Section 2e: Nutrition (human) Flashcards
(20 cards)
Proteins
Carbon, hydrogen, oxygen, nitrogen and sulfur (some)
Long chains of amino acids
Grow new tissue and repair
Carbohydrates contain…
Complex carbs are made up of?
Function
Carbon, hydrogen and oxygen
Complex carbs are made up of long chains of monosaccharides (glucose or fructose)
Supply energy
Lipids
Carbon, hydrogen and oxygen
Glycerol and 3 fatty acids
Store and provide long term energy
Water
Carry substances around the body and replace loss water
Fibre
Keeps digestive system healthy and prevent constipation
Eg. Bran
Vitamin A
Makes chemicals in retina, protects surface of eye and tissue
Fish liver oils and carrots
Vitamin C
Sticks together cell linings surfaces in body
Citrus fruits, veg
Vitamin D
Helps bones absorb calcium and phosphorous
Fish liver oils and sun
Calcium
Makes bones/ teeth
Dairy/ veg
Iron
Makes haemoglobin in red blood cells
Red meat, green leafy veg
What is food energy
Amount of energy set free when food is burned
What is used to measure food energy industrially?
Food calorimeter
1 calorie in joules?
4.2
Equation for food energy
Energy (j/g)= (temp rise x 4.2 x mass of water)/ mass of food
Enzymes
Proteins that catalyse biochemical reactions; biological catalyst
Order of bases in DNA…
Determines order of amino acids in a protein
What is an active site
The part of folded protein where substrate attaches to.
Shape of substrate is complementary to the shape of the active site- key into lock
Enzyme action
Substrate binds into active site
Enzyme-substrate complex forms
Reaction takes place
Product no longer fits into active site- released
Enzyme free to be used again (only catalyst)
Factors that affect enzyme activity
Temperature; optimum- highest rate of reaction- 37 degrees in humans
Above optimum- enzymes denature, active site changes shape (over 40-45 degrees)
PH: (in stomach is 2-3) in small intestine and normally is 7
Enzyme and substrate concentration
Alimentary canal
Muscular tube from mouth to anus
