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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Answer
The technique used to identify the criminal is DNA profiling, which involves analyzing the DNA patterns of individuals.
Step 2
2.1.2 Who is the possible criminal?
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The possible criminal is Jennie, as her DNA profile matches the DNA from the crime scene.
Step 3
2.1.3 Explain your answer to QUESTION 2.1.2.
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Jennie's DNA profile corresponds to the DNA bands found in the sample from the crime scene. This means that the genetic markers observed in both samples are identical, indicating that she is the source of the blood found.
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, to establish biological relationships between individuals.
Step 5
2.2.1 What is cloning?
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Cloning is the process of producing genetically identical organisms, resulting in offspring that are clones of a single parent organism.
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 a complete set of chromosomes (diploid) needed for cloning, while a sperm cell contains only half the genetic material (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 only the genetic material from the muscle cell is present in the cloned embryo, thus preventing any mixing of genetic material.
Step 8
2.2.4 State ONE benefit of cloning.
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One benefit of cloning is the conservation of endangered species, allowing for the preservation of genetic diversity.
Step 9
2.3.1 How many alleles control the inheritance of blood groups?
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There are three alleles that control the inheritance of blood groups: A, B, and O.
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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Blood group B exhibits complete dominance over blood group O, meaning that the presence of the B allele will determine the phenotype when combined with an O allele.
Step 11
2.3.3 Use a genetic cross to show all the possible genotypes and phenotypes of their children.
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The genetic cross can be illustrated as follows:
egin{array}{c|c|c}
P_1 & Blood ext{ group } AB & Blood ext{ group } B \\
ext{Genotype:} & I^{A}I^{B} & I^{B}i \\
ext{Gametes:} & I^{A}, I^{B} & I^{B}, i \\
ext{F}_1 & Blood ext{ group } AB & Blood ext{ group } A \\
ext{Phenotype:} & I^{A}I^{B} & I^{B}i \\
ext{All possible genotypes:} I^{A}I^{B}, I^{B}i \\
ext{Corresponding phenotypes:} AB, B \\
ext{Meiosis and fertilisation occurs creating the final genotypes.}
ight)
Step 12
2.4.1 What is a gene mutation?
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A gene mutation is a change in the sequence of nucleotides in a gene, which can lead to changes in the protein produced by that gene.
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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Nigeria had the highest number of children born with sickle cell disease, with a total of 90,128 reported cases.
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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2.4.4 Use the letters D and d to give the genotype of a person who:
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(a) Suffers from sickle cell disease: dd
(b) Carries the allele but does not suffer from the disease: Dd
Step 16
2.5.1 Name the type of diagram shown.
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The diagram shown is a pedigree diagram, which illustrates the inheritance of traits through generations.
Step 17
2.5.2 How many:
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(a) There are 6 females in this family.
(b) There is 1 male in the F1-generation with Goltz syndrome.
Step 18
2.5.3 Give Gabby's genotype.
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Gabby's genotype is XgX.
Step 19
2.5.4 Anju and Pilusa have four children. Give the phenotype of their children.
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The phenotype of their children would include a mix of affected and unaffected, depending on the allele combinations inherited from Anju and Pilusa.
Step 20
2.5.5 Explain your answer to QUESTION 2.5.4.
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Children from Anju could inherit either Xg (affected) or X (unaffected) and from Pilusa either X (unaffected) or Y (male). This results in varying phenotypes for each child, reflecting their genotypes.
