Organisation Flashcards
give the definition for tissue
a group of similar cells working together to carry out a particular function
give the definition for organs
a group of tissues working together to perform a specific function
give the definition for an organ system
a group of organs that work together to form whole organisms
what is an enzyme
a biological catalyst
- *something that speeds up the rate of reaction without being changed or used up in the reaction
what is the lock and key method?
every enzyme has a substrate that fits perfectly with it
- once the enzyme is in place, the enzyme and substrate bind together to form a substrate-enzyme complex; the reaction takes place rapidly; the products are released from the surface of the enzyme; enzyme is free to use again
what are the three digestive enzymes?
carbohydrase enzymes, protease enzymes, lipase enzymes
what is an example of a carbohydrase enzyme?
amylase
what does a carbohydrase enzyme break down?
carbohydrates (starch)
what does starch break down into?
simple sugars
where is amylase found?
salivary glands, small intestine, pancreas
what do protease enzymes break down?
proteins
what do proteins break down into?
amino acids
where is protease found?
stomach, small intestine, pancreas
what do lipase enzymes break down?
lipids
what do lipids break down into?
glycerol and fatty acids
where is lipase found?
small intestine, pancreas
what are the two roles of bile?
NEUTRALISES the stomach’s ph 2 into a ph 7.5 ready for enzymes made in the pancreas and small intestine
EMULSIFIES large molecules of lipids into smaller pieces of lipids (droplets) so the enzymes have a larger surface area to work with
how is the small intestine adapted to gas exchange? (4)
- covered in millions and millions of villi which increase the surface area
- villi covered in microvilli which further increases the surface area
- villi has a network of capillaries = good blood supply
- villi have a thin membrane = ensures a shorter diffusion path
what is the route the blood takes through the heart? (6)
- de-oxygenated blood comes back to the heart through the vena cava
- passes through the right atrium, through the tricuspid valve and into the right ventricle
- leaves the heart through the pulmonary artery to go to the lungs
- oxygenated blood returns to the heart through the pulmonary vein
- passes through the left atrium, through the bicuspid valve and into the left ventricle
- leaves the heart through the aorta to be taken to the body cells
repeats
what is the purpose of the coronary arteries?
- to provide oxygen to the muscle cells of the heart
how is resting heart rate naturally controlled?
a group of cells in the wall of the right atrium that act as a pacemaker, they send electrical impulses to the muscle cells of the heart so that it contracts