NEW nutrition of plants - photosynthesis (to be refined)

Function of chlorophyll in photosynthesis

It absorbs light energy and converts it into chemical energy.

Two main reasons most life depends on photosynthesis

It provides an energy source and a source of oxygen.

Word equation for photosynthesis

Carbon dioxide + water → glucose + oxygen (light energy, chlorophyll)

Type of energy light is converted into during photosynthesis

Chemical energy

Two ways to determine the rate of photosynthesis

Measure the decrease in a reactant or the increase in a product.

Glucose use NOT done by plants (MCQ)

C) Production of oxygen

Factor NOT affecting photosynthesis rate (MCQ)

D) Humidity

How to measure amount of oxygen produced in photosynthesis (2 ways)

Count bubbles over time or measure oxygen volume using a gas syringe.

Energy conversion during photosynthesis

Light energy → Chemical energy

Type of energy chlorophyll traps

Light energy

Uses of glucose produced from photosynthesis (CASFM)

Converted to cellulose (cell walls), amino acids (proteins), sucrose or starch (storage), fats, or oxidized for energy in respiration.

Importance of photosynthesis

Source of food/energy; removes CO₂ and produces O₂.

Tool to measure CO₂ concentration decrease

Hydrogen carbonate indicator

How hydrogen carbonate indicator works

Color changes based on CO₂ concentration; observe over fixed time.

How to test for starch in leaves

Use iodine solution on a decolorised leaf to observe color change.

Steps for starch test (iodine test)

Destarch plant → Boil leaf in water → Boil in ethanol in hot water → Wash leaf → Place on tile → Add iodine → Observe color change

Positive result for iodine test (starch present)

Solution turns blue-black

Negative result for iodine test (no starch)

Solution stays yellowish-brown

Factors affecting rate of photosynthesis

Light intensity, CO₂ concentration, and temperature

How to vary light intensity in experiments

Change distance of lamp from plant setup

How to vary temperature in experiments

Use water bath; adjust with hot or cold water

How to vary CO₂ concentration in experiments

Adjust sodium hydrogen carbonate concentration

Light intensity and ROP relationship

Higher light intensity → Higher ROP due to more light energy

CO₂ concentration and ROP relationship

Higher CO₂ → Higher ROP since CO₂ is a photosynthesis substrate

Temperature and ROP relationship (Stage 1 - Low temp)

Low temp → Low ROP due to inactive enzymes and fewer collisions

Temperature and ROP relationship (Stage 2 - Increasing temp)

Higher temp → Higher ROP due to more kinetic energy and collisions

Temperature and ROP relationship (Stage 3 - Optimum exceeded)

ROP peaks at optimum temp; above that, enzymes denature and ROP decreases