Topic C- Diet And Digestion Flashcards
describe the tests for glucose and starch
testing for starch
- put some stratch solution into a test-tube
- add a few drops of iodine solution
- colour in the test tube to show what colour the startch wet
- it went black-blue
Testing for glucose
- put some glucose solution into a test tube
- add a few drops of Benedict’s solution
- put the test tube in a beaker of boiling water
- colour in the test-tube to show what colour the glucose went
- it went yellow, green , brown, orange, brick red
what are enzymes?
- they are all the same
- each enzyme controls one particular reaction
- they can be used again and again
- they are affected by temperature
- they are affected by PH
what enzymes break down carbohydrates?
carbohydrases
what enzymes break down protein?
proteases
what enzymes break down fats?
lypases
what is the optimum PH for enzymes?
- about PH 7 ( neutral)
where are enzymes found?
- inside cells ( contrilling reactor)
- in the alimentary canal ( digestion)
what is the optimum temperature for enzymes?
- 37-40 degrees
what happend when an enzyme dinatures?
- the active site changes shape and no longer fits the substrate
what chemical elemets are present in carbohydrates and lipids?
Carbohydrates and lipids (fats and oils) are both made of:
- Carbon
- Hydrogen
- Oxygen
what chamical elements are present in proteins?
Proteines consist of:
- Carbon
- Hydrogen
- Oxygen
- Sulphur
- Phosphorous
- Nitrogen
describe the structure of lipids
- a fat molecule is made up of fatty acid and glycerol molecules
describe the structure of proteins
- a protein molecule is made up of many different amino acids
describe the structure of carbohydrates
- a starch molecule is made up of many glucose molecules
what is the function of protein? identify source
- for growth and repair
- found in: meat, fish ,eggs, andn legumes ( peas and beans)
what is the function of carbohydrates? identify source
- needed to release energy in our cells
- found in pasta, bread, rice
what is the function of fat? identify source
- insulation to maintain body temperature, store of energy.
- protects organs from damage
- it is found in: oils, milk products, butter, cheese, oily fish and nuts
what is the function of Vitamin A? identify sources
- helps cells to grow and keep skin healthy
- helps eyes to see in poor light
- its found in: liver, vegetables, butter, fish, oil and milk
what is the function of Vitamin B? identify sources
- for healthy skin
- to keep the nervous system working properly
- found in: meat, eggs, vegetables, fish and milk and yeast extract
what is the function of Vitamin C? identify sources
- for heathy skin
- teeth
- gums
- found in: citrus fruit and green vegetables
what is the function of Vitamin D? identify sources
- for strong bones and teeth
- found in: fish, eggsm liver, cheese and milk
what is the function of Calcium? identify sources
- needed for strong teeth and bones
- found in: milk and eggs
what is the function of iron? identify source
- needed to make haemoglobin in red blood cells
- found in meat and spinach
what is the function of fibre? identify source
- adds bulk to food so it can be easily moved along the digestive system by peristausis. Fibre is thought to help prevent bowel cancer
- found in: cell walls of plants
what is the function of water? identify source
- necessary for all life process
What is the function of the oesophagus?
- this tube connects you mouth and stomach. It is next to the trachea which is covered by the epiglottis when you swallow so the food only enters the oesophagus.
- Peristalsis- or muscular contractions- moves the food downward.
what is the function of the stomach?
- Churning mechanically digests whilst enzymes do so chemically.
- Chyme is the name for liquid food existing in the stomach.
what is the function of the mouth?
- Mechanical digestion happens here- your jaw action.
- A bolus is created; this is a ball of food covered in saliva. This is help full as the food is lubricated to enable swallowing and enzymes in the saliva can begin to break down the food. (amylase)
what is the function of the small intestine?
- This absorbs digested molecules into the blood stream.
- Villi cover the inside giving it a large surface area which many molecules can diffuse through into the blood.
what is the function of the large intestine?
- This absorbs water from undigested food, producing faeces.
what is the function of the pancreas?
- This produces the enzymes lipase, amylase and protease.
what is digestion?
- chemical breakdown, of large molecules into small, soluble molecules
what is absorption?
- passage of digested molecules from the alimentary canal into the blood stream
what is assimilation?
- the use of absorbed molecules by cells
what is peristalsis?
- rhythmic contraction of the muscle of alimentory canal pushing food along
what is egestion?
- The act or process of voiding or discharging undigested food as faeces.
explain how and why food is moved through the gut by peristalsis
- Food is moved through the gut by peristalsis.
- Muscles move food because mechanical action is needed to get food through the system.
how is bile produced?
- by the liver and storred in the gall bladder
- works in small intestine
- it’s not an enzyme
- neutralises stomach acids and is used for emulsifying lipids
describe the structure of a villus and explain how this helps absorption of the products of digestion in the small intestine
- he villi are in the small intestine. The are like lumps on this inside of the small intestine. They are the surface through which food diffuses into the blood stream.
- They have very thin walls, only one cell thick, this enables molecules to pass through easily.
- They also increase the surface area of the small intestine wall meaning that there is a lot of surface for diffusion to happen through.
On the outside of villi there are capillaries which pick up the diffused food into the blood stream.
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