Biology Term 3 Flashcards
(36 cards)
why are enzymes important
- reactions can be slow without
- reaction can work in low temperature
- reduces activation energy
What are the factors affecting enxyme activity?
- Temperature
- if temp is 0, enzyme activity also 0
- if temp increase, enzyme activity also increase
- if temp go above limit:
- denatured
- enz activity = 0
- shape of active site not complimentary to shape of substrate
- pH
- if pH over/less than limit, denatured
- Enzyme and substance concentration
What is digestion? How is it different from absorption?
- digestion: the breakdown of large insoluble molecules to small soluble molecules permanently without chemi reaction
- absorption: food molecules going through wall of intestine to the blood.
What is mechanical digestion?
- contraction/relaxation of muscles to break down food and move it through digestive system.
What is chemical digestion?
- when acids and enzymes break down the food into nutrients
What is the difference between ingestion and egestion?
- ingestion: the take in of substance to body from mouth
- egestion: the take out of non digested food through the anus
Name main parts of the alimentary canal:
- mouth
- oesophagus
- stomach
- small intestine: duodenum & ilieum
- large intestine: colon
- rectum
- anus
What are the functions of the mouth?
- chews the food up
- mixes with saliva to help dissolve
Functions of the oesophagus:
- takes food down to stomach
Functions of stomach:
- muscle contract/relax to churn food
- stomach wall have goblet cell - have protese enz making HCL
- Pepsin secreated to breakdown polypeptides
- Works well in acidic condition - kill bacteria
Function of small intestine:
- narrow - 5m long
- pancreatic juice secreated from pancreas through pancreatic duct
- fluid contains enzyme: amylase, protese, lipase (typsin)
Function of Bile (s.i):
- yellowish green alkaline - neutralises acid from stomach
- made in liver - stored in gall bladder
- no enzyme but help digest fats
- emulsification: 2 substance combined that don’t mix easily tgth usually
- easy for lipase to digest fat
- emulsification: 2 substance combined that don’t mix easily tgth usually
Function of villi (s.i):
- secreates enzymes for digestion
- maltase
- sucrase
- peptisade
- lipase
- lactase
- has villius covered with cell
- Contain blood capillaries - A.A, monosacharides, minerals etc taken to liver then body
- one cell thick - fast diffusion
- goblet cells secrete mucus to protect from protese, lipase, physiscal damage, acid from stomach
Function of large intestine:
- to absorb water and nutrients
* mostly water absorbed in colon
What is the purpose of the circulatory system?
- to transport oxygen and nutrients to body
What are the 3 main things the C.S relies on?
- blood
- blood vessels
- cappillaries
What is a double circulatory system?
- the blood goes through the heart twice to complete one circuit
Function of the heart:
- pums blood around body
*2 upper chamber: atria
2 lower chamber: vetricles
How does the blood flow into the heart?
Body -> inferior/superior vena cava -> deoxygenated right atrium -> tricuspid valve -> right ventricle -> pulmonary arteries -> oxygenated lung -> pulmonary veins -> left atrium -> bicuspid valve -> left ventricle -> aortic valve -> aorta -> body
What is the purpose of the valve?
- to stop blood from flowing backwards
Function of aorta:
- recieves blood from body/lung - supplies to ventricle
Function of ventricles:
- bring blood to heart
- thicker, muscular walls than atria
Difference in left and right ventricle:
Left: pump blood to body - higher pressure
Right: pump blood to lung
Causes of CHD (oronary heart disease):
Causes
- too much cholesteral & fat in diet
- genetics
- narrows the lumen making it hard to pump blood
- increase blood pressure
- heart attack
Caused by:
- Lack of exercise
Prevention
- more exercise, no smoking, reduce cholesteral intake etc.
