B3: Living and Growing (OCR Gateway Biology)

Types of protiens:

• structural                   (eg. collagen- substance that holds our body together)
• hormonial                  (eg. insulin- breaks down sugars)
• carrier molecule        (eg. hemoglobin- in red blood cells and cary oxygen from lungs to body                                            cells)
• enzyme                     (eg. amylase- a catalyst) 

Protien molecules

• are built up from a chain of amino acids 
  • has it's own number and sequence
• has its own particular shape to do it's job

• Denaturing is irreversable, the enzyme is perminantly damaged
• enzymes work slowly at a low temperature because the substrates enter the active site more slowly.
• Q₁₀: Temperature coefficient
  • a measure of the rate of change of a reaction when the temperature is increased by 10℃
• Q₁₀ = rate at high temperature     (there is 10℃ difference between the high and low                                                                           <--  temperature)
•           rate at low temperature

eg. what is the Q₁₀ of a reaction when at 20℃ the reaction was at 10units/min and was 24 units/min at 30℃

Q₁₀= 24÷10 

=2.4

Blood is used to transport materials around the body

plasma contains:

• red blood cells- carry oxygen in hemoglobin around the body
• white blood cells- fight diseases
• platelets- form scabs (help to clot up blood)
• amino acids
• fatty acids
• urea
• sugar

• Red blood cells can be small and lets blood pass through the capillaries
• they are a flattened disk shapes and have a large surface area for rapid diffusion of oxygen
• they contain haemoglobin to absorb the oxygen in the lungs to release in the body
• they have no nucleus to save space for haemoglobin

aerobic respiration: glucose + oxygen → carbon dioxide + water  (+energy in the form of ATP)                                        C₆H₁₂O⁶ + 6O₂     →  6CO₂               + 6H₂O   (+ energy in the form of ATP)

• the rate of respiration can be found by measuring:
• the increased oxygen consumption
• the increased carbon dioxide production
• Respiratory Quotent (RQ)
• = CO₂ produced
•       O₂ used
• anaerobic respiration: glucose → lactic acid (+ little energy, small amount of ATP)
  • lactic acid is carried to liver where oxygen is used to break it down 
• ATP: substance that is used as the energy source for many processes in cells
• Oxygen debt: amount of oxygen needed to oxidise lactic acid to CO₂ and H₂O
• metabolic rate: the rate at which energy is used in the body

• mutations are the changesto the genetic code in a gene
• DNA mutation changes the amino acid sequence this changes the different protein produced, the cells may not function properly

Types of mutations

• spontaneous: mistake made during copying or creation of cells or gametes
• induced: chance of mutation increased by radiation, x rays, UV lights, chemicals

• occasionally it (mutations) can give an organism an advantage, sickle cell anemia gives you resistance to malaria
• most mutations are harmful, they can cause cells to multiply out of control (cancer) or in a gamete can cause a feotus to die

• doesn't permanently change an organisms genes
• copies of a functioning gene/ allele may be inserted into certain body cells who have a recessive genetic disorder
• (it takes place after the organism is fully grown)