PIG - enzymes

1
PIG - enzymes
2

• What are enzymes? 3

3
3 of the following

• Biological catalysts
• Globular proteins
• Increase the rate of (chemical) reaction
• Complimentary substrate shape to its active site
• Have an active site

4

• What is activation energy? 2

5

• Energy barrier
• Molecules must overcome this barrier in order to
  take part in the reaction

6

• Name the 2 enzyme theories explain them. 4

7

• Lock Key theory 1
• Active site and substrate are complimentary
  shapes
• Induced fit theory 1
• Arrival of the substrate causes a change in the
  shape of the active site

8

• Which inhibitor fits the enzymes active site?
  1

9

• Competitive inhibitor

10

• Explain how a non-competitive inhibitor affects
  the rate of an enzyme related reaction. 3

11

• Reduces rate of reaction
• Fits into site on enzyme away from the active
  site
• Attaches to tertiary structure of enzyme
• Changes shape of the active site
• Substrate can no longer bind with active site
• Permanent

12

• Why does increasing substrate concentration
  eventually have no effect on the rate of
  reaction? 2

13

• V max
• All active sites are occupied at all times

14

• What are coenzymes? 2

15

• Organic, non-protein molecule
• (Often) carry chemical groups between enzymes
• So enzyme controlled reactions can link together
  in sequence

16

• What is a prosthetic group? 1

17

• A coenzyme that is a permanent part of an enzyme
  molecule.

18

• What is it called when an enzyme and substrate
  fit together? 1

19

• Enzyme-substrate complex

20

• How does lowering the pH of a solution affect an
  enzymes tertiary structure? 3

21

• Increased concentration of H ions means lower pH
• Hydrogen ions are positive so are attracted to
  negatively charged molecules
• Hydrogen bonds hold tertiary structure in place
• Hydrogen ions react with hydrogen bonds which
  alters the tertiary structure

22

• What is an enzyme inhibitor? 1

23

• A substance or molecule which slows down the rate
  of an enzyme controlled reaction.

24
Nucleic Acid PIG
25
Describe the structure of DNA
26

• Polynucleotide
• Contains bases adenine, guanine, cytosine and
  thymine
• Double stranded

27
Name some differences between DNA and RNA
28

• RNA contains
• Ribose sugar
• Has uracil instead of thymine
• Single stranded
• Exist in 3 forms Mrna, tRNA and rRNA

29
Explain how DNA replicates
30

• During interphase
• Double helix untwisted
• Hydrogen bonds broken
• DNA unzips
• Free DNA nucleotides hydrogen bonded onto exposed
  bases
• Covalent bonds between phosphates and sugars
  forming backbone

31
Explain the term anti-parallel
32

• The strands lie opposite each other, parallel,
  but run in opposite directions (the 3 end goes
  with the 5 end)

33
What is complementary base pairing
34

• Complementary base pairs pair up
• C-G
• A-T or U in RNA
• Hydrogen bonds link base pairs

35
What is a gene
36

• A sequence of DNA nucleotides that codes for a
  polypeptide

37
Outline the role of DNA in protein synthesis
38

• DNA provides the template strand for mRNA and
  determines the sequence of amino acids and
  therefore the structure of proteins

39
What is mRNA for?
40

• Messenger RNA
• Complementary to the DNA Strand
• Contains Uracil instead of Thymine
• Passes through the nuclear pore and attaches to a
  ribosome

41
What happens at the ribosome and what is the role
of tRNA
42

• tRNA brings amino acids to the ribosome in the
  right order according to the base sequence on the
  mRNA
• Amino acids then joined together by peptide bonds
  to give a protein