Flashcards in Key Area 1-Food Supply, Plant Growth And Productivity Deck (43):
What is food security?
Food security concerns human access to enough good quality food
Why is there an increasing demand for food production?
-world population continuing to increase
-people are concerned with food security
What is sustainable food production?
Being able to produce enough food for a long period of time causing minimum destruction to land
What is food production dependant on?
The area to grow food crops is.....
What are the four main foods?
How can we increase food supply?
-reduce limiting factors
-higher yielding cultivars
-protection for pests/diseases
What are four characteristics breeders may want to develop?
-higher nutritional values
-pest and disease resistance
-characteristics suited to rearing and harvesting
-ability to thrive in particular environments
Do crops or livestock give more energy?
Describe efficiency of food chains
Longer food chains are less efficient as only 10% of energy is passed on at each stage of the food chain, therefore more energy is lost
Why are some areas more suitable for livestock rather than plant crops?
Livestock can survive harsher conditions
What is photosynthesis?
When plants convert light energy into chemical energy
What is the photosynthesis equation?
Water + carbon dioxide ———
Glucose + oxygen
What are the possible fates of light when it hits a leaf?
What are the three photosynthetic pigments?
What is the role of photosynthetic pigments?
They absorb different wavelengths of light to cause photosynthesis
What colours do the pigments absorb?
Chlorophyll absorbs red and blue
Carotenoids absorb in between
What is the absorption spectrum?
Shows different wavelengths of light that pigments absorb
What is the action spectrum?
Shows how much photosynthesis is happening at different wavelengths
Compare the action spectrum to the absorption spectrum
Both graphs show the same pattern therefore you can conclude pigments cause photosynthesis
What is the function of carotenoids?
Go absorb wavelengths of light that chlorophyll cannot absorb
What is the advantage of carotenoids?
They allow for more photosynthesis
What is the first stage of photosynthesis?
What happens to electrons in chlorophyll when light energy is absorbed?
They get excited
What is released as electrons are passed along the electron transport chain?
How is energy released from high energy electrons used to generate ATP?
It pumps hydrogen across the membrane creating a concentration gradient for ATP synthase to generate ATP
How does energy released from electrons generate hydrogen and oxygen?
Energy splits water into oxygen and hydrogen
What happens to hydrogen released?
Hydrogen combines with the hydrogen acceptor NADP to become reduced NADPH
Where does photolysis occur?
What is the second stage of photosynthesis?
The Calvin cycle
What does carbon dioxide combine with?
Ribulose biphosphate (RuBP)
What enzyme catalyses the reaction?
How does RuBP split?
Splits into two 3c:
What is ATP from photolysis used for?
To add a hydrogen to 3-phosphoglycerate to make G3P
What can become of G3P?
-can regenerate into RuBP
-joins with another G3P to make glucose
What are the three fates of glucose?
-stored as starch
-energy for respiration
What is biomass?
The total dry mass of a particular organism
What is net assimilation?
The overall gain in dry mass of a plant due to photosynthesis minus the loss in mass due to respiration
What is productivity?
The rate at which plants generate new biomass, measured in unit area per unit time
What is lead area index?
As the size of the leaf increases, the productivity increases until leaves are too large that they shade lower leaves and productivity levels off
What is harvest index?
A calculation that divides the economic yield by the biological yield (usually converted into a percentage)
What is biological yield?
The total biomass of a crop plant, e.g.-whole potato plant including stem and leaves above ground