organisation Flashcards
what are cells
the basic structure of all living things
what is tissue and give an example
a group of specialised cells with a similar structure or function an example would be muscular tissue
what is an organ and give an example
formed from a number of different tissues, working together to complete a specific function an example would be the stomach
how are organs organised, an give an example
into organ systems, they work together to perform a specific function an example would be the digestive system
what is the digestive system
an example of an organ system. the digestive system helps break down food for your body cells to absorb it
what organs is digestive system made up of and what are their jobs
- mouth - breaks down carbohydrates by enzymes
- oesophagus
- stomach - contracts to mix food, pepsin breaks down proteins, produces hydrochloric acid to kill bacteria and create the correct environment for pepsin
4.small intestine - digested food is absorbed into bloodstream. pancreas makes most of the digestive enzymes ang gets pushed into small intestine. gallbladder released bile (which is made in the liver) to neutralise acid from the stomach and emulsifying fats - large intestine - absorbs excess water and stored as faeces
how is food absorbed into the bloodstream from the small intestine
an example of an exchange surface
- villi increase the surface area meaning digested food absorbed quicker
- villi only have a single layer of surface cells meaning nutrients only diffuses small distances
- villi have good blood supply, maintains the concentration gradient
what is an enzyme
a type of catalyst made by living organisms (biological catalyst) - something that speeds up a reaction without being used up
what are enzymes made of
large proteins made up of long chains of amino acids. they then fold up to fit different spaces and catalyse different chemical reactions
what is active site
the part of the enzyme that is complementary to the substrate. if substrate doesn’t fit, the reaction wont be catalysed. this allows the enzyme to be really specific with what reaction to speed up.
explain the two enzyme actions
lock and key: this is the original idea
- scientists thought that substrate has to fit perfectly into the active site
induced fit: realistic idea
- the enzyme changes shape slightly as it binds to the substrate. the active site is complementary to the substrate
how does temperature increase enzymes activity and therefore the rate of reaction
as the temperature increases so does the rate of reaction. this increases because the particles have more kinetic energy and are more likely to collide and have enough energy to react
how does a high temperature effect the rate of reaction
when temperature is over 37 degrees (normally) it breaks apart the bonds holding enzymes together. The active site begins to change shape and becomes denatured. this means the enzymes won’t be able to bind to substrate
what is PH
a measure of acidity
what happens if the PH is too high or too low and explain why
it will decrease the rate of reaction because the bonds holding the enzymes will break. the active site begins to change shape. at first the substrate still fits but now as well meaning the rate of reaction is slowed. yet, as time goes on, the substrate can no longer fit and becomes denatured.
what is the optimum ph of different enzymes
most common enzymes have a PH of neutral or 7
stomach enzymes have a PH of around 2 to be able to function in the stomach which has an acid environment
what do enzymes do in the digestive system
help break down large molecules of food into smaller soluble molecules that are absorbed into lining
explain carbohydrate enzymes
- pasta/ potatoes
- starch is broken down by amylase into maltase
- made in the salivary glands, pancreases, small intestine
explain protein enzymes
- nuts/ meats/ beans
- broken down by protease into amino acids
- made in the stomach (pepsin), pancreas and small intestine
explain fat/lipid enzymes
- cheese/ oil/ chocolate
- broken down by lipase into glycerol and fatty acids
- made in pancreas/ small intestine
what is the circulatory system
organ system which transports oxygen and nutrients around the body
annotate a diagram of a heart
include:
- atriums ( top two)
- ventricles (bottom two)
- vena cava
- pulmonary artery
- thick muscular walls
what do valves do
prevent blood from flowing backward
explain the process of blood flowing in the heart to flow through the body
- blood (deoxygenated coming from the loop around the body) flows through the vena cava. blood (oxygenated coming from the lungs) flows through the pulmonary vein these flow into the right and left atrium.
- the blood is pushed into the ventricles by the atriums pushing together.
- ventricles then contract, pushing blood out.
- the pulmonary artery carries blood out of the heart to the lungs and through the aorta to the rest of the body
