Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Biology A LEVEL > Proteins > Flashcards

Proteins Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

What are the 4 functions of proteins?

A

Structural- collagen, keratin

Signalling- hormones

Catalysts- enzymes that speed up reactions

Transport- haemoglobin transports oxygen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the specific name for protein monomers?

A

Amino acids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the specific name for protein diamers?

A

Dipeptides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the specific name for protein polymers?

A

Polypeptides (peptide is a short polypeptide)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Draw and label the structure of an amino acid:

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How many different amino acids are there?

A

20 which all have the same general structure only the variable group changes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Draw and label the formation of a dipeptide:

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How are amino acids joined together to form a dipeptide?

A

-Condensation reaction
-Water is removed
-Peptide bond forms between OH of carboxyl and H or amine group

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the 4 levels of protein structure?

A
  1. Primary structure
  2. Secondary structure
  3. Tertiary structure
  4. Quaternary structure
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the sequence of amino acids determined by?

A

Your genes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What can the secondary structure of protein formation be described as?

A

The initial folding of a polypeptide into an alpha helix or beta pleated sheet due to hydrogen bonding.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Where do hydrogen bonds form during protein formation?

A

between the C=O groups of the carboxyl group of one amino acid and the H in the amine group of another amino acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What can the tertiary structure of protein formation be described as?

A

-The further folding of the secondary structure
-To form a unique 3D shape.
- Held in place by ionic, hydrogen and disulphide bonds.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Where do the ionic and disulphide bonds form during protein formation?

A

-The ionic and disulphide bonds form between the R groups of different amino acids.
-Disulphide bonds only sometimes occur, as there must be a sulfur in the R groups for this bond to occur

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What can the quaternary structure of protein formation be described as?

A

A protein made up of more than one polypeptide chain e.g haemoglobin formed from 4 polypeptide chains

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Why is the primary structure of a protein so important?

A

If even one amino acid in the sequence is different then it will cause the ionic/hydrogen/disulphide bonds to form in a different location and make a diff 3d shape.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the impact of even one amino acid changing in the sequence?

A

-Enzymes will have a different shaped active site (will be non-functioning)
-Carrier proteins will have a different shaped binding site

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are enzymes?

A

Biological catalysts that increase the rate of reaction by lowering the activation energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the activation energy?

A

The energy required to cause molecules to collide hard enough to react (to break and form new bonds)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the active site of an enzyme?

A

the region where a complementary substrate can bind to form an enzyme-substrate complex

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is a metabolic pathway?

A

a series of enzyme catalysed reactions where the product of a reaction is the reactant in the next reaction eg. respiration

22
Q

What is the lock and key model for enzymes?

A
  1. The shape of the active site is fixed and does not change shape
  2. Active site is complementary to substrate before during and after forming an enzyme-substrate complex
23
Q

What is the induced model of enzyme action?

A
  1. Before the reaction, the active site is NOT complementary to substrate
  2. Shape of active site changes as enzyme-substrate complex forms
  3. This stresses bonds or brings substrates closer together
  4. Lowers the activation energy
24
Q

What type of structure do enzymes have?

A

A complex tertiary structure

25
Q

What do enzymes control?

A

All intracellular and extracellular reactions in organisms

26
Q

Why would a molecule not get broken down by a specific enzyme?

A

The specific structure of the active site is complementary to the shape of one substrate, forming an enzyme-substrate complex

27
Q

What are the two types of non-functional proteins?

A
  1. Mutations
  2. Denatured
28
Q

How do you know if a protein has mutated?

A
  • Changes to the base sequence of DNA
  • Change to the base sequence of mRNA
  • Change to the primary structure of protein which leads to change to tertiary structure
29
Q

How do you know if a protein has denatured?

A
  • Increase in kinetic energy
  • breaks the hydrogen + ionic bonds between variable groups
  • change to the tertiary structure of the protein
30
Q

What is the result of a protein mutating or denaturing?

A
  • changes the shape of the active site
  • substrate is no longer complementary
  • no enzyme-substrate complex forms
31
Q

What are the 5 factors that affect the rate of enzyme-catalysed reactions?

A
  1. Temperature
  2. PH
  3. Enzyme concentration
  4. Substrate concentration
  5. Inhibitors
32
Q

Describe and explain the graph for enzyme rate of reaction against temperature:

A
  • At 0 degrees enzymes are frozen and catalyse no reactions
  • The peak of the curve shows the optimum temperature for enzyme activity is 37 degrees
  • When the graph hits the x axis again it shows that enzymes have denatured
33
Q

Explain the effect of temperature on enzyme catalysed reactions:

A
  • As temperature increases, the rate of reaction increases due to molecules gaining more kinetic energy.
  • Most enzyme-substrate complexes form at optimum temperature
  • As temp increases past 37 degrees, the rate of reaction decreases due to enzymes denaturing until it stops
34
Q

Describe what the graph for time against volume of product for the effect of temp on an enzyme catalysed reaction looks like:

A
35
Q

What is hydrogen peroxide?

A

toxic cellular waste product that must be broken down

36
Q

What is the equation for the breakdown of hydrogen peroxide?

A

Hydrogen peroxide ———> water + oxygen

catalase enzyme breaks down

37
Q

What does the first part of the graph for the progress of an enzyme reaction graph mean?

A

-initially lots of substrate and empty active sites
-many E-S complexes can form
-reaction starts off fast

38
Q

What does the graph for the progress of an enzyme reaction look like?

A
39
Q

What does the second part of the enzyme progress reaction graph mean?

A

-less substrate, more product
-more difficult for E-S complex to form
-reaction slows

40
Q

What does the third part of the enzyme progress reaction graph mean?

A

-no more substrate
-no E-S complexes
-reaction stopped

41
Q

How do you calculate the mean rate of reaction?

A

amount of product formed/ time taken to form product

42
Q

Describe the graph for enzyme rate of reaction against PH:

A
  • Enzyme activity increases until it reaches optimum PH
  • Enzyme activity begins to decrease as enzyme is being denatured due to acidic conditions
43
Q

Explain the effect of PH on enzyme catalysed reactions:

A
  • Enzymes have an optimum temp
  • Increasing or decreasing PH away from optimum causes enzyme activity to decrease
  • The H+ or OH- will interact with hydrogen or ionic bonds
  • Changes tertiary structure and active site shape so less e-s complexes form
44
Q

What happens at PH 2 during an enzyme catalysed reaction and what does this graph look like?

A

-increased H+ attracted to amino acids of enzymes
-hydrogen/ ionic bonds of 3 degrees disrupted
-active site denatures
-fewer e-s complexes form

45
Q

Describe the graph for enzyme rate of reaction against enzyme concentration:

A
46
Q

Explain the effect of enzyme concentration on enzyme catalysed reactions:

A
  • Rate increases with enzyme conc in positive correlation
    -because there are more e-s complexes forming (more successful collisions)
    -if substrate runs out, adding more enzymes will make no diff to rate of reaction
47
Q

Describe the graph for enzyme rate of reaction against substrate concentration:

A
  • Rate increases with substrate conc in positive correlation
    -because there are more e-s complexes forming (more successful collisions) until all active sites are occupied
    -enzyme conc is now the limiting factor and adding more substrate will not change rate
48
Q

What do enzyme inhibitors do?

A

Slow down enzyme catalysed reactions

49
Q

What are the two types of inhibitors that affect the rate of enzyme-catalysed reactions?

A
  1. Competitive
  2. Non-competitive
50
Q

What does the graph for effect of competitive and non-competitive inhibitors on enzyme activity look like?

A
51
Q

Explain the effect of competitive inhibitors on enzyme activity:

A
  • Competitive inhibitors have a similar shape to substrate
    -They can also bind to active site
  • This stops e-s complexes from forming
    -The proportion of substate to competitive inhibitor will affect how much the rate of reaction changes
52
Q

Explain the effect of non-competitive inhibitors on enzyme activity:

A

-Non-competitive inhibitors bind to the enzyme but not at the active site
-Changes the tertiary structure of the active site permanently
-No more e-s complexes form as no longer complementary
-Changing conc of substrate won’t make any difference

Biology A LEVEL (7 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions