Yr 9 Diet and Bodily Functions 1 Flashcards
What’s a balanced diet?
Eating a sufficient amount of all 7 food groups
What are the 7 food groups?
-protein
-carbohydrates->sugars
->starches
-vitamins
-minerals
-fibre
-lipids (fats)
-water
What are the sources of carbohydrates (sugars)?
-sweets
-cakes
-fruit
-chocolate
What function in the body do carbohydrates (sugars) play a role in?
-they are used in respiration to release energy for the body to use
What are some sources of carbohydrates (starch/polysaccharides)?
-bread
-rice
-cereals
-pasta
-potatoes
What function in the body do carbohydrates (starch/polysaccharides) play a role in?
-digested into sugars and then used in respiration
-stored in the liver as glycogen (an energy store)
What are some sources of lipids?
-butter
-oils
-cream
-red meat
What function in the body do lipids play a role in?
-used as an energy store
-can be broken down and used in respiration
-have to be carried in the blood combined with protein (lipoprotein)
What are some sources of protein?
-meat
-eggs
-fish
-nuts
-peas
-legumes (lentils,chickpeas etc.)
What function in the body does protein play a role in?
-used for growth and repair of tissues
-makes enzymes and hormones that do reactions in your cells
What are some sources of vitamins?
-many sources depending on the nutrient
What function in the body do vitamins play a role in?
-needed in tiny amounts to keep the body functioning
What are some sources of minerals?
-many different sources depending on the nutrient
e.g. iron comes from red meat (like steaks) and green vegetables (like spinach)
What function in the body do minerals play a role in?
-needed in tiny amounts to keep the body functioning
What are some sources of fibre?
-cereals
-vegetables
-fruit
-basically any plant material
What function in the body does fibre play a role in?
-helps food move through digestive system
-prevents constipation
-reduces the risk of bowel diseases like colon cancer
What are some sources of water?
-drinks
-most fruit and vegetable
What function in the body does water play a role in?
-dissolves chemicals in cells and tissue fluids
-makes up most of your body
What factors mean a person needs more energy intake from their food?
-they are actively exercising daily
-they are children/adolescents (need more energy to grow)
-they are pregnant
-they have a higher metabolism
-they are male(usually)
What factors mean a person needs less energy intake from their food?
-they are female(usually)
-they have a slower metabolism
-they are adults
Why does an elderly person need less energy in their diet than a teenager?
-a teenager is going through puberty and has a much faster metabolism than an old person
-means it needs more food to develop and grow
What is the metabolic rate?
-how fast/slow your body processes food
What are some health problems linked to obesity?
-heart attack
-diabetes
-breathing problems
What are some symptoms of starvation?
-being very thin
>where your muscles waste away
-your immune system can’t work properly
>meaning you get more infections
-women may get irregular periods or may lose it all together
What happens if you take in more energy than you use?
-you get fat in your body
What happens if you use up more than you eat?
-you lose mass
energy in kiloJoules-> energy in kiloCalories
4.2 x energy in kiloCalories
How do you test for sugar?
-blue Benedict’s solution is added and heated
-if sugar is present, it will turn red/orange/yellow/green
How do you test for starch?
- yellowy brown iodine solution is added
- if starch is present, it will turn black
How do you test for protein?
-blue Biuret is added
-if protein is present, it will turn purple
How do you test for fat?
-add ethanol+water and then shake
-if fat is present, it will turn cloudy
Salivary glands
-produce saliva especially when you are hungry/sense food
>acts as a lubricant, making it easier to swallow food
-produces amylase
Oesophagus
-thin, 20cm tube that connects mouth and stomach
-helps move food quickly easily to stomach
Stomach
-small organ between oesophagus and small intestine
-produces protease
-releases stomach acid
-takes around 6-8 hours for food to pass through your stomach to the small intestine
Liver
-found to the left of your stomach
-produces bile (green liquid)
-food doesn’t actually pass into the liver
Pancreas
-produces carbohydrase, protease + lipase
-the pancreas then releases these into the small intestine
Small intestine
-longest single part of the digestive system (7m)
-narrower than large intestine
-absorbs the products of digestion into the blood
>then transported around the body through the blood to where they are needed
Villi
-microscopic finger-like projections of the lining of your small intestine
-greatly increase surface area and allow much more digested food to be absorbed into your blood
-contain blood capillaries
>providing a rich blood supply to move food molecules
Large intestine
-food entering is mainly indigestible fibre
-wider than small intestine but 1.5m long
-absorbs water and salts from remaining digested food
Anus
-opening at the end of digestive system
-controls when you poo (defecation)
Enzyme
-biological catalyst
-speed up chemical reactions in living things
-made of protein
Substrate and active site
-like a lock in key
-substrate and enzyme must collide and bind together at the active site in order for the reaction to occur
How does the concentration of the substrate affect the rate of enzyme action?
-the more of it there is, the more likely it is for it to collide and react
-but it stops increasing when all enzymes are going as fast as they can
How does the temperature affect the rate of enzyme action?
-more energy so enzymes move more, making them more likely to collide and react
-high temperature after 37 degrees denatures enzymes
How does denaturing work?
-high temperatures start to break the bonds holding the enzymes together
-active site starts to change shape
>will not be able to go back
Amylase
-breaks down starch into sugars
-found in:
>salivary glands
>small intestine
>pancreas
Protease (pepsin/trypsin)
-breaks down protein into amino acids
-found in:
>stomach (pepsin)
>pancreas (trypsin)
>small intestine (trypsin)
Lipase
-breaks down lipids into fatty acids+glycerol
-found in:
>pancreas
>small intestine
Stomach acid
-lowers pH to make optimum conditions for the protease pepsin
-kills bacteria/virus/pathogens in food and drink
Bile
-produced by liver
-high pH
-neutralises contents of small intestine (nice neutral pH for enzymes)
-emulsifies fats (making it into small droplets with a large surface area for the enzymes)
Order of digestive system:
- Mouth
2.Oesophagus
3.Stomach - Liver
- Gallbladder (stores bile)
6.Pancreas
7.Small intestine
8.Large intestine
9.Anus
pH Experiment
- Make a water bath using a 400cm3 beaker, and fill it 2/3 full with hot and cold water in order to attain a target temperature
- Use a thermometer to check the temperature
-might want to set it 2-3 degrees above the target temperature as it will cool when you set it up - label 3 test tubes with different pH levels
1-pH 4 2-pH 7 3-pH 10
4.Add 10cm3 of starch solution to each of these test tubes,using a pippette - Place these test tubes in the bath and leave them there for 2 minutes to equilibrate with temperature
- Add the corresponding pH buffer solution to each test tube to achieve the desired pH levels
- Add amylase to the 1st test tube, shake for them to mix, put it back in the bath and time how long it takes for the starch solution to get broken down using a timer
- Repeat step 7 for the rest of the test tube
- Repeat the experiment two times for accuracy
10.record your results and calculate the mean
