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Biology - Biological Molecules > Proteins and Enzymes > Flashcards

Proteins and Enzymes Flashcards

1
Q

Biological catalyst

A

Substance produced by living tissue that speeds up rate of reaction without being altered by the reaction

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2
Q

Structure of an enzyme

A

3D globular, water-soluble protein with H-bonds, disulphide bridges and ionic bonds

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3
Q

Specificity of enzymes

A

Some are specific to particular substrates
Some are specific to particular substrate groups
Enzymes are complementary in shape to substrate

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4
Q

Intracellular enzymes

A

Inside cell
Respiratory enzymes in mitochondria
Photosynthetic enzymes in chloroplast
Hydrolytic enzymes in lysosomes

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5
Q

Extracellular enzymes

A

Outside cell
Digestive enzymes in the digestive system

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6
Q

How do enzymes catalyse reactions

A

They reduce the activation energy needed for the reaction to occur

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7
Q

Exergonic reaction

A

Reaction that releases energy —> hydrolysis of ATP

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8
Q

Endergonic reaction

A

Reaction that takes up energy —> synthesis of ATP

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9
Q

lock and key model

A

substrate already precisely complementary in shape to AS
enzyme remains unchanged

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10
Q

induced fit theory

A
  • substrate not initially precisely complementary in shape to substrate
  • substrate moves into AS, forcing a slight modification of AS to substrate
  • when substrate leaves, AS returns to original shape
  • enzyme remains unchanged
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11
Q

how to calculate rate of production of a product and units used

A

gradient between set points
y units . x units-1

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12
Q

how to calculate percentage change in a reaction and units

A

gradient between set points x 100
units = %

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13
Q

calculate initial rate of reaction and units

A

gradient of tangent going through origin
y units . x units-1

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14
Q

rate of reaction at particular point on graph and units

A

gradient of tangent at that point
y units . x units-1

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15
Q

rate of reaction from raw data and units when DV=time taken

A

rate = 1/T(seconds) (x1000)
s-1 / s-1 x 10-3

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16
Q

rate of reaction from raw data and units when DV=mass or volume

A

rate = vol/T or M/T
volume - cm3 s-1 mass - g s-1 (e.g.)

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17
Q

4 factors affecting enzyme reaction

A

temperature, pH, enzyme concentration and substrate concentration

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18
Q

explain the graph showing affect of substrate concentration on enzyme action

A

as substrate concentration increases, ROR also does –> substrate concentration = limiting factor
further increase and ROR remains the same –> enzyme concentration = limiting factor

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19
Q

explain graph showing affect of enzyme concentration on enzyme action

A

as enzyme concentration increases, ROR does also –> enzyme concentration = limiting factor
further increase in enzyme concentration = ROR remains the same –> substrate concentration = limiting factor

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20
Q

shape, binding, max. ROR

competitive inhibitor

A
  1. complementary shape to enzyme AS = similar shape to sub
  2. binds to AS, blocks sub and prevent ESC so slows ROR
  3. max. ROR can be achieved by increasing sub concentration as more chance of reaching AS than inhibitor
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21
Q

shape, binding, action, max. ROR

non-competitive inhibitor

A
  1. not complementary in shape to AS = different shape to sub
  2. binds to diff part of enzyme than AS = ollosteric site
  3. changes shape of enzyme therefor AS (denatured) so no longer complementary
  4. max. ROR cannot be achieved
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22
Q

end-product inhibition

A
  • self regulate end-product of metaboic pathway to prevent excess product build up
  • when in excess, becomes non-competitive inhibitor for one of previous enzymes in pathway
  • once concentration of end-product falls, it cn no longer inhibit enzyme so pathway starts again
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23
Q

give an example of a pathway that has end-product inhibition

A

synthesis of ATP

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24
Q

anabolic reaction

A

reactions that build up = condensation reactions

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25
catabolic reactions
reactions that break down = hydrolysis reactions
26
can enzymes catalyse reactions that otherwise wouldn't occur?
no
27
why are proteins polymers?
they are a chain of repeating amino acids
28
how many naturally occurring amino acids are there?
20
29
what type of reaction joins amino acids?
condesation
30
what bond is formed between amino acids?
peptide
31
what are the chemical elements of proteins?
carbon, hydrogen, oxygen, nitrogen and in some, sulphur
32
where is sulphur found in a protein if it is present?
R group of an amino acid
33
7 types of protein
1. contractile fibres 2. hormones 3. receptors 4. enzymes 5. pigments (respiratory) 6. antibodies 7. structural proteins
34
function of contractile fibres
muscle contraction, cell adhesion, cytokinesis and trasnport
35
is an oxygen bridge formed between amino acids in a condensation reaction?
no
35
function of hormones
chemical messengers controlliing functions in the body
36
function of structural proteins
form connective tissue with high tensile strength
37
function of recepetor proteins
respond to stimuli to change activity of the cell
38
structure of an amino acid
contains a central carbon, with hydrogen, a COOH group, an NH3 group and a variable R group attached
39
where is the peptide bond between amino acids?
between the COOH group of one amino acid and the NH3 group of the other
40
four degrees of protein structure
1. primary 2. secodary 3. tertiary 4. quaternary
41
catalase
converts hydrogen peroxide into water and oxygen
42
two ends of a polypeptide chain
N-terminal and C-terminal
43
primary structure of a protein
number, type and sequence of amino acids in a polypeptide chain
44
secondary structure of a protein
folding or twisting of the primary structure into a regular arrangement, either alpha helix or beta-pleated sheet
45
what happens if the seuence of amino acids in a protein is changed?
it does not change the protein but may result i a non-functioning protein
46
bonds holding primary structure of a protein together
peptide
47
bonds holding secondary structue of a protein together
H-bonds between COOH group of one amino acid and NH group od another
48
tertiary structure of a protein
further folding/twisting of secondary structure to form a 3D globular shape
49
bonds holding tertaiary structure of a protein
H-bonds disulphide bridges (covalent bond between two sulphurs) ionic bonds (sharing electrons) hydrophobic interactions
50
quaternary structure of a protein
a functional protein with 2 or more polypeptide chains
51
what type of polypeptides make up quarternary structure protein
either same or different either secondary or tertiary
52
bonds holding quarternary structure
H-bonds, ionic bonds, disuphide bridges, hydrophobic interactions
53
cause of denaturation
bonds holding protein shape breaking H-bonds = increase in temperature inoic bonds = extreme pH
54
impact of denaturation to fibrous and globular proteins
fibrous = fall alpart, lose structural strength globular = become inactive and insoluble ands hydrophobic amino acids move out
55
fibrous protein structure
either: 1 single secondary structure polypeptide forming a functioning protein multiple secondary structure polypeptides forming a functioning protein
56
bonds in a fibrous protein
H-bonds
57
function and features of a fibrous protein
structural function high-tensile strength insoluble in water
58
globular protein structure
either: 1 single tertiary structure polypeptide forming a functioning protein multipe tertiary structure polypeptides forming a functioning protein
59
bonds in a globular protein
H-bonds, ionic bonds, disulphide bridges
60
what is the function of a globular protein dependent on and the effect if this is changed?
its 3D globular shape if altered, won't functioni properly
61
7 examples of globular proteins
1. hormones 2. enzymes 3. Hb 4. transport proteins 5. antibodies 6. antigens 7. receptors
62
are globular proteins soluble in water?
yes
63
conjugated protein
protein that has a non-protein component
64
prosthetic group
a non-protein substance associated with polypeptides of a protein --> e.g. haem group in Hb
65
What is the name of COOH
Carboxyl group
66
What is the name of NH3
Amine/amino group

Biology - Biological Molecules (7 decks)

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