DNA, genes and protein synthesis Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

What is a gene?

A

Section of DNA coding for an amino acid sequence/ polypeptide or functional RNA

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

How many bases code for an amino acid?

A

3

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

What doe the code being degenerate mean?

A

Many triplet codes can code for the same amino acid

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

What is the start code always coding for?

A

methionine

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

What do the last 3 triplets form?

A

Stop code

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

What are 3 properties of DNA?

A

Non overlapping, degenerate and universal

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

What are coding sequences called?

A

exons

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

What are non coding sequences called?

A

introns

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

What type of cells are introns present in?

A

Eukaryote

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

What do some of the introns code for?

A

Ribosomal and transfer rna

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

What is prokaryotic DNA like?

A

Short, circular, not associated with proteins so no chromosomes

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

What us eukaryotic DNA like?

A

Longer, line, associated with proteins called histones and in chromosomes

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

What is mitochondria and chloroplasts DNA like?

A

Prokaryotes DNA

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

When are chromosomes visible?

A

In cell division

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

What are chromosomes made up of?

A

two chromatids and a centromere

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

What are homologous chromosomes?

A

Chromosomes with a diploid number where half the DNA is from the mother and half from the father that carry the same gene but not necessarily the same allele

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

What is an allele?

A

One of a number of alternative forms of a gene

18
Q

What leads to mutations?

A

Changes in the base sequence of a gene which produces a new allele

19
Q

Why are mutations often bad?

A

New polypeptide chain makes a protein which may not fit substrate so can’t perform it’s function

20
Q

What happens when each part of the DNA is read?

A

Transcribed into messenger RNA

21
Q

What is a codon on mRNA?

A

sequence of 3 bases that codes for an amino acid

22
Q

What is a genome?

A

Complete set of genes including mitochondria and chloroplasts DNA

23
Q

What is the proteome?

A

Full range of proteins produced by the genome

24
Q

What structure is RNA?

A

Single strand

25
Q

What makes up an RNA nucleotide?

A

Ribose, phosphate and either A,U,C or G base

26
Q

What are the two main types of RNA?

A

messenger RNA and Transfer RNA

27
Q

Is tRNA or mRNA more stable?

A

mRNA

28
Q

How long is mRNA and what are the bases determined by?

A

1000s of nucleotides the bases are determined by bases on DNA during transcription

29
Q

Where does mRNA go?

A

It leaves the nucleus enters cytoplasm and associates with the ribosomes and acts as a template strand for protein synthesis

30
Q

How is information arranged in mRNA?

A

In codons where 3 bases are complementary to the bases in DNA and the codons code for a amino acid which determines the sequence.

31
Q

What is the shape of tRNA

A

Single strand folded into a clover shape where one end extends so specific amino acid can attatch and other end 3 bases make up the anticodon.

32
Q

What are the two main stages of protein synthesis?

A

Transcription and translation

33
Q

What happens first in transcription?

A

Part of DNA molecule unwinds and unzips due to hydrogen bonds being broken between bases which is catalysed by DNA helicase

34
Q

What happens after DNA has been unwinded in transcription?

A

RNA polymerase catalyses the addition of free nucleotides which complementary base pair to form pre mRNA molecules

35
Q

How is it ensured that the molecule remains stable?

A

DNA strand joins on after so only 12 nucleotides are ever exposed at once.

36
Q

What happens in translation in eukaryotes which doesn’t in prokaryotes?

A

Splicing where introns are removed

37
Q

What happens first in translation?

A

mRNA is passed out the nuclear pore and a ribosome attaches to the start codon of and the complementary anticodon carries a specific amino acid

38
Q

What happens to the two tRNA amino acids in translation?

A

Joined by a peptide bond using an enzyme and ATP

39
Q

What happens once the 3rd amino acid is joined?

A

1st tRNA molecule can leave and can collect another amino acid from the cytoplasm

40
Q

When does the polypeptide chain stop growing?

A

When it reaches the stop codon

41
Q

What is a polysome system?

A

When a number of ribosomes combine

42
Q

How is the protein assembled at the end of protein synthesis?

A

Polypeptide is coiled or folded producing a secondary structure which is folded again to give the tertiary structure and different polypeptide chains along with non protein groups link to form tertiary structure