Topic 4 - Bioenergenics Flashcards
Label and state the functions the layers in the leaf
Palisade mesophyll- photosynthesis
Spongy mesophyll- diffusion of gases
Xylem- transport of water and minerals
Phloem- transport of sugars
Guard cells- open and close the stomata
Stomata- allow gas exchange and control water loss
Explain how the structures are adapted to their function
Palisade- contain many chloroplasts
Spongy- contains air spaces
Xylem- hollow tubes
Phloem- contains cell sap and pores at each end of cell
Guard cells- can change shape
What is meristem tissue?
Stem cells - undifferentiated plant cells
Where is the meristem tissue found?
The tips of roots and shoots
What is the word equation for photosynthesis ?
carbon dioxide + water –> glucose + oxygen
Write the balanced word equation for photosynthesis ?
6CO2 + 6H2O –> C6H12O6 + 6O2
Is photosynthesis endothermic or exothermic
Endothermic as it requires light energy
What do plants need for photosynthesis other than carbon dioxide and water
Chlorophyll and light
What are the 4 limiting factors of photosynthesis ?
Carbon dioxide concentration, light intensity, temperature, chlorophyll
What factors does a farmer need to consider when running a greenhouse ?
Maximising photosynthesis and therefore plant growth, but also maximising profit, so balancing spending on light and heat with the amount of crop produced.
What is the independent variable? (photosynthesis limiting factor practical)
Distance between lamp and pondweed (Light intensity)
What is the dependent variable? (photosynthesis limiting factor practical)
Number of bubbles per minute (rate of photosynthesis)
What are the control variables (photosynthesis limiting factor practical)
CO2 concentration, temperature, type of pondweed, length of pondweed
What is the pattern of the graph? (photosynthesis limiting factor practical)
As distance decreases, the number if bubbles produced per minute increases
Explain the pattern of the graph?(photosynthesis limiting factor practical)
As the lamp gets closes to the pondweed the light intensity increases. This increases the rate of photosynthesis, so more oxygen is produced.
What are the functions and adaptations of the xylem?
Transports water and minerals. Cells are strengthened by lignin join end to end to form a tube
What is transpiration?
Evaporation of water and loss through stomata of leaf
What are the 4 factors that affect transpiration rate?
Temperature, humidity, light intensity, air movement
What are the functions and adaptations of the phloem?
Transports dissolved sugars from leaves to the rest of the plant. Cells join to form hollow tubes
What is translocation?
The movement of dissolved sugars through phloem
What are the 5 uses of glucose ? (CROPS)
C - cellulose
R - respiration
O - oils/fats
P - proteins
S - starch
Explain how glucose is used in each situation
Cellulose for cell walls,
Respiration to release energy
Oils and fats for cell membranes and seeds
Proteins for enzymes, starch for Storage
How do you check a leaf for starch ?
Iodine
Colour chain orange to blue-black
How do you check a leaf for protein ?
Biuret’s solution
Colour change blue to purple
How do you check a leaf for glucose ?
Benedicts’s solution
Colour change blue to brick red/orange
What is the purpose of cellular respiration?
To release energy
What is the use of the energy produced by cellular respiration ?
*chemical reactions to build larger molecules
*movement
*keeping warm
What is the equation for aerobic respiration ?
oxygen + glucose —> carbon dioxide + water
What is the balanced symbol equation for aerobic respiration ?
C6H12O6 + 6O2 –> 6CO2 + 6H2O
Is cellular respiration endothermic or exothermic ?
Exothermic as it releases energy
What is anaerobic respiration ?
Respiration without oxygen
What is the word equation for anaerobic respiration in plant cells and yeast ?
glucose –> ethanol + carbon dioxide
What is the word equation for anaerobic respiration in human cells ?
glucose –> lactic acid
Which releases more energy anaerobic or aerobic respiration ?
Anaerobic respiration releases less energy
Explain how anaerobic respiration in yeast is used in food production
Anaerobic respiration in yeast is called fermentation. It is used in baking as the carbon dioxide released causes bread to rise and in brewing to make alcoholic drinks.
What effects does exercise have on the body?
The heart rate, breathing rate and breath volume increase
Why do these changes happen?
To supply the muscles with more oxygenated blood, so aerobic respiration can occur to release energy for contracting muscles.
What happens when there s not enough oxygen supplied to the muscles
Anaerobic respiration takes place which can lead to oxygen debt and lactic acid production
What is oxygen debt ?
Incomplete oxidation of glucose causes a build up of lactic acid which requires oxygen to break down.
How is lactic acid removed form the body?
Blood flowing through the muscles transports the lactic acid
to the liver where it is converted back into glucose. Oxygen debt is the
amount of extra oxygen the body needs after exercise to react with the
accumulated lactic acid and remove it from the cells.
What is metabolism ?
The sum of all the reactions in a cell or the body.
What molecule controls metabolism ?
Enzymes
What three new molecules are built from glucose?
Starch, glycogen and cellulose
How are lipids formed?
From a molecule of glycerol and three molecules of fatty acids
How are protein molecules formed?
Glucose and nitrate ions form amino acids which in turn are used to synthesise proteins
What happens to excess protein ?
Broken down to form urea for excretion.
