Topic 4 - Bioenergetics

Question 1

What is the products of photosynthesis?

Answer 1

Glucose and Oxygen

Question 2

What are the reactants in photosynthesis?

Answer 2

Carbon dioxide and Water

Question 3

How is glucose used in photosynthesis?

Answer 3

Respiration-Transfers energy from glucose enabling the plant to convert the rest of the glucose into other useful substances.
Making Cellulose-Converted to cellulose to make strong plant cell walls.
Amino Acids-Combines with nitrate ionsto make amino acids which is then made into proteins.
Stored as Oils or Fats-Turned into lipids for storing in seeds.
Stored as Starch-Stored in roots and stems ready to use when photosynthesis isnt happening, like in winter.

Question 4

How is chlorophyll a limiting factor in photosynthesis?

Answer 4

Environmental stress such as lack of nutrients can cause chloroplasts to become damaged or not make enough chlorophyll meaning photosynthesis is reduced because they can’t absorb as much light.

Question 5

How is light intensity a limiting factor in photosynthesis?

Answer 5

Too little and there is not enough energy for the reaction to occur.

Question 6

How does carbon dioxide concentration effect the rate of photosynthesis?

Answer 6

It is needed for photosynthesis to occur as it is a reactant.

Question 7

How does temprature effect the rate of photosynthesis?

Answer 7

It gives the particles energy to collide and react.

When the temprature is too high the enzymes will denature.

Question 8

Describe the experiment if using pondweed to test the rate of photosynthesis.

Answer 8

A source of white light is placed a specific distance away from the pondweed.
The pondweed is left to photosynthesise for a set amount if time and the oxygen released will collect in the capillary tube.
At the end of the experiment a syringe is used to draw the gas bubble in the tube alongside a ruler and the length of the gas bubble is measured.
The experiment is repeated with the light source at different distances from the pondweed at each time.

Question 9

What is respiration?

Answer 9

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

Question 10

What is the equation for aerobic respiration?

Answer 10

Glucose + Oxygen = Carbon Dioxide + Water

Question 11

What is the equation for anaerobic respiration?

Answer 11

Glucose = Lactic Acid

Question 12

What is anaerobic respiration in yeast?

Answer 12

Fermentation

Question 13

What is the word equation for anaerobic respiration kn yeast?

Answer 13

Glucose = Ethanol + Carbon Dioxide

Question 14

What can fermentation be used to make?

Answer 14

It can make bread and alcoholic drinks like beer and wine.

Question 15

What is oxygen debt?

Answer 15

It is the amount of extra oxygen your body needs to react with the build up of lactic acid and remove it fron the cells.

Question 16

What are the control variables in the pondweed experiment?

Answer 16

Temperature.

Time pondweed is left to photosynthesise.

Question 17

How can you alter the pondweed experiment to measure the effect of temperature?

Answer 17

You can put the pondweed in a waterbath at a set temperature and repeat with different temperatures of water to see how it effects it.

Question 18

How can you alter the pondweed experiment to measure the effect of carbon dioxide?

Answer 18

A measured amount of sodium hydrogencarbonate can be put in the water which gives off carbon dioxide and you can repeat with different concentrations of it.

Question 19

What does limiting factor mean?

Answer 19

Its stopping photosynthesis from happening any faster.

Question 19

How can you create the ideal conditions for farming?

Answer 19

Greenhouses trap the suns heat to make sure the temperature doesnt become a limiting factor. In winter they might use a heater to keep the temperature an ideal level or if its too hot in summer they might use shades and ventilation to cool it down.
Supplying artificial light at night to give the plants more time for photosynthesis.
Using a paraffin heater to increase the carbon dioxide level as it is a byproduct of the paraffin heater.
Keeping plants enclosed keeps them free from pests and diseases.
Fertilisers in the soil provides all the minerals for healthy growth.

Question 19

What are advantages and disadvantages of artificially creating idel conditions for plants?

Answer 19

It costs money but using the correct amount of each thing for photosynthesis the crops will grow much faster and can be harvested more often and sold.
However needs to supply the right amounts-enough for the plants to grow well but not more than the plants need as it would waste money.

Question 20

What type of reaction is respiration?

Answer 20

Exothermic as it transfers energy to the environment.

Question 21

How do organisms use the energy transferred by respiration?

Answer 21

To build up larger molecules from smaller ones.
To allow muscles to contract so animals can move.
To keep body temperature steady in colder surroundings.

Question 22

What is metabolism?

Answer 22

The sum of all of the reactions thay happen in a cell or the body.

Question 23

How is lactic acid formed?

Answer 23

The incomplete breakdown of glucose.

Question 24

How else can the body cope with high levels of lactic acid?

Answer 24

The lactic acid goes into the blood from our muscles and transports it to the liver where it is converted back to glucose.

Question 25

Why do you repsire more when you exercise?

Answer 25

Your muscles contract more frequently so you meed more energy from respiration. This allows more oxygen to the your cells so your breathing rate increases to get the oxygen into your blood and your heart rate increases so it gets more oxygenated blood to the muscle cells quicker.
However doing vigourous exercise means you cant supply oxygen to your muscles so you being to respire anaerobically which causes lactic acid to build up in the muscles.

Question 26

How can you investigate the effect of exercise on the body?

Answer 26

Take your pulse sitting down, after five minutes of gentle walking, after slow jogging, then after running.
Then calculate pulse rate and plot your results on the bar chart.
The pulse rate will increase the more intense the exercise as your body needs more oxygen in the muscles and more carbon dioxide away from the muscles.

Question 27

How would you reduce random errors when investigating the effect of exercise?

Answer 27

Do it as a group and plot the aberage pulse rate for each exercise.