ORGANISATION Flashcards
what is differentiation?
the process in which a cell becomes speciallised for a function
when does differentiation occur?
during the development if multicellular organism
what do speciallised cells form?
tissues which then form organs which then form organ systems
what is a tissue?
a group of similar cells that work together to carry out a specific function
give examples of tissues types in mammals (3)
muscular - contracts to move
glandular - makes/secrets chemicals (enzymes/hormones)
epithelial - covers part of the body
what is an organ system?
a group of organs working together to perform a function
organ systems work together to form..
organisms
what are enzymes?
catalysts produced by living things
what is a catalyst?
a substance that increases the speed of a reaction without being used up/changed
what is an enzyme?
proteins that act as biological catalysts
what does every enzyme have?
an active site with a unique shape that fits onto the substance involved
what is an induced fit of enzyme action?
when the active sit changes shape as the substances binds to get a tighter fit
enzymes need the right….
temperature
pH
why do enzymes need the right temperature?
changing the temp vhanges the rate of an enzyme-catalysed reaction.
temp increases it
too hot -> bonds of enzymes break -> changes shape of active site - substrate wont fit
all enzymes have an optimum temp they work best at
why do enzymes need the right pH?
too high/low -> bond is effected -> shape of active site changes -> enzyme denatures
optimum pH is usually 7
pepsin works best at pH 1-2
enzyme PRACTICAL
- put a drop of iodine solution in every well of a spotting tile
- place a bunsen burner on a heat proof mat
- put a tripod and gauze over the bunsen burnder
- put a beaker of water on the tripod
- heat the water til its at 35C using a thermometer to track it
- use a syringe to add 1cm3 of amylase and 1cm3 of buffer solution with a pH of 5 to a boiling tube
- using test tube holders, put them into the beaker of water
- wait for 5 mins
- add 5cm3 of starch solution to the boiling tube
- mix everything in the boiling tube and start a stopwatch
- using a pipette, take a sample of the boiling tube every 30s and add a drop to a well
- when the iodine stays browny-orange, starch is no longer present and stop the stopwatch
- repeat experiment with different pH to see how pH affects time taken for starch to break down
rate of reaction =
1000/time
why are big molecules (starch, fat, protein) broken down?
theyre too big to pass through walls of the digestive system so digestive enzymes break them down to sugars, amino acid, glycerol and fatty acids which can be absorbed into the bloodstream
carbohydrase converts….
carbohydrates to simple sugars e.g amylase - made in salivary glands, pancreas, small intestine
protease converts….
proteins to amino acids
protease is made in stomach (pepsin), pancreas, small intestine
lipases converts…
lipids into glycerol and fatty acids
lipase made in pancreas and small intestine
what does bile do?
neutralises stomach acid - hydrochloric acid in the stomach makes it too acidic for enzymes to work properly. bile is alkaline which will neutralise the acid
emulsifies fat (breaks down fat) - bigger SA for lipase to work on, speeding up digestion
where is bile produced?
liver
where is bile stored?
gall bladder
what is the breakdown of food catalysed by?
enzymes
where are digestive enzymes produced in?
by cells in the glands and gut lining
what do salivary glands produce?
amylase enzyme in the saliva
what is the gullet?
oesophagus
what is produced in the liver?
bile
what does the gall bladder do?
stores bile before its released into the small intestine
where is excess water is absorbed?
large intestine
what is stored in the rectum?
faeces
what does the small intestine do?
produces protease, amylase and lipase enzymes
digested food is absorbed out, into the blood
what does the pancreas do?
produces protease, amylase and lipase enzymes
releases them into small intestine
what does the stomach do?
pummels food with its muscular walls
produces pepsin and hydrochloric acid (to kill bacteria and give right pH (2) for pepsin to work
food test PRACTICAL - preparing food sample
- get a peice of food and break it up using a pestle and mortar
- transfer the ground up food into a beaker
- add some distilled water to the beaker
- mix it to dissolve it
- filter the solution using a funnel lined with filter paper to get rid of solid bits
testing for sugar PRACTICAL (bendict)
- prepare a food sample
- put 5cm3 of it into a test tube
- set a water bath to 75C
- add benedict solution to the test tube using a pipette
- put the test tube in the bater bath and leave for 5 mins
- if it contains sugar: blue -> green, yellow or brick-red (depending on the amount of sugar in it)
testing for starch PRACTICAL (iodine)
- transfer 5cm3 of the food sample to a test tube
- add some iodine using a piette
- gently shake the test tube to mix the contents
- if starch is present: brown/orange -> blue/black
testing for proteins PRACTICAL (biuret)
- transfer 2cm3 of food sample into a test tube
- add 2cm3 of biuret solution to the sample and gently shake
- if contains protein: blue -> purple
testing for lipids PRACTICAL (sudan III)
- transfer 5cm3 of the unfiltered food sample to a test tube
- use a piette to add 3 drops of sudan III solution
- gently shake the test tube
- if lipids present: mixture will be separated into 2 layers (top layer bright red)
what is the bronchi split into?
bronchioles
where does gaseous exchange take place?
in the lungs where millions of alveoli exist, surrounded by capillaries
what is the pathway of oxygen (gaseous exchange)?
air enters through the nose/mouth -> throat (pharynx) and passes through the voice box (larynx) -> trachea -> left/right bronchus -> bronchioles -> alveoli
what is the pathway of blood (circulatory system)?
deoxygenated blood:
superior vena cava -> right atrium -> right ventricle -> pulmonary valve -> pulmonary arteries -> lungs (gaseous exchange)
oxygenated blood:
pulmonary vein -> left atrium -> left ventricle -> aorta -> body
what are the walls of the heart made of?
muscle tissue
what feature of the heart prevents backflow of blood?
valves