Digestion And Food Flashcards
Sources and Functions of:
Proteins
We need it for growth and repair of tissue.
Sources - meat, fish, cheese, eggs, beans and nuts
Sources and functions of:
Carbohydrates
Body’s main fuel for supplying cells with energy.
Sources: potatoes, rice, wheat
Sources and functions of:
Lipids
Form an essential part if the structure of cells and fat is deposited in parts of the body as a long-term store of energy.
Sources - oils, meat, butter, milk, oily fish
How villi help absorption
(In the ileum)
Only 1-2mm long, but millions of them. Lots of area in contact with digested food each surface cell also has microvilli, which increase the area for absorption as well.
Chemical elements present in:
Carbohydrates
Carbon, hydrogen, oxygen
Chemical elements present in:
Proteins
Carbon, hydrogen, oxygen, nitrogen an sulphur
Chemical elements present in:
Lipids
Carbon, hydrogen and oxygen
The role of enzymes as biological catalysts in metabolic reactions
Enzymes take part in reaction but are unchanged afterwards.
They speed up digestion wit hough being used up themselves. They’re made by tissue and glands.
Tests for:
Glucose
Blue Benedict’s solution turns orange-red when heated if simple sugars, like glucose, are present.
Tests for:
Starch
Reddish-brown iodine solution turns blue-black if starch is present.
Process of absorption
The products of digestion are absorbed into blood stream in the small intestine. Villi in the small intestine are adapted for effective diffusion. They have a large surface area, a good supply to maintain a steep concentration gradient, and short diffusion distances.
Process of assimilation
The digested food products are absorbed into the cells of the body by diffusion a be assimilated. They are used for energy and to build into chemicals needed by the cells.
Process of Egestion
Water, undigested food, enzymes, dead cells, bile pigments and mucus move through the large intestine. Water is removed. The remaining material is passed out of the anus as faeces.
Bile and its role
Bile is produced by the liver and stored in the gall bladder.
It neutralizes stomach acids and emulsifies lipids.
Digestion of starch
Amylase - starch to maltose
Maltase - maltose to glucose
Digestion of proteins
Protease: proteins to amino acids
Digestion of lipids
Lipase: lipids to fatty acids and glycerol
How and why food is moved through the gut by peristalsis
Waves of muscle contractions move along the gut, pushing food along. So we don’t need to depend in gravity.
Sources and functions of:
Calcium
Making teeth and bones
From - dairy products, fish,
Sources and functions of iron
Part of haemoglobin in red blood cells, helps carry oxygen.
From - red meat, liver, eggs
Sources and functions of water
Hydration
From - water
Sources and functions of dietary fibre
Prevents constipation
Keeps food in the gut moving.
Sources - fresh fruits and vegetables
Sources and functions of vitamin A
Making a chemical in the retina
From - liver, butter, margarine
Sources and Functions if vitamin C
Sticks together cells lining surfaces such as the mouth.
From - fresh fruit and vegetables
Sources and Functions of Vitamin D
Helps bones absorb calcium and phosphate
From - the sun
A balanced diet should include appropriate proportions of…
Carbohydrates Proteins Lipids Vitamins Mineral ions Calcium Iron Water And dietary fibre
Energy requirements vary with..
Age
Activity levels
Pregnancy
A balanced diet should include appropriate proportions of…
Carbohydrates Proteins Lipids Vitamins Mineral ions Calcium Iron Water And dietary fibre
Energy requirements vary with..
Age
Activity levels
Pregnancy
Experiment to measure the energy content of food
Use a crisp
Find mass
Add 20cm3 of water to a boiling tube and measure temperature
Mount crisp on needle and put over Bunsen burner until it catches fire
Then put food beneath boiling tube to heat it. Continue to relight food until it can no longer burn.
Measure final temp of water
Energy in joules per gram=
(Temperature difference) x 20 x 4.2 / mass of food
