Section 2 - Human Nuturition Flashcards
What elements do carbohydrate molecules contain (3)
- Hydrogen - Oxygen - Carbon
Starch and glucose are large, …… carbohydrates, made up of many smaller units, joined together in a …. ……
- complex - long chain
What are proteins made up of (2)
- Amino Acids
- Long chains
What elements do amino acids contain (4)
- Carbon - Nitrogen - Hydrogen - Oxygen
What are lipids made up of (2)
- Fatty acids - Glycerol
What elements do lipids contain (3)
- Carbon - Hydrogen - Oxygen
Describe how to test for glucose (5)
- Benedict’s test
- Add blue Benedict’s reagent to a sample and heat it
- Make sure the solution doesn’t boil
- If glucose is present, it will forma a coloured precipitate
- The higher the conc of glucose, the further the colour change goes (use to compare)
For the Benedict’s test, what are the colours for varying conc’s of glucose (3)
None -
Low -
High
Describe how to test for starch (2)
- Add iodine solution
- If starch is present, sample changes from brown/orange to a dark, blue/black colour
What are the 5 essential nutrients (5)
- Carbs
- Protein
- Fats
- Vitamins & Minerals
- Water
+ Fibre
What is the function of Vitamin A, C and D and what are they found in (6)
Vitamin A - Liver - Improve vision, keep your skin and hair healthy
Vitamin C - Oranges - Prevent scurvy
Vitamin D - Eggs - Needed for calcium absorption
What 2 mineral ions de we need, what are their functions and what can we find them in (6)
Calcium - Milk, cheese - make bones and teeth
Iron - Red meat - needed to make haemoglobin for healthy blood
What is dietary fibre’s function and what is it found in (2)
- Aids the movement of food through the gut
- Wholemeal bread
Describe an experiment to show how much energy is in food (9)
- Find a food that burn’s easily; a peanut
- Weigh a small amount of the food and then skewer it with a mounted needle
- Add 25cm3 of water to a boiling tube, and measure its temperature
- Set fire to the food using a bunsen burner
- Hold the burning food under the boiling tube until it goes out
- Relight and hold again, until no longer possible
- Measure the temperature of the water
Use : 25 x temp change x 4.2 = energy in food
Use : energy/mass = energy per gram of food (J/g)
Describe a way to make the energy from food practical more accurate (2)
- Insulate the boiling tube with foil
- Minimises heat loss and keeps more energy in the water
Why are digestive enzymes needed in the body (3)
- Digestive enzymes break down big insoluble molecules into smaller soluble ones
- Starch, proteins and fats are too big to pass through the walls of the digestive system
- Digestive enzymes allow starch, proteins and fats to be soluble and pass through the walls of the digestive system to be digested
The digestive enzyme ……. converts starch into …….
Amylase
Maltose
The digestive enzyme ……. converts maltose into …….
maltase
glucose
The digestive enzyme ……. converts proteins into …….
protease
amino acids
The digestive enzyme ……. converts lipids into ……. and ……..
Lipase
Fatty acids and glycerol
Where is bile produced, stored and released into (3)
Produced - liver
Stored - gall bladder
Released into small intestine
What does bile do (3)
- Bile neutralises hyrdochloric acid in the stomach
- Allowing enzymes in the small intenstine to work properly
- Bile emulsifies fats, making digestion faster as there is a bigger surface area of fat
The ………… …….. is another name for the gut (1)
alimentary canal
Label all 10 partS (10)
A - Mouth
B - Oesophagus
C - Liver
D - Stomach
E - Pancreas
F - Large Intestine
G - Small Intestine
H - Appendix
I - Anus
J - Gall bladder
What is A and what is its purpose (3)
- Mouth
- Salivary glands produce amylase enzymes in the saliva
- Teeth break down food mechanically
What is B and what is its purpose (2)
- Oesphoagus
- Muscular tube that connects the mouth and stomach
What is C and what is its purpose (2)
- Liver
- Where bile is produced
What is D and what is its purpose (4)
- Stomach
- Pummels food with its muscular walls
- Produces protease enzyme, pepsin
- Produces HCL;
to kill bacteria
to give the right pH for the protease enzyme to work
What is E and what is its purpose (3)
- Pancreas
- Produces protease, amylase and lipase enzymes
- It releases these into the small intestine
What is F and what is its purpose (2)
- Large intestine
- Where excess water is absorbed from the food
What is G and what is its function (3)
- Small intestine
- Uses protease, amylase and lipase enzymes to complete digestion
- Where nutrients are absorbed out of the alimentary canal into the body
What is I and what is its purpose (2)
- Anus
- Where faeces are egested
What is J and what is its purpose (2)
- Gall bladder
- Where bile is stored
What is peristalsis (3)
- Waves of circular muscle contractions
- Allowing food to squeeze through your gut and not get clogged
- Occurs in muscular tissue all the way down the alimentary canal
Describe the digestive process (5)
- Ingestion : Food taken into your mouth
- Digestion : Break down of large, insoluble molecules to smaller soluble ones. Can be mechinal (e.g teeth) or chemical (e.g bile)
- Absorption : Digested food molecules are absorbed in the small intestine; water mainly in the large. Absorption is he process of moving molecules through the walls of the intestines in the blood
- Assimilation : When digested molecules bcome part of cells (e.g digested amino acids assimilated, used by cells to make cellular proteins
- Egestion : All the undigested molecules form faeces, you get rid of them through the anus.
Explain how villi in the small intestine help with absorption (6)
- Villi found on duodenum and ileum
- It’s very long, time to break down and absorb all the food before it reaches the end
- Large surface area for absorption, because the walls are covered with millions of villi
- Villi are finger like projections which increase surface area
- Each cell on the surface of a villus has microvilli, increasing the surface area even more
- Villi have a single permeable layer of surface cells and a very good blood supply to assist quick absorptionn.
Label the two missing parts and give their function (4)
Duodenum - Recieves partially digested food from the stomach, crucial role in chemical digestion
Illeum - mainly to absorb vitamin B12 and bile salts
