9 Ass 5 pt 1 Nucleotides and Genetic Control Flashcards
A piece of double-stranded DNA containing 12x10^3 nucleotides is transcribed and translated to produce a single polypeptide. What is the maximum number of amino acids in this polypeptide?
2x10^3
Are purines and pyrimidines the same size?
No, they’re different sizes
How many hydrogen bonds does Adenine have with thymine and Uracil?
2
Are the base pairs in a molecule of DNA of different lengths and widths?
No. Base pairs are of equal length and width
How many rings does adenine have in its structure?
two
How many rings does guanine have in its structure?
two
How many rings does Uracil have in its structure?
one
How many rings does thymine have in its structure?
one
How many rings does cytosine have in its structure?
one
Q4 fill in table
See written qp
What is the carbohydrate in DNA
deoxyribose
what is the carbohydrate in RNA?
Ribose
Why are the two sugar-phosphate chains in a DNA molecule a constant distance apart?
Each purine base is linked to a pyrimidine base
Which bases are pyrimidines?
Thymine, Uracil and cytosine
Q10 what is 2?
ribose
q10 How many hydrogen bonds in 3?
3 hydrogen bonds
Q11 which mutated DNA would result in a polypeptide with 1 different amino acid?
CCA TTC ACG CCG TTA GCC
12 The mRNA sequences of the three stop codons are shown:
UAA UAG UGA
which mutation in the template (transcribed) strand of DNA sequence that codes for a polypeptide would cause translation to stop prematurely?
ACC changed to ATT
When a gene for protease is activated, which nucleic acid will be formed?
mRNA
Put the process of translation in order 4
mRNA binds to the ribosome,
tRNA enters the ribosome carrying a specific amino acid,
Hydrogen bonds form between the anticodon and the codon
A peptide bond forms between adjacent amino acids
During transcription, how many hydrogen bonds are formed when adjacent mRNA codons of AAU and CUG bind to complimentary tRNA anticodons? (do the maths)
Adenine and Uracil have 2 hydrogen bonds
Total no of adenine & uracil: 4
4x2=8
Guanine & cytosine have 3 hydrogen bonds
total no. of cytosine and guanine: 2
2x3=6
8+6=14
so 14
how many hydrogen bonds does guanine have with cytosine?
three hydrogen bonds
How many nucleotides in an amino acid?
three
Do codons count as amino acids?
No
Which events occur twice during transcription before the mRNA molecule leaves the nucleus?
Bonds break between complementary bases
bonds form between complementary bases
A length of mRNA is 747 nucleotides long, including stop & start codons, how many amino acids will be produced in the polypeptide?
247
How many genes are needed to code for a single haemoglobin molecule?
2
What is the correct tRNA anticodon coding for the amino acid GGT (proline)?
GGU
(it’s not complementary bc it’s a tRNA copy of that strand, so the same but U)
An antibiotic enters cells through a membrane channel protein, P.
some bacterial cells have shown resistance to this antibiotic by acquiring a mutation which alters P. This mutation prevents the entry of the antibiotic into the cell
which conclusions can be drawn about how resistance to this antibiotic developed i these bacteria?
The mutation resulted in the production of P with an altered tertiary structure
Which bases are purines?
Guanine and adenine
