Storing and Using genetic information Flashcards

1
Q

What is the phenotype of an organism?

A

Outward, physical appearance

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2
Q

What is the genotype of an organism?

A

Full hereditary information

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3
Q

What is a nucleotide monomer?

A

Makes up chains for DNA

Made of a sugar, base and phosphate group

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4
Q

How do the molecules bind in DNA?

A
  • Phosphate bind to 5th and 3rd C of sugar

- Base binds to 1st C

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5
Q

How are the bases structured in the double helix?

A

Bases are in the centre of the helix and bound by the outside to the sugar-phosphate backbone

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6
Q

What is the name of the sugar used in DNA?

A

2-deoxyribose

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7
Q

What is the name of the sugar in RNA?

A

Ribose - OH instead of H on 2nd C

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8
Q

How many bases per turn of helix?

A

10

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9
Q

What is meant by the chains of DNA running antiparallel to each other?

A

One runs from 5’ to 3’ from the top of the helix whilst the other is the opposite

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10
Q

What structure contains most of the cell’s genetic material (DNA)?

A

Nucleus

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11
Q

What occurs in the nucleus?

A

Replication of DNA and first steps in protein synthesis

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12
Q

What are DNA molecules packaged into in the nucleus?

A

Chromosomes

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13
Q

What are chromosome?

A

Single piece of DNA containing many genes, regulatory elements and other nucleotide sequences

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14
Q

What is a nucleosome?

A

Bundles of histones (proteins) with DNA wrapped around it

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15
Q

What is a chromatin?

A

Mixture of DNA, proteins and RNA that package DNA within the nucleus
Molecules that form a chromosome

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16
Q

What are two types of chromatin?

A

Heterochromatin (condensed and euchromatin (extended) forms

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17
Q

List stages of DNA packaging from smallest to largest

A
  1. Nucleosome
  2. Coils
  3. Supercoils
  4. Chromosome
18
Q

Why must the double helix strands separate during transcription & replication?

A

To remove the histones & folding barriers so enzymes have access to DNA

19
Q

What are two mechanisms which make chromatin maple accessible to enzymes?

A
  • Histones enigmatically modified
  • Histones displaced by chromatin remodelling complexes

Both reversibly

20
Q

What type of chromatin is more favourable for RNA polymerase and why?

A

Requires looser structure therefore euchromatin

21
Q

What does semi-conservative replication mean?

A

It means the 2 new DNA molecules contains 1 stand from the original and one from the new strand

22
Q

In what direction is the DNA replicated by DNA polymerase?

A

3’ to 5’ - the antisense strand

23
Q

What are the coding region in DNA?

A

Exons

24
Q

What is telomerase used for?

A

Replicating DNA strand from the 5’ to 3’ end

25
Q

What are the non-coding regions in DNA?

A

Introns

26
Q

What happens to introns and extols during transcription?

A

Introns spliced out and ends on exons join

27
Q

How many codons code for an amino acid?

A

3 but the number of codons is greater than the number of AA

28
Q

What are synonyms?

A

Condons which refer to the same AA

29
Q

How does degeneracy minimises effect of genetic mutations?

A

Variation of synonyms at 3rd codon means that changes to codon sequence are less likely to alter coded protein

30
Q

What is degeneracy?

A

Amino acids are encoded by more than one codon

31
Q

Which AA are an exception to degeneracy?

A

Methionine and tryptophan

32
Q

What type of mutation of codon sequence who alter the protein?

A

Codon that encodes for a stop or termination signal

33
Q

What disorder can single point mutations cause?

A

Sickle cell anaemia - Glu to Val - clumps haemoglobin together

34
Q

How can single point mutations cause dysfunctional proteins?

A

Base change = change in amino acid = change in structure = change in function

35
Q

mRNA role

A

Transcribes DNA in nucleus and moves to cytoplasm for protein synthesis

36
Q

What is the pre-mRNA strand?

A

Complement strand to DNA template which contains introns and exons

37
Q

What is alternative splicing?

A

Process where introns of pre-mRNA are spliced out and exon ends are brought together

38
Q

What is a strand of codons bound by in RNA?

A

An initiation codon and a termination codon

39
Q

Why are reading frames required in translation?

A

Reading frames required to read RNA strand by tRNA to deliver correct AA

40
Q

Role of tRNA?

A

Translate mRNA sequences into AA sequence

41
Q

Role of rRNA?

A

transported from nucleus to cytoplasms where they combine the proteins to form a ribosome