Nutrition - plants + human Flashcards
What is photosynthesis?
Conversion of light energy into chemical energy (sunlight to sugars)
Word equation for photosynthesis
carbon dioxide + water –> (light, chlorophyll) glucose + oxygen
Symbol equation for photosynthesis
6CO2 + 6H20 –> (light, chlorophyll) C6 H12 O6 + 6O2
Explain the process of photosynthesis
- Sunlight is transferred to the chloroplasts
- Energy from sunlight is absorbed by chlorophyll
- Green plants use this energy to make glucose
- At the same time, oxygen is made and released as a waste product
What are the 3 factors affecting rate of photosynthesis
- light intensity
- CO2 concentration
- temperature
How does light intensity affect photosynthesis
- higher the intensity, faster the rate of photosynthesis
How does temperature affect photosynthesis
- higher the temp the faster the rate of photosynthesis
- more kinetic energy, more collisions
How does carbon dioxide conc affect photosynthesis
- higher the carbon dioxide levels, faster the rate of photosynthesis
- more raw materials available for photosynthesis
What are the 7 parts of the leaf structure
- waxy cuticle
- upper epidermis
- palisade mesophyll
- spongy mesophyll
- lower epidermis
- guard cell
- stomata
How is the waxy cuticle adapted for photosynthesis
- thin cuticle made of wax, protects the leaf without blocking sunlight
How is a leaf adapted for photosynthesis
- Large sa for diffusion of CO2 and absorption of light
- Thin - allows CO2 to diffuse to palisade mesophyll quickly
How is the epidermis adapted for photosynthesis
- thin and transparent to allow more light to reach the palisade cells
How is the palisade cell layer adapted for photosynthesis
- at the top of leaf to absorb more light
How is the spongy layer adapted for photosynthesis
- air spaces allow gases to diffuse through
How is the chloroplasts adapted for photosynthesis
- high chloroplasts density in palisade mesophyll cell, chlorophyll absorbs more light
How are the vascular bundles adapted for photosynthesis
- thick cell walls of tissue in the bundles, help support the stem and leaf
What mineral ions are needed for plant growth
Nitrogen and magnesium
Why is nitrogen needed for plant growth
nitrates needed to make amino acids (protein)
if deficient causes yellowing of leaves, stunted growth
Why is magnesium needed for plant growth
needed to make chlorophyll
if deficient causes yellowing between veins
What are the 7 items needed for a balanced diet
- carbs
- protein
- lipid
- vitamins
- minerals
- water
- dietary fibre
Sources and function of carbs
function - source of energy
sources - bread, pasta, rice
Sources and function of protein
function - growth and repair
sources - meat, fish, eggs, nuts
Sources and function of lipid
Function - insulation, energy storage
sources - butter, oil , nuts
Sources and function of dietary fibre
function - bulk for intestine to push food through
sources - vegetables, whole grains
Sources and function of vitamins
function - maintain health
sources - fruits and vegetables
Sources and function of minerals
function - maintain health
sources - fruits and veg. , meats, dairy
Sources and function of water
function - for chemical reactions to take place in cells
sources - water, juice, milk
Sources and function of Vitamin D
Function - helps abosrb calcium, strong bones
sources - dairy, oily fish, sunlight
Sources and function of calcium
Function - strong teeth bones
Sources and function of Vitamin C
function - forms collagen protein, skin, hair, gum, bones
sources - citrus fruit, green veg
lack causes scurvy
Sources and function of vitamin A
function - pigment in retina for vision
sources - meat, dairy, green veg, eggs
Sources and function of iron
function - to make haemoglobin, pigment in red blood cells
source - red meat, liver, leafy green veg
How do energy requirements vary?
age
- increases towards adulthood
- children need more
- adult less
activity levels
- more active more energy
pregnancy
- energy req. increases
- more iron and calcium
breastfeeding
- energy req. increase, more calcium
sex
- male requires more (more muscle more energy)
What is the alimentary canal
passage through which food flows through the body starting at the mouth ending at the anus
What happens in the mouth
teeth chew food, amylase enzymes digest starch into maltose
What happens in the oesophagus
The tube that connects mouth to stomach
food is swallowed by wave like contraction pushing the food down
What happens in the stomach
food is mechanically digested by churning while protease enzymes digest proteins
hydrochloric acid kills the bacteria in food
What happens in the small intestine
First section - duodenum food enters
Second section - ileum absorption of digest food molecules take place, lined with villi to increase sa
What happens in the large intestine
water is absorbed, remaining material produces faeces stored in rectum removed through anus
What happens in the pancreas
produces amylase protease and lipase
What is peristalsis
- mechanism that helps move food along the alimentary canal
- circular muscles contract to reduce the diameter of the lumen
- longitudinal muscles contract to reduce the length of the section
What do digestive enzymes do?
break down large insoluble molecules to smaller soluble molecules by enzymes
how are carbs chemically digested
Starch to maltose through amylse, maltose to glucose through maltase
How is protein chemically digested
protein to short chains of amino acids through protease, short chains of amino acids to single amino acids through trypsin
how are lipids chemically digested
lipids to fatty acids + glycerol through lipase
What is bile, how is it produced and where is it stored
bile is an alkaline substance produced by cells in the liver and stored in the gallbladder
- emulsifies fats
- neutralises stomach acid
What is the role of bile
emulsifies fats and neutralises hydrochloric acid from stomach
How is the small intestine adapted for absorption
- very long and has folded surface with millions of villi
- increases sa of the small intestine, faster more efficient absorption
How are villi adapted for absorption
- large sa
- short diffusion distance
- conc gradient
