proteins 1.6

Question 1

what are proteins made of

Answer 1

amino acids

Question 2

what does the sequence of DNA bases determine

Answer 2

the order of amino acids

Question 3

what does the order of amino acids determine

Answer 3

the structure and function of the protein

Question 4

name the 5 types of proteins

Answer 4

structural, enzymes, hormones, antibodies and receptors

Question 5

describe structural proteins

Answer 5

• they make up many essential components of the cell membrane and they help hold the structure of the cell membrane
• examples of structural proteins are keratin that’s found in hair and nails and collagen found in skin, bones and tendons

Question 6

describe enzymes

Answer 6

• biological catalysts because they speed up chemical reactions in every living cell and they remain unchanged
• because they remain unchanged they can be used over and over again without being used up

Question 7

describe hormones

Answer 7

• are chemical messengers released by glands in our bodies and travels in the bloodstream
• they travel to somewhere else in the body act according their functions
• involved in growth and metabolism

Question 8

describe antibodies

Answer 8

• y-shaped molecules that are made of lymphocytes that defend the body from disease
• antibodies stay in our bodies so the next time our bodies come into contact with a specific pathogen it can respond fast

Question 9

describe receptors

Answer 9

molecules which allow specific molecules to bind to them and receptors are found on the surface of cells and on the inside of cells

Question 10

what is a chemical reaction

Answer 10

a process in which one or more substances is changed into one or more different substances

Question 11

what is a product

Answer 11

the substances presence after the reaction takes place

Question 12

what is activation energy

Answer 12

when chemical reactions need a certain amount of energy to take place

Question 13

what produces enzymes

Answer 13

all livings cells

Question 14

why are enzymes so important

Answer 14

because without enzymes chemical reactions within the body the reactions would be too slow to support life

Question 15

how do enzymes work

Answer 15

they work by lowering the activation energy of the reaction so the reactions can take place at lower temperatures

Question 16

how is the shape of the enzymes activation site determined

Answer 16

by the sequence and bonding of amino acids

Question 17

the enzymes mechanism of action

Answer 17

1. the specific substrate enters the enzymes active site
2. the enzyme-substrate complex is formed and the substrate has enough energy for the reaction to take place
3. the reaction takes place and the substrate turns into products
4. the products are released from the enzyme and the enzyme remains unchanged

Question 18

the 2 types of enzyme reactions

Answer 18

degrading reactions and synthesis reactions

Question 19

describe degrading reactions

Answer 19

when one large substrate is broken down into two or more smaller products

Question 20

describe synthesis reactions

Answer 20

when two or more smaller substrates are built up into one large product

Question 21

what is digestion

Answer 21

the process in which the large molecules in food we eat are broken into smaller molecules and this allows them to be absorbed into the bloodstream

Question 22

examples of degrading reactions

Answer 22

SAM, PPP, Lipase and HPCOW

Question 23

example of synthesis reactions

Answer 23

GPS

Question 24

describe amylase

Answer 24

a digestive enzyme found mainly in our stomachs and saliva

Question 25

what does amylase break starch into

Answer 25

it breaks down starch into maltose

Question 26

describe pepsin

Answer 26

it breaks down protein and is found in the stomach

Question 27

what does pepsin break protein into

Answer 27

breaks down protein into peptides

Question 28

describe lipase

Answer 28

it breaks down fats

Question 29

what does lipase break fats down into

Answer 29

fatty acids and glycerol

Question 30

what does catalase break hydrogen peroxide into

Answer 30

oxygen and water

Question 31

describe phosphorylase

Answer 31

it’s a synthesis enzyme and catalyses the synthesis of glucose-1-phosphate into starch

Question 32

how do you determine if starch is present

Answer 32

test with iodine solution. it it stays a yellow/brown colour there’s no starch present but if the iodine solution turns a blue/black colour there’s starch present

Question 33

the 3 types of experimental design

Answer 33

validity, reliability, controls

Question 34

explain validity

Answer 34

- is to do with the “fairness” of the investigation | - in any experiment only one factor should be changed and all other variables should be kept the same

Question 35

explain controls

Answer 35

- is identical to the original experiment in every way except that the factor that causes the change is removed - it is then replaced by something that doesn’t bring about change

Question 36

explain reliability

Answer 36

to ensure reliability of the results and experiment, the experiment has to be repeated and several readings and sample have to be taken

Question 37

what are the effects of temperature on enzymes

Answer 37

- at low temperatures the enzymes have very little energy and therefore do not collide often with substrate molecules - as the temperature increases, enzyme substrate molecules collide more often meaning that reaction rate increases

Question 38

what is the optimum temperature

Answer 38

the temperature at which an enzyme is most active

Question 39

describe denatured

Answer 39

when the increased temperature breaks the bonds holding the amino acids together - this causes the shape of the enzymes active site to be altered and the enzyme can’t bing to the substrate - the enzyme is now denatured and permanently inactive

Question 40

when is amylase most active

Answer 40

pH 7

Question 41

what is pepsin optimum pH

Answer 41

pH 2

Question 42

what are enzymes made of

Answer 42

amino acids

Question 43

what does it mean when it says enzymes are specific

Answer 43

the different enzymes have different shaped active sites that are complementary to the substrate that binds to them and each different enzyme acts on one substrate only

Question 44

what is an active site

Answer 44

position on the surface of an enzyme molecule to which specific substrate molecules can bind

Question 45

what is a substrate

Answer 45

the substance in which an enzyme acts upon