Paper
The chemistry of life
(Living things made mostly of carbohydrates, fat and protein)
CARBOHYDRATES energy producer
Contain carbon, hydrogen and oxygen
Glucose is the simplest (dissolves easily in water) monosaccharide
Starch is also common (solid, lots of glucose molecules in a chain (condensation)) disaccharide
Starch is broken down into glucose as well (add waterhydrolysis)
FAT energy producer insulation and energy store
Contain carbon, hydrogen and oxygen
Contains more carbon + hydrogen
Fat molecule is made up of glycerol and fatty acids.
Condensation and hydrolysis play parts here?
PROTEIN
Contain carbon, hydrogen, oxygen, nitrogen (and sulphur)
Made of blocks (amino acids) and links (peptide links)
22 amino acids in nature
Hydrolysis chain of proteins split (polypeptides) then broken to small amino acids
Reverse in condensation
Soluble proteins make up enzymes.
Denaturalisation occurs when molecule shape changes when heated.
CHEMICAL REACTIONS
Occur mainly in gut and cells
Reactions in cells is metabolism
Breaking down or joining options
All reactions are catalysed by enzymes.
Enzymes
IMPORTANCE
To speed up reactions
They are biological catalysts
TYPES
Extracellular enzymes are produced and leave cell to work outside
Intracellular enzymes work inside cell
ENZYME CONTROLLED REACTION
Maltose (substrate) maltase (enzyme) glucose (product)
PROPERTIES
Always proteins
Specific
Reusable
Destroyed by heat over 45 Celsius
Sensitive to pH
HOW DO THEY WORK?
Enzyme molecule has active site
Substrate fits into active site
Reaction takes place
Products leave site.
HELPING HINDERING
Anything which helps substrate reach enzyme speeds up reaction
Poisons stop temporarily/ permanently the active site
ENZYME USE
Biological washing powders
Tenderising meats, skinning fish, removing hairs
Softening vegetables, removing seed coats
Syrups, fruit-juices, chocolates
Food and Diet
OUR DIET
Carbohydrates
Fats
Proteins
Water
Minerals
Vitamins
CARBOHYDRATES
Sugar gives energy
Starch are normally found in small grains called starch granules they also give us energy
Cellulose for plants make a cell wall for humans it makes a dietary fibre keeping the food moving along the gut
FATS
Mainly give us energy
Saturated means that there is no more room for atoms to add on to the existing molecule.
Unsaturated is the opposite.
PROTEINS
Needed for growth repair and slight amounts of energy
Kwashiorkor disease with the lack of protein
Proteins are made of amino acids
Essential amino acids are ones we cannot make but instead take in digestively
WATER
Absolutely essential
Needed in all life forms and contained in mostly all substances
MINERALS
Sodium. Is a salt. It helps messages to be sent and muscle contraction. Lack of causes cramps in muscles
Calcium used for hardening our bones and teeth. Hardening can only take place when they take up calcium phosphate and carbonate (calcification). Lack of causes rickets (soft, weak, deformed bones).
Phosphorus. We need it to be absorbed into the calcium. It occurs in membranes.
Iron. Present in haemoglobin (transports O2). Lack of cause anaemia: less O2 transported, less energy.
Iodine. Trace element: needed in tiniest quantities. We get from sea food and drinking water. Needed to make thyroxine. Lack of causes goitre or ?Derbyshire neck?: swelling of thyroid gland next to Adam?s apple.
Fluorine. Trace element. Prevents tooth decay.
VITAMINS
Collection of organic substances which control reactions in the body.
(A). Retinol: important for our eyes. Lack of causes night-blindness or xerophthalmia. Fat soluble
(B). Niacin (nicotinic acid). Lack of: Pellagra. Thiamine: lack of is Beri-beri. Riboflavin: causes sores in skin around mouth. Water soluble
(C). Ascorbic acid. Keep epithelia healthy. Lack of cause scurvy: bleeding in various parts of the body. Water soluble
(D). Calciferol. Helps child?s bones become strong. Lack of cause rickets. Can be obtained from fish liver oil or the body through sunlight. Fat soluble
(E). Found in milk and egg yolk. Lack of cause sterility. Fat soluble
(K). Helps blood clot. Lack of causes internal, external bleeding. Fat-soluble.
Composition of different foods helps us identify useful substances.
Vegetarian: eats no animal meat but does eat products. Vegans do not eat animal products.
Food additives: substances that are added to food. Some give change to colour, taste, preservation or consistency.
How substances are stored
WHY DO ORGANISMS STORE SUBSTANCES?
So that they can survive when food is unavailable or scarce
Man can survive several weeks
WHERE ARE SUBSTANCES STORED?
The main storage place is the liver for humans.
For plants they swell up and make the swelling the storage place. The plant storage organ can survive harsh conditions then a new plant spouts and the food is moved there.
PLANTS STORAGE SYSTEM
Green plants produce glucose that is either used straight away or turned into starch and converted back to glucose when needed.
Other substances can be made from glucose in plants (oil, sugar)
REQUIREMENTS FOR TURNING STARCH INTO GLUCOSE
Enzyme
Can be tested with starch
HOW STARCH IS TURNED INTO GLUCOSE
Glucose molecules join together and coil up forming a starch grain (condensation)
The starch grain can de-coil and split up forming Glucose (hydrolysis)
ANIMALS STORAGE SYSTEM
Get glucose from food
They turn glucose into glycogen
Glycogen is a bondage of glucose molecules linked together
Stored in the liver
It is also stored as fat
MOBILISATION
This is when a solid form of food has to be transported and it is broken down into a solution.
Starch and glycogen are broken down into glucose.
Fat is broken down into fatty acids and glycerol
IMPORTANCE OF FOOD STORES
Storage of food in organisms usually mean they are going to be packed together closely, this means anything like this can be a rich source for humans
Obtaining energy from food
FOOD CONTAINING ENERGY
We can check this by burning food and estimating the amount of heat given out. (kJ)
kJ per Gram carbohydrates-17, fat-39, protein-18
ENERGY CONTAINED IN FOOD
determines how it should be cooked
Depends on substances inside the food.
ENERGY PER DAY
Basal metabolic rate: rate at which body processes take place
Roughly 7000kj per day if lying down doing nothing
At least 9200 kJ per day for doing nothing but essential tasks
EXCESS EATING
Most excess not used is turned into fat. Body weight increases
Obesity is when we take in more energy (through food) than we give out.
More exercise, consumption of less energy-containing foods stop or decrease obesity
MINIMAL EATING (STARVATION)
First energy stores from fat will be used up.
Takes energy from muscles
Becomes thin and weak
Anorexia nervosa: psychological loss of appetite
Marasmus wasting away due to starvation
Energy release-respiration
FOOD BURNING
Oxygen is needed
Carbon dioxide, water and heat are produced
ENERGY PRODUCTION IN HUMANS
C6H12O6 + 6O2 6CO2 + 6H2O + ENERGY
We can check the relationship between O2+CO2 and breaking down of food by using radioactive tracers and mice.
ENERGY USES
Animal-movement, messages, transportation, warmth, growth, cell division, osmosis, and life!
Plants taking up mineral salts, opening/closing stomata, transporting food substances, growth, cell division, osmosis, and life!
CHEMISTRY OF RESPIRATION
Respirometer measures amount of oxygen taken in
Energy produced from glucose is linked to adenosine triphosphate (ATP)
Breakdown of glucose is used to make ATP
ATP not Glucose gives energy towards muscle contractions
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