B4 - Bio energetics

Reactants for photosynthesis

carbon dioxide + water

products of photosynthesis

glucose + oxygen

Word equations for photosynthesis

carbon dioxide + water —\> glucose + oxygen

What energy is required for photosynthesis?

Light

Where does photosynthesis take place?

Chloroplasts

What substance is in chloroplasts enables photosynthesis?

Chlorophyll

What are the limiting factors of photosynthesis?

light intensity, carbon dioxide concentration and temperature

How is glucose used in plants?

Respiration, cellulose production, amino acids production, stores

How is glucose used in respiration?

Energy is transferred from glucose

How is cellulose used?

To make cell walls

How are amino acids used by plants?

Make proteins

Other than amino acids, what else is used in production of proteins?

Nitrate ions

What forms is glucose stored as?

lipids and starch

Where are lipids stored in plants?

seeds

Where is starch stored in plants?

roots, stems, leaves

When are starch stores used?

When photosynthesis isn't happening

Give 2 examples of when starch stores are used.

night, winter

What is the required investigation into limiting factors?

Effect of light intensity on rate of photosynthesis of pondweed

What is the independent variable for the pondweed practical?

light intensity

How is the light intensity changed?

moving the pondweed away from the lamp

How is the light intensity measured? (in this practical)

cm away from the lamp

What is the dependent variable in the pondweed practical?

rate of photosynthesis

How is the rate of photosynthesis measured? (in this practical)

bubbles of CO2 released per minute

What are the control variables for the pondweed practical?

temperature, measuring period, lamp, pondweed

What is the relationship between light intensity and distance?

light intensity α 1/ d²

respiration

the process of transferring energy from the break down of glucose

Where does respiration happen?

mitochondria

When does respiration happen?

all the time

What are the 2 types of respiration?

aerobic and anaerobic

aerobic respiration

respiration using oxygen

Equation for aerobic respiration

glucose + oxygen → water + carbon dioxide

Equation for anaerobic respiration in animals

glucose → lactic acid

Equation for anaerobic respiration in plants

glucose

Which type of respiration is used during exercise?

Anaerobic (animal)

Why is anaerobic respiration less used during exercise?

to supply enough oxygen to the body

Why does your heart rate increase when you exercise?

to get oxygen to cells and carbon dioxide out of the body faster

Lactic acid

unoxidised (not fully broken down) glucose

What does a build up of lactic acid cause?

muscle fatigue

What happens after you stop anaerobically respiring?

oxygen debt

oxygen debt

the amount of oxygen required to break down lactic acid produced during anaerobic respiration

Why does your pulse remain high after exercise?

to fully oxidise lactic acid, remove carbon dioxide, transport lactic acid to the liver

What happens to lactic acid in the liver?

converted back to glucose

What is the equation for anaerobic respiration (plants)?

glucose (yeast) → ethanol + carbon dioxide