3.1 Food Supply, Plant Growth and Productivity Flashcards
Define <em>‘Food Security’</em>
The ability of a population to access food of sufficient quality and quantity
What are the three factors that influence food security?
Food Availability
Food Use
Food Access
Why is food security becoming harder to achieve?
Due to the increasing rate of population growth and lack of available land to grow food
What does food availability depend on?
Sustainable Agricultural Methods
What does ‘Sustainable’ mean in relation to plant growth
Sustainable - does not degrade the natural resources on which agriculture depends on
How can you increase crop production without expanding the area?
<ul>
<li>Grow High Yielding Cultivars</li>
<li>Applying nitrogen based fertilisers</li>
<li>Reducing pests/diseases</li></ul>
What is the word equation for photosynthesis?
Carbon Dioxide + Water —> Glucose + Oxygen
What are some factors that affect the rate of photosynthesis?
Water Availability
Temperature
Light Availability
Why are plants produce more food per unit area than livestock?
Due to the energy loss at each tropic level
Why are livestock sometimes chosen over plant production in certain areas?
Chosen in areas unsuitable for plant growth due to ability to grow (eg. mountains)
What is the net assimilation of a plant?
Increase in dry mass due to photosynthesis - loss in dry mass due to respiration
Why is dry mass a more accurate measure of plant productivity?
Because it doesn’t contain water. Water levels are too varied and so will then make comparisons invalid.
What is plant productivity?
Rate at which light energy is converted to glucose in photosynthesis
How can the harvest index be calculated?
<u>Economic Yield</u>
Biological Yield
What is the biological yield of a plant?
Total increase in biomass
What is the economic yield of a plant?
Mass of desired product in a plant
What are the two stages in photosynthesis?
Light Dependant Stage
Calvin Cycle
Where does the light dependant stage take place?
Grana
Where does the Calvin Cycle take place?
Stroma
What are the three fates of light hitting a leaf?
<ol> <li>Absorbed</li> <li>Reflected</li> <li>Transmitted</li> </ol>
What is the main photosynthetic pigment?
Chlorophyll A
What regions of the absorption spectrum does chlorophyll A absorb light from?
<span></span>
<div>
<span>Red</span>and
<div>Blue</div>regions</div>
</span>
What are the two accessory pigments called?
Carotene and Xanthophyll
State an advantage of having accessory pigments
Extend the absorption spectrum and pass energy to chlorophyll
Which regions of the absorption spectrum do the carotenoids absorb?
Yellow and Green
Define the ‘Absorption Spectrum’
Absorption spectrum shows which colours of light are absorbed by the photosynthetic pigments
Define the ‘Action Spectrum’
Action Spectrum shows the efficiency of each colour of the absorbed light at driving photosynthesis
How can pigments in a leaf be extracted?
Thin Layer Chromatography
What is the role of light energy in the production of ATP?
Light energy excites the electrons and puts them in a high energy state
Which co-enzyme is responsible for picking up hydrogen?
NADP
What is the reduced state of NADP?
NADPH
What two products of the light dependant stage enter the calvin cycle?
NADPH and ATP
How many carbons in Glucose?
6 carbons
How many carbons in carbon dioxide?
1 carbon
How many carbons in 3 phosphoglycerate
3 carbons
How many carbons in G3P?
3 carbons
How many carbons in RuBP?
5 carbons
