Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Biology - OCR A > 2.3 - Nucleic Acids > Flashcards

2.3 - Nucleic Acids Flashcards

1
Q

What is a triplet code?

A

A triplet code is where each codon, consists of three nuceoltides that each code for amino acids.

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

What is a codon?

A

A codon is a DNA or RNA sequence of three nucleotides on a section on mRNA.

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

What is an anticodon?

A

An anticodon is a trinucleotide sequence located at one end of a tRNA molecule, which is complementary to a corresponding codon in the mRNA.

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

Why is genetic code universal?

A

Genetic code is universal because nearly every organism uses the same code.

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

What is the structure of a nucleotide?

A
  • Phosphate
  • Pentose sugar
  • Nitrogenous base (A, C, G and T)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the structure of a nucleotide?

A
  • Phosphate
  • Pentose sugar
  • Nitrogenous base (A, C, G and T)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What pentose sugar does a DNA nucleotide have?

A

Deoxyribose sugar

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

What pentose sugar does a RNA nucleotide have?

A

Ribose sugar

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

What is the structure of ATP?

A
  • Adenine
  • Ribose sugar
  • 3x phosphates
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the name of the process when a phosphate group is added?

A

Phosphorylation

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

What are 2 types of pyrimidines?

A

Cytosine and thymine

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

What are 2 types of purines?

A

Adenine and guanine

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

Why is DNA replication necessary?

A

For cells to divide and replicate

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

What does a DNA helicase do?

A

It breaks the hydrogen bonds that hold the two strands together

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

What do DNA polymerase do?

A

They add nucleotides to the template strand

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

How do the DNA polymerase know where to start adding nucleotides?

A

RNA primers are added to the strands

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

What is a leading strand?

A

The strand that the DNA polymerase progress down the strand

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

What is a nucleotide?

A

It is a monomer from which nuclei acids, like DNA and RNA, are formed

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

How can you tell that a nucleotide is a purine?

A

2 carbon ring structure

20
Q

How can you tell that a nucleotide is a pyrimidine?

A

1 carbon ring structure

21
Q

What can be categorised according to their ring structure?

A

Nitrogenous bases

22
Q

What bases are complementary?

A
  • Thymine (or uracil in RNA) and Adenine
  • Guanine and Cytosine
23
Q

What reaction does DNA and RNA undergo to form a phosphodiester bond?

A

A condensation reaction

24
Q

Where does the phosphodieser bonds form?

A

Between 2 nucleotide monomers to create a polymer

25
What is a phosphodiester bond (nucleotides)?
It is a strong covalent bond between the pentose sugar and a phosphate of different nucleotides
26
What is ATP used for?
Metabolism as it is an immediate source of energy for biological molecules
27
When is ATP made?
In respiration (mostly aerobic)
28
How is ATP made?
A condensation reaction using the enzyme ATP synthas ADP + Pi —> ATP +H2O
29
What happens when ATP is hydrolysed?
It breaks one of the bonds between the phosphate group which releases a small amount of energy
30
What does DNA do (nucleic acids)?
It codes for a sequels of amino acids in the primary structure of a protein which determines the final 3D structure
31
What is the structure of a DNA strand?
DNA polymers forms a double helix made of 2 antiparallel starands that are joined together by hydrogen bonds between the bases of the 2 strands
32
How does DNA’s structure relate to its function?
Stable structure - due to the sugar-phosphate backbone and the double helix Double stranded - both strands can be used as templates in replication Weak hydrogen bonds - easy separation of the 2 strands A large molecule - can carry lots of information Complementary base pairings - identical copies can be made
33
What are the 3 types of RNA?
mRNA - messenger RNA tRNA - transfer RNA rRNA - ribosomal RNA
34
What does rRNA do?
It makes up the bulk of ribosomes
35
What is mRNA?
A single strand with a copy of every 3 bases from the DNA
36
What does mRNA do?
It is created in the nucleus and it leaves via the nuclear pores to carry a copy of the genetic code to a ribosome
37
Where is tRNA found?
In the cytoplasm
38
What is the shape of tRNA?
Single stranded but folded to create a cloverleaf shape and is held in place by hydrogen bonds
39
What does tRNA do?
It brings an amino acid to the ribosome depending on the 3 bases found which are complementary to the codon on the mRNA
40
What is semiconservative DNA replication?
One strand is conserved and one new strand is created
41
How do copying errors in DNA replication occur?
They happen randomly and spontaneously
42
What happens when a copying error is made in DNA replication?
It changes that DNA base sequence resulting in a mutation
43
When does DNA replication occur in the cell cycle?
S-phase of interphase
44
What happens in transcription?
1. The target gene on the DNA unwinds because of the DNA helicase 2. Free RNA nucleotides match up to their complementary bases on the open strand 3. The RNA nucleotides bond together along the backbone with phosphodiester bonds in a 5’-3’ direction to produce a copy of mRNA 4. The single strand of mRNA moves out through the nuclear pores to the ribosomes, and the DNA zips back up
45
What happens in translation?
1. Once the mRNA reaches the ribosome it moves through it in codons 2. For each codon a tRNA with the complementary anticodons temporarily bind 3. Each tRNA carries a specific amino acid depending on the anticodon sequence 4. The amino acids bind together with peptide bonds and eventually form a polypeptide chain 5. The tRNA molecules move away and the newly synthesised polypeptide can be modified by the ribosome
46
What happens in secretion?
1. After translation the protein is then pinched off into vesicles and goes to the golgi body 2. The vesicle fuses with the golgi body where the protein is processed and packaged 3. The packaged protein is then put in a vesicle and goes to the plasma membrane 4. The vesicle fuses with the membrane and it opens up releasing the protein

Biology - OCR A (25 decks)

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