Photosynthesis & Plants Flashcards
Photosynthesis
5 marks
Endothermic process that takes place in the Chloroplasts.
(Chemical reaction) used by plants to make glucose + O2 from CO2 + water, using light energy.
O2 is a by-product of photosynthesis.
Algae subsumed within plants and some bacteria are also photosynthetic.
Photosynthesis Word Equation:
5 marks
Carbon Dioxide + Water —(Light)—> Glucose + Oxygen
Photosynthesis Balanced Chemical Equations:
4 marks
6CO2 + 6H2O —> C6H12O6 + 6O2
The plant uses the glucose it produces (during photosynthesis) for:
(3 marks)
Respiration
Storage
Useful Substances
Glucose Uses: Respiration
1 mark
The Glucose is used to provide energy.
Glucose Uses: Storage
2 marks
The Glucose is converted into Starch and Oils.
Glucose Uses: Useful Substances
3 marks
The Glucose is converted into -
Cellulose for Cell Walls,
Protein for Growth
and Chlorophyll.
Transparent Waxy Cuticle
4 marks
Protective layer - that allows light to enter the leaf.
Waterproof adaptations - in order to prevent water loss by evaporation.
Types of Epidermis
2 marks
Upper and Lower Epidermis.
Upper Epidermis
1 mark
Transparent to allow light to pass through (into the leaf).
Lower Epidermis
3 marks
Protective layer on bottom of leaf.
Contains stomata + guard cells.
Stomata and (their job) in Lower Epidermis of a Leaf
3 marks
Apertures through which gases are exchanged
- allows Carbon Dioxide + Oxygen to enter/leave leaf.
Open during day + closed at night.
Guard Cells (and their job) in Lower Epidermis of the Leaf
3 marks
Allows for Gas Exchange - allows CO2 in and out.
Through opening and closing Epidermis.
Palisade Mesophyll Layer
3 marks
Uniform shape, tightly compact with chloroplasts-
Packed together at the top of the leaf.
Job of Chloroplasts in Upper Epidermis
1 mark
To trap as much light as possible.
Leaves are adapted for:
2 marks
Light absorption
Gas Exchange
Why are adaptations made in the leaf?
1 mark
Maximise Light Absorption
Spongy Mesophyll
7 marks
Leaf cells - Irregular shaped Mesophyll contains very few Chloroplasts.
Contains large Surface Area to allow Storage Gases/Gas Exchange
- increases the diffusion of CO2 + O2 and allows CO2 to travel to Cells.
Surface Area and Gas Exchange In Spongy Mesophyll
2 marks
Increases the diffusion of Carbon Dioxide and Oxygen.
Allows CO2 to travel to Cells.
When do Stomata usually open and close?
2 marks
Open during day.
Close at night.
Where is Stomata usually found?
2 marks
Lower end of leaf.
In Epidermis of Leaves/Stems.
What surrounds Stomata in Plants?
1 mark
2 Guard Cells.
Intercellular air spaces within the Spongy Mesophyll Layer
2 marks
Allow the diffusion of carbon dioxide and oxygen.
Adaptations to maximise Gas Exchange
3 marks
Spongy Mesophyll
Stomata
Intercellular Air Spaces
Important parts of leaves for Light Absorption and Gas Exchange
(9 marks)
- Transparent Waxy Cuticle
- Upper Epidermis
- Chloroplasts
- Palisade Mesophyll Layer
- Spongy Mesophyll
- Intercellular Air Space
- Lower Epidermis
- Stoma
- Guard Cells
Adaptations to Maximise Light Absorption
6 marks
Each leaf is not in the shade of another.
Transparent Waxy Cuticle.
Epidermis (Upper and Lower).
Palisade Mesophyll Layer.
Leaves are thin with a large Surface Area.
Kinetic
1 mark
The energy an object possesses due to its motion.
Ethanol
2 marks
Alcohol produced as a result of fermentation of sugars by yeast.
Iodine
3 marks
Chemical reagent
Changes from yellow-brown to blue-black in the presence of starch.
Plateau
1 mark
Staying at the same level for a period of time.
Endothermic
1 mark
A reaction that absorbs energy from its surroundings.
Pigment
1 mark
A coloured chemical.
Spongy Mesophyll: Simplified
3 marks
Plant tissue in a leaf which has loosely packed cells and air spaces between them
to allow gas exchange.
Chlorophyll
2 marks
The green chemical inside the chloroplasts of plant cells.
It enables photosynthesis to take place.
Stomata
4 marks
Tiny holes in the epidermis (skin) of a leaf
- control gas exchange by opening + closing
- involved in loss of water from leaves.
Singular; stoma.
