Nutrition and Biological Molecules Flashcards
What is the chemical equation for photosynthesis?
6CO2 + 6H2O —> C6H12O6 + 6O2
What is required for photosynthesis to occur?
Light energy and chlorophyll
What does photosynthesis do?
Converts light energy to chemical energy
How does carbon dioxide concentration affect the rate of photosynthesis?
The higher the concentration of carbon dioxide the higher the rate of photosynthesis occurs
How does light intensity affect the rate of photosynthesis?
The higher the light intensity the higher the rate of photosynthesis
How does temperature affect the rate of photosynthesis?
Up to 30C temperature increases the rate of photosynthesis but after that the rate starts to decrease
What is a limiting factor?
The component of the reaction which is in short supply so it limits the rate at which the reaction can take place
What are Magnesium ions used for in plants?
Part of the chlorophyll molecule
What are nitrate ions used for in plants?
Making amino acids and proteins
What are phosphate ions used for in plants?
Part of the cell membrane and DNA
What are potassium ions used for in plants?
Needed for enzymes of respiration and photosynthesis to work
What does the cuticle of a leaf do?
Reduced water loss by evaporation and acts as a barrier to the entry of pathogens
How is the upper epidermis adapted for photosynthesis?
It is transparent to allow light to enter the leaf
How are palisade cells adapted for photosynthesis?
1) densely packed
2) lots of chloroplasts
3) absorb light
What is the role of spongy cells in photosynthesis?
Main gas exchange surface absorbing carbon dioxide and releasing oxygen and water vapour
What is the role of the air spaces in a leaf?
Allow gas exchange in and out of the leaf
How are guard cells adapted for photosynthesis?
Open and close the stomata as in light fill with water and bend out, opening (vice versa for dark)
Describe experiment to measure photosynthesis using pond weed
1) place pondweed in a beaker of water
2) place a lamp 10cm away from the beaker
3) record the number of bubbles produced per minute for 10 minutes
4) repeat each time moving the lamp 10cm further away from the beaker
How do you test leaves for starch?
1) kill leaf in boiling water for 30 seconds
2) remove colour in boiling ethanol for 2 minutes
3) wash with cold water to soften the leaf
4) spread out leaf on tile and ass iodine solution to test for starch
5) any parts of the leaf containing starch then blue black
Describe an experiment to investigate the effect of light in gas exchange by a leaf
1) put 10cm3 of hydrogencarbonate indicator in the base of 4 boiling tube
2) add a large leaf to 3 of the boiling tubes
3) cover one tube with silver foil and one with translucent material and place the other in bright light
4) after 3 hours heck the colour of the indicator
What is the colour of hydrogencarbonate indicator in low, normal and high concentrations of carbon dioxide?
Low=purple
Normal=orange
High=yellow
What should a balanced diet contain?
Carbohydrates, proteins, lipids, vitamins, minerals, water and dietary fibre
What is a source of carbohydrates?
Bread, pasta and rice
What is a source of protein?
Meat, fish and cheese
What is a source of lipid?
Butter, oil and eggs
What is a source of vitamin A?
Fish liver oils, butter and carrot
What is a source of vitamin C?
Citrus fruits and vegetables
What is a source of vitamin D?
Fish liver oils, butter and skin makes in sunlight
What is a source of calcium?
Milk, cheese and fish
What is a source of iron?
Red meat, eggs and spinach
What is a source of dietary fibre?
Fruit and vegetables
What is the function of dietary fibre?
Helps move materials through the gut
What is the function of vitamin A?
1) make chemicals in the retina
2) protect surface of the eye
3) part of connective tissues
What is the function of vitamin D?
Helps absorb calcium and phosphorous
What is the function of vitamin C?
Makes connective tissues that stick together cells lining surfaces of the body
What is the function of calcium?
Creates and strengthens teeth and bones
What is the function of iron?
1) part of hemoglobin in red blood cells
2) helps transport oxygen round the body for respiration
What causes energy requirements to vary?
Age, activity levels and pregnancy