DNA and Genes Flashcards
(94 cards)
1
Q
Where is DNA found?
A
in the nucleus
2
Q
Where are genes located?
A
encoded into DNA
3
Q
What is DNA the template for?
A
RNA
4
Q
What is RNA a template for?
A
proteins
5
Q
What is the process called where RNA is formed from DNA?
A
transcription
6
Q
What is the process called where proteins are formed from RNA?
A
translation
7
Q
Who first discovered the double helix?
A
Watson and Crick
8
Q
What are the names of the DNA bases?
A
adenine, thymine, cytosine and guanine
9
Q
Which bases bond with each other?
A
adenine to thymine and guanine to cytosine
10
Q
Which base pairs are joined by a double bond?
A
adenine and thymine
11
Q
Which base pairs are joined by a triple bond?
A
guanine and cytosine
12
Q
What is a nucleosome the packing unit of?
A
chromosomes
13
Q
What is nucleosome formed of?
A
2 wraps of DNA around a protein
14
Q
How many stages of folding are involved in forming chromosomes?
A
6
15
Q
What do hox genes define?
A
body position/axis
16
Q
By what process is hereditary information passed along?
A
templated polymerisation
17
Q
What is the function of replication origins?
A
open up DNA down the centre for templated polymerisation
18
Q
What cell phase does DNA replication occur in?
A
interphase
19
Q
After what point can mitosis occur?
A
when DNA is fully copied
20
Q
What does a gene contain?
A
the entire nucleotide sequence necessary to produce mRNA which codes for a protein
21
Q
What additional sequences may be encoded in a gene that are not involved in protein coding?
A
regulatory region, promoter, intron, exon
22
Q
What do regulatory regions and promoters do in DNA?
A
help to decide if a gene will be translated
23
Q
What do introns do in genes?
A
encodes for mRNA but not protein, are removed
24
Q
What do exons do in genes?
A
encode for mRNA and protein
25
What is the enzyme used in the transcription of DNA to RNA?
RNA polymerase
26
What happens in the first stage of DNA transcription?
RNA polymerase and associated factors unwind small region of DNA helix and initiate RNA synthesis using one strand of DNA as template
27
What strand of DNA does RNA polymerase make an RNA copy of?
sense strand
28
What strand of DNA is used as the template for RNA polymerase?
anti-sense strand
29
In what direction does RNA polymerase move along the template strand (anti sense)
3' primed to 5' primed
30
What primed end of the RNA chain are nucleotides added to?
3'
31
What is the sugar in DNA?
deoxyribose
32
What are the bases in DNA?
adenine, thymine, guanine and cytosine
33
What is the sugar in RNA?
ribose
34
What are the bases in RNA?
adenine, guanine, cytosine and uracil
35
What happens to intron sequences when pre mRNA matures?
form looped structures and are spliced out
36
At what primes is mRNA modified?
5' and 3' ends
37
What happens during capping of mRNA?
cap structure is added to 5' end of mRNA shortly after transcription is initiated
38
What is the cap on mRNA important for?
efficient translation and stabilising message
39
What happens to mRNA during polyadenylation?
at 3' end of RNA poly A polymerase adds 100-300 A residues to form poly A tail
40
What is a poly A tail required for?
efficient translation and stabilising message
41
What factors affect what gene is expressed?
transcription factors
42
Out of how many amino acids are proteins formed?
20
43
How many DNA/RNA base pairs code for an amino acid?
3
44
What is the name for the 3 base pairs that code for an amino acid?
codon
45
How many codons code for 20 possible amino acids and stop codons?
64
46
How many stop codons are there?
3
47
In what direction is coding sequence of mRNA read
5' to 3'
48
What molecule is the coding sequence of mRNA read by?
transfur RNA (tRNA) molecules
49
What does tRNA have at one end?
anticodon triplet
50
What is the anti codon triplet on tRNA complimentary to?
codon sequence on mRNA molecule
51
What is attached to the other end of the tRNA molecule once the codon sequence on mRNA has been read?
amino acid that corresponds to the codon sequence
52
What happens to the amino acids attached to the end of the tRNA molecule?
they are incorporated onto the growing polypeptide chain
53
what part of the amino acid structure is at the beginning and end of the amino acid chain?
begins with an amino group on front end and when protein is finished it will have a carboxyl group at the ens
54
What sort of RNA do ribosomes associate with?
tRNA and mRNA
55
What do ribosomes catalyse?
formation of the peptide chain
56
What type of proteins do ribosomes associate with?
regulatory proteins
57
give 2 examples of regulatory proteins involved in protein synthesis in ribosmomes
initiating and releasing factors
58
What is the initiator amino acid for all proteins?
methionine
59
What is the codon for methionine?
AUG
60
What is the sequence from initiator to stop codon known as?
open reading frame (ORF)
61
Where is methionine found on the amino acid chain?
amino terminus (front end)
62
How many subunits is a ribosome composed of?
2
63
What is the name of the 2 subunits of a ribosome?
large and small ribosomal sub units
64
What are ribosomes composed of?
protein and RNA
65
What is the function of a large ribosomal sub unit?
catalyses addition of amino acids to extending peptide chain
66
What is the function of the small ribosomal sub unit?
binds tRNA and mRNA
67
What codon is translation initiated by?
AUG codon
68
What does the small ribosomal sub unit do during initiation?
scans along mRNA from 5' end
69
Once mRNA has been scanned what do the large and small ribosomal sub units do during initiation?
assemble at initiator and begin to translate the protein
70
What direction do ribosomes move along mRNA during peptide chain elongation?
5' to 3' direction
71
What do tRNA bind to in order to interpret the code?
codon
72
what does ribosome catalyse during chain elongation?
addition of new amino acids to the peptide chain
73
What is recognised at the end of ORF to stop translation?
stop codon
74
what causes the ribosome to fall apart when the stop codon is reached?
releasing factor
75
what does the ribosome falling apart terminate?
translation of the protein
76
What do protein motifs do?
target proteins to different compartments of the cell (e.g. ER and golgi apperatus)
77
When a protein is targeted what happens when it reaches its target location?
signal peptide is cleaved off
78
What happens to membrane associated and secretory proteins when they are passed into the ER?
they are trafficked in residues to golgi apperatus
79
What happens to proteins during their progress through ER and golgi apperatus?
they are modified
80
In what 4 ways may proteins be modified during their progress through ER and golgi apperatus?
addition of sugar residues, protein folding and formation of inter and intra molecular disulphide bonds, attachment of lipid modifications to membrane bound proteins, other protein modifications (e.g. phosphorylation)
81
What is the addition of sugar residues to proteins in the ER and golgi apperatus known as?
glycosylation
82
What molecule binds to transient receptors in the plasma membrane to cause them to join together?
signal molecule
83
What does the binding of a signal molecule to 2 identical receptors cause?
the receptors are bound together and therefore phosphorylate each other
84
What can the phosphorylation of 2 receptor molecules cause?
cascade of events that can trigger gene regulatory proteins and target proteins
85
What gene signals limb outgrowth?
FGF
86
How can we tell what function a gene provides?
by knocking it out
87
What is involved in the process of knocking out a gene?
chromosome is altered so that gene required is knocked out, cell containing mutant gene is removed and allowed to multiply, injected into the host blastocyst and becomes part of the inner cell mass. Mutation caused by knocked out gene will be shown in offspring with homozygos gene pair with knocked out gene.
88
What are reverse genetics?
finding the phenotype that arises when you knock out a certain gene
89
what are forwards genetics?
look at a disease or pathology and want to find out what gene causes it.
90
What can SNP markers help with?
locating genetic mutations on chromosomes
91
on which chromosome is CF located?
7
92
What is a respiratory elevator?
mucus that traps debris gained during inhalation which can then be lifted out of the lungs by cilia
93
How are micro tubules formed?
alpha beta tubulin is joined to make protofilament which are then wound together to create micro tubules
94
What drives the movement of cilia?
dynine motors climb the micro tubules in rotation
