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Nucleic Acids Flashcards

1
Q

What are the nitrogenous based in DNA called?

A

Adenine ——— Thymine

Cytosine ——— Guanine

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2
Q

How are the components of a nucleotide joined?

A

Via condensation reactions

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3
Q

What are the nitrogenous based in RNA called?

A

Adenine —— Uracil

Cytosine —— Guanine

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4
Q

Name the roles of different types of RNA

A

Transferring genetics from DNA to ribosomes

Making up ribosome

Protein synthesis

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5
Q

What sugar makes up

DNA

RNA

A

DNA = deoxyribose

RNA =ribose

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6
Q

what do DNA + RNA stand for?

A

Deoxyribonucleic acid

Ribonucleic acid

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7
Q

What are the purine bases called?

A

Adenine

Guanine

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8
Q

What are the pyrimidine bases called?

A

Thymine

Cytosine

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9
Q

What does anti-parallel mean?

A

They are parallel but run in opposite directions

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10
Q

Why are the polynucleotides in DNA anti-parallel?

A

DNA polymerase is only complementary to 3 prime end so can only bond nucleotides in one directions

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11
Q

What are chromatins?

A

DNA +Histone

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12
Q

What makes two DNA molecules different?

A

Proportions and sequence of bases

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13
Q

Why is DNA charged?

A

Phosphate group are negative

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14
Q

Why must DNA be stable?

A

To ensure genetics are passed in unchanged

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15
Q

How is DNA a stable molecule?

A

Phosphodiester bonds= strong covalent bond

Sugar phosphate Backbone and double helix = protect more chemically reactive bases

Hydrogen bonds= collectively strong

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16
Q

What is base stacking ?

A

Forces of attraction between adjacent bases on one polynucleotide

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17
Q

Why is it useful for hydrogen bonds to be present between bases?

A

To easily separate polynucleotides for DNA replication

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18
Q

What allows DNA to carry so much genetic info?

A

Very large molecule

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19
Q

What do the backbone and helical structure ensure?

A

Protection of genetic info from chemical and physical forces

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20
Q

Why is base pairing used?

A

For easy transfer of information (as RNA) and replication of DNA

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21
Q

What biological molecule was thought to carry genetic info? +why

A

Proteins

DNA was though to have to few components

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22
Q

Briefly describe the puemonia experiment

A

Nice injected with:
Dead harmful strain= alive
Live safe strain= alive
Both= dead

Safe strain developed ability to produce toxins using DNA from dead strain.

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23
Q

What were the possible explanations for the puemonia experiment?

A

1) not all harmful strain was killed
2) Safe strain mutated (unlikely as repeats were taken)
3) safe strain used DNA as instructions to produce toxins

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24
Q

How were viruses used to prove DNA is hereditary material ?

A

One viruse has radioactive DNA
other virus had radioactive Protein

Only bacteria infected with first virus showed signs of radioactivity

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25
What’s a bacteriophage?
A virus that infects and kills bacteria
26
How are viruses made to have radioactive protein and DNA
DNA= Radioactive phosphorus Protein= radioactive sulfur (r groups)
27
What are the two main stages of DNA replication?
Nuclear division- Nucleus divides by mitosis or meiosis Cytokinesis- Whole cell divides
28
What conditions are necessary for DNA replication to occur and why
DNA polymerase must be present- to catalyse formation of phosphodiester bonds Free nucleotides- to form new polypeptide Energy- in form of ATP Two DNA strands- act as template
29
What is the first stage of DNA replication?
Breaking hydrogen bonds between base pairs Replication form forms ATP activates free nucleotides
30
What is stage two of DNA replication?
Polynucleotide strands act as templates Hydrogen bonds form between complementary base pairs between free and original bases
31
What is stage three of DNA replication?
DNA polymerase catalyses the condensation reaction to form phosphodiester bonds between nucleotides on new polynucleotide.
32
Why is DNA replication called semi-conservative?
Half of the original DNA is preserved
33
What occurs to speed up DNA replication?
Two replication forks form
34
What is conservative DNA replication?
Where the original DNA is unchanged and acts like a template for the new strand
35
What is dispersive DNA replication?
When the original DNA is dispersed and combines with free nucleotides randomly
36
Who conducted an experiment to prove semi-conservative DNA replication?
Meselson and Stahl
37
What were the conditions for Meselsons and Stahls experiment?
Bacteria grown in light (14) nitrogen Bacteria grown in heavy (15) nitrogen For many generations
38
Briefly describe Meselsons and Stahls experiment?
1) grow bacteria in 15N for many generations 2) transfer to 14N for one generation 3) Centrifuge 4) repeat for 2nd and 3rd generation
39
Describe the distribution of 15N and 14N in the first and second and third generation
15N. 14N 0) 100. 0 1) . 50. 50 2) . 25. 75 3) . 12.5. 87.5
40
How was nitrogen supplied in Meselson and Stahls experiment?
By ammonium ions NH4+
41
What were the expected results for Meselson and Stahls experiment for the conservative model of DNA replication?
Never hybrid DNA (No medium density) Only ever heavy and light DNA After generations more light DNA forms
42
What were the expected results for Meselson and Stahls experiment for the dispersive model of DNA replication?
Only ever hybrid DNA
43
What does ATP stand for?
Adenosine triphosphate
44
When is ATP produced?
During oxidation of organic molecules Aerobic and anaerobic respiration And photosynthesis
45
Is ATP soluble or insoluble?
Soluble
46
What does ATP comprise of?
Adenine Ribose sugar Three phosphate groups
47
What is ATP also know as ?
A phosphorylated RNA nucleotide Or Nucleotide derivative
48
Name the enzyme involved in the hydrolysis of ATP
ATP hydrolase
49
What is the removed phosphate group uses for after ATP hydrolysis?
To phosphorylate other molecules
50
Why does ATP hydrolysis have a low activation energy?
Due to unstable bonds
51
What is required for ATP hydrolysis?
Water
52
What enzyme is involved in the formation of ATP?
ATP synthase
53
What symbol represents a phosphate group?
Pi
54
Is the synthesis of ATP exothermic or endothermic?
``` Endothermic Because: Reversible reaction ATP hydrolysis releases energy so must be exothermic Other direction= endothermic ```
55
Where does the energy stores in ATP come from?
The hydrolysis of carbohydrates or lipids
56
What type of reaction is the synthesis of ATP?
Condensation reaction
57
Where does ATP synthesis occur?
In chloroplasts + mitochondria
58
What are the different ways ATP can be made?
1) photophosphorylation During photosynthesis in chlorophyll 2) oxidative phosphorylation Animal and plant cells during respiration 3) substrate-level phosphorylation In animal and plant cells when donor molecular provide phosphate
59
Why is ATP used as an immediate energy source not glucose?
The hydrolysis of ATP occurs in one quick reaction whereas the hydrolysis of glucose is slower. ATP provides immediate energy ATP stores less energy than glucose so energy released is more manageable. No waste (thermal) energy.
60
Why is ATP an immediate energy source?
Because of its unstable bonds
61
How many ATP molecules are made from one glucose molecule?
38
62
What are the main uses or ATP?
1) movement 2) metabolic processes 3) activating molecules 4) active transport 5) secretion
63
How is energy used for movement?
Allows muscle filaments to slide past each other so whole muscle shortens
64
How is energy used in metabolic processes?
In the condensation reactions needed to form larger molecules
65
How is energy used in secretion?
For the formation of lysosomes
66
How is energy used in active transport?
To alter the shape of carrier proteins in the plasma membranes allowing molecules to move against the concentration gradient
67
How is ATP used in the activation of molecules ?
The phosphate groups removed via condensation reactions attach to other molecules which lowers their AE
68
How can you tell that lots of movement, active transport, secretion, metabolic processes or activation of molecules occurs within a cell/ tissue ?
Large and/or many mitochondria for ATP synthase
69
What is a dipolar molecule?
A molecule with two poles
70
What bonds cause cohesion ?
Hydrogen: between oxygen and hydrogen
71
What is specific heat capacity?
The energy needed to raise 1KG of a substance by 1 degree
72
Does water have a high or low specific heat capacity? | + why
High: | Due to hydrogen bonds which are collectively strong
73
Why is waters specific heat capacity important to organisms?
1) allows an optimum temperature for proteins so they don’t denature 2) provides a thermo stable environment for organisms to live in. (Aquatic) 3) provides thermo stable environment within organisms (blood)
74
How does waters high specific heat capacity link to its function?
Allows water to act as a buffer against sudden temperature changes
75
What is latent heat of vaporisation?
The energy needed to change state of 1KG of a substance from liquid to gas without a temp change
76
Does water have a high or low latent heat of vaporisation ? | +why
High: | Due to the high amounts of energy required to break hydrogen bonds
77
How many calories are needed to evaporate 1g of water?
577
78
How does waters latent heat of vaporisation link to its function?
Allows lots of energy to be removed from body. Thermal energy (placed into breaking hydrogen bonds) converted to kinetic energy in water molecules
79
What is surface tension?
A measure of the force needed to stretch/ break the surface of a liquid
80
Why is waters surface tension so high?
Due to cohesion and adhesion
81
Why is waters high surface tension useful for organisms ?
Allows animals to live on water Allows water to travel up xylem
82
How does water latent heat of vaporisation and surface tension link?
High surface tension means water is pulled into body of water instead or evaporating
83
How much of a mammals body is water?
65%
84
How much of a jellyfishes body is water?
98%
85
What are the main functions of water?
1) a metabolite 2) a solvent 3) cooling 4) allowing light through 5) structure
86
What is a metabolite?
A substance used up in a metabolic reaction
87
How is water used in reactions?
In hydrolysis In photosynthesis (as raw material) Reactions occur whilst aqueous
88
Why is water a good solvent ?
Is dipolar - has ability to attract charges particles to opposite ends of particle - can separate molecules
89
What can water dissolve?
``` Urea Oxygen Polysaccharides Amino acids Enzymes Ammonia ```
90
Why is it important for water to be a good solvent?
To allow the transportation of substances
91
Why does water offer support?
Not easily compressed Responsible for the turgid pressure of plants and hydrostatic skeleton of earthworms
92
Why is it useful for water to be transparent?
Allow light through jelly-like substance in eye to retina To allow light through palisade layer for photosynthesis
93
What is an inorganic ion?
An atom or compound that has lost or gained electrons
94
Where can inorganic ions be found?
Cytoplasm Body fluids
95
Give examples of inorganic ions and their functions
Iron: Transport oxygen Phosphate: ATP and DNA formation Hydrogen: Regulate PH to allow optimum conditions for proteins Sodium: Transport glucose and amino acids across plasma membranes
96
Who proposed the theory of semi-conservative DNA replication?
Watson and crick
97
Why is waters high latent heat of vaporisation an efficient tool?
Allows lots of energy to be transferred to the environment without losing lots of energy
98
What is the role of single stranded DNA in DNA replication?
Act as a template | Determines order of bases
99
What is a nucleotide made of?
Pentose sugar Nitrogenous base Inorganic phosphate ion
100
Why is there variability in the stability in the stability of DNA?
3 H bonds between C+G Only 2 between A+T

biology (28 decks)

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