Proteins (biochemistry)

Question 1

What elements do proteins contain?

Answer 1

Carbon, Hydrogen , Oxygen, Nitrogen (and Sulfur)

Question 2

What are proteins polymers of?

Answer 2

amino acids

Question 3

How many different types of amino acids are there?

Answer 3

20

Question 4

What is an R group?

Answer 4

the variable group in an amino acid

Question 5

What do all amino acids contain?

Answer 5

an amine group, a carboxyl group, an variable group, alpha Carbon + hydrogen

Question 6

What is a zwitter ion?

Answer 6

when H from COOH has moved to the lone pair on the N in the NH2 group

Question 7

What is it called when 2 amino acids are linked?

Answer 7

Dipeptide

Question 8

What reaction enables formation of a dipeptide?

Answer 8

condensation reaction

Question 9

What bond is formed between 2 amino acids?

Answer 9

peptide bond

Question 10

How is a peptide bond broken?

Answer 10

Hydrolysis

Question 11

Where does the peptide bond form during condensation reaction of 2 amino acids?

Answer 11

the peptide bond forms between the C atom of the carboxyl group of one amino acid and the Nitrogen Atom of the amine group of the adjacent amino acid

Question 12

What is a polypeptide?

Answer 12

consists of a chain of amino acids linked by peptide bonds

Question 13

What do the ends of a polypeptide look like?

Answer 13

at one end there is an amine group at the other end there is a carboxyl group

Question 14

What are the 4 structures that a protein can show?

Answer 14

primary
secondary
tertiary
quaternary

Question 15

What is primary structure in a protein?

Answer 15

the type, number, and sequence of amino acids in a polypeptide linked by peptide bonds only, forming a linear chain

Question 16

What is the most common secondary structure in a protein?

Answer 16

most common is alpha helix formed by hydrogen bonding

Question 17

Where do hydrogen bonds from in alpha helix structure?

Answer 17

between oxygen atoms of carboxyl groups and hydrogen atoms of amine groups

Question 18

what is another secondary structure of proteins?

Answer 18

a beta-pleated sheet

Question 19

What is tertiary structure of a protein?

Answer 19

the folding of the alpha helix as shown by globular proteins, to form very specific 3-d shapes. (one polypeptide)

Question 20

What other bonds forms in a tertiary structure?

Answer 20

disulfide bridges, ionic bonds, hydrogen bonds (secondary), hydrophobic interactions

Question 21

What is quaternary structure?

Answer 21

Where 2 or more polypeptide chains in tertiary form combine to form complexes

Question 22

What is an example of a protein with quaternary structure?

Answer 22

Haemoglobin

Question 23

What are the 2 groups of proteins?

Answer 23

globular and fibrous

Question 24

What is the function of a globular protein?

Answer 24

metabolism (soluble)

Question 25

What is the function of a fibrous protein?

Answer 25

structural (insoluble)

Question 26

What is the molecular shape of a globular protein?

Answer 26

Spherical in tertiary or quaternary structure

Question 27

What is the molecular shape of a fibrous protein?

Answer 27

Chains in secondary structure

Question 28

What are examples of globular proteins?

Answer 28

Enzymes (lysozome), insulin

Question 29

What are examples of fibrous proteins?

Answer 29

keratin, collagen

Question 30

What is the function of keratin?

Answer 30

strengthens hair, nails, scales, feathers etc.

Question 31

What is the function of collagen?

Answer 31

strengthens bones, tendons, ligaments, skin

Question 32

What is elastin?

Answer 32

elastic fibrous tissue that allows many tissues in the body to resume their shape after stretching or contracting

Question 33

What does elastin do?

Answer 33

helps skin to return to its original position when it is stretched

Question 34

What test is used for proteins?

Answer 34

Biuret test

Question 35

What is a negative result for biuret test?

Answer 35

blue

Question 36

What is a positive result for biuret test?

Answer 36

violet