Bioenergetics

Photosynthesis

A process that plants use to convert water and carbon dioxide into glucose and oxygen.

What are the limiting factors of photosynthesis?

Light, Carbon Dioxide concentration, chlorophyll and temperature

Why is the rate of photosynthesis low at hot tempertaures

The enzymes denature

Why is the rate of photosynthesis low at low temperatures?

The enzymes have low kinetic energy, it is unable to catalyse water and CO2 quickly.

Uses for glucose in plants

Respiration, Cellulose, Making amino acids, Storing as starch, Moving minerals.

Why is glucose stored in starch?

Starch is insoluble, where as glucose is soluble.

Why does the rate of photosynthesis change throughout the day?

It’s because during the day plants receive more light for photosynthesis.

What is the waxy cuticle?

It prevents pathogens from entering and reduces water loss

Upper epidemis

Is transparent, allows light to travel through

Palisade layer

Contains many chloroplasts to absorb sunlight and complete photosynthesis

Spongy Mesophyll

Air pockets that allow gases to diffuse through

Guard Cell

Cells used to open and close the stomata

Stomata

Small gaps to allow gases and water to diffuse through

Anaerobic respiration (in humans)

Glucose → Latic acid

How much energy is produced in anaerobic respiration (in humans)

There is an incomplete oxidation of glucose, released less energy

Oxygen Debt

Latic acid must be removed. It is then oxidised to into carbon dioxide and water.

Fermentation

It is the incomplete breakdown of glucose in plants

Anaerobic respiration (in plants)

Glucose → ethanol + carbon dioxide

Aerobic Respiration (factors)

Requires oxygen, produces CO2, moderate intensity exercises, Oxygen + glucose → CO2 + Water, No oxygen debt, No yeast/fermentation required, Provides energy over long periods of time

Anaerobic respiration (factors)

Doesn’t require oxygen. Plants: Produces CO2, Glucose → CO2 + ethanol, yeast required. In Humans: high intensity exercise, Glucose → lactic acid, Body goes into oxygen debt, Provides energy for a short amount of time.

Glycogen

Form of glucose, when you have excess amounts of glucose. Found in the liver and muscles.

Why is water important in root hair cells for mineral salts?

The mineral salts dissolve in the water and the water transports the salts through the plant.