Answer 11

1. vigorous exercise like sprinting means your body can’t supply enough oxygen to your muscles
2. so you have to resort to anaerobic respiration whereby you convert glucose into energy.
3. this produces a build up of lactic acid in the muscles which can give you cramp
4. after resorting to anaerobic respiration, when you stop you’ll have an oxygen debt.(epoc)
5. you have to keep breathing hard for a while to get more oxygen into the blood. your heart rate stays high to get the oxygen to your muscles , where it converts the toxic lactic acid to harmless co2 and water.

Question 12

Word equation for photosynthesis.

Answer 12

CO2 + water =(sunlight+chlorophyll) = glucose +oxygen

Question 13

How are plants able to make their own food ?

Answer 13

They have chloroplasts which contain chlorophyll. They absrob energy in sunlight and convert it into co2 and water into glucose, oxygen is a by product.

Question 14

What is the word equation for photosynthesis ?

Answer 14

co2 + water (sunlight+ chlorophyll )= glucose + oxygen.

Question 15

How are leaves adapted for photosynthesis ?

Answer 15

1. broad= large surface area exposed to light
2. contain chlorophyll in chloroplasts to absorb light
3. stomata opens and closes to let co2 and O2 in and out and let water vapour escape.

Question 16

What are the limiting factors for photsynthesis ?

Answer 16

light intensity, co2 concentration and temperature.

Question 17

Explain the photosynthesis experiment ?

Answer 17

1. Place Canadian pondweed in a beaker with water and attach a gas syringe to it.
2. This is to collect the oxygen the plant makes during photosynthesis
3. measure the amount of oxygen produced in a given time to show fast photosynthesis happens.
4. you can then measure how different factors affect the rate of photosynthesis.

Question 18

Describe a light intensity/ photosynthesis graph ?

Answer 18

1. rate of photosynthesis increases with light intensity

2. after a certain point it won’t make any difference because co2 and or temperature is the limiting factor.

Question 19

Describe a co2/photosynthesis graph?

Answer 19

co2 only increases photosynthesis to a point , then the graph flattens out because light or temp is the limiting factor.

Question 20

Describe a temp/photosynthesis graph ?

Answer 20

1. If temp is too low , enzymes needed for photosynthesis work slowly
2. if temp is too hot , enzymes with denature around 45 degrees.

Question 21

How do you keep the photosynthesis experiment test fair ?

Answer 21

By keeping all the variables constant apart from the one your testing.

1. use bench lamp to control light intensity
2. put beaker in a water bath to try and keep temp constant
3. dissolve different amounts of sodium hydrogencarbonate which gives of co2 in the water. ( change it each time )

Question 22

What is the function of Phloem tubes ?

Answer 22

They transport food made in the leaves to all the other parts of the plant.
They carry sugars fats , proteins to growing regions in the shoot tips and root tips and to/from storage organs in the roots.

Question 23

What is the function of Xylem tubes ?

Answer 23

They carry water and minerals from the roots up to the leaves in a transpiration stream.

Question 24

Explain Transpiration

Answer 24

Is a loss of water from a plant and is caused by evaporation and diffusion of water inside the leaf. This creates a water shortage in the leaf so water from other parts are taken in the xylem vessels to replace it. Thus, more water is taken from the roots so there is a constant transpiration stream of water through the plant for photosynthesis.

Question 25

Define Osmosis

Answer 25

Osmosis is the movement of water molecules across a partially permeable membrane from a region of high water concentration to a region of low water concentration.

Question 26

What happens in osmosis ?

Answer 26

Tiny molecules of water can pass through partially permeable membrane but bigger molecules like sugar can’t. Water molecules pass both ways through the membrane.

Question 27

What is a steady net flow ?

Answer 27

Because there more water molecles on one side than on the other, there’s a steady net flow of water into the region with fewer water molecules.

Question 28

Is osmosis a type of diffusion ?

Answer 28

yes because it has a passive movement of water particles from an area of high concentration to an area of low water concentration.

Question 29

Describe an experiment for Osmosis.

Answer 29

1. cut a potato into identical cylinders.
2. put some cylinders in a rich sugar solution and others in pure water.
3. measure initial length of cylinders then leave them for 30 mins then measure them again.
4. In pure water the potato cylinders swell because water enters their cells by osmosis. in rich sugar solution they shrink because water leaves their cells due to osmosis.

Question 30

How do root hairs take in water ?

Answer 30

1. root cells grow into long hairs that stick into the soil. each branch of root is covered in millions of microscopic hairs
2. this gives plant a big surface area for absorbing water from the soil
3. usually a high concentration of water in the soil and low concentrations in the plant, thus water diffuses by osmosis into the root hair cell.

Question 31

How do root hairs take in minerals ?

Answer 31

1. Concentration of minerals in the soil is low and high in the root hair cell.
2. so instead of diffusion , active transport uses energy from respiration to help the plant pull minerals into the root hair against the concentration gradient which is essential for growth.

Question 32

Explain how pooters collect ground insects.

Answer 32

1. Pooters are jars with rubber bungs sealing the top and two tubs stick through the bung.
2. if you suck on the shorter tube and put the longer one over an insect, it will be sucked in the jar.
3. fine mess is used over the end of the shorter tube to stop insects being breathed in.
4. suck as many insects as you can from the base of a tree. then count the number of insects you’ve collected.
5. repeat in another area with a similar size and compare finding.

Question 33

Explain how a pitfall traps collect ground insects.

Answer 33

1. Pitfall traps are steep sided containers sunk into the ground , the top is partly open
2. leave trap overnight in sample area and count how many insects are in the container the next day,
   3, repeat this in second sample area and compare findings.

Question 34

Describe sweep nets.

Answer 34

1. used for collecting animals from long grass
2. net is lined wit strong cloth for collecting
3. stand still in sample are and sweep net once and turn insects out into a container to count them
4. repeat in second sample area and compare findings.

Question 35

Describe pond nets.

Answer 35

1. used for collecting pond animals
2. stand in sample area and sweep net along the bottom of the pond /river. Turn net over into a white tray with a bit of water and count organisms you’ve caught.
3. sweep pond net in second sample area and compare findings.

Question 36

How does a Quadrat.

Answer 36

1. place 1m2 quadrat on the ground within sample area in a radom point.
2. split grid and use random number generator to pick coordinates. otherwise results wont be reproducible.
3. count all organisms your interested in within quadrat.
4. repeat steps 1 and 2 a number of times because the large the sample size the better.
5. work out mean in sample area
6. repeat experiment in second sample area
7. compare means

Question 37

What is the mean equation ?

Answer 37

mean = total number of organisms/ number of quadrats

Question 38

How do you work out population size ?

Answer 38

1. work out mean number of organisms per m2

2. multiply mean by total area of habitat.

Question 39

How do you investigate the gradual changes of the distribution of organisms ?

Answer 39

1. mark out a line in the area you want to study
2. put a quadrat down at the start of the line and count organisms
3. then instead of moving it to a second sample area, you move it along the line.

Question 40

How do you measure environmental factors ?

Answer 40

1. use a thermometer to measure the temperature in different places
2. use a light sensor to measure light intensity
3. use indicator liquid or a electronic pH monitor to measure pH of soil by comparing the color you get to a pH chart.