Nutrition Flashcards
What is photosynthesis
The process where plants make their own food.
Light energy from the sun is absorbed by chlorophyll to convert CO2 and water to glucose and oxygen.
Equation for photosynthesis
Chemical and word
Water + carbon dioxide–> glucose + oxygen
6H2O + 6CO2–> C6H12O6 + 6O2
What factors affect the rate of photosynthesis?
CO2- it is a reactant so if you lower the amount of CO2, it becomes a rate limiting factor.
Light intensity- if the amount of light is less, there is less energy provided so the reaction slows down.
Temperature- cold temp/high = little/ no photosynthesis as enzymes are not at optimum temp.
Waxy cuticle
Thin waxy layer of protection which prevents water loss, but does not prevent sunlight from entering.
Upper epidermis
Thin transparent layer so light can easily reach the palisade layer.
Spongy mesophyll
Full of air spaces to increase the surface area for diffusion of gases.
What are the basic structures in leaves?
Large surface area: allows them to absorb more sunlight
Thin: shorter distance for CO2 to diffuse through
Opening and widening of stoma: increases the amount of CO2 entering.
What minerals do plants need and why?
Magnesium ions= produce chlorophyll which traps sunlight for photosynthesis
Nitrate ions: needed to make amino acids and to make protein.
Describe experiment to investigate rate of photosynthesis
1) place pond weed under water
2) vary light intensity (different lamp distances) and amount of CO2 (soda lime) and measure amount of O2 gas.
* lamp far away=little oxygen=less photosynthesis
* little CO2= less oxygen= less photosynthesis
What is a balanced diet
A diet that supplies proteins, fats, lipids, carbohydrates, water, minerals, vitamins and dietary fibre in the correct quality and proportion.
Source and function of carbs
Pasta, rice, bread and vegetables
–> immediate energy
Protein sources and function
Red meat, fish, nuts and beans
Helps with growth and repair of cells and muscles.
Fats sources and functions
Eggs, dairy meat
Long germ energy source and is used to protect and insulate important organs.
Vitamin A sources and functions
Deficiencies
In Liver and orange veggies.
-so cells can produce pigments
-embryos can develop properly
-so immune system can maintain the integrity of skin and mucus cells in the lining of the breathing and digestive system.
Deficiencies= causes poor vision in the dark
Vitamin C sources and functions
Deficiencies
Oranges and citrus fruits
- helps cells stick together
- makes collagen
- growth and repair of tissues
Deficiencies - bleeding gums and scurvy
Vitamin d sources and function
Deficiencies
Salmon, mackerel, eggs
Helps the body with the absorption of calcium
Cam develop rickets if deficient
Sources and function of iron
Deficiencies
Red meat, liver, green and leafy veggies
Helps produce haemoglobin needed by RBC.
Deficiencies: anaemia= weak and tired
Sources functions of Calcium
Deficiencies?
Dairy such as milk, cheese , yoghurt
Production of strong teeth and bones
Involved in chemical reactions of blood clotting and muscle contraction.
Why do we need water in our diets?
All cells require oxygen to function and we lose 2-3 quarters of water a day.
Dietary fibre sources and function
Deficiency
Cereals, bread, rice, beans and nuts
Assists with bowel movement in the colon
Deficiencies= constipation
What do energy requirements depend on?
Height Weight Age Pregnancy Lifestyle
What is the first stage of digestion?
Mouth
Mechanical: teeth cut large and complex molecules of food into smaller snd less complex ones to create a larger surface area for enzymes to act on.
Chemical: salivary amylase breaks down starch into maltose and moistens food to reduce friction.
Where do food molecule go after the mouth and what happens there
Oesophagus
Peristaltic movement= waves of muscular contractions to push food down to the stomach
Mucus= released by goblet cells to reduce friction
What happens in the stomach
HCL= released to kill bacteria and to provide optimum pH for pepsin Mechanical= peristaltic movements mix up contents of food to make them smaller Chemical= protease is released to break large molecules of protein into smaller amino acids and peptides.
Adaptations of stomach
- Muscular walls that can stretch
- 2 tight rings of muscle at top and bottom to control entry and exit of materials
- cells in the stomach secrete mucus to protect its lining
- as material leaves, alkaline juices are released to neutralise material and prevent damage to small intestines
Small intestines
Duodenum- partially digested food enters here and is absorbed out to the body
Neutralisation= stomach acid is neutralised by pancreatic juices.
Enzymes= enzymes are added to complete digestion
Large intestines role in digestion
Colon= where most of the water is reabsorbed, leaving behind faeces Rectum= where faces are stored
What does the pancreas do?
Releases enzymes
Amylase= starch–> maltose
Protease= protein–> amino acids and peptides
Lipase= fats–> fatty acids and glycerol
They realises alkaline juices to neutralise stomach acid to prevent damage to small intestines.
What is ingestion?
The process of material being taken in
What is digestion
The process of larger and complex food being broken down into smaller and less complex molecules by mechanical and chemical digestion
What is absorption
This is when small molecules from digestion pass into the blood supply of the ileum (by diffusion or active transport)
What is assimilation
When small molecules are absorbed into the blood are passed out to body cells to make chemicals needed by the body.
What is egestion
The removal of undigested material, dead cells and bacteria from the body.
What is peristalsis
Waves of muscular contractions to he,o move food move down the oesophagus. It’s also a form of mechanical digestion in the stomach.
Amylase
Starch to maltose
Maltase
Maltose to glucose
Protease
Protein to amino acids and peptides
Lipase
Fatty acids and glycerol
What is the role of the ileum?
It is the last region of digestion and is where the final process of absorption takes place. (E.,g Molecules such as glucose, amino acids, vitamins, minerals, fatty acids and glycerol)
How are villi adapted to their function?
Folded surface area- large surface area
Finger like projections= villi
Micro villi= even larger surface area
Rich blood supply because of capillaries allow diffusion of food to take place quickly
1 cell thick= shortens diffusion distance.
How do you calculate energy content in food sample
Burn a piece of food under tube of water
Calculate temperature rise
Change in temp * mass of water * 4.18
= energy in joules
