Unit 1: Proteins

Question 1

What are proteins made up of?

Answer 1

amino acids

Question 2

What determines the structure and the function of the protein?

Answer 2

The type and order of the amino acids

Question 3

What is the structure of an amino acid?

Answer 3

has a central alpha carbon
an amino group (NH2)
a carboxyl group (COOH)
an R group (variable)
H atom

Question 4

What is the R group of an amino acid?

Answer 4

It is the variable part of the amino acid structure and gives the amino acid unique chemical properties

Question 5

What are the different R group classifications?

Answer 5

Acidic, basic, uncharged polar and non polar

Question 6

what is an acidic side chain?

Answer 6

it is hydrophilic and is COOH group

Question 7

what is a basic side chain?

Answer 7

it is hydrophilic and is NH2/NH3+ group

Question 8

what is an uncharged polar chain?

Answer 8

is it hydrophilic and is OH or CONH2

Question 9

what is a non-polar side chain?

Answer 9

it is hydrophobic and is a hydrocarbon including an aromatic ring

Question 10

amino acids link together by which bond?

Answer 10

a covalent peptide bond

Question 11

to form a peptide what reaction occurs?

Answer 11

condensation reaction between carboxyl group and amino group

Question 12

what is a residue?

Answer 12

amino acids joined by peptide bonds

Question 13

what bonds apart from peptide bonds are important in protein structure?

Answer 13

hydrogen bonds and ionic bonds

Question 14

what is the primary structure of a protein?

Answer 14

the sequence of amino acids in a polypeptide chain

Question 15

what determines the secondary and tertiary structure of a protein?

Answer 15

the primary structure

Question 16

what are the two main types of secondary structure?

Answer 16

alpha helix and beta sheet

Question 17

describe the alpha helix structure

Answer 17

polypeptide chain is coiled into a right handed helix held in place by hydrogen bonds between N-H bonds and C=O of another peptide bond

Question 18

describe the beta sheet

Answer 18

polypeptide chain linked in a side to side configuration and can be parallel or antiparallel by hydrogen bonds between NH bonds and C=O of another.

Question 19

what is a tertiary structure

Answer 19

The way in which a protein folds to give the final protein structure

Question 20

what are van der waals

Answer 20

very weak attractions between the electron clouds of atoms

Question 21

what are protein domains?

Answer 21

these are produced by any polypeptide chain that can fold independently into a compact, stable structure. protein is mad of one or more domains

Question 22

what is a protein motif?

Answer 22

motifs are elements of secondary structure that form in a particular way

Question 23

What is a prosthetic group?

Answer 23

final aspect to tertiary structure in proteins is the incorporation of non-protein groups e.g.. iron atom in catalase

Question 24

what is a secondary structure due to?

Answer 24

hydrogen bonds between the atoms of the peptide bond

Question 25

what is a tertiary structure due to?

Answer 25

interactions between the R groups

Question 26

what is a quaternary structure

Answer 26

when protein has more than one polypeptide sub-unit

Question 27

what is the function of an enzyme and give an example?

Answer 27

catalysis of bond breaking and bond making. e.g. amylase

Question 28

what is the function of structural proteins and give an example?

Answer 28

provides mechanical support of cells and tissues. e.g. collagen

Question 29

what is the function of a transport protein and give an example?

Answer 29

carries small molecules and ions. e.g. haemoglobin

Question 30

what is the function of a motor protein and give an example

Answer 30

generates movement in cells and tissues. eg. myosin in skeletal muscle

Question 31

what is the function of a storage protein and give an example

Answer 31

stores small molecules and ions. e.g. iron

Question 32

what is the function of a signalling proteins and give an example

Answer 32

carries signals from cell to cell. eg. insulin

Question 33

what are receptor proteins and give an example

Answer 33

detect signals and transmit to cell’s response machinery. eg. insulin receptor

Question 34

what is a gene regulatory protein and give an example

Answer 34

bind to DNA to switch on or off genes. e.g. repressor protein in lac operon

Question 35

what is the isoelectric point of a protein?

Answer 35

pH at which the protein has no overall charge