SAFOLO — 2e.1 — Nutrition in plants Flashcards
Photosynthesis?
The production of Glucose and oxygen in cells using light energy, carbon dioxide and water.
Light energy to chemical energy in photosynthesis?
Light energy from the sun is absorbed by Chlorophyll to produce Glucose (chemical energy) and is stored as starch for growth while Oxygen is a waste product.
Chloroplasts are responsible for changing light energy to chemical energy
Equation for photosynthesis?
Carbon dioxide + Water —> Glucose + Oxygen
6CO2 + 6H2O —> C6H12O6 + 6O2
Limiting factors of photosynthesis?
- Carbon dioxide
- Temperature
- Light Intensity
How does Carbon dioxide affect the rate of photosynthesis?
- As conc. of CO2 increases, rate of Photosynthesis will increase
- However, as conc. of CO2 increases beyond a certain point, rate of Photosynthesis will plateau (something else is limiting the rate of carbon dioxide)
How does temperature affect the rate of photosynthesis?
- As temperature increases towards optimum, rate of Photosynthesis will increase
- However as temperature increases above optimum, enzymes involved in Photosynthesis will denature, causing rate of Photosynthesis to decrease
How does light intensity affect the rate of photosynthesis?
- As light intensity increases, rate of photosynthesis will increase
- However, as light intensity increases beyond a certain point, rate of photosynthesis will plateau (something else is limiting the rate of photosynthesis)
Waxy cuticle?
Outer protective layer that prevents water loss via evaporation
Upper epidermis?
Thin and transparent layer of cells that allow light to enter Palisade Mesophyll
Palisade mesophyll?
Layer tightly packed with chloroplasts to maximise light absorption for photosynthesis
Spongy mesophyll?
Layer containing air spaces to increase SA:V ratio for more efficient diffusion of gases (mainly CO2)
Lower epidermis?
Contains:
- Guard cells which control the opening and closing of the stomata by absorbing and losing water to regulate gas exchange and prevent water loss
- Stomata: opening controlled by guard cells to regulate gas exchange (CO2 in, O2 out) and prevent water loss
How is a leaf adapted for photosynthesis?
- Large surface area: increases SA:V ratio for diffusion of CO2 and absorption of light
- Thin: Short diffusion length
- Chlorophyll
- Vascular bundles
- Stomata
Chlorophyll?
Found in the chloroplasts, responsible for the green colour, absorb light energy
Vascular bundles?
Support the leaf
Transport water for photosynthesis from roots to stems and leaves - Xylem
Carbohydrates produced by photosynthesis transported from leaves to roots - Phloem
Why do plants require magnesium ions?
- To build Chlorophyll for growth
- Deficiency: Leaves turn yellow
Why do plants require nitrate ions?
- To produce Amino acids to build protein and DNA
- Deficiency: Leaves turn yellow and stunted growth
Experiment: effect of light intensity on Photosynthesis
Independent variable: distance of lamp from pondweed or light intensity
Dependent variable: amount of oxygen bubbles produced
Control: Temperature of water, length of pondweed, species of plant, colour of light
How do plants store all of the glucose produced during photosynthesis?
They convert glucose into larger starch molecules. They are insoluble, cannot move between cells and are stored in the leaves.
Testing a leaf for starch: Heat the leaf?
Because it destroys the enzymes, and if that isn’t done then the enzymes in the leaf may interfere with the experiment. The heat will also break down the waxy layer of the leaf.
Testing a leaf for starch: Put in ethanol?
To dissolve the chlorophyll and the leaf get decolourised (because of the loss of the chlorophyll pigment). It will be plain yellow in colour.
Testing a leaf for starch: Iodine to leaf?
Because iodine is an indicator to show if starch is present- if it is, the leaf will turn blue-black.
Chloroplast
Converts light energy into relatively stable chemical energy via the photosynthetic process.
What is glucose used for in a plant?
Glucose is used by plants for energy and to make other substances like cellulose, starch, proteins and amino acids
Where do plants get minerals from?
Plants get water through their roots. This is how they get minerals, too. From the roots, the minerals travel to the stems.
