2.1 Detectives were investigating a crime scene and found blood on a broken window - NSC Life Sciences - Question 2 - 2020 - Paper 2
Question 2
2.1 Detectives were investigating a crime scene and found blood on a broken window. They suspected that the blood was that of the criminal. To identify the criminal,... show full transcript
Worked Solution & Example Answer:2.1 Detectives were investigating a crime scene and found blood on a broken window - NSC Life Sciences - Question 2 - 2020 - Paper 2
Step 1
2.1.1 Name the technique that was used to identify the criminal.
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The technique used to identify the criminal is DNA profiling.
Step 2
2.1.2 Who is the possible criminal?
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The possible criminal is Jennie.
Step 3
2.1.3 Explain your answer to QUESTION 2.1.2.
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Jennie is identified as the possible criminal because her DNA profile matches the DNA profile obtained from the crime scene. In DNA profiling, specific DNA patterns are compared, and matching profiles indicate biological similarity.
Step 4
2.1.4 State ONE other use of the technique identified in QUESTION 2.1.1.
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One other use of DNA profiling is for proof of paternity, where it can determine the biological relationship between a parent and a child.
Step 5
2.2.1 What is cloning?
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Cloning is the process of creating genetically identical organisms or cells. It involves producing an organism that has the exact same genetic material as another.
Step 6
2.2.2 Explain why the nucleus of a muscle cell was used and not the nucleus of a sperm cell.
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The nucleus of a muscle cell was used because it contains all the genetic material necessary for the development of a new organism, while a sperm cell only has half of the genetic material, making it haploid.
Step 7
2.2.3 Explain why the nucleus of the ovum was removed.
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The nucleus of the ovum was removed to ensure that the resultant embryo has the full diploid set of chromosomes, which comes exclusively from the muscle cell nucleus, thereby allowing for successful development.
Step 8
2.2.4 State ONE benefit of cloning.
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One benefit of cloning is the conservation of endangered species, as it can help in reproducing individuals of species that are on the brink of extinction.
Step 9
2.3.1 How many alleles control the inheritance of blood groups?
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Three alleles control the inheritance of blood groups: IA, IB, and i.
Step 10
2.3.2 Describe the type of dominance that occurs in the inheritance of blood group B in the woman.
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In this case, blood group B (IB) is dominant over blood group O (i), thus, the woman has a genotype of either IB IB or IB i, where IB is dominant.
Step 11
2.3.3 Use a genetic cross to show all the possible genotypes and phenotypes of their children.
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To illustrate the genetic cross:
Parental Generation:
Man's blood group: AB (IA IB)
Woman's blood group: B (which can be either IB IB or IB i)
Punnett Square:
IB
i
IA
AB
IB
BB
Possible Genotypes: AB, BB, A, B
Possible Phenotypes: Blood groups AB, B, A.
Step 12
2.4.1 What is a gene mutation?
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A gene mutation is defined as a change in the sequence of nucleotides in a gene, which can result in alterations to the produced protein.
Step 13
2.4.2 Which region had the highest number of children born with sickle cell disease in that year?
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The region with the highest number of children born with sickle cell disease in that year is the Democratic Republic of Congo.
Step 14
2.4.3 What percentage of the worldwide total of children born with sickle cell disease came from the Democratic Republic of Congo? Show all calculations.
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To calculate the percentage:
[ \text{Percentage} = \left( \frac{39,746}{305,733} \right) \times 100 \approx 13% ]
Therefore, approximately 13% of the worldwide total came from the Democratic Republic of Congo.
Step 15
2.4.4 Use the letters D and d to give the genotype of a person who:
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a) dd for a person who suffers from sickle cell disease.
b) Dd for a person who carries the allele but does not suffer from the disease.
Step 16
2.5.1 Name the type of diagram shown.
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The type of diagram shown is a pedigree diagram.
Step 17
2.5.2 How many:
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(a) There are 6 females in this family.
(b) 1 male in the F2 generation has Goltz syndrome.
Step 18
2.5.3 Give Gabby’s genotype.
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Gabby’s genotype is XgX (affected female).
Step 19
2.5.4 Anju and Pilusa have four children. Give the phenotype of their children.
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The possible phenotypes of Anju and Pilusa's children are: 2 unaffected males, 1 affected male, and 1 unaffected female.
Step 20
2.5.5 Explain your answer to QUESTION 2.5.4.
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The reasons for the phenotypes of their children are based on the inheritance of the X-linked trait (Goltz syndrome). Anju (XgX) and Pilusa (XY) can produce children with varying combinations of affected and unaffected traits depending on the X chromosome inherited.
