food and digestion

Question 1

what are the five groups of food your body needs to stay healthy

Answer 1

carbohydrates, lipids, proteins,minerals, vitamins

Question 2

what is carbohydrates role in the body

Answer 2

they are the bodys main fuel for supplying cells with energy. cells release this energy by oxidizing glucose by respiration.

Question 3

where do we get most of our carboydrate from in our diet

Answer 3

starch which is a polymer of glucose ( made from long chains of hundreds of glucose molecules joined together.)

Question 4

what is cellulose?

Answer 4

a carbohydrate that is a polymer of glucose. humans arent able to digest it cause we dont have the enzyme we need to brake it down however it forms dietry fibre which helps with constipation.

Question 5

what are carbohydrates made of

Answer 5

carbon hydrogen and oxygen

Question 6

what are lipids made up of

Answer 6

same three elements as carbohydrates- proportion of oxygen in a lipid much lower than in a carbohydrate.

Question 7

what is the role of lipids

Answer 7

they form an essential part of the structure of all cells and fat is deposited around certain parts of the body as a long term store of energy.
fat layers also acts as insulation and protects organs

Question 8

what are lipids made out of?

Answer 8

glycerol and fatty acids. a molecule of glycerol is joined to three fatty acid molecules.

Question 9

what does too much lipid do?

Answer 9

too much lipids especially saturated fat and a lipid compound called cholesterol which can be linked to heart disease.

Question 10

what is the role of proteins in the body?

Answer 10

growth and repair of tissues
catalysts for chemical reactions

Question 11

what is the protein deficiency disease called?

Answer 11

kwashiorkor

Question 12

what are proteins made out of?

Answer 12

amino acids- all amino acids contain four chemical elements: carbon, hydrogen, oxygen along with nitrogen.

Question 13

shape of amino acids and why it affects the function of the protein?

Answer 13

because there are 20 different amino acids they can be arranged in any order as a result there are thousands of different kinds of proteins in organisms

Question 14

minerals (location/role in body, examples of food rich in the mineral)


Answer 14

calcium - making teeth and bones (dairy products, fish, bread, vegetables)

phosphorus - making teeth and bones; part of many chemicals, e.g. DNA and ATP (most foods)

sodium in body fluids, e.g. blood (common salt, most foods)

chlorine - in body fluids, e.g. blood (common salt, most foods)

magnesium - making bones; found inside cells (green vegetables)

iron - part of haemoglobin in red blood cells, helps carry oxygen (red meat, liver, eggs, some vegetables)

Question 15

what is rickets formed by

Answer 15

lack of calcium(bones cant grow properly or harden)
lack of vitamin D (needed for growing bones)

Question 16

what is anaemia?

Answer 16

iron deficiency - if they don’t get enough iron, they cant make enough hemoglobin for their red blood cells. this causes anaemia. people with anaemia become tired as their blood doesn’t carry enough oxygen.

Question 17

vitamins(use in body,effect of deficiency, food that have vitamins)

Answer 17

A - making a chemical in the retina; also protects the surface of the eye night blindness, damaged cornea of eye (fish liver oils, liver, butter, margarine, carrots)

B1 - helps with cell respiration beri-beri (yeast extract, cereals)

B2 - helps with cell respiration poor growth, dry skin (green vegetables, eggs, fish)

B3 - helps with cell respiration pellagra (dry red skin, poor growth, and digestive disorders) liver, meat, fish.

C - sticks together cells lining surfaces such as the mouth scurvy (fresh fruit and vegetables)

D - helps bones absorb calcium and phosphate rickets, poor teeth( fish liver oils; also made in skin in sunlight)

Question 18

what is beri-beri and scurvy

Answer 18

beri-beri= lack of vitamin B1 results in weakening of the muscles and paralysis.
scurvy= vitamin C deficiency wounds fail to heal and bleeding occurs in various places in the body

Question 19

Practical test for starch

Answer 19

1) Starch placed on spotting tile
2)drop of yellow brown iodine added to starch
3)starch reacts with iodine forming dark blue or blue black color

Question 20

practical test for glucose

Answer 20

1) small amount of glucose product placed in test tube
2) little water added
3) tube shaken to dissolve glucose
4) several drops of benedicts solution added to tube, enough to turn the mixture blue
5) test tube placed in water bath
6) clear blue solution turns to cloudy orange or brick red if glucose is present

all sugars except sucrose will change colour however sucrose isnt a reducing sugar so it stays a clear blue

Question 21

practical test for protein

Answer 21

1) a little protein product added to test tube
2) little water added
3) tube shaken to mix
4) an equal volume of potassium hydroxide solution added to tube
5) tube shaken again
6) two drops of copper sulfate solution added
7) if protein present, a purple colour develops

Question 22

practical test for lipids

Answer 22

fats and lipids insoluble in water but do dissolve in ethanol
1) pippette places one drop of lipid at the bottom of test tube
2) 2cm of ethanol added
3)shaken to dissolve
4) solution poured into test tube that is three quarters full with cold water
5) white cloudy layer forms on top of water because the ethanol dissolves in the water and leaving lipid behind

Question 23

the amount of energy a person needs depends on

Answer 23

physical work you do
age
body size (greater weight,greater energy needed)
sex
pregnancy,menstruation (needs more iron and calcium)

Question 24

what is digestion?

Answer 24

digestion is the breaking down of components of food into their building blocks before they can be absorbed through the wall of the gut.
the digested molecules (sugars, fatty acids, glycerol, amino acids, minerals,vitamins, water) can be carried around the body in the blood.
When they reach the tissues they are reassembled into the molecules that make up our cells.

Question 25

difference between chemical digestion and mechanical digestion

Answer 25

chemical digestion- digestion is sped up by enzymes (biological catalysts) mechanical digestion - physical breakdown of food eg chewing, cutting food into having larger surface area which means the enzymes can act on the food quicker. chemical digestion is helped by mechanical digestion

Question 26

what is peristalsis?

Answer 26

muscles are also responsible for moving the food along the gut. The walls of the intestine contain two layer of muscles circular layer- has fibers arranged in rings around the gut longitudinal muscle layer- has fibers running along the length of the gut. together these layers push food along. when the circular muscles contract, longitudinal muscles relax and other way round. waves of muscle contraction like this pushes food along the gut

Question 27

describe the process of digestion

Answer 27

the mouth chews the food and saliva helps break it down and moisten, it contains the enzyme amylase. chewed lump of food passes along the oesophagus to the stomach food held in stomach for a few hours. it secreates hydrochloric acid so stomachs contents are acidic which kills bacteria which helps us be protected from food poisining pepsin enzyme made in stomach helps speed up when the sphincter muscle relaxes it releases food into small intestine several enzymes addedto food in the dudenum(part of small intestine) liver makes bile stored in gallblader and passes down the bile duct onto the food. Bile breaks down large lipid globules in the food into an emulsion of tiny droplets

Question 28

how is the ileum adapted to absorb digested food

Answer 28

lining of ileum has a high surface area- it can quickly and efficiently absorb soluble products of digestion into the blood. the villi provides massive area in contact with digested food to absorb the products. each villus is covered in micro villi (extra surface area)

Question 29

how are the villi adapted?