Nucleic Acids Flashcards

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1
Q

What does rna Do

A

Transfers genetic information from dna to ribosomes

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2
Q

What does a nucleotide contain

A

A pentose sugar, nitrogen containing base and a phosphate group

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3
Q

What are the components of a dna nucleotide

A

Deoxyribose, phosphate group and either A,C,T or G

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4
Q

The components of RNA

A

Ribose, phosphate group and either A,C,G or Uracil

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5
Q

How and where is a phosphodiester bond formed

A

From a condensation reaction between the sugar and a new phosphate between 2 nucleotides

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6
Q

Describe the dna structure (Watson and crick)

A

A double helix made of 2 long polynucleotides, joined by hydrogen bonds between specific base pairs

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7
Q

The physical look of RNA

A

A single, short polynucleotide chain

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8
Q

How is DNA adapted to carry out functions

A

It is a very stable structure which passes down and rarely mutating
Strands are joined with H bonds which allows them to separate during replication
Very large (more information)
Having base pairs protected by backbone, generic info is protected
Base pairing means easy replication

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9
Q

The two stages of cell division

A

Nuclear division and cytokinesis

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10
Q

What is need for semi conservative replication to take place

A

4 different bases, both strands to act as template, DNA polymerase, a source of chemical energy to drive the process

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11
Q

How does semi conservative replication ensure genetic continuity

A

Because genetic information is passed on as each strand serves as a template for the new one

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12
Q

Describe the process of semi conservative replication

A
  1. Dna helicase unwinds and unzips the dna molecule, separating two strands and breaking hydrogen bonds (both strands act as templates) 2. Free activated rna nucleotides are attracted to their complementary base pairs (complementary base pairing) 3. DNA polymerase joins adjacent nucleotides and phosphodiester bonds are formed and H bonds reform 4. Example of semi conservative replication
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13
Q

Which direction is the new strand synthesised in

A

5 to 3

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14
Q

What is the structure of ATP

A

Adenine (nitrogen containing organic base) , ribose (pentode sugar) and 3 phosphates

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15
Q

Is ATP a nucleotide

A

Yes

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16
Q

How does ATP store energy

A

The bonds between the 3 phosphates are unstable so have low activation energy (easily broken) when they break they release energy and one phosphate is removed

17
Q

Describe the hydrolysis of ATP

A

Water is used to convert ATP to adenosine Diphosphate with an inorganic phosphate group and is catalysed by ATP hydrolase

18
Q

Which enzyme catalyses hydrolysis ATP

A

ATP hydrolase

19
Q

Describe the synthesis of ATP

A

Energy can be used to add an inorganic phosphate to ADP to reform ATP

20
Q

Which enzyme catalyses the synthesis of ATP

A

ATP synthase

21
Q

What can the inorganic phosphate released be used for

A

To phosphorylate other compounds, often making them more reactive

22
Q

What kind of reaction is the synthesis of ATP

A

Condensation

23
Q

In what 2 ways does ATP synthesis occur with addition of a phosphate

A

During photosynthesis or during respiration

24
Q

Is ATP a short or long term energy source

A

A short term immediate energy source

25
Q

Why is ATP a better immediate energy source than glucose

A

Releases less energy so is more manageable and the hydrolysis is a single reaction which is quicker than the breakdown of glucose

26
Q

Can ATP be stored

A

No it has to be made

27
Q

What processes is ATP used in

A

Phosphorylation of compounds, making them more reactive, active transport, muscle contraction, anabolism (in protein synthesis). Secretion during exocytosis

28
Q

ATP is useful in many biological processes, exemplain why (e.g. what features does it have that makes it useful)

A
  1. It releases energy in small manageable amounts 2. It is broken down in one step (quickly hydrolysed) means energy is available rapidly (immediate source of energy) 3. It is reformed/ made again 4. It cannot pass out of a cell
29
Q

Describe the evidence for semi conservative replication (meselsohn and stahl)

A

They grew N14 and N15 bacteria, then transferred the N15 bacteria to an N14 medium to replicate for one generation and centrifuged the results to separate out the different weights. Found that after 1 gen, the dna had one heavy N15 strand and one light N14 strand

30
Q

What is the difference between conservative and semi conservative replication

A

Conservative means the original dna remains intact and a new daughter dna is produced with completely new material. Semi conservative is when original dna is split into 2 strands and each is replicated in the mirror image so each has one old and one new strand

31
Q

How does the structure of DNA result in accurate replication

A
  1. There are 2 strands so semi conservative replication is possible 2. Complementary Base pairing/ H bonds hold strands together but are weak and easily broken which allows strands to separate. 3. Base sequences act as template