module 4

Question 1

What does photosynthesis use to change co2 and water into glucose and oxygen?

Answer 1

Energy. Energy is transferred to chloroplasts from environment by light.

Question 2

Where does photosynthesis take place?

Answer 2

In chloroplast in green plant cells-contain green pigment like chlorophyll and absorb light.

Question 3

What type of reaction is photosynthesis?

Answer 3

Endothermic-means energy is transferred from environment in process.

Question 4

What is the word and symbol equation of photosynthesis?

Answer 4

Carbon dioxide+water=(light)=glucose+oxyge

6co2+6h20=(light)=c6h12o6+602

Question 5

What are the ways that plants use glucose?

Answer 5

For respiration-transfer energy from glucose which enables plants to convert rest of glucose into various other useful substances. Making glucose-glucose converted into cellulose for making strong plant cell walls. Making amino acids-glucose combined with nitrate ions (absorbed by soil) to make amino acids than made into proteins. Sorted as oils or fats-glucose turned into lipids (fats and oils) for storing in seeds.

Question 6

How do plants use glucose to store starch?

Answer 6

glucose turned into starch and stored in roots, stems and leaves, ready for use when photosynthesis isn’t happening, e.g. in winter. Starch is insoluble, which makes it much better for storing than glucose-a cell with lots of glucose in would draw in loads of water and swell up.

Question 7

What are the limiting factors of photosynthesis?

Answer 7

rate of photosynthesis affected by intensity of light, concentration of co2 and temperature. Any of 3 factors can become limiting factor (stopping photosynthesis from happening any faster). Factors have combined effect on rate of photosynthesis, which factor is limiting factor depends on environmental conditions: At night light is limiting factor, in winter temperature is often it, if warm and bright enough amount of co2 is usually it.

Question 8

How can chlorophyll be a limiting factor?

Answer 8

Amount of chlorophyll in plant can be affected by disease or environmental stress, e.g. lack of nutrients. Factors can cause chloroplasts to become damaged or to not make enough chlorophyll. Means rate of photosynthesis is reduced because can’t absorb as much light.

Question 9

How can the amount of light affect the rate of photosynthesis?

Answer 9

Light provides energy needed for photosynthesis. As light level raised, rate of photosynthesis increases steadily-but only up to certain point. Beyond, won’t make difference-as light intensity increases, rate will no longer increase. Because be either temperature of co2 levels which is limiting factor not light. In lab can change light intensity by moving lamp closer or further away from plant. But is just plot rate of photosynthesis against “distance of lamp from plant” get weird graph. Need to measure light intensity at plant using light meter.

Question 10

How can carbon dioxide affect the rate of photosynthesis>

Answer 10

co2 is one of raw materials needed for photosynthesis. As with light intensity, amount of co2 will only increase rate of photosynthesis up to point. After graph flattens out-as amount of co2 increases, rate no longer increases. Shows that co2 is no longer limiting factor. As long as light and co2 are in plentiful supply then factor limiting photosynthesis must be temperature.

Question 11

How can temperature affect rate of photosynthesis?

Answer 11

Usually temperature is limiting factor, because too low-enzymes needed for photosynthesis work more slowly at lower temperatures. If plant gets too hot, enzymes it needs for photosynthesis and its other reactions will be damaged. Happens at about 45 Celsius.

Question 12

How can you use pondweed to find how light intensity can affect the rate of photosynthesis?

Answer 12

Canadian pondweed can be used to measure the effect of light intensity on rate of photosynthesis. Rate at pondweed produces oxygen corresponds to rate at which it’s photosynthesising-faster rate of oxygen production, faster rate of photosynthesis.

Question 13

How does the experiment to find how light intensity affects the rate of photosynthesis?

Answer 13

Source of white light is placed at specific distance from pondweed. Pondweed left to photosynthesise for set amount of time. As photosynthesising, oxygen released will collect in capillary tube. At end of experiment, syringe used to draw gas bubble in tube alongside ruler and length of gas bubble is measured. Proportional to volume of o2 produced. For experiment any variables that could affect results should be controlled e.g. temperature, time pondweed left to photosynthesise. Experiment repeated twice with light source at same distance and mean volume of o2 produced is calculated. Experiment repeated with light source at different distances from pondweed.

Question 14

How can the apparatus be altered to measure effect of temperature or co2 on photosynthesis in pondweed experiment?

Answer 14

E.g. test tube of pondweed can be put into water bath at set temperature or measured amount of sodium hydrogencarbonate can be dissolved in water (gives off co2). Experiment can be repeated with different temperatures of water/concentrations of sodium hydrogencarbonate.

Question 15

What is the light intensity and light?

Answer 15

Inversely proportional to each other. Inverse square law is when light intensity deacreases in proportion to square distance is inverse square law =light intensity = 1/distance. Means if ahlve distance, light intensity 4 times greater 3 rd of distance 9 times greater. Use 1/d squared as measure of light intensity

Question 16

How does a greenhouse work?

Answer 16

Trap sun’s heat, and make sure temperature doesn’t become limiting. In winter farmer or gardener might use heater as well to keeep temperature at ideal level. In summer could get too hot, so might use shades and ventilation to cool things down. Keeping plants in enclosed in greenhouse makes esasier to keep them free from pests and disease. Farmer can add fertilisers to soil as well, to provide all minerals needed for healthy growth.

Question 17

When is arteficial light used for photosynthesis by commercial farmers?

Answer 17

After sun goes down to give plants more quality of photosynthesis time.

Question 18

How can farmers and gardeners increases the levels on co2 in greenhouse?

Answer 18

Using paraffin heater to heat greenhouse. As paraffin burns, makes co2 as by-product.

Question 19

How do crops grow the quickest and be decent crop be harvested more often for sale?

Answer 19

Keep right amount of heat, light etc. Enough to make plants grow well, but not more than plants need, as would just be wasting money.

Question 20

What is respiration?

Answer 20

Reactions, respiration transfers energy that the cell needs to complete activities. Respiration isn’t breathing. It is a process of transfering energy to breakdown glucose-happens in the cell. Happens in plants too. Respiration is an exothermic reaction, transfers enenrgy to the environment.

Question 21

What is the definition of respiration?

Answer 21

Respiration is the process of transferring energy from glucose which goes on in every cell.

Question 22

What are the 3 examples of how organisms use the energy transferred by respiration?

Answer 22

To build up larger molecules from smaller ones. In animals, used to allw muscles to contract. In mammals and birds, energy used to keep body temperature steady in colder surroundings.

Question 23

What is metabolism?

Answer 23

In cell there are lots of chemical reactions happening all the time, controlled by enzymes. Many link together to form bigger reactions: reactant=(enzyme)=product=(enzyme)=product=(enzyme)=product.

Question 24

What are the examples of larger molecules being made from smaller ones?

Answer 24

Lots of small glucose joined together in rections to form strach,glycogen and cellulose. Lipid molecules are each made from 1 molecule of glycerol and 3 fatty acids. Glucose is combined with nitrate ions to make amino acids, then made into proteins.

Question 25

What are the examples of larger molecules being broken down into smaller ones?

Answer 25

Glucose is broken down in respiration. Respiration transfers energy to power all reactions in the body that make nmolecules. Excess protein is broken down in a reaction to produce urea. Urea is then extracted in urine.

Question 26

What is the definition of motabilism?

Answer 26

The sum of the ractions that happen in a cell or the body.

Question 27

What is aerobic respiration?

Answer 27

Respiration using oxygen, most efficient way to transfer energy to glucose, aerobic respiration goes on all the time in plants and animals. Most reactions in aerobic respiratoin happes inside the mitochondria.

Question 28

What is the symbol and word equation for aerobic respiration?

Answer 28

glucose+oxygen=carbon dioxide+water

c6h1206+602=6co2+6h2o.

Question 29

What is anaerobic respiration?

Answer 29

When excersise can’t supply enough oxygen to muscles, so perform anerobic erspiration and aerobic. Anerobic is the incomplete breakdown of glucose making lactic acid. It doesn’t fully transfer as much energy cas aerobic respiration. Because glucose isn’t fully oxidised. Not useful in emergencies.

Question 30

What is the word equation for anerobic respiration?

Answer 30

glucose=lactic acid.

Question 31

How do plants and yeast use anerobic respiration?

Answer 31

They respire anerobically to produce ethanol and carbon dioxide.Anerobic respiration in yeast is called fermentation-in food and drink industry used to make bread and alcoholic drinks. To make bread uses co2 from fermentation to make bread rise. In beer/wine industry uses fermentation to produce alcohol.

Question 32

Why do you respire more when you excersise?

Answer 32

Muscles need energy to contract. Muscles contract more in excersise-need more energy-increased respiration. Increase in respiration in cells means get more oxygen in them.

Question 33

What happens to breathing volume/breathing rate during exercise?

Answer 33

Increases to get more oxygen to blood, heart rate increases to get oxygenated blood around body faster. Removes co2 more quickly at same time.

Question 34

What happens during vigorous exercise?

Answer 34

Can’t supply oxygen to muscles quickly enough, start anerobic respiration. Not best way to transfer energy from glucose-lactic acid builds up in muscles-pain.

Question 35

What happens as a result of long periods of exercise?

Answer 35

Muscle fatigue, muscles get tired, and can’t contract efficiently.

Question 36

What is an oxygen debt?

Answer 36

When restoring anerobic respiration when stop esercising, will have oxygen debt. Is the amount of oxygenneeded to react with build up of lactic acid and remove it from cells. Oxygen reacts with lactic acid to form co2 and water. To repay oxygen muscles didn’t get in time. Have to keep breathing after stop exercising to get more oxygen into blood. Pulse and breathing rate will stay high. Will be high levels of lactic acid and co2.

Question 37

How can you measure breathing rate by counting breaths and heart rate?

Answer 37

Taking pulse. Pulse rate will increase in more excersise as body needs more oxygen to muscle and take more co2 from muscles. To reduce effort of any random errors on results, do as group and find average rate after excersise.

Question 38

When can you take pulse rates?

Answer 38

sitting for 5 minuites
walking for 5 minuites
slow jog for 5 minuites
run for 5 minuites.