Nucleic Acids and Protein Synthesis
397 questions· page 1 of 40
Which diagram correctly represents one of the base pairs of DNA?
Options
The diagram represents the process of transcription of a gene in the nucleus of an animal cell.
Which row correctly identifies P, Q and R?
Options
| P | Q | R | |
|---|---|---|---|
| A | mRNA | transcribed strand | template strand |
| B | primary transcript | transcribed strand | template strand |
| C | mRNA | template strand | non-transcribed strand |
| D | primary transcript | template strand | non-transcribed strand |
Which statements are correct?
1 All polypeptides are coded for by genes.
2 All genes are made up of a sequence of nucleotides.
3 All gene mutations result in a change to the nucleotide sequence.
4 All gene mutations will result in an altered polypeptide.
Options
A 1, 2 and 3 and 4
B 1, 2 and 3 only
C 1 and 4 only
D 2 and 3 only
A double-stranded DNA molecule was analysed and 29% of its nucleotide bases were found to be adenine.
Which percentage of its nucleotide bases will be cytosine?
Options
A 21%
B 29%
C 42%
D 58%
In some cells, non-coding sequences of RNA are removed after transcription.
Which row correctly states the name of these non-coding sequences of RNA and the type of cell in which the non-coding sequences are removed?
Options
| name of non-coding sequences | type of cell in which non-coding sequences are removed | |
|---|---|---|
| A | exons | eukaryotic |
| B | exons | prokaryotic |
| C | introns | eukaryotic |
| D | introns | prokaryotic |
Sometimes hydrogen bonds form temporarily between the bases of two strands of RNA.
How many hydrogen bonds form when guanine and uracil each bind to their complementary base?
Options
| guanine | uracil | |
|---|---|---|
| A | 3 | 3 |
| B | 3 | 2 |
| C | 2 | 3 |
| D | 2 | 2 |
The table shows all the possible DNA triplet codes for some amino acids.
| amino acid | DNA triplet code |
|---|---|
| cysteine | ACA |
| cysteine | ACG |
| tryptophan | ACC |
| isoleucine | TAA |
| isoleucine | TAG |
| isoleucine | TAT |
| methionine | TAC |
The amino acid sequence is shown.
methionine – isoleucine – cysteine – tryptophan
What is the maximum number of different DNA sequences that could produce this amino acid sequence?
Options
A 1
B 4
C 6
D 7
Which statement about a macromolecule is correct?
Options
A Amylose is a branched polymer made of -glucose and -glucose monomers.
B DNA is an association of two polymers made of nucleotide monomers.
C Haemoglobin is an association of four polymers made up of monomers of haem groups and amino acids.
D Triglycerides are polymers made of fatty acids and glycerol.
Which statements about tRNA are correct?
1 Hydrogen bonds between bases temporarily bond tRNA to mRNA.
2 The base sequences in the tRNA molecules are the same as the base sequences in the mRNA that is being translated.
3 Some codons in mRNA do not have corresponding tRNA anticodons.
Options
A 1, 2 and 3
B 1 and 2 only
C 1 and 3 only
D 2 and 3 only
Why is the genetic code described as universal?
Options
A Each codon is made up of a sequence of three bases.
B More than one codon can represent one amino acid.
C Mutations can change the genetic code in all organisms.
D The genetic code is the same in all organisms.