Bioenergetics

Question 1

Photosynthesis

Answer 1

It is the process that produces ‘food’ in plants

Question 2

Word equation for photosynthesis

Answer 2

carbon dioxide + water = glucose + oxygen

Question 3

Chloroplasts

Answer 3

. They contain chlorophyll which is a green pigment that absorbs light.
. It is where photosynthesis takes place

Question 4

Uses of Glucose

Answer 4

1. Respiration
2. Making cellulose
3. Making amino acids

Question 5

Glucose : Making cellulose

Answer 5

Glucose is converted into glucose for making strong cell walls which support and strengthen the cells.

Question 6

Glucose : Making amino acids

Answer 6

.Glucose is combined with nitrate ions, which are absorbed from the soil to make amino acids.
.Amino acids are the building blocks which make up proteins.
.When they are joined together in a specific sequence they make up a particular protein.

Question 7

Storage of Glucose

Answer 7

1.Lipids - they are stored in seeds
2.Starch - It is stored so that it is ready to be used when photosynthesis isn’t happening as much, like in winter. It is stored in roots, stems, seeds and leaves

Question 8

Limiting factors in photosynthesis

Answer 8

.light intensity
.volume of carbon dioxide
.temperature
.amount of chlorophyll (sometimes)

Question 9

Effect of light intensity

Answer 9

as light intensity increases, the rate of photosynthesis increases - but only up to a certain point. Beyond that point it won’t make any difference - as the light intensity increases but the rate will no longer increase.

Question 10

Effect of carbon dioxide

Answer 10

as the volume of carbon dioxide increases, the rate of photosynthesis increases - but only up to a certain point. Beyond that point it won’t make any difference - as the volume of carbon dioxide increases but the rate will no longer increase.

Question 11

Effect of temperature

Answer 11

.Enzymes increase the rate of photosynthesis in plant cells. The speed at which enzymes work is affected by temperature
.Enzymes needed for photosynthesis work more slowly at low temperatures.
.But if the temperature gets too hot, the enzymes needed for photosynthesis and its other reactions will be damaged which happens at around 45°C.

Question 12

Aerobic respiration

Answer 12

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

Question 13

Word equation for respiration

Answer 13

glucose+oxygen = carbon dioxide+water

Question 14

Energy from respiration

Answer 14

.Organisms use energy to build up larger molecules from smaller ones. E.g. proteins from amino acids
.Animals use energy to allow their muscles to contract
.Mammals and birds have the energy to keep their body temperature steady.

Question 15

Anaerobic respiration

Answer 15

the incomplete breakdown of glucose, making lactic acid

Question 16

Word equation for anaerobic respiration

Answer 16

glucose -> lactic acid

Question 17

Oxygen debt

Answer 17

.When you stop exercising, you’ll have an ‘oxygen debt’
.It is the amount of extra oxygen the body needs after exercise to react with the build up of lactic acid and remove it from the cells

Question 18

Removing lactic acid

Answer 18

. The pulse and breathing rate stay high whilst there are levels of lactic acid and carbon dioxide to deliver more oxygen to the cells and take away the carbon dioxide
. The blood that enters your muscles can also transport the lactic acid to the liver where it is converted back into glucose

Question 19

Metabolism

Answer 19

the chemical processes that occur within a living organism in order to maintain life

Question 20

Examples of Metabolism

Answer 20

.Lipid molecules are made up of one molecule of glycerol and 3 fatty acids
.Glucose is broken down in respiration. Respiration transfers energy to power all the reactions in the body that make up molecules.