Nucleic Acids / Enzymes Flashcards
(77 cards)
1
Q
What does DNA stand for
A
Deoxyribose nuclei acid
2
Q
Describe genes
A
Small sections of chromosomes
Code for for different characteristics
Inherited
3
Q
AT and GC are called
A
Complimentary base pairs
4
Q
A change in one base is enough to
A
Change the structure of the protein and disrupts how it works
5
Q
What two bases go together
A
Adenine +thymine
Cytosine + guanine
6
Q
What are the two types of nucleic acids
A
DNA
RNA
7
Q
What are the three types of RNA
A
mRNA
tRNA
rRNA
8
Q
What monomer makes up nucleic acids
A
Nucleotides
9
Q
What does RNA do
A
Read and translate information for protein synthesis
Genetic code exists out the nucleus
10
Q
What does DNA do
A
Stores information
Found in nucleus
11
Q
Nucleotides are made of what 3 units
A
Phosphate group
5 carbon sugar (pentose )
Organic nitrogenous base (ATGC)
12
Q
The base and sugar join with a ? Bond
A
Glycosidic
13
Q
The phosphate and sugar ion with a ? Bond
A
Phosphodiester
14
Q
Glycosidic and phosphodiester bonds both require a ? Reaction to occur
A
Condensation
15
Q
Describe purines
A
Double ringed structures
Adenine and guanine
16
Q
Describe pyrimidines
A
Single ringed structures
Thymine and cytosine
17
Q
What is a monomer
A
Molecules that when separated make up polymers
18
Q
What is semi conservation replication
A
1/2 of the original DNA strand is conserved
19
Q
What’s the anti parallel sugar phosphate back bone
A
Runs in opposite directions
5 3
3 5
Carbon prime ends
20
Q
Hydrogen bonding between complementary bases form rungs stabilise the
A
Structure
21
Q
Why must DNA be stable
A
Otherwise the code (instructions ) could go wrong
22
Q
How does DNA replicate
A
- DNA unwinds
- enzyme helicase unzips the double helix
- parent stands act as a template
- free floating nucleotides join firm the cytoplasm
- they join to the exposed complementary base pairs (AT-GC)
- hydrogen bonds form
- sugar phosphate backbone forms
- each new molecule has 1 old and 1 new strand
23
Q
Describe lagging strand
A
New strands synthesised in short sections, then joins together
24
Q
Describe leading strands
A
Synthesised in one continuous length
25
DNA needs to be replicated for
Growth
26
What is RNA
A template of DNA
27
How does RNA and DNA differ
Ribose is smaller and shorter
The nucleotides contain ribose sugar where as DNA contain deoxyribose
RNA- the nitrogenous base uracil instead of thymine - U is complimentary to A
28
What is transcription
The process by which DNA is read to produce a stand of mRNA
29
What's the transcription process
- the gene unwinds and unzips
- hydrogen bonds between complementary nucleotide bases break
- RNA polymerase catalyses the formation of temporary hydrogen bonds between RNA nucleotides and their complementary unpaired DNA bases- A+T, C+G ,G+C, U+A, TEMPLATE STARND
- A length of RNA that is complementary to the template strand of the gene is produced . it is therefore a copy of the other DNA starnd, the coding strand
- the mRNA now passes out the nucleus ,through the nuclear envelope and attaches to ribosomes
30
What is translation
formation of a protein, at ribosomes , by assembling amino acids into a particular sequence according to the coded instructions carried from DNA to the ribosomes by mRNA
31
What are enzymes
They're made of protein , so they are made inside ribosomes
32
If the base sequence is wrong , what happens
| Enzymes
Mutation
The recipe is wrong so the enzyme won't have its amino acid in the right order
Won't work properly
33
DNA determines the sequence of
Amino acids
34
The sequence of amino acids in the enzyme determines its final shape , called the ? Structure
Tertiary
35
Enzymes are
Soluble in water
Globular
36
Enzymes are biological catalysts , what are biological catalysts
Thy speed up metabolic reactions but aren't altered by them
37
What factors can effect enzymes
Temperature
PH
38
How fast an enzyme works is called
Turn over rate
39
Catalase can convert ? Hydrogen peroxide molecules per second to water and oxygen
6,000,000
40
Examples of enzymes
Catalase
Amylase pepsin
41
Describe catalase
Found in nearly all organisms exposed to oxygen
It breaks down harmful hydrogen peroxide into oxygen and water
Intracellular
42
Describe anabolic
Process - binds prod us together
43
Describe catabolic
Process - breaking products
44
What is extracellular
Outside of the cell
45
What is intracellular
Inside the cell
46
Adding an enzyme reduces the
Amount of activation energy required for the reaction to take place
47
Describe the lock and key mechanisms
The enzyme splits the substrate molecule into two smaller products . Enzymes can catalyse the reverse reactions
Substrate fits into the active site
48
Describe the induced fit model
The two substrates don't quite fit until the enzyme engulfs the substrate abut
49
What is the rate of reaction
The speed at which the reactant or Substate is changed into a product
50
How can you monitor the rate of reaction
By measuring how fat the product is made by or product disappear
51
Describes the initial rate of reaction
When a reaction happens , substrate gets used up and Product gets formed. As this process the enzyme had less Substate to work on . So it's rate slows down
52
What is a limiting factor
Is one that can alter the rate of a reaction if all factors are kept constant
53
Heating enzymes increase
Kinetic energy of Substate and enzyme molecules leading to an increased frequency of random collisions
54
More collisions of enzymes means
Higher reaction rates
55
How heating affects molecules
Also vibrates molecules , this creates weaker binds which hold the tertiary structure together . Can be broken . This changes the shape of the enzyme and its active site . The Substate no longer fits
56
Acidic=
Neutral =
Basic =
0
7
14
57
What does PH mean
The amount of H+ ions
58
How does PH affect enzymes
Their charge interferes with the ionic and hydrogen binds which hold their tertiary structure together . This changes their shape of enzymes and active site. Binding of Substate is compromised
59
Extreme PH can lead to
Denature
60
Optimum PH leads to
Maximum rate of reaction
61
Describe cofactors
Molecules that increase the rate of reaction
Not proteins , they help proteins
Example iron and zinc
62
Describe coenzymes
Organic molecules
Binds to enzymes and help them function
Contain carbon
Derived from vitamins
Sit at active site
Shuttle chemical groups from one enzyme to another
63
Describe prosthetic groups
Cofactors that bond tightly to proteins or enzymes
Can be organic or metal and attach to proteins by covalent bonds
Can bind to proteins other than enzymes
Permanent bond
64
How can you control the rate
Changes the amount of enzymes
Change the amount is Substate
Change the PH
Change the temperature
65
Name the two inhibitors
Reversible
Irreversible
66
Describe reversible inhibitors
His type is inhibitor can increase and decrease
67
Describe irreversible / permanent inhibitors
This will stop the enzyme working forever
68
What are the two types of reversible inhibitors
Competitive
Non competitive
69
Describe competitive inhibitors
A substance competes with the substrate for the active site concentration of substrate and inhibitors are important
70
Explain non competing inhibitors
not compete with the Substate for the active site
Only concentration of the inhibitor is important
71
Describe end product inhibition
After catalysed reactions has reached completion , product molecules may stay tightly bound to the enzyme . Enzymes cannot form more products
72
Describe metabolic sequences
Involves a series of enzymes catalysed reactions
The product of one enzyme becomes the Substate for the next enzyme catalysed reaction in the metabolic pathways
73
Describe how snake venom works
Acts as a competing inhibitor preventing the acetylcholine from being broken down by acetycholinestrerase after impulse transmissions. This stops nerve impulses from being transmitted and stops muscles contractions causing paralysis
74
Examples of no competitive inhibitors
Copper sulphate / catalase
75
Examples of competitive inhibitors
Snake venom
76
Describe the non competitive inhibitor process
- the inhibitor enters the enzymes environment
- the shape of the inhibitor is different to the shape of the Substate
- the shape of the inhibitor does however match with a different part of the enzyme
- this part is called the allosteric site
- the inhibitor binds with site causing the reaction to occur which alters the enzymes tertiary structure
- the enzyme Substate can no longer fit into the active site
- if the inhibitor is reversible it can dissociate with the enzyme allowing the enzyme to regain its tertiary structure
77
Competitive inhibitor process
- due to kinetic energy all of the molecules are moving around
- the inhibitor enters the enzyme environment
- sometimes an inhibitor arrives at an active site before a Substate
- the shape on the inhibitor matches with the shape of the Substate
- other enzymes active sites are available to a reaction can still occur but just at a slow rate
- the inhibitor binds with the enzyme active site , preventing a Substate from binding
- if the amount of inhibitor were to increase this would slow down the rate further
