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Biology > 1.2 Nucleic acids > Flashcards

1.2 Nucleic acids Flashcards

(49 cards)

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1
Q

what does DNA stand for?

A

deoxyribonucleic acid

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2
Q

what does RNA stand for?

A

ribonucleic acid

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3
Q

what monomers make up DNA and RNA?

A

nucleotides

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4
Q

what three components make up a nucleotide?

A

phosphate group, pentose sugar and nitrogenous organic base

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5
Q

what nitrogenous organic bases are components of DNA nucleotides?

A

adenine, thymine, guanine, cytosine

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6
Q

what nitrogenous organic bases are components of RNA nucleotides?

A

adenine, uracil, guanine, cytosine

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7
Q

name the pentose sugar found in DNA nucleotides

A

deoxyribose sugar

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8
Q

name the pentose sugar found in RNA nucleotides

A

ribose sugar

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9
Q

what bond is formed when two nucleotides join together?

A

phosphodiester bond

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10
Q

describe how two nucleotides join together in a DNA molecule [3]

A
  • phosphodiester bond
  • between deoxyribose sugar and phosphate group
  • condensation reaction
  • catalysed by DNA polymerase
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11
Q

describe the structure of DNA [5]

A
  • polymer of nucleotide monomers
  • nucleotides made of a phosphate group, deoxyribose sugar and nitrogenous organic base
  • phosphodiester bonds between nucleotides form sugar-phosphate backbone
  • antiparallel strands coil into double helix shape held by hydrogen bonds
  • hydrogen bonds between complimentary base pairs: adenine and thymine, guanine and cytosine
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12
Q

describe the structure of RNA [5]

A
  • polymer of nucleotide monomers
  • nucleotides made of a phosphate group, ribose sugar and nitrogenous organic base
  • phosphodiester bonds between nucleotides form sugar-phosphate backbone
  • short, single-stranded chain
  • exposed nitrogenous organic base pairs: adenine and uracil, guanine and cytosine
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13
Q

state four differences between the structures of DNA and RNA

A
  • in DNA, adenine pairs with thymine, but in RNA it pairs with uracil
  • DNA has two strands coiled into a double helix, whereas RNA is single-stranded
  • RNA is much shorter than DNA
  • pentose sugar is deoxyribose in DNA, but ribose in RNA
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14
Q

how many hydrogen bonds form between adenine and thymine?

A

two

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15
Q

how many hydrogen bonds form between guanine and cytosine?

A

three

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16
Q

how many hydrogen bonds form between adenine and uracil?

A

two

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17
Q

when was DNA first observed?

A

1800s

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18
Q

when was the double helix structure of DNA discovered?

A

1953

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19
Q

who discovered the double helix structure of DNA?

A

Watson and Crick

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20
Q

do strands of DNA run in the same direction?

Study These Flashcards
A

no, they are antiparallel

21
Q

in what direction do the two strand run in a DNA molecule?

Study These Flashcards
A

they are antiparallel
one runs in 5’ to 3’ direction
other runs in 3’ to 5’ direction

22
Q

describe and explain how DNA is a stable molecule [3-4]

Study These Flashcards
A
  • sugar-phosphate backbone protects chemically reactive organic base inside double helix
  • hydrogen bonds between complimentary base pairs form bridges between DNA strands
23
Q

how does the proportion of G-C pairings affect the stability of a DNA molecule?

Study These Flashcards
A

G-C pairings have three hydrogen bonds between them, whilst A-T pairs have two, meaning the higher the proportion of G-C pairings, the more stable the DNA molecule will be.

24
Q

what is the function of DNA?

Study These Flashcards
A

to store genetic information and pass it between cells and down generations

25
what is the main function of RNA?
to transfer genetic information from DNA to ribosomes
26
what are ribosomes made of?
RNA and proteins
27
how is the structure of DNA suited to its functions? [4-6]
- two strands joined by hydrogen bonds allows them to separate during DNA replication and protein synthesis - sugar-phosphate backbone and helical shape protect base pairs and genetic information from outside chemical and physical forces - complimentary base pairing allow DNA to replicate and transfer information as mRNA
28
why does DNA replicate before cell division?
so that each new cell has the full amount of DNA
29
by what process does DNA replicate?
semi-conservative replication
30
name for requirements for DNA replication to take place
- presence of free nucleotides with either adenine, thymine, guanine or cytosine as their organic base - both DNA strands act as templates for free nucleotides to attach to - presence of DNA polymerase enzyme - a source of chemical energy
31
describe the process of semi-conservative replication [5-6]
- enzyme DNA helicase breaks hydrogen bonds between complimentary base pairs - double helix separates and unwinds to form two single strands - each exposed strand acts as a template for a new strand - free nucleotides bind to complimentary base pairs on template strands with hydrogen bonds - DNA polymerase joins new nucleotides together to form the new sugar-phosphae backbone - two new strands are identical and contain half of the original DNA material
32
what does ATP stand for?
adenosine triphosphate
33
why is energy important?
plant and animal cells need energy for biological processes to occur
34
what components make up ATP?
adenine, ribose, three phosphate groups
35
where is energy stored in ATP?
phosphate bonds between the phosphate groups
36
how is energy released from ATP?
ATP is broken down into ADP bonds between phosphate groups break hydrolysis reaction catalysed by ATP hydrolase hydrolysis of phosphate bonds releases energy
37
what molecule is released when ATP breaks down to ADP?
inorganic phosphate
38
how can ADP be converted back to ATP
add an inorganic phosphate molecule condensation reaction catalysed by ATP synthase
39
what type of reaction converts ATP to ADP
reversible reaction
40
how can the inorganic phosphate lost from the conversion of ATP to ADP be used?
phosphorylation it can be added to another compound to make it more reactive
41
give two reasons why ATP is a better immediate energy source than glucose
- ATP releases smaller amounts of energy than glucose, meaning its much more manageable - hydrolysis of ATP to ADP is a single reaction, so releases energy immediately, whilst breakdown of glucose is multiple reactions so takes longer
42
name the two products of ATP hydrolysis
ADP and an inorganic phosphate
43
give two ways in which the hydrolysis of ATP is used in cells
- to provide energy for other reactions - to add phosphate to other substances and make them more reactive
44
name the process of adding phosphate to a substance to increase its reactivity
phosphorylation
45
describe the atomic structure of water
two hydrogen atoms covalently bonded to one oxygen atom
46
describe/explain the polarity of water
- dipolar molecule - no overall charge - oxygen atom slightly negatively charged - hydrogen atoms slightly positively charged
47
how are multiple water molecules bonded together?
- water is dipolar - opposite poles attract - positive oxygen on one molecule attracts negative hydrogens of another and vice versa - attractive forces are hydrogen bonds
48
explain five properties that make water important for organisms [5]
- metabolite in condensation and hydrolysis reactions - good solvent to transport substances - high specific heat capacity to buffer temperature change - high latent heat of vaporisation to provide cooling effect through evaporation - cohesion between water molecules to support continuous column of water in plants
49
what is a metabolite?
substance involved in a metabolic reaction

Biology (14 decks)

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