nutrition in plants

photosynthesis word equation

carbon dioxide + water sunlight chlorophyll > glucose + oxygen

photosynthesis balanced equation

6CO₂ + 6H₂O sunlight chlorophyll > C₆H₁₂O₆ + 6O₂

factors affecting photosynthesis

light, amount of CO₂, temperature

light intensity in photosynthesis

The more light, the faster photosynthesis occurs until another factor limits it.

CO₂ in photosynthesis

The more CO₂, the faster photosynthesis occurs until another factor limits it. Plants can’t survive in pure CO₂

temperature in photosynthesis

The higher the temperature, the faster photosynthesis occurs because temperature affects enzymes controlling photosynthesis. Photosynthesis can’t happen above 45 degrees as the enzymes denature.

limiting factor

the factor at a lowest level which limits a reaction

starch experiment

1. de-starch plant by leaving in dark place

2. boil leaf for 30 seconds

3. place boiling ethanol test tube in boiling water beaker

4. place leaf in test tube and switch off flame to remove chlorophyll

5. use forceps to remove leaf and rinse under tap

6. spread leaf on white tile

7. drip iodine on leaf

8. if iodine turns from yellow brown to blue black, starch is present

photosynthesis experiment for chlorophyll

variegated leaf has some parts with no chlorophyll, do starch test to see if chlorophyll made starch

photosynthesis experiment for CO₂

place plant in sealed bell jar and use soda lime to absorb CO₂ then do starch test

photosynthesis experiment for light

place black paper on part of leaf then do starch test

rate of photosynthesis experiment

use aquatic plant such as Elodea (pondweed) and count oxygen bubbles or measure volume produced

Leaf structure (diagram)

Waxy cuticle

Prevents water loss but transparent

Upper epidermis

Protect plants from pathogen and transparent

Palisade mesophyll

Tall thin cells packed together with many chloroplasts for maximum light absorption

Spongy mesophyll

Allow carbon dioxide to move through leaf and diffuse into palisade mesophyll

Lower epidermis

Has stomata to get carbon dioxide and guard cells to prevent water loss

Vascular bundle

Contains xylem, which brings water in, and phloem, which brings glucose and oxygen out

Nitrogen in plants

Needed to make amino acids, DNA and hormones, lack of it causes leaves to turn yellow and die and growth to be stunted

Magnesium

Needed to make chlorophyll, enzymes and DNA, lack of it causes leaves to turn yellow and growth to slow down