2.1 The diagram below represents a single-stranded nucleic acid found in the nucleus - NSC Life Sciences - Question 2 - 2017 - Paper 2
Question 2
2.1 The diagram below represents a single-stranded nucleic acid found in the nucleus.
Identify the molecule represented in the diagram.
2.1.2 Identify:
(a) Pa... show full transcript
Worked Solution & Example Answer:2.1 The diagram below represents a single-stranded nucleic acid found in the nucleus - NSC Life Sciences - Question 2 - 2017 - Paper 2
Step 1
Identify the molecule represented in the diagram.
96%
114 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The molecule represented in the diagram is mRNA (messenger RNA).
Step 2
Identify: (a) Part X
99%
104 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Part X is a nitrogenous base.
Step 3
Identify: (b) Sugar Y
96%
101 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Sugar Y is ribose.
Step 4
Describe the process of transcription.
98%
120 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Transcription is the process by which a double-stranded DNA molecule unwinds and separates. The hydrogen bonds break, allowing the strands to part. One of the strands then serves as a template to form mRNA. RNA nucleotides are utilized from the nucleoplasm, pairing with the DNA template strand (A pairs with U, and C pairs with G). This process is controlled by enzymes.
Step 5
Give THREE sources of genetic variation in a species.
97%
117 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Crossing over
Random arrangement of chromosomes during meiosis
Random fertilization.
Step 6
Differentiate between continuous variation and discontinuous variation.
97%
121 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Continuous variation occurs when there is a range of phenotypes for the same characteristic, showing intermediate forms. Discontinuous variation occurs when phenotypes fit into separate or distinct categories without intermediate forms.
Step 7
Give the: (a) DNA triplet for the third amino acid from the left in the sequence for protein 2.
96%
114 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The DNA triplet for the third amino acid from the left in the sequence for protein 2 is ACC.
Step 8
Give the: (b) Codon for lysine.
99%
104 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The codon for lysine is AAA.
Step 9
Give the: (c) Anticodon for serine.
96%
101 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The anticodon for serine is UCA.
Step 10
How many of EACH of the following is involved in the formation of this protein? (a) Genes
98%
120 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
1 gene is involved in the formation of this protein.
Step 11
How many of EACH of the following is involved in the formation of this protein? (b) RNA nucleotides
97%
117 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
198 RNA nucleotides are involved in the formation of protein 1.
Step 12
How many of EACH of the following is involved in the formation of this protein? (c) Codons
97%
121 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
66 codons are involved in the formation of protein 1.
Step 13
Describe how the mutation caused a change in the structure of the protein.
96%
114 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The mutation resulted in a change in one of the base triplets in the DNA sequence, changing ACG to ACC. This influences the amino acid sequence, altering the coding for cysteine to tryptophan, leading to a change in the structure of the protein.
Step 14
State the: (a) Independent variable.
99%
104 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The independent variable is the temperature at which clover plants are grown.
Step 15
State the: (b) Dependent variable.
96%
101 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The dependent variable is the number of clover plants that survived, or the percentage survival.
Step 16
State TWO ways in which the scientists could have improved the reliability of the investigation.
98%
120 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Repeat the investigation multiple times.
Set up more greenhouses at each temperature.
Step 17
Describe how the scientists calculated the percentage survival of clover plants.
97%
117 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
They counted the number of clover plants that survived, divided it by the original number (200) and multiplied it by 100.
Step 18
Explain if the hypothesis will be accepted or rejected.
97%
121 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The hypothesis will be accepted if more clover plants survive at the higher temperature, indicated by a higher percentage survival.
Step 19
Apart from temperature, explain ONE other way in which the survival rate of clover plants at different temperatures can be affected.
96%
114 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The survival rate can also be affected by water availability, as inconsistent watering can stress the plants.
Step 20
How can the mutation in the clover plants affect their survival rate?
99%
104 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The mutation can affect survival positively by producing cyanide, deterring herbivores. However, in colder climates, the release of cyanide may lead to plant fatalities, thus impacting overall survival rates.
