Hb1 - We Are What We Eat

Front 1

what foods is energy obtained from?

Back 1

carbs, fats and some from protein

Front 2

where is fat stored?

Back 2

around organs and under the skin

Front 3

what happens when you take in less energy than you use over a long period of time?

Back 3

all fat stores will be used up then the body will start to break down other parts of the body so body proteins are used up. e.g. muscle tissue

Front 4

what are the three diff types of sugar?

Back 4

intrinsic - found within cells of food e.g. in fruit

extrinsic - not contained within cells of food e.g. processed foods

milk - found in milk and milk products - milk sugar e.g. lactose

Front 5

why is it recommended that more of our energy comes from starches and not other sugars?

Back 5

-energy from starch is released more slowly

- eating more starch and less sugar stops blood glucose levels rising too sharply and stops hunger for longer

Front 6

what factors affect BMR?

Back 6

- women have lower than men because they have a higher ratio of adipose tissue which has a lower metabolic rate than muscle tissue

- higher body mass = higher bmr bcos more respiring tissue

- tall&slim have higher bar than short&fat of same mass because they loose more body heat due to surface area:volume

- children have higher because they are growing rapidly

- older have lower because they have less muscle tissue

- pregnant have higher because foetus is growing and respiring rapidly

Front 7

how do scientists test glycemic index?

Back 7

- feed 10 volunteers enough of one food to give 50g of carbs

- take blood samples over the next two hours to measure level of blood glucose

- the average values will be found and will be converted into the glycemic index out of 100

Front 8

what happens when your blood glucose level increases?

Back 8

- pancreas is stimulated to release insulin

- insulin causes liver and muscle cells to store glucose as glycogen

- if blood gluc. levels stay high for too long the excess will be stored as fat

- release of insulin causes blood gluc. levels to drop, if a lot is released this will happen sharply

- this could lead to a dip in blood gluc. and lead to hunger again

Front 9

what are the levels of GI?

Back 9

- more than 70 - high

- 56-69 - med

- 55 or less - low

Front 10

what factors affect GI?

Back 10

- shape and branching of starch molecules will affect how quickly it is hydrolysed and absorbed into the blood

- whether starch is combined with dietary fibre, DF slows the absorption of sugars into he blood

- other components in food, for e.g. fat affects the rate of carb digestion, adding vinegar, lowers ph which can slow digestion and absorption of carbs

Front 11

how do you calculate glycemic load?

Back 11

carb content of food (g) x GI/100

Front 12

what are the levels of glycaemic load?

Back 12

- 20 or more - high

- 11-19 - med

- 10 or less - low

Front 13

what is the aim of low carb diets?

Back 13

reduce overreacting by eating foods that don't increase blood glucose too suddenly or too much

Front 14

why do some people feel concerned by low crab diets?

Back 14

often high in fats, especially sat fats which can cause heart disease

Front 15

what do vitamins do?

Back 15

interact with important enzymes involve in cell processes

Front 16

name a vitamin we don't ned to rely on food for?

Back 16

D & K2

Front 17

how to we obtain vitamin D?

Back 17

- made by the action of uv rays on the skin

- light skinned people will not need to rely on it D from foods

- darker skinned people have more melanin in their skin so will make less vitamin D

Front 18

why do we need vitamin D?

Back 18

- so that we can absorb calcium ions from the food in our guts and assist in depositing calcium in bone cells

- a lack of can lead to rickets

- rickets in kids gives soft bones which won't grow properly, joints will be swollen and bombs and chest bones may bend

- in adults deficiency causes gradual bone softening which could become painful and likely to fracture

Front 19

give 2 examples of minerals and their roles

Back 19

- calcium - constant of bones and teeth, needed for blood clotting

- phosphate - constituent of nucleic acids, ATP, phospholipids and bones and teeth

- iron - constituent of haemoglobin and myoglobin

- sodium - needed for nerve and muscle action

Front 20

what is the role of vitamin A?

Back 20

used to make the pigment rhodopsin for rod cells which are needed for vision in dim light

- a deficiency can lead to blindness through scarring and inflammation of the cornea

Front 21

How do we obtain vitamin K?

Back 21

K1 - through eating dark green veg and some oils

K2 - produced by intestine bacteria e.g. E.coli

Front 22

how does E. coli. produce vit K2?

Back 22

uses K2 in respiration and when bacteria dies it releases K2 from its cells

Front 23

what is haemorrhagic disease of the newborn?

Back 23

- condition in which blood doesn't clot properly

- causes intestinal bleeding, skin bleeding and mucous membranes e.g. nose and gums, bleeding from umbilical stump

- prevented by giving baby it K on 1st day of life

Front 24

what happens if the bodys water level falls too low?

Back 24

- reactions in cells slow or stop

- too little in blood plasma then blood can't be pumped easily

Front 25

how is water lost from the body?

Back 25

- water vapour when breathing out

- water in sweat

- water in faeces & urine

Front 26

what are diuretics?

Back 26

drinks that increase the amount of water lost in urine causing the body to loose more water than normal

Front 27

give 2 diuretics

Back 27

- alcohol

- caffine

Front 28

what is lost from the body during exercise?

Back 28

- lots of water in sweat

- inorganic ions in sweat

- glucose in respiration

Front 29

how do sports drinks work?

Back 29

- they are isotonic with blood plasma

- should replace the lost water and ions as well as providing glucose of respiration

Front 30

give 2 recommendations for a healthy diet

Back 30

- base meals on starchy foods

- eat 5 fruit and veg a day

- include protein based foods

- keep fat and sat fat to a minimum

- keep amount of sugar and salt eaten to a minimum

Front 31

what can result from having high salt levels in your diet?

Back 31

- can cause hypertension

- which leads to damage of artery walls

- which increases the fatty plaque build up and risk of CHD

Front 32

What effects does dietary fibre have?

Back 32

- can't be broken down by the gut

- make absorption of carbs slower

- which reduces insulin release and makes development of diabetes less likely

- increases feeling of fullness which reduces overeating

- reduces chances of developing diseases such s colon cancer

Front 33

what is food processing?

Back 33

altering the raw food product to make it last better, last longer or look more appealing

Front 34

give a disease thats been linked to processed food consumption and why

Back 34

obesity/type 2 diabetes because processed foods contain more fats and sugars than consumers are aware of

Front 35

give 3 additives and why they are added to foods

Back 35

antioxidants - make food last longer

colours - replace natural colour which is lost during processing/storage

emulsifiers - help mix ingredients that would otherwise separate

flavourings - added to give a taste or small

preservatives - gives food longer shelf-life

Front 36

give 2 reasons for the increase in obesity recently

Back 36

- spending more leisure time on computers/ watching tv rather than active things

- tend to drive to school rather than walk/cycle

- increased income so can afford plenty of food

- sedentry jobs rather than traditional manual jobs

- fast food outlets are common

Front 37

give 3 diseases linked to obesity

Back 37

- hypertension

- some cancers like breast cancer or colon and kidney cancers

- osteoarthritis and rheumatoid arthritis because of extra by weight putting a strain on joints and bones

- CHD because of increased blood pressure and cholesterol levels

- type 2 diabetes

Front 38

what does type 2 diabetes occur?

Back 38

when a person cannot control their blood glucose levels

produce enough insulin but body doesn't respond

Front 39

what are the risks to health that come with type 2 diabetes?

Back 39

- higher blood pressure leads to

- heart disease, angina, strokes

- type 2 can lead to blindness, poor nerve function and poor circulation in limbs which could lead to amputation

Front 40

give 2 examples of disaccharides and their composition

Back 40

maltose - 2 glucose

sucrose - 1 glucose 1 fructose

Front 41

how are polysaccharides made?

Back 41

many monosaccharides joining by a condensation reaction

Front 42

why do plants store starch?

Back 42

- compact molecule

- insoluble so doesn't interfere with osmosis

- branched structure so can be released easily when needed

Front 43

give 2 features of glycogen

Back 43

compact

insoluble

branched

Front 44

why can't humans use cellulose as an energy source?

Back 44

no enzymes in body to digest it

Front 45

why should we eat fibre in our diet?

Back 45

- prevents constipation

- increases rate at which food moves through intestines so toxin have less chance of causing damage - reduces colon cancer risk

Front 46

what are the 3 components of amino acids?

Back 46

carboxylic acid group (COOH)

amino group (NH2)

r group

Front 47

why do animal protein contain more essential amino acids than plant proteins?

Back 47

were more closely related to animals

Front 48

how is the tertiary structure of a protein held together?

Back 48

- weak hydrogen bonds between the r-groups of amino acids

- amino acids with sulfer in their R-groups can form strong disulphide bridges

Front 49

what happens in denaturation of a protein?

Back 49

hydrogen bonds break so the tertiary structure is changed and the protein can no longer carry out its function properly

- polypeptide chains loose tertiary structure and tangle up with each other

Front 50

whats the structure of a lipid?

Back 50

a glycerol molecule joined to 3 fatty acids

Front 51

how is a triglyceride formed?

Back 51

- glycerol has 3 -OH groups
- fatty acids each have a COOH group

- FAs line up along side glycerol so that the groups can join

- 3 condensation reactions occur

Front 52

whats the difference/similarity between sat fatty acids and unsat fatty acids?

Back 52

- both have a -COOH group

- rest o both molecules is made of a hydrocarbon chain

- in sat fat, bonds between carbon are all single means max number of hydrogen can attach

- in unsat fat some carbon have double bonds meaning that for same no. of carbon they have less hydrogen

Front 53

when is a triglyceride said to be unsaturated?

Back 53

when it contains an unsaturated fatty acid

Front 54

why do we need lipids in our diets?

Back 54

- for use in phospholipids in cell membranes

- synthesis of hormones

- cholesterol needed for cell membranes

Front 55

what are trans-fatty acids?

Back 55

fatty acids developed by the food industry to give a longer shelf life

have straighter chains

unsaturated fats

increase risk of CHD

Front 56

what happens during digestion?

Back 56

large molecules are broken down into the monomers tat they're made up of which are soluble and can be transported into the blood to the body parts that need them

Front 57

how do enzymes interact with digestion?

Back 57

- used to hydrolyse food molecules in the digestive system

- diff enzymes digest diff polymers at diff pHs so each enzyme works best at diff pH

Front 58

what's the method of chromatography?

Back 58

- starting line marked on chromatography paper using pencil, origins are marked on lie

- micropipette used to make small spots of the test substance on an origin, spot drys then is reapplied multiple times

- known sugars are spotted on the other origins

- paper suspended in solvent until its nearly at top of paper, final position of solvent marked in pencil - solvent front

- chromatogram is removed from solvent and dried

- sometimes a locating agent is needed to see compounds

Front 59

how do you identify what's in a mixture using a chromatogram?

Back 59

- sometimes compared distance travelled to known substance

- usually use Rf value = distance travelled by spot/distance traveled by solvent

Front 60

how do you compare what's in a compound using an Rf value?

Back 60

compared with Rf values from known the substances on the paper or with Rf values for same solvent in reference table