Nutrition Flashcards
Define photosynthesis
The process by which plants make carbohydrates from raw materials, using energy from light.
Describe photosynthesis
- Light energy is absorbed by chlorophyll
- Absorbed light energy is used to convert CO2 from the air and water from the soil into a sugar called glucose
- Oxygen is released as a by-product.
Give the word equation for photosynthesis
Carbon dioxide + water -> (light) (chlorophyll) -> glucose + oxygen
Give the symbol equation for photosynthesis
6CO2 + 6H2O -> (light) (chlorophyll) -> C6H12O6 + 6O2
What is glucose used for
- some is used for respiration
- some is converted into starch (storage form)
Describe how light intensity affects photosynthesis
At first, as light intensity increases the rate of photosynthesis also increases as light energy is needed for photosynthesis. However, the rate then plateaus due to other limiting factors.
Describe how CO2 concentration affects rate of photosynthesis
As CO2 conc increases, rate of photosynthesis also increases as CO2 is one of the reactants in photosynthesis. However, the rate then plateaus due to other limiting factors.
Describe how temperature affects rate of photosynthesis
At a low temperature, enzymes do not have enough KE to complete photosynthesis so rate will be low. Post the optimum temperature, enzymes become denature so photosynthesis rate will be low.
Describe the waxy cuticle of a leaf.
Waterproof layer that protects the leaf
Describe the upper epidermis of a cell.
Transparent layer used for protection
Describe the palisade mesophyll of a cell
Tightly packed layer of cells for photosynthesis
Describe spongy mesophyll of a cell
Loosely packed for efficient gas exchange
Describe lower epidermis of a cell
Contains stomata which allow entry of gas
Describe guard cells of a leaf
Cells surrounding the stomata and controlling them.
Give 4 adaptations of leaves.
- large SA
- thin (short diffusion distance for CO2)
- thin waxy cuticle
- thin transparent epidermis
How are mineral ions absorbed in plants?
Through the roots by active transport, as mineral ions are dissolved in the soil water.
What is the use of magnesium in plants?
Needed for making chlorophyll
Give a result of magnesium deficiency in plants
Leaves turning yellow
What are nitrates needed for in plants
For making amino acids
Give one effect of nitrate deficiency in plants.
Stunted growth
Give a cause of eutrophication
Overuse of nitrogen fertilisers by farmers.
What is eutrophication?
When excess nitrates/phosphates enter rivers, lakes and fields leading to the death of fish by causing over bloom of algae, depleting oxygen.
Give the method for observing evolution of oxygen in a plant.
- Place pondweed in a beaker of water underneath an upturned funnel
- Fill a boiling tube with water and place it over the end of the funnel
- As oxygen is produced, bubbles of gas will collect in the boiling tube and displace the water.
How to test for presence of oxygen
Hold glowing splint near test tube to see if it relights.
How can you increase/decrease CO2 concentration in water?
Increase: add sodium bicarbonate
Decrease: add sodium hydroxide
Give one way of changing amount of chlorophyll in a plant for an investigation
Use a variegated plant- green leaves = chlorophyll, white leaves = no chlorophyll
Give a method to investigate production of starch in a plant
- Heat a plant leaf in boiling water for 30 seconds (stops chemical reactions)
- Heat it in boiling ethanol for a few minutes (removes colour)
- Wash with water and spread onto a white tile.
- Add iodine solution from a dropping pipette.
Give the 7 components of a balanced diet
Carbohydrates Protein Lipids Vitamins Minerals Water Dietary fibre
Give 3 sources of carbohydrates
Pasta, rice, potatoes
Give a function of carbohydrates
Source of energy
Give 3 sources of protein
Meat, fish, eggs
Give a function of proteins
growth and repair
Give 3 sources of lipids
Butter, oils, nuts
Give 2 functions of lipids
- Source of energy
2. In the body, lipids probide storage and insulation
Give 3 functions of vitamin A
- good vision
- healthy skin
- immunity against infection
Give 2 sources of vitamin A
Milk and dairy products, such as cheese and yoghurt. Oily fish such as mackerel.
Give a deficiency symptom of vitamin A
Night blindness
Give 2 functions of vitamin C
Heal wounds, maintain healthy connective tissue
Give 2 sources of vitamin C
Citrus fruits such as oranges, lemons, limes and leafy green vegetables such as sprouts and broccoli.
Give and explain a deficiency result of vitamin C
Scurvy- bleeding of gums, loss of teeth, tiredness, muscle and joint pain.
Give a function of vitamin D
To maintain healthy bones and teeth
How can vitamin D be made?
Vitamin D is made when a body is exposed to sunlight
Give 3 sources of vitamin D
Eggs, oily fish, margarine
Give deficiency results of vitamin D
Rickets and bone pain
Give 3 functions of calcium
- maintain healthy bones and teeth
- normal blood clotting
- control of muscle contractions
Give 3 sources of calcium
Cheese and milk, eggs, green leady vegetables such as broccoli and cabbage
Give 3 deficiency results of calcium
Weak bones and teeth, poor blood clotting, muscle spasms
Give a function of iron
Produce haemoglobin
Give 4 sources of iron
- liver
- red meat
- beans and nuts
- dried fruits such as dried apricots
Give and explain a deficiency result of iron
Anaemia, tiredness and weakness due to the lack of haemoglobin which prevents blood from carrying enough oxygen.
How much of our body is made up of water?
2/3 of our body is water
Where is water stored?
Water is found in the cytoplasm of cells and in body fluids like blood.
Give 3 sources of water
Food, drink, metabolic processes such as aerobic respiration
What does dietary fibre consist of?
Dietary fibre consists of material in food that cannot be digested, for examole cellulose from plant cell walls.
Give 3 sources of dietary fibre
Fruits, vegetables, cereals
What is the function of dietary fibre?
Dietary fibre provides bulk, which helps the walls of the small intestine move food and faeces along the gut.
Give a deficiency result of dietary fibre
Constipation
Give 3 factors influencing energy requirement in humans.
- age
- activity levels
- pregnancy
Give a way that activity levels affect energy requirement in humans.
People who are sedentary tend to need less energy than active people. For example, an office worker needs around 10,000 kJ/day and a manual worker would need around 15,000 kJ/day
State the energy requirements for varying ages (0-16)
0 (newborn)- 2,000 kJ 2- 5,000 kJ 6- 7,500 kJ 13 (girl)- 9,000 kJ 13 (boy)- 11,000 kJ 16 (girl)- 9,000 kJ 16 (boy)- 12,000 kJ
The energy needs of adults — —— as they age.
Go down
Why do energy requirements decrease with age?
As you age, there is a dhange in body composition; a decrease in lean body tissue (muscle) and an increase in fat tissue
Describe and explain the effect of pregnancy of energy reaquirements
A woman’s energy requirement increases during pregnancy as she is carrying extra mass, and the greater a person’s mass, the more energy needed.
Give the equation for energy transferred.
Energy transferred = mass of water (g) x 4.2 (J/kg ‘C) x temperature increase
Give the method for a calorimetry experiment
- Pour cold water into a boiling tube and record its starting temperature
- Record the mass of the food sample
- Heat the food until it catches fire
- Use the flame of the food to heat the water
- Record the final temperature of the water
Describe the function of the mouth
Where food enters the alimentary canal and digestion begins.
Describe the function of the salivary glands
Produce saliva containing amylase
Describe the function of the oesophagus
A muscular tube which moves ingested food to the stomach
Describe the function of the stomach
produces hydrochloric acid. It kills many harmful micro-organisms that might have been swallowed along with the food. The enzymes in the stomach (protease) work best in acidic conditions – at a low pH. Protein digestion starts here.
Describe the function of the pancreas
To produce digestive enzymes
Describe the function of the liver
Produces bile
Describe the function of the gall bladder
Stores bile before releasing it into the duodenum
Describe the function of the duodenum
Where food is mixed with digestive enzymes and bile
Describe the function of the ileum
Where digested food is absorbed into the blood and lymph
Describe the function of the colon
Where water is reabsorbed
Describe the function of the rectum
Where faeces are stored
Describe the function of the anus
Where faeces leave the alimentary canal
Define digestion
The breakdown od large, insoluble food molecules into small, water soluble molecules
What is ingestion?
When food enters the digestive system through the mouth.
Describe and explain peristalsis
Peristalsis js the contraction if fhe circular and longitudinal muscles, which reduce the diameter and length of the gut when contracting. This helps food mobe through the digestive system
Give 2 examples of mechanical digestion
Chewing in the mouth, churning in the stomach
Define chemical digestion
Digestion that involves enzymes
Salivary amylase
Produced in= salivary glands
used in= mouth
Substrate= starch
End-product= maltose
Pancreatic amylase
Produced in = pancreas
Used in = small intestine
Substrate = starch
End product = maltose
Maltase
Produced in = small intestine
Used in= small intestine
Substrate = maltose
End-product = glucose
Protease
Produced in = small intestine and pancreas
Used in = stomach and small intestine
Substrate = protein
End-product = amino acids
Lipase
Production = pancreas
Used in = small intestine
Substrate = lipids
End product = fatty acids + glycerol
Where is bile produced and stored?
Bile is produced in the liver and stored in the gall bladder
Where is bile used and why?
Bile is used in the small intestine (duodenum) because enzymes in the small intestine work best at alkaline conditions
Give 2 functions of bile
- Neutralises stomach acid, providing alkaline conditions needed in the small intestine
- Emulsifies fats, providing a larger SA for enzymes
Define absorption
The movement of digested food molecules through the wall of the intestine into the blood or lymph
What are villi?
Finger-like projections that increase the SA of the small intestine.
Give and explain 4 adaptations of villi.
- Walls one cell thick- short distance for absorption by diffusion and active transport
- Network of blood capillaries- transport glucose and amino acids away from small intestine in the blood
- Large SA
- Lacteal (internal structure)- transports fatty acids and glycerol away from the small intestine
Define assimilation and give 2 examples
The movement of digested food molecules into the cells in the body where they are used.
- glucose for respiration
- amino acids to build new proteins
Give 3 functions of the liver
- Converts glucose into glycogen
- Converts amino acids into proteins
- Deamination
Describe deamination
The removal of the nitrogen containing part of amino acids to for urea, and the release of energy from the remainder of the amino acid.
Give 3 components of faeces
- Bacteria (living and dead)
- Cells from the lining of the gut
- Indigestible substances (eg cellulose)
Define egestion
When faeces pass out of the body through the anis.
