organisation - cell organisation and Enzymes

Question 1

what is the process by which cells become specialised for a particular job

Answer 1

differentiation

Question 2

when does differentiation occur

Answer 2

during the development of a multicellular organism

Question 3

what are large multicellular organisms made up of

Answer 3

organ systems

Question 4

what do these specialised cells form, what does that form etc

Answer 4

tissues, which form organs, which form organ systems, which form large multicellular organisms

Question 5

large multicellular organisms have different systems for

Answer 5

exchanging and transporting materials

Question 6

what is a tissue

Answer 6

a group of similar cells that work together to carry out a particular function

Question 7

what are some examples of tissues and explain there purpose
3 points

Answer 7

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

Question 8

what is an organ

Answer 8

an organ is a group of different tissues that work together to perform a certain function

Question 9

what tissues is the stomach made out of
3 points

Answer 9

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

Question 10

what is an organ system

Answer 10

an organ system is a group of organs working together to perform a particular function

Question 11

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

Answer 11

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

Question 12

what organs are in the digestive system and their function
5 points

Answer 12

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

Question 13

organ systems work together to make

Answer 13

organisms

Question 14

what is the definition of an enzyme

Answer 14

enzymes are catalysts produced by living things

Question 15

what is a catalyst

Answer 15

a catalyst is a substance which increases the speed of a reaction without being changed or used up in the reaction

Question 16

why is raising the temperature to speed up the rate of reaction bad

Answer 16

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

Question 17

what do enzymes reduce the need for and what reactions do they speed up

Answer 17

1) high temperatures
2) they speed up only useful reactions

Question 18

what are enzymes

Answer 18

large proteins

Question 19

what are proteins made up of
2 points

Answer 19

1) proteins are made up of chains of amino acids
2) these chains are folded into unique shapes

Question 20

what do chemical reactions usually involve

Answer 20

things either being split apart or joined together

Question 21

what does every enzyme have
2 points

Answer 21

1) an active site
2) with a unique shape that fits onto the substance involved in a reaction

Question 22

enzymes usually only catalyse

Answer 22

one specific reaction

Question 23

why do enzymes usually only catalyse one specific reaction
2 points

Answer 23

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

Question 24

draw a ‘lock and key model’ of enzyme action

Answer 24

look page 47 of aqa biology text book

Question 25

what is the ‘induced fit’ of an enzyme reaction

Answer 25

where the active site changes shape a little as the substrate binds to it to get a tighter fit

Question 26

what affects the rate of an enzyme-catalysed reaction
2 points

Answer 26

1) the temperature
2) the pH

Question 27

how does the temperature affect a reaction
5 points

Answer 27

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

Question 28

how does the pH affect enzymes
4 points

Answer 28

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