proteins

Question 1

what chemical elements are proteins made of

Answer 1

C,H,O,N and sometimes S

Question 2

are proteins polymers

Answer 2

yes

Question 3

whats the name of the monomers that make up proteins

Answer 3

amino acids

Question 4

what is the name of polymers of proteins

Answer 4

polypeptides

Question 4

what determines the function of a protein

Answer 4

its shape

Question 5

what determines the shape of a protein

Answer 5

the sequence,type and number of amino acids within a protein/the amino acid sequence of a protein

Question 6

name everything that proteins form

Answer 6

-enzymes
-cell membrane proteins
-transport proteins e.g haemoglobin
-immunoglobulins
-structural proteins like collagen, keratin
-hormones
-contractile proteins

Question 7

state some functions of proteins

Answer 7

-cell growth
-repair of tissues and cell
-acts as carrier molecules r in cell membranes e.g hormones,antibodies,enzymes
-structurally important like collagen

Question 8

what happens if a mutation occurs and the sequence of amino acids changes

Answer 8

the shape of the protein,its tertiary structure which will alter the function of the protein

Question 9

how many amino acids exist in living organisms

Answer 9

20

Question 10

draw the structure of an amino acid

Question 11

what is the R group detrmine in an amino acid

Answer 11

-determines the chemical properties of an amino acids,it gives it its unique characteristics

Question 12

what distinguishes one amino acid from another

Answer 12

the R group contained within each amino acid

Question 13

what can the R group within an amino acid by

Answer 13

-polar/non-polar
-basic/acidic
-have sulfur
-have rings
-hydrophilic/hydrophobic
-positively charged/negatively charged

Question 14

what determines whether an amino acid is polar or non-polar

Answer 14

the R group contained in the amino acid’s basic structure

Question 15

what is the peptide bond

Answer 15

-a type of covalent bond that occurs between adjacent amino acids
-it forms in a condensation reaction

Question 16

describe how a peptide bond forms

Answer 16

In a condensation reaction,a hydroxyl group within the carboxylic group of one amino acid interacts with the hydrogen atom of the amino group of another amino acid to release a molecule of water and form a peptide bond.

Question 16

hoe does a dipeptide form

Answer 16

forms from the condensation reaction between 2 amino acids

Question 17

draw the structure of a dipeptide

Question 18

how does a polypeptide form

Answer 18

from the condensation reaction between more than 3 amino acids

Question 18

how many polypeptide chains can a protein have

Answer 18

one or multiple polypeptide chains interacting with each other

Question 19

describe how a peptide bond is broken

Answer 19

in a hydrolysis reaction a water molecule is added to break the peptide bond between amino acids resulting in the dipeptide/polypeptide being broken down into two separate amino acids

Question 20

describe the primary structure of a protein

Answer 20

its the specific sequence of amino acids .bonded together by peptide bonds to form a polypeptide chain

Question 20

what determines the primary sequence of a protein

Answer 20

dna determines the sequence of amino acids,carries information which codes for the primary structure of a protein

-instructs a cell to add certain amino acids in specific quantities,and sequence

Question 21

what happens to the shape and function of a protein if the primary structure of the protein undergoes changes-What if a mutation occurs ?

Answer 21

the primary structure of a protein influences how a polypeptide folds into its tertiary structure which determines the shape of the protein.Thus any changes to the primary structure will result in a change in the shape of the protein and so will alter its function

Question 22

describe the secondary structure of a protein

Answer 22

ist when hydrogen bonds occur between nearby amino acids in a polypeptide chain, making the polypeptide either coil into an alpha helix shape or fold into a beta-pleated sheet

Question 22

where do the hydrogen bonds occur to form an alpha helix

Answer 22

-hydrogen bonds occur between amino acids within a polypeptide chain -this pulls the polypeptide chain in,forcing it to coil into an alpha helix

Question 22

where do the hydrogen bonds occur to form a beta-pleated sheet

Answer 22

-hydrogen bonds occur between the amino acids of parallel polypeptide chains, joining them together -they then fold to form a beta-pleated sheet

Question 23

describe the tertiary structure of a protein

Answer 23

its the folding of a protein into its final shape -the tertiary structure determines the function of a protein -The folding/coiling of the polypeptide chain into its secondary structure brings the R groups of different amino acids closer together -Various bonds form between the R groups of different amino acids which stabilise and hold the tertiary structure of a protein together. -The bonds that form cause the polypeptide chain to fold into its final shape

Question 23

what do ionic bonds form between

Answer 23

-form between positively and negatively charged R groups- -between oppositely charged R groups

Question 24

what do hydrogen bonds form between

Answer 24

they form between slightly positive charges and slightly negatively charged R groups

Question 25

what to disulphide bonds form between

Answer 25

-occur between R groups which contain sulfur -strongest

Question 26

what to weak hydrophobic/hydrophilic interactions form between

Answer 26

-occur between polar and non-polar R groups

Question 26

which bonds holding the tertiary strcuture of a protein together are the strongest and which the weakest

Answer 26

disulphide bonds are the strongest, hydrogen bonds are the weakest

Question 27

which is stronger ionic or hydrogen bonds

Answer 27

ionic

Question 28

what is the most common bonds that form in a tertiary structure of a protein and which are rare

Answer 28

hydrogen bonds as can occur between wide range of R groups -ionic,disulphide and hydrophobic, hydrophilic are not common

Question 29

what breaks disulphide bonds

Answer 29

oxidation

Question 30

what breaks ionic bonds

Answer 30

ph changes

Question 31

describe the quaternary structure of a protein

Answer 31

its the 3d structure of protein,only present in proteins that have more than 1 polypeptide chain -Multiple bonds interact with one another, and various of bonds form between the polypeptide chains - the same as the bonds that form in tertiary structure but form between different polypeptide chains -This causes a protein to fold into its final £D structure

Question 32

what can subunits be

Answer 32

both identical or different

Question 32

how many subunits does haemoglobin have

Answer 32

4 ,2 alpha and 2 beta subunits

Question 33

what are different polypetide chains known as in quartenary structure

Answer 33

subunits

Question 34

how many levels of structure does a protein with 1 polypeptide chain have

Answer 34

3

Question 35

what is a negative result in the test

Answer 35

solution remains blue

Question 35

describe the test for proteins

Answer 35

-use the biuret test to test for proteins -first add sodium hydroxide to the sample to make the conditions slightly alkaline -then add copper II sulfate to the sample which is blue

Question 36

how many levels of structure does a protein with more than 1 polypeptide chain have

Answer 36

4

Question 37

what is a positive result in the test

Answer 37

colour change from blue to purple,might nee dto use a white tile as the colour change is very subtle

Question 37

state limitation of the test

Answer 37

- if the sample contains amino acids or dipeptide the result will be negative as there must be at least 2 peptide bonds present to be detected -test is qualitative and doesn't give a quantitative value of how much protein is present in the sample

Question 37

what is the name of the test used to test for proteins

Answer 37

biuret test

Question 38

what detrmines how proteins fold into their teriatury structure

Answer 38

-hydrophobic and hydrophilic interaction -proteins are assembled in an aqueous environment,in the cytoplasm hydrophobic R groups clump together on the inside of the protein,away from the aqueous environment,while the hydrophilic R groups are pushed on the outside surface of the protein.