2E nutrition-humans

Question 1

what must a balanced diet include?

Answer 1

the appropriate proportions of carbs, proteins, lipids, vitamins, minerals, water, dietary fibres

Question 2

why do we need food?

Answer 2

to supply us with ‘fuel’ for energy
to provide materials for growth and repair of tissues
to help fight disease and keep our bodies healthy

Question 3

what is the function of carbs?

Answer 3

they are the body’s main fuel for supplying cells with energy. Cells release this energy by oxidising a sugar called glucose, in the process of cell reparation. Glucose is one of the sugars belonging to carbohydrates

Question 4

what is starch?

Answer 4

starch is a carbohydrate. it is a large insoluble molecule

Question 5

where can starch be found?

Answer 5

potatoes, rice, wheat, millet, (pasta)
it can only be found in plant tissues, but animals can contain a similar carb called glycogen

Question 6

what is starch a polymer of?

Answer 6

glucose. this means it is made of hundreds of glucose molecules joined together.

Question 7

what is glycogen a polymer of?

Answer 7

glucose

Question 8

where can glycogen be found?

Answer 8

in tissues such as the liver, and muscle and it acts as a store of energy for these organs

Question 9

what happens during digestion to starch and glycogen?

Answer 9

they are broken down into simple sugars, so they can be absorbed into the blood

Question 10

what is cellulose a polymer of?

Answer 10

glucose

Question 11

can humans digest cellulose? why is it important?

Answer 11

no because we don’t have the enzyme. in our diet, it forms dietary fibre which gives the muscles of the gut something to push against as food is moved through the intestine (avoids constipation, prevents colitis and bowel dance)

Question 12

where can cellulose be found

Answer 12

cell walls of plants

Question 13

name as many sugars as you can

Answer 13

glucose, fructose, sucrose, lactose (idk if there are any more)

Question 14

what are carbs made up of (elements)

Answer 14

carbon, hydrogen, oxygen

Question 15

what elements make up lipids?

Answer 15

carbon, hydrogen, oxygen

Question 16

draw a diagram of glucose, a part of a starch molecule, sucrose

Answer 16

glucose should just be single hexagons
starch- many hexagons joints by lines (in a line)
sucrose- a molecule of fructose and glucose together(2 hexagons joined by one line but different colours)

Question 17

what can lipids be found in?

Answer 17

meat, butter, cheese, oil, oily fish,

Question 18

what % body mass do lipids, carbs proteins make up?

Answer 18

C- 1%
L-10%
P-18%

Question 19

what are lipids used for?

Answer 19

long term energy store e.g., under skin, around heart
insulation (fat layer under skin) to reduce heat loss
fat around organs protects them from mechanical damage e.g., kidneys

Question 20

what are lipids made up of?

Answer 20

glycerol and fatty acids

Question 21

draw a lipid molecule

Answer 21

glycerol is like a rod with 3 zig zags (fatty acids) attatched

Question 22

what is glycerol

Answer 22

an oily liquid

Question 23

why can lipids be bad?

Answer 23

a saturated fat, a type of lipid, can a lipid compound called cholesterol are substances which have been linked to heart disease

Question 24

why do we need protein? what is its function?

Answer 24

all cells contain protein and it is used for growth and repair of tissues. Many compounds are also made from protein including enzymes

Question 25

what type of food contains protein

Answer 25

meat, fish , cheese, eggs

Question 26

what is a protein deficiency called?

Answer 26

kwashiorkor - symptoms include a swollen belly due to fluid connecting in tissue, loss of weight, poor muscle growth, flaky skin

Question 27

what are proteins

Answer 27

polymers

Question 28

what are proteins made up of?

Answer 28

amino acids (20 different types)

Question 29

what elements make up protein (amino acids)?

Answer 29

carbon, hydrogen, oxygen, nitrogen, (sulfur)

Question 30

how are amino acids linked? how does their shape relate to their function?

Answer 30

they are linked together in long chains, which are usually folded up or twisted into spirals, with cross-links, holding the chains together. the shape and order of a protein is important because the shape is important in allowing it to carry out its function and the order of the amino acid decides its shape.

Question 31

what minerals do we need?

Answer 31

calcium, phosphorus, sodium, chlorine, magnesium, iron

Question 32

where can calcium be found/what is its role? name some examples of foods which are rich in it.

Answer 32

making teeth and bones
found in dairy products, fish, bread, vegetables

Question 33

where can phosphorus be found/what is its role? name some examples of foods which are rich in it.

Answer 33

-making teeth and bones
- part of many chemicals e.g., DNA, ATP
-found in most foods

Question 34

where can sodium be found/what is its role? name some examples of foods which are rich in it.

Answer 34

-found in body fluids e.g., blood
-common salt, most foods

Question 35

where can chlorine be found/what is its role? name some examples of foods which are rich in it.

Answer 35

• in body fluids, e.g., blood
• common salts, most foods

Question 36

where can magnesium be found/what is its role? name some examples of foods which are rich in it.

Answer 36

-making bones
-found inside cells
- green vegetables

Question 37

where can iron be found/what is its role? name some examples of foods which are rich in it.

Answer 37

-part of haemoglobin in red blood cells, helps carry oxygen
- red meat, liver, eggs, some vegetables, e.g., spinach

Question 38

what is Vitamin A used for in the body? (what is the effect of deficiency?) what are some foods that are a good source of this vitamin?

Answer 38

-making chemical in the retina
- protects the surface of the eye
- (night blindness, damaged cornea of eye)
- fish liver oil, liver, butter, margarine, carrots

Question 39

what is Vitamin A used for in the body? (what is the effect of deficiency?) what are some foods that are a good source of this vitamin?

Answer 39

-making chemical in the retina
- protects the surface of the eye
- (night blindness, damaged cornea of eye)
- fish liver oil, liver, butter, margarine, carrots

Question 40

what is Vitamin B1,2,3 used for in the body? (what is the effect of deficiency?) what are some foods that are a good source of this vitamin? (DO NOT NEED TO KNOW THIS FULLY)

Answer 40

-helps with cell
-B1 deficiency - beri-beri
-B2 deficiency -poor growth, dry skin
-B3 deficiency -pellagra
- b1 found in yeast extract, cereal
-b2 found in green veg, eggs, fish
-b3 found in liver, meat, fish

Question 41

what is Vitamin C used for in the body? (what is the effect of deficiency?) what are some foods that are a good source of this vitamin?

Answer 41

• sticks together cell lining surfaces such as the mouth
• scurvy
• fresh fruit, veg

Question 42

what is Vitamin C used for in the body? (what is the effect of deficiency?) what are some foods that are a good source of this vitamin?

Answer 42

• sticks together cell lining surfaces such as the mouth
• scurvy
• fresh fruit, veg

Question 43

what is Vitamin C used for in the body? (what is the effect of deficiency?) what are some foods that are a good source of this vitamin?

Answer 43

• sticks together cell lining surfaces such as the mouth
• scurvy
• fresh fruit, veg

Question 44

what is Vitamin D used for in the body? (what is the effect of deficiency?) what are some foods that are a good source of this vitamin?

Answer 44

-helps bones absorb calcium and phosphate
-rickets, poor teeth
- found in fish liver oil, also made in skin in sunlight

Question 45

how does energy requirements very with activity levels, age, pregnancy

Answer 45

generally the greater the person’s weight, the more energy they need, which is why men need more energy than women generally
this also explains why pregnant women need more energy. (the type of food she eats also changes due to the needs of the baby)
more muscle activity also requires more energy so if you are more active, you need more energy
if you are growing a lot e.g., in puberty, you will need more energy

Question 46

what is digestion?

Answer 46

the chemical and mechanical breakdown of food. it converts large insoluble molecules into small soluble molecules, which can be absorbed into the blood

Question 47

what is digestion?

Answer 47

the chemical and mechanical breakdown of food. it converts large insoluble molecules into small soluble molecules, which can be absorbed into the blood

Question 48

how is digestion speeded up

Answer 48

by enzymes (biological catalysts)

Question 49

what is mechanical digestion?

Answer 49

the physical breakdown of food e.g., in the mouth when you chew and the walls o the stomach churning up food whilst it is being chemically digested

Question 50

what is chemical digestion?

Answer 50

the process of breaking down large food molecules into smaller molecules using enzymes so that the body can absorb them

Question 51

what is peristalsis

Answer 51

the involuntary, wave-like contractions of the muscles in the digestive tract that move food through the body

Question 52

describe peristalsis step by step

Answer 52

1. the walls in the intestine contain 2 layers of muscle:
   one has fibres containing rings around the gut (the circular muscles) and the other has fibres running along the length of the gut (the longitudinal muscle layer)
2. when the CM contract the LM relax so the gut is made narrower. when the opposite happens it becomes wider and the wave like contractions push the food along

Question 53

what are the two muscles int he wall fo the intestines called?

Answer 53

the walls in the intestine contain 2 layers of muscle:
one has fibres containing rings around the gut (the circular muscles) and the other has fibres running along the length of the gut (the longitudinal muscle layer)

Question 54

describe the alimentary canal in order

Answer 54

mouth (salivary gland, tongue), oesophagus, stomach, small intestine (duodenum then ileum), (food broken down by enzymes from panaceas/gut wall in duodenum), large intestine (colon, rectum), anus
(+appendix+liver+gall bladder)

Question 55

what are the three main classes of enzymes which break down food

Answer 55

carbohydrases, lipases, proteases (+amylase)

Question 56

what does the salivary gland do?

Answer 56

secretes saliva which moistens food and contains the enzyme amylase which breaks down starch into maltose

Question 57

where is bile produced?

Answer 57

liver

Question 58

where is bile stored?

Answer 58

gall bladder

Question 59

where is bile produced and stored

Answer 59

produced-liver
stored-gall bladder

Question 60

what is the function of the mouth/salivary glands

Answer 60

Mechanical digestion: teeth chew food to break it into smaller pieces and increase its surface area to volume ratio
Chemical digestion: amylase enzymes in saliva start digesting starch into maltose
The food is shaped into a bolus (ball) and lubricated by saliva so it can be swallowed easily?

Question 61

what is the function of the Oesophagus?

Answer 61

The tube that connects the mouth to the stomach
Wave-like contractions take place to push the food bolus down without relying on gravity

Question 62

what is the function of the Small intestine?

Answer 62

The first section is called the duodenum; this is where digestion of the food exiting the stomach is completed by enzymes that are present in the duodenum lining and secreted by the pancreas
The pH of the small intestine is slightly alkaline; around pH 8-9.
The second section is called the ileum and is where the absorption of water and digested food molecules takes place; the ileum is long and lined with villi to increase the surface area over which absorption can take place

Question 63

what is the function of the Stomach?

Answer 63

Food is mechanically digested by churning actions while protease enzymes start to chemically digest proteins.
Hydrochloric acid is present to kill bacteria in food and provide the optimum pH for protease enzymes to work.

Question 64

what is the function of the Large intestine?

Answer 64

Water is absorbed from the remaining material in the colon to produce faeces
Faeces are stored in the rectum and exit the body via the anus

Question 65

what is the function of the Pancreas?

Answer 65

Produces all three types of digestive enzymes: amylase, protease and lipase
Secretes enzymes in an alkaline fluid into the duodenum for digestion; this raises the pH of fluid coming out of the stomach

Question 66

what is the function of the liver?

Answer 66

Amino acids that are not used to make proteins are broken down here (deamination), producing urea
Produces bile to emulsify fats (break large droplets into smaller droplets), an example of mechanical digestion

Question 67

what is the function of the gall bladder ?

Answer 67

Stores bile to release into the duodenum

Question 68

what are the stages of food breakdown?

Answer 68

• Food taken into the body goes through six different stages during its passage through the alimentary canal(the gut):
  
  • Ingestion - the taking in of substances, e.g. food and drink, into the body through the mouth
  • Mechanical digestion - the breakdown of food into smaller pieces without chemical change to the food molecules
  • Chemical digestion - the breakdown of large, insoluble molecules into small, soluble molecules
  • Absorption - the movement of small food molecules and ions through the wall of the intestine into the blood
  • Assimilation - the movement of digested food molecules into the cells of the body where they are used, becoming part of the cells
  • Egestion - the passing out of food that has not been digested or absorbed (as faeces) through the anus

Question 69

what is ingestion

Answer 69

• Ingestion - the taking in of substances, e.g. food and drink, into the body through the mouth

Question 70

what is mechanical digestion

Answer 70

• Mechanical digestion - the breakdown of food into smaller pieces without chemical change to the food molecules

Question 71

what is chemical digestion

Answer 71

• Chemical digestion - the breakdown of large, insoluble molecules into small, soluble molecules

Question 72

what is absorption

Answer 72

• Absorption - the movement of small food molecules and ions through the wall of the intestine into the blood

Question 73

what is assimilation

Answer 73

• Assimilation - the movement of digested food molecules into the cells of the body where they are used, becoming part of the cells

Question 74

what is egestion

Answer 74

• Egestion - the passing out of food that has not been digested or absorbed (as faeces) through the anus

Question 75

name some types of carbohydrases? what do they do? where do they come from (source)? where does it act in the gut?

Answer 75

amylase:
starch-> maltose
comes from the salivary glands and acts in the mouth, it also comes from the pancreas and acts in the small intestine
maltase:
maltose->glucose
comes from wall of small intestine and acts in small intestine

Question 76

name some types of proteases? what do they do? where do they come from (source)? where does it act in the gut?

Answer 76

pepsin:
proteins->peptides (comes from the stomach wall and acts in the stomach)
trypsin:
proteins->peptides (comes from pancreas and acts in small intestine)
peptidases:
peptides-> amino acids (from the wall of the small intestine and acts in small intestine)

Question 77

name some types of lipase? what do they do? where do they come from (source)? where does it act in the gut?

Answer 77

lipase:
lipids-> glycerol + fatty acids (comes from pancreas and acts in small intestine)

Question 78

what happens in the stomach?

Answer 78

food is held in the stomach for hours, while initial digestion of protein takes place. the stomach secretes Hal os the stomach contents are strongly acidic. this kills the bacteria taken along by the food and protects us from food poisoning. pepsin (a protease) has to be able to work in these conditions. the semi-digested food is then held back by the stomach by a ring of muscle at the outlet of the stomach, called the sphincter muscle when it relaxes it releases the food into the duodenum

Question 79

what happens in the stomach?

Answer 79

food is held in the stomach for hours, while initial digestion of protein takes place. the stomach secretes Hal os the stomach contents are strongly acidic. this kills the bacteria taken along by the food and protects us from food poisoning. pepsin (a protease) has to be able to work in these conditions. the semi-digested food is then held back by the stomach by a ring of muscle at the outlet of the stomach, called the sphincter muscle when it relaxes it releases the food into the duodenum

Question 80

why is the stomach so acidic?

Answer 80

to kill bacteria carries by food

Question 81

what happens in the duodenum?

Answer 81

several digestive enzymes are added. these are made by the pancreas and digest starch, proteins and lipids. As well this, the liver makes a digestivee juice Called bile.

Question 82

how is bile released? what does it do?

Answer 82

stored in the gall bladder and passes down the bile duct on to the food. it is green and doesn’t have any enzymes. It emulsifies fats. In addition, bile and pancreatic juice it alkaline so it neutralises the semi-digested food and enzymes coming from stomach

Question 83

what happens in the ileum?

Answer 83

food is absorbed.

Question 84

how is the ileum adapted to absorb the digested food?

Answer 84

the lining of the ileum has a very large surface area, which means that is can quickly and efficiently absorb the soluble products of digestion into the blood.
the length of the small intestine also helps provide a large surface area, which is aided by the folds in the lining
the ileum has villi (which have microvilli) which increase the SA:VOL
each villus has a network of blood capillaries

Question 85

what are villi?

Answer 85

tiny projections in the small intestine that help absorb nutrients

Question 86

what is a lacteal?

Answer 86

a tube in the middle of the villus which fat droplets can go through. The lacteals form part of the body’s lymphatic system which transports a liquid called the lymph which eventually drains into the blood system

Question 87

how are villi adapted to its function?

Answer 87

villi (which have microvilli) which increase the SA:VOL
each villus has a network of blood capillaries
the surface is made of a single layer of cells called an epithelium. - short diffusion distance between blood capillaries and products fo digestion
what is special about the epithelium cells? they contain many mitochondria, which supply the energy needed for active transport of some substances
each villus is made of muscle fibre which contract and move the villus, keeping them in contact with the contacts of the ileum and maintaining steep conc. gradient for diffusion of the products of digestion

Question 88

what do the blood vessels of the ileum join up to?

Answer 88

a large blood vessel called the hepatic portal vein which leads to the liver. it breaks some molecules down and builds up and stores others.

Question 89

what happens in the large intestine?

Answer 89

the waste material, which consists mostly of cellulose (fibre) and other indigestible remains, waste, dead and living bacteria cells lost from the lining of the gut is stored in the rectum and expelled out of the body through the anus. however before this, before this, int he colon, the rest of the water is absorbed leaving semi-solid waste.