protein structure + function

Question 1

how shape of protein is made

Answer 1

polypeptide chain folds in on itself to form specific shapes

Question 2

difference between levels of structure in protein (general)

Answer 2

-levels 1-3 in protein structure =single polypeptide chain
-level 4 = 2+ polypeptide chains

Question 3

primary structure definition

Answer 3

sequence of amino acids bonded by covalent peptide bonds

Question 4

secondary structure definition

Answer 4

contains hydrogen bonds

Question 5

where to h bonds occur

Answer 5

between h atoms and N/O atoms in polypeptide chains

Question 6

how weak are h bonds

Answer 6

contains about 10% the energy of covalent bonds

Question 7

when do h bonds form

Answer 7

when the h atoms come closer to larger atoms like n or o

Question 8

when does polarity occur

Answer 8

H atoms elecrton becomes attracted to larger nucleus

Question 9

what does polarity mean for the molecule

Answer 9

charge in molecule isnt evenly distributed

Question 10

what does polarity lead to

Answer 10

weak electrostatic attraction between molecules - hydrogen bond

Question 11

are hydrogen bonds evenly disrupted

Answer 11

yes- by higher temperatures or phs

Question 12

how many types of secondary structures in proteins

Answer 12

1 - alpha helix
2 - beta pleated sheet

Question 13

when is a alpha helix formed

Answer 13

when an H bond forms between every fourth peptide bond (between the oxygen of the carboxyl group and the hydrogen of the amine group)

Question 14

when does a beta pleated sheet form

Answer 14

when the protein folds so that two parts of the polypeptide chain are parallel to each other enabling hydrogen bonds to form between parallel peptide bonds

Question 15

when does a tertiary structure occur

Answer 15

interactions between the different R groups of the amino acids that form the primary sequence / polypeptide chain

Question 16

types of things that occur in tertiary structure

Answer 16

• Some R groups are polar and so form H-bonds
  
  • The R group of the amino acid cysteine contains Sulfur - so 2 cysteine R together can form a covalent S-S bond called a disulfide bridge.
  • Some R groups are charged - they form ionic bonds
  • Some non-polar R groups form very weak temporary interactions when close together (London forces)

Question 17

when does quaternary structure occur

Answer 17

when 2 or more polypeptide chains attach together to form even more complex proteins.

Question 18

what type of protein is catalase

Answer 18

globular protein

Question 19

two typed of proteins

Answer 19

fibrous and globular