Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Biology A-Level OCR > Nucleotides, DNA replication and Protein Synthesis > Flashcards

Nucleotides, DNA replication and Protein Synthesis Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

Name the components of a nucleotide?

A

Phosphate group, nitrogenous base, covalent bond, pentose sugar and an ester bond

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

What are nucleotides?

A

Monomers of larger polymers nucleic acids

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

What does DNA stand for?

A

Deoxyribonucleic acid

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

What does RNA stand for?

A

Ribonucleic acid

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

What are features of DNA?

A

Double stranded, its pentose sugar is deoxyribose, its nitrogenous bases are A, T, C and G, and it is very long

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

What are the features of RNA?

A

Single strand, its pentose sugar is ribose, its nitrogenous bases are A, U, C and G, it is very short (one gene long)

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

What are the differences between DNA and RNA?

A

DNA stays in the cell, RNA goes out of the cell. DNA is very long, RNA is very short. DNA uses thymine, RNA uses uracil. DNA is in a double helix, RNA is in a single helix, DNA is more stable than RNA

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

What is a purine molecule? What nitrogenous bases are purines?

A

A molecule with two rings, guanine and adenine

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

What is a pyrimidine molecule? What nitrogenous bases are pyrimidines?

A

A molecule with a single ring, cytosine, thymine and uracil

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

How many rings are there in complementary base pairing?

A

3 rings, because purine have 2 rings and pyrimidines have 1 ring

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

What are the roles of nucleotides?

A

Synthesis and repair of nucleic acids, metabolic functions such as ATP

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

What reaction bonds together nucleotides?

A

Condensation reactions

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

Where is the phosphodiester bond on a nucleotide?

A

5th Carbon on the phosphate group and 3rd carbon on the hydroxyl group

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

What is a phosphodiester bond?

A

A covalent bond between 2 pentose sugars

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

What bonds are between the complementary base pairs?

A

Hydrogen bonds

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

How many hydrogen bonds are between the base pairs?

A

2 hydrogen bonds for A-T and 3 hydrogen bonds for C-G

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

What does ‘anti-parallel’ mean in context to DNA strands?

A

On the sugar phosphate backbone, one strand is from carbon 3 to carbon 5 but the other strand is the opposite: carbon 5 to carbon 3

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

Why is complementary base pairing important?

A

Ensures same distance between pairs, ensures faithful replication, maintains high fidelity of replication- and is bi-directional

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

What is transcription?

A

The process of turning DNA into RNA

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

Where does transcription occur and why?

A

The nucleus because DNA is too big to fit outside of the nucleus

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

What is translation?

A

The process of going from mRNA to proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Where does translation occur?

A

Ribosomes

23
Q

What is protein synthesis?

A

Transcription then translation

24
Q

What are the three types of RNA?

A

mRNA, tRNA and rRNA

25
Q

How is mRNA made?

A

On the template strand complementary to the DNA coding strand with uracil instead of thymine

26
Q

What is the function of mRNA?

A

To carry information out of the nucleus

27
Q

What is tRNA?

A

Transfer RNA: attaches amino acids via peptide bonds to form poly peptides

28
Q

Name the features of tRNA

A

Clover shaped, single stranded, folded, anticodon at the end to bind to mRNA at its codon via complementary base pairing

29
Q

What enzyme does transcription use?

A

RNA polymerase

30
Q

What is the RNA transcribed from the DNA templates called?

A

A gene

31
Q

List the steps of transcription

A

1- RNA polymerase separates the DNA strands partially
2- RNA nucleotides align opposite on the coding strand due to complementary base pairing
3- RNA polymerase bind the nucleotides covalently, which forms phosphodiester bonds
4- The gene is synthesised so RNA polymerase detaches from the DNA molecule and the double helix reforms

32
Q

Which direction is RNA formed?

A

RNA polymerase ‘walks’ in a 3’ to 5’ direction but mRNA is formed at a 5’ to 3’ direction

33
Q

In transcription, what is initiation?

A

When the RNA polymerase binds to the DNA at a region called the promoter region

34
Q

Describe transcription’s initiation

A

RNA polymerase binds to a promoter region, then the DNA behinds to partially unwind in a 3’ to 5’ direction

35
Q

What is transcription’s elongation?

A

When the RNA polymerase begins to move along the DNA template strand to catalyse the formation of phosphodiester bonds to join the nucleotides to the strand of mRNA

36
Q

What is transcription’s termination?

A

When the RNA polymerase detaches from a DNA strand and the synthesised mRNA detaches so the double helix reforms (stop codon)

37
Q

Where are ribosomes found and how does that effect their function?

A

Free in cytoplasm (proteins for inside the cell), on rough endoplasmic reticulum (proteins for export outside of cell)

38
Q

What subunits do ribosomes consist of?

A

Large and small

39
Q

What are ribosome subunits made of?

A

Proteins and rRNA

40
Q

What is the role of peptidyl transferase in ribosomes?

A

Catalyse formation of peptide bonds between amino acids

41
Q

What does translation depend on?

A

Complementary base pairing between the mRNA codons and the tRNA anticodons

42
Q

List the steps of translation

A

1- ribosome binds to the mRNA and moves along the molecule from 5’-3’
2- tRNA with the anticodon to match the start codon is needed to start translation
3- mRNA reads one codon at a time
4- ribosomes catalyse formation of peptide bonds between adjacent amino acids via condensation reactions
5- this continues until the ribosome reaches a stop codon
6- the polypeptide is released

43
Q

Which 2 amino acids contain sulfur

A

Cysteine and methionine

44
Q

Why is the amino acid sequence important?

A

Defines shape of protein

45
Q

What are the key points of DNA replication?

A

Original strand is called the template strand, strand being complementary base paired is coding strand, one strand is newly synthesised, this is called semi-conservative

46
Q

What is DNA replication in terms of mitosis?

A

Anaphase

47
Q

Name the steps of DNA replication

A

1- helicase unwinds and unzips DNA strands, so each strand is a template
2- DNA polymerase binds to primer and joins DNA nucleotides from 3’ to 5’
3- the leading strand continuously synthesised due to its 5’ to 3’ formation
4- however the lagging strand is made 5’ to 3’ so is made in Okazaki fragments
5- DNA ligase joins strands together which makes 2 new molecules of DNA

48
Q

What are the enzymes used in DNA replication?

A

Helicase, DNA polymerase and DNA ligase

49
Q

Why is DNA replication semi-conservative?

A

Because each DNA molecule is made of one old strand and one new strand

50
Q

What are the 2 strands in DNA replication

A

Leading strand and lagging strand

51
Q

What are Okazaki fragments?

A

A fragment of DNA on the lagging strand that is made 5’ to 3’

52
Q

What is the role of helicase in DNA replication?

A

Unwinds and unzips the DNA molecule into 2 template strands that run anti-parallel to each other (catalysing breakage of hydrogen bonds)

53
Q

What is the role of DNA polymerase in DNA replication

A

Synthesises new DNA molecules from 2 template strands by forming phosphodiester bonds between nucleotides

54
Q

What is proof for the semi-conservative theory?

A

Meselson and Stahl experiment with ‘heavy’ and ‘light’ nitrogen

Biology A-Level OCR (26 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions