Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Biology A level > 1.5 Nucleic Acids > Flashcards

1.5 Nucleic Acids Flashcards

1
Q

What are the functions of DNA?

A

Carries the genetic code for protein synthesis
Replication for making new cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is mRNA?

A

Messenger RNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is rRNA?

A

Ribosomal RNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is tRNA?

A

Transfer RNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is a monomer of nuclei acids called?

A

Nucleotide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is a polymer of nucleotides called?

A

Polynucleotide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How is a polynucleotide formed?

A

Condensation reaction between two nucleotides with a phosphodiester bond

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How many polynucleotide chains does DNA have?

A

2 found in the nucleus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How many polynucleotide chains does RNA have?

A

1 found in the ribosomes and in the nucleus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Describe the structure of a general nucleotide

A

Nitrogenous base attached to c1
Pentose sugar so ribose/ deoxyribose
Phosphate group attached to c4
All bands between atoms are covalent bonds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are the 5 different bases?

A

Thymine
Guanine
Cytosine
Uracil
Adenine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Which pentose sugar is present in DNA?

A

Deoxyribose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are purine bases?

A

Double ring structure bases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are the two purine bases?

A

Adenine and guanine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are pyrimidine bases?

A

Single ring structured bases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the 3 pyrimidine bases?

A

Thymine
Cytosine
Uracil

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How many H bonds are between C and G?

A

3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

How many H bonds are between A and T/U?

A

2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What nitrogenous bases are present in ribose?

A

Adenine and uracil
Guanine and cytosine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

How is a molecule of DNA formed?

A

Condensation reaction = the pentose sugar of one nucleotide and the P group of another
Phosphodiester bond forms
Repeated condensation reactions = a single chain of repeating nucleotides = polynucleotide
It has a strong sugar-phosphate back bone
The chains run anti-parallel
H bonds between bases Which joins the polynucleotides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

How would you describe the polynucleotide chains in DNA?

A

They run antiparallel to each other
One running 3’ to 5’ and the other running 5’ to 3’

22
Q

What is the role of the sugar-phosphate backbone in DNA?

A

Gives strength to the DNA molecule

23
Q

What is the hydrogen bonds between chains in DNA role for DNA replication?

A

H bonds are weak so the chains can be separated for transcription and replication

24
Q

What is the role of DNA coiled structure?

A

Protects H bonds therefore reducing corruption of genetic code

25
What is the role of many weak H bonds in DNA?
Makes DNA a stable molecule
26
What is the role of sequencing of DNA bases in DNA?
It allows info to be stored
27
What is the role of DNA being a long molecule?
Can store a lot of genetic information (genes)
28
Describe DNA’s structure
A double helix structure of 2 polynucleotides which are joined together on a condensation reaction and form a strong sugar-phosphate backbone
29
What are the 3 fundamentals in DNA replication?
Complementary base pairing DNA has to unzip itself = break h bonds and separate chains The new polynucleotides would use the original polynucleotide as a template
30
What are the 3 hypotheses for DNA replication?
Conservative Semi-conservative Dispersive
31
What is conservative DNA replication?
The original double helix will unzip Produces 2 DNA molecules one with the new synthesised DNA with two new polynucleotide chains And the other is a direct replication of the original DNA double helix
32
What is semi-conservative DNA replication?
The DNA strands unzip which provides the template for the new DNA Produces 2 new DNA molecules both have one strand of the newly synthesised polynucleotide and one strand of the original DNA
33
What is dispersive DNA replication?
Regions of the original DNA double helix and regions of newly synthesised double helix are present in the two molecules of DNA produced
34
Who carried out the DNA replication experiment to prove the hypotheses?
Meselson and stahl
35
Why did meselson and stahl use E.coli?
It has a short generation time It’s DNA is not bound by a nuclear membrane
36
What is N14?
Light nitrogen
37
What is N15?
Heavy nitrogen
38
Why is nitrogen used in the DNA replication experiment?
Nitrogen is used to synthesise nitrogenous bases to form DNA
39
What are the first steps of M and S experiment?
They cultured 2 populations One on N14 agar and the other on N15 agar
40
What did M and S do after putting the bacteria on the N14 and N15 agar?
Bactria that had only been on N14 and N15 had their DNA extracted Other bacteria was transferred to N14 agar and the samples were removed after different generations 1,2 and 3
41
What happened to the DNA after being extracted from the bacteria in M and s experiment?
The DNA extract was suspended in a special solution which was then placed in a centrifuge
42
What was shown in the test tube In The M and S experiment after N15 placed on N14 for 1 generation?
There was a mix of DNA strands 1 N14 and 1 N15
43
What hypothesis does M and S experiment prove and how?
Semi-conservative = both new DNA double helixes contain the original polynucleotide and the new polynucleotide
44
Describe DNA replication (semi-conservative)
Both original polynucleotide chains act as a template Both new DNA double helixes contain the original polynucleotide the original polynucleotide of one new polynucleotides
45
Describe the process of semi-conservative replication in DNA
DNA helicase unwinds and unzips (h bonds broken) the double helix The 2 polynucleotides have exposed bases that act as a template Free DNA nucleotides in the nucleoplasm align themselves against each template strand H bonds form between complementary base pairings DNA polymerase Enzymes rewind DNA molecules back into a double helix Each newly formed DNA molecules has 1 original and 1 new strand
46
What is the role of DNA polymerase in semi-conservative replication?
Joins adjacent DNA nucleotides catalyses condensation reactions for the formation of phosphodiesther bonds between adjacent nucleotides
47
What would the 3rd generation on N14 display after DNA extraction?
There would be a thicker band of N14 synthesised DNA than the 2nd generation
48
What are 2 differences of an ATP molecule and an RNA molecule?
RNA only has 1 phosphate group, triphosphate in ATP RNA has 4 different nitrogenous bases, there is only adenine in ATP
49
How does ATP carry out its role as an energy donor?
Hydrolyses the bond between the 2nd and 3rd phosphate group by ATP hydrolase This is n exogonic reaction
50
Describe the structure of DNA
Polymer of nucleotides  Each nucleotide formed from deoxyribose, a phosphate (group) and an organic/nitrogenous base  Phosphodiester bonds (between nucleotides);    Double helix/2 strands held by hydrogen bonds;   (Hydrogen bonds/pairing) between adenine, thymine and cytosine, guanine;   
51
How is a phosphodiesther bond formed?
Condensation (reaction)/loss of water;    (Between) phosphate and deoxyribose;    (Catalysed by) DNA polymerase;   
52
What are features of DNA which aids semi-conservative replication?
weak H bonds - allows strands to be separated two stands- both act as templates comp pairing - accurate replication

Biology A level (36 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions