Organisation - Cell Organisation and Enzymes 45-48 Flashcards
what is the process by which cells become specialised for a particular job
differentiation
when does differentiation occur
during the development of a multicellular organism
what are large multicellular organisms made up of
organ systems
what do these specialised cells form, what does that form etc
tissues, which form organs, which form organ systems, which form large multicellular organisms
large multicellular organisms have different systems for
exchanging and transporting materials
what is a tissue
a group of similar cells that work together to carry out a particular function
what are some examples of tissues and explain there purpose
3 points
1) Muscular tissue - contracts to move whatever it’s attached to
2) Glandular tissue - makes and secretes chemicals like enzymes and hormones
3) Epithelial tissue - covers some parts of the body e.g. the inside of the gut or stomach
what is an organ
an organ is a group of different tissues that work together to perform a certain function
what tissues is the stomach made out of
3 points
1) muscular tissue - to churn up the food
2) glandular tissue - make digestive juices to digest food
3) Epithelial tissue - covers the outside and inside of the
stomach
what is an organ system
an organ system is a group of organs working together to perform a particular function
what are some examples of organ systems in humans and their purpose
8 points but don’t have to name all systems but should name their functions
1) digestive - breaks down and absorbs food
2) respiratory - breathing
3) circulatory - blood circulation
4) endocrine - hormone production
5) urinary - waste elimination
6) reproductive - reproduction
7) nervous - communication between and coordination of all the body systems
8) muscular/ skeletal - provides form, support, stability, and movement to the body
what organs are in the digestive system and their function
5 points
1) glands e.g. the pancreas and salivary glands - produce digestive juices
2) the stomach - digest food
3) the liver - produces bile
4) the small intestine - digest food and absorb soluble food molecules
5) large intestine - absorbs water from undigested food, leaving faeces
organ systems work together to make
organisms
what is the definition of an enzyme
enzymes are catalysts produced by living things
what is a catalyst
a catalyst is a substance which increases the speed of a reaction without being changed or used up in the reaction
why is raising the temperature to speed up the rate of reaction bad
1) raising the temp would speed up useful reactions but also the unwanted ones
2) there’s also a limit to how high you can raise the temp before cells get damaged
what do enzymes reduce the need for and what reactions do they speed up
1) high temperatures
2) they speed up only useful reactions
what are enzymes
large proteins
what are proteins made up of
2 points
1) proteins are made up of chains of amino acids
2) these chains are folded into unique shapes
what do chemical reactions usually involve
things either being split apart or joined together
what does every enzyme have
2 points
1) an active site
2) with a unique shape that fits onto the substance involved in a reaction
enzymes usually only catalyse
one specific reaction
why do enzymes usually only catalyse one specific reaction
2 points
1) because for the enzyme to work, the substrate has to git into its active site
2) if the substrate doesn’t match the active site then the reaction won’t be catalysed
draw a ‘lock and key model’ of enzyme action
look page 47 of aqa biology text book
what is the ‘induced fit’ of an enzyme reaction
where the active site changes shape a little as the substrate binds to it to get a tighter fit
what affects the rate of an enzyme-catalysed reaction
2 points
1) the temperature
2) the pH
how does the temperature affect a reaction
5 points
1) at first a higher temperature increases the rate
2) but if it gets too hot, some of the bonds holding the enzyme together break
3) this changes the shape of the enzyme’s active site so the substrate won’t fit anymore
4) the enzyme is said to be denatured
5) all enzymes have an optimum temp that they work best at
how does the pH affect enzymes
4 points
1) is it’s too high or low, the pH interferes with the bonds holding the enzyme together
2) this changes the shape of the active site and denatures the enzyme
3) all enzymes have an optimum pH they work best at
4) this is usually pH 7 but not always e.g. pepsin in the stomach works best at pH 2
