2.1 The diagram below is a representation of the chromosomes in a human cell - NSC Life Sciences - Question 2 - 2017 - Paper 2

The individual is identified as female because the diagram shows two X chromosomes (denoted as XX). In humans, females have two X chromosomes, whereas males have one X and one Y chromosome.

The evidence indicating a genetic disorder can be identified by the presence of an abnormal number of chromosomes. In this case, there are three chromosomes present at position 21, suggesting a trisomy.

The genetic disorder indicated by the presence of an additional chromosome at position 21 is known as Down's Syndrome or Trisomy 21.

The process that led to this genetic disorder is called nondisjunction, which occurs when chromosomes fail to separate properly during cell division, resulting in an abnormal distribution of chromosomes.

The process of copying a DNA molecule is known as DNA replication. It involves several key steps:

1. Unwinding the DNA: The double-stranded DNA molecule unwinds and separates into two strands as hydrogen bonds between bases break.
2. Template Formation: Each original strand serves as a template for the construction of the new strands.
3. Base Pairing: Free nucleotides align with their complementary bases on the template strands (A-T and C-G pairing).
4. Synthesis of New Strands: DNA polymerase enzymes synthesize new DNA strands by adding nucleotides to form a complementary strand to each template strand.
5. Resulting DNA Molecules: Ultimately, two genetically identical DNA molecules are formed, each consisting of one old and one new strand. This entire process ensures genetic continuity during cell division.

There are three alleles that code for blood groups: ( I^A ), ( I^B ), and ( i ).

Mary's blood group is A.

Joseph's genotype is ( I^A I^B ).

The possible genotypes of Joseph's father, considering he must contribute one allele to Joseph, are as follows:

• ( I^A I^B ) (AB)
• ( I^A i ) (A)
• ( I^B i ) (B)

The process by which the Bt gene is inserted into corn is known as genetic modification or genetic engineering.

The hypothesis of this investigation is that the Bt corn will have a higher yield than the non-Bt corn when subjected to the European Corn Borer (ECB) infestation.

The independent variable in this investigation is the type of corn (Bt corn vs. non-Bt corn).

The dependent variable is the average crop yield measured in bushels per acre.

One way reliability was ensured in this investigation was by repeating the experiment multiple times (specifically four times) to account for variability in results and to establish an average yield.

One benefit of using Bt corn for a farmer is that it reduces the need for chemical pesticides/herbicides. This not only lowers production costs but also minimizes the environmental impact of farming, leading to a more sustainable agricultural practice.