B6 Flashcards
(64 cards)
What absorbs the required energy for photosynthesis?
Chlorophyll
Where in the cell does photosynthesis take place?
The chloroplasts
What is the word equation for photosynthesis?
Carbon dioxide + water –> Glucose + Oxygen
What is the balanced symbol equation for photosynthesis?
6CO2 + 6H2O –> C6H12O6 + 6O2
What type of reaction is photosynthesis?
An endothermic one
What can the glucose made in photosynthesis be used for?
Stored as starch for later and respiration
What is the symbol equation for glucose?
C6H12O6
How do plants get carbon dioxide for photosynthesis?
It diffuses from the air to the leaves through the stomata
How do plants get water for photosynthesis?
It diffuses from the soil into root hair cells by osmosis
Why is starch a good long term storage molecule?
It is compact, insoluble and can be easily broken down when needed
What 2 things do you need to make an amino acid?
Glucose and nitrate
What are the 5 main uses of glucose in plants?
Cellular respiration for breaking down the glucose to release energy
Making cellulose for strong cell walls, Making amino acids for proteins and making lipids for storing the energy as fats/oil for later use
What is the inverse square law?
Light intensity = 1 / distance (from light source) squared
Give 2 reasons a plant may not have enough chlorophyll?
They lack the required nutrients or they may have a disease like tobacco mosaic virus
What are the 3 environmental factors that affect the rate of photosynthesis?
Light, temperature and carbon dioxide
How does an increase in temperature affect photosynthesis and why?
An increase in temperature will cause the rate of photosynthesis because the particles will have more energy and move quicker, so react more frequently. The highest rate is at the optimum temperature for the enzymes, at the higher temperatures the rate decreases because the bonds holding the enzymes together begin to break and so the enzyme changes shape. The rate then falls to 0 as the enzymes denature
Describe the affect of carbon dioxide on the rate of photosynthesis and explain it
An increase in carbon dioxide will cause the rate of photosynthesis to gradually increase up to a point where it will plateau. Up to a point carbon dioxide is the limiting factor, so the rate of photosynthesis is increasing, but after that point there is enough carbon dioxide for the plant so it doesn’t affect the rate of photosynthesis, meaning something else is the limiting factor
Describe the affect of light intensity on the rate of photosynthesis and explain it
An increase in light intensity will cause the rate of photosynthesis to gradually increase up to a point where it will plateau. Up to a point light intensity is the limiting factor, so the rate of photosynthesis is increasing, but after that point there is enough light intensity for the plant so it doesn’t affect the rate of photosynthesis, meaning something else is the limiting factor
Why do farmers use greenhouses?
To trap heat energy from sunlight, and so increase the temperature. They also keep out pests that could damage the plants
How can farmers ensure photosynthesis happens 24 hours a day?
Use artificial lighting
What are 2 benefits of paraffin heaters for photosynthesis?
They release heat and carbon dioxide
What are the 4 levels of plant organisation?
Cells –> Tissues –> Organs –> Organ systems
What part of a cross section of a leaf is at the very top?
The waxy cuticle
What part of a cross section of a leaf is below the upper epidermis?
The palisade mesophyll layer
