Leaf Structure Flashcards
What is carbon dioxide needed for?
Photosynthesis
What is oxygen needed for?
Respiration
How do gases get in and out of the leaf?
By diffusion through the stomata
What is diffusion?
The movement of particles from an area of higher concentration to an area of lower concentration, down a concentration gradient
What is aerobic respiration?
The breakdown of glucose to release energy in the presence of oxygen
What is the word equation for respiration?
Glucose + Oxygen ——–> Carbon Dioxide + Water
What is the word equation for photosynthesis?
Carbon Dioxide + Water ———-> Glucose + Oxygen
What is photosynthesis?
The conversion of light energy into chemical energy stored in the bonds of glucose molecules made from atoms from carbon dioxide and water
How do air spaces in the spongy mesophyll affect gas exchange?
Air spaces increase the surface area to volume ratio for the carbon dioxide absorption
How do the guard cells affect gas exchange?
Allows the stomata to open and close to allow the diffusion of gases
How does the broad shape of the leaf affect gas exchange?
Increases surface area to absorb more sunlight and carbon dioxide for photosynthesis
How does the thin shape of the leaf affect gas exchange?
Shorter diffusion pathway for carbon dioxide to diffuse into the leaf cells and for oxygen to diffuse out of the leaf cells
How do the stomata affect gas exchange?
Open to allow carbon dioxide into the leaf for photosynthesis and the diffusion of oxygen and water vapour out of the leaf.
Where are stomata located?
Lower epidermis of the leaves
What happens to the stomata during the day?
The guard cells will photosynthesise meaning the water concentration inside the leaf would decrease
Water is absorbed by osmosis into the leaf and the stomata becomes turgid
What happens to the stomata during the night?
The guard cells will not photosynthesise meaning the water concentration in the leaf would increase
Water is lost from the leaf and the stomata becomes flaccid
Does respiration take place in the day or the night?
All the time
Does photosynthesis take place in the day or the night?
Day only because photosynthesis requires sunlight
What indicator is used to show carbon dioxide concentration in a solution?
Hydrogencarbonate indicator
What colour does hydrogencarbonate indicator go in high carbon dioxide concentrations?
Yellow
What colour does hydrogencarbonate indicator go in low carbon dioxide concentrations?
Purple
What colour does hydrogencarbonate indicator go in atmospheric conditions of carbon dioxide?
Red
What is the relationship between temperature and photosynthesis?
As temperature increases, the rate of photosynthesis also increases until the temperature reaches the optimum
What is the relationship between light intensity and photosynthesis?
The more light the plant receives, the faster the rate of photosynthesis
What is the relationship between carbon dioxide concentration and photosynthesis?
The more carbon dioxide present, the faster the rate of photosythesis
What is a limiting factor?
Something that is limiting the rate of reaction - temperature, light intensity and carbon dioxide concentration
What is the waxy cuticle?
The protective layer on top of the leaf that prevents water from evaporating
What is the upper epidermis?
Thin and transparent part of the leaf that allows light to penetrate the palisade cells
What is the palisade mesophyll?
Cells which are tightly packed with chloroplasts to maximise photosynthesis
What is the spongy mesophyll?
The part of the leaf that contains internal air spaces allowing for gas exchange by diffusion quicker
What is the lower epidermis?
The part of the leaf that contains the guard cells and stomata
What is magnesium needed for?
Needed to make chlorophyll - if there is a deficiency there are yellowed leaves
What are nitrates needed for?
To make amino acids to build proteins and DNA - if there is a deficiency there is stunted growth
