2.1 The diagram below is a representation of the chromosomes in a human cell - NSC Life Sciences - Question 2 - 2017 - Paper 2
Question 2
2.1 The diagram below is a representation of the chromosomes in a human cell.
2.1.1 How many autosomes are in this cell?
2.1.2 This individual is a female. Explai... show full transcript
Worked Solution & Example Answer:2.1 The diagram below is a representation of the chromosomes in a human cell - NSC Life Sciences - Question 2 - 2017 - Paper 2
Step 1
How many autosomes are in this cell?
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Answer
In humans, there are 46 chromosomes total, consisting of 22 pairs of autosomes and 1 pair of sex chromosomes. Therefore, the number of autosomes in this cell is 44.
Step 2
This individual is a female. Explain why this conclusion is made.
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Answer
The presence of two X chromosomes (XX) indicates that the individual is female. In humans, females have two X chromosomes, while males have one X and one Y chromosome.
Step 3
What evidence is there to show that this individual has a genetic disorder?
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The presence of three chromosomes at position 21 suggests that this individual has a genetic disorder. This is indicative of Down syndrome, also known as Trisomy 21.
Step 4
Identify the genetic disorder mentioned in QUESTION 2.1.3.
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The genetic disorder referred to in QUESTION 2.1.3 is Down syndrome.
Step 5
Name the process that resulted in this genetic disorder.
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The process that resulted in this genetic disorder is nondisjunction, where chromosomes fail to separate properly during cell division.
Step 6
Describe the process whereby a copy of a DNA molecule is made.
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The process of making a copy of a DNA molecule is known as DNA replication. Double-stranded DNA unwinds and separates into two strands when the hydrogen bonds break. Each strand serves as a template to form a complementary DNA strand. This results in two genetically identical DNA molecules, thus completing the replication process.
Step 7
How many alleles code for blood groups?
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There are three alleles that code for blood groups: A, B, and O.
Step 8
Give: Mary's blood group
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Mary's blood group is A.
Step 9
Give: Joseph's genotype
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Joseph's genotype is AB.
Step 10
Give: All the possible genotypes of Joseph's father
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The possible genotypes of Joseph's father could be IAIB or IAi.
Step 11
Name the process by which the Bt gene is inserted into corn to make Bt corn.
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The process by which the Bt gene is inserted into corn to make Bt corn is called genetic modification or genetic engineering.
Step 12
State the hypothesis of this investigation.
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The hypothesis of this investigation is that the Bt corn will yield a higher crop yield than the non-Bt corn.
Step 13
State the: Independent variable
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The independent variable is the type of corn variety (Bt corn vs. non-Bt corn).
Step 14
State the: Dependent variable
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The dependent variable is the average crop yield measured in bushels per acre.
Step 15
Describe ONE way in which the reliability was ensured in this investigation.
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Reliability was ensured by repeating the experiment multiple times (four trials) to calculate an average yield, minimizing random errors.
Step 16
Explain ONE benefit to a farmer of using Bt corn.
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One benefit to a farmer of using Bt corn is that it reduces the need for pesticides, leading to lower costs and increased crop safety.
