DNA, translation, Transcription

?
What nucleotides differ in quantity amongst species?
Adenine can differ to guanine
1 of 64
what nucleotides remain relative to each other in quantity?
Adenine - Thymine and Guanine - Cytosine
2 of 64
what is the name given to A- T and G - C
Base pair complementarity
3 of 64
what are nucleotides composed of?
Nitrogenous Base, Sugar (ribose etc) and Phosphate group
4 of 64
how are nucleotides joined?
Covalently via Phosphodiester Bonds
5 of 64
Where does a phosphodiester bond join
Between the 5' carbon of one sugar and the 3' Carbon of another
6 of 64
what is the structure/shape of DNA?
Antiparallel double helix
7 of 64
What is a gene?
A specific sequence of nucleotides (DNA) which codes for a specific protein
8 of 64
what are the bonds which form between base pairs
Hydrogen
9 of 64
what is the size of a nucleotide?
around 1nm (3.4 angstroms)
10 of 64
what is the size of one turn of the helix?
around 10nm (34 angstroms)
11 of 64
What is the name for the most common type of DNA?
B-form
12 of 64
Why is B-form DNA the most common type?
Has the highest -ΔG (most exergonic) therefore energetically favourable
13 of 64
When does DNA condense into chromosomes
During prophase of mitosis
14 of 64
Where are telomeres located?
At the end of chromosomes
15 of 64
where are centromeres located
in the middle of chromosomes
16 of 64
what are the two identical DNA strands called in a chromosome
Sister chromosomes
17 of 64
What is the basic unit of chromosomes
Nucleosomes
18 of 64
What do nucleosomes form?
Chromatin
19 of 64
What is heterochromatin?
Highly organised/ tight that restricts gene expression
20 of 64
what is euchromatin
Loosely organised that enables gene expression.
21 of 64
what charge is the phosphate backbone
Very negatively charged
22 of 64
what protein is used to condense DNA
Histones
23 of 64
What are the types of histones used in the formation of nucleosomes
H2A, H2B, H3 AND H4
24 of 64
How does DNA wrap around histones
Histones are +charged and phosphate backbone is negative, attraction
25 of 64
what is the name of the large histone complex of a nucleosome
octameric histone core
26 of 64
Around how many nucleotides are wrapped around the histone core
150 nucleotides
27 of 64
What is the name of the DNA which is inbetween each nucleosome
Linker DNA
28 of 64
roughly how many turns does the DNA strands wrap around histone core
2
29 of 64
What is the purpose of H1 histones
To lock of each nucleosome
30 of 64
chromatin is further wrapped/condensed into what?
solenoids
31 of 64
What is the name given to changing from heterochromatin to euchromatin?
Self-propagating
32 of 64
what can heterochromatin determine?
The expression of genes (therefore phenotype)
33 of 64
What modifications can occur on histones to change the accessibility of DNA
Acetylation and Demethylation
34 of 64
what is acetylation?
addition of acetyl group to positive lysines to become more negatively charged
35 of 64
what is methylation?
the addition of methyl groups on usually cytosine
36 of 64
how can methylation effect gene expression?
more methyl groups = +charge = tighter coiling = more restriction
37 of 64
what are the three types of RNA?
rRNA, mRNA and tRNA
38 of 64
what is the function of tRNA
Transport amino acids to mRNA to make proteins
39 of 64
what is the function of mRNA
Carries Complimentary DNA sequence to cytoplasm (messenger)
40 of 64
what is the function of rRNA
Produce ribosomes which make proteins
41 of 64
what is the name of the strand that is produced from transcription
Sense strand
42 of 64
what is the name of the enzyme responsible for transcription for proteins
RNA Polymerase II
43 of 64
what are the THREE phases of mRNA synthesis
Initiation, elongation and Termination
44 of 64
what initiates mRNA synthesis
Promotor sequence on DNA strand
45 of 64
what are the two post-transcriptional modifications required for mRNA
5' capping and 3' polydenylation
46 of 64
What is 5' capping?
the addition of Methylyguanosine to 5' end of mRNA
47 of 64
what is 3' polydenylation
the addition of lots of Adenine to 3' end of mRNA
48 of 64
how does 5' capping occur?
phosphate of 5' is removed - 5' to 5' triphosphate linkage of mehtylguanosine occurs
49 of 64
how does 3' polydenylation occur?
internal sequence AAUAAA - 11 to 30 nucleotides away from this addition of 50 - 250 A's
50 of 64
What are introns?
Non-coding spacer mRNA
51 of 64
what are exons?
Coding sections of mRNA
52 of 64
what molecule carriers out Splicing of introns
snoRNPS called spliceosomes
53 of 64
how many amino acids are they?
20 amino acids
54 of 64
how many codons are they?
64 codons
55 of 64
what is meant by degeneracy in terms of genetic code
multiple codons code for the same amino acid
56 of 64
which amino acids only have 1 codon?
methionine and tryptophan
57 of 64
what are the 4 stages of translation?
activation, initiation, elongation and termination
58 of 64
what is the activation stage of translation?
amino acid activated via ATP- tRNA synthetase attaches amino acids to specific tRNA
59 of 64
What is the initiation stage of translation?
mRNA attaches to 40s ribosomal subunit - initiator tRNA attaches to start codon (AUG)
60 of 64
what is the elongation stage of translation?
codon(mRNA) - anticodon(tRNA) complementarity attaches amino acids in specific sequence
61 of 64
what is the termination stage of translation?
STOP codon , polypeptide chain cleaved and mRNA released and degraded
62 of 64
where does translation occur?
cytoplasm of a cell (at a ribosome)
63 of 64
what is the protein and rna ratio in fractions?
2/3 rRNA and 1/3 protein
64 of 64

Other cards in this set

Card 2

Front

what nucleotides remain relative to each other in quantity?

Back

Adenine - Thymine and Guanine - Cytosine

Card 3

Front

what is the name given to A- T and G - C

Back

Preview of the front of card 3

Card 4

Front

what are nucleotides composed of?

Back

Preview of the front of card 4

Card 5

Front

how are nucleotides joined?

Back

Preview of the front of card 5
View more cards

Comments

No comments have yet been made

Similar Human Biology resources:

See all Human Biology resources »See all Biochemistry resources »