Unit 1 Cells and Proteins: Key Area 2 Proteins (Structure)

Question 1

what is a distinguishing feature of proteins?

Answer 1

there folded nature and ability to bind specifically to other molecules.

Question 2

what are proteins polymers of?

Answer 2

amino acids.

Question 3

what are 2 functional groups of amino acids?

Answer 3

the amine and acid group

Question 4

what does wide range of functions carried out by proteins result from?

Answer 4

the wide range of functions carried out by proteins results from the diversity of R groups.

Question 5

what determines the structure of the protein?

Answer 5

the sequence of amino acids.

Question 6

what makes each amino acid different?

Answer 6

the R group.

Question 7

what are 5 components of amino acids?

Answer 7

the amine group, acid group, R-group, hydrogen atom and central carbon.

Question 8

what are amino acids linked together by and what does this produce?

Answer 8

peptide bonds which produces a polypeptide.

Question 9

what are the 4 main R-groups of amino acids?

Answer 9

polar, hydrophobic, acidic (negatively charged), basic (positively charged).

Question 10

what can R-group of amino acids vary in?

Answer 10

size
shape
charge
hydrogen bonding
capacity
chemical reactivity

Question 11

what are the key features of an acidic R-group?

Answer 11

• ends with a negatively charged group
• hydrophilic
• key component is a carboxylic acid group
• COOH

Question 12

what are the key features of a basic R-group?

Answer 12

• ends with a positively charged group
• hydrophilic
• key component of their R-groups is an amine group

Question 13

what are the key features of a polar R-group?

Answer 13

• slightly charged
• hydrophilic
• key component: carbonyl (CO), (OH), or amine (NH)

Question 14

what are the key features of a hydrophobic R-group?

Answer 14

• hydrophobic
• do not have charge
• non-polar
• key component is a hydrocarbon - CH3, long chain of CH and rings

Question 15

what are the other level of proteins structure other than the sequence and binding of amino acids?

Answer 15

• Primary structure
• Secondary structure
• Tertiary structure
• Quaternary structure

Question 16

what is the primary structure?

Answer 16

the primary structure is the sequence in which the amino acids are synthesised into the polypeptide

Question 17

what happens in the primary structure?

Answer 17

amino acids link by peptide bonds to form a polypeptide

Question 18

what results in regions of a secondary structure?

Answer 18

hydrogen bonding along the backbone of the protein strand results in regions of secondary structure

Question 19

what are the 3 types of secondary structure?

Answer 19

• alpha helix
• beta sheets
• turns

Question 20

how are alpha helix formed?

Answer 20

by twisting the polypeptide into a spiral/ helix then establishing with hydrogen bonds. where the R-groups stick out

Question 21

what are the 2 types of beta sheet?

Answer 21

• parallel: the chains run in the same direction

- anti-parallel: the chains run in opposite directions

Question 22

what’s stabilises the alpha helix?

Answer 22

hydrogen bonding

Question 23

what is the tertiary structure?

Answer 23

further folding of secondary shapes into an overall three- dimensional shape

Question 24

how is the tertiary structure established?

Answer 24

by many different interactions between the R-groups of the amino acids