Chimpanzees, Gorillas, and Orangutans Have DNA Sequences That Are Almost

question 19

Multiple Choice

Chimpanzees, gorillas, and orangutans have DNA sequences that are almost identical to those of humans; however, these genes are found on 24 pairs of chromosomes in apes, while humans have 23 pairs. The C2 chromosome in humans is a large chromosome with similar banding pattern and DNA sequences to two smaller chromosomes in apes (C2 and C4) . In addition it appears to have both a vestigial second centromere and telomere sequences in the middle of the strand.
-What could explain these observations?

• A)The human ancestor originally had 24 pairs but complete fusion of C2 and C4 occurred, reducing the total number of chromosomes.
• B)A nondisjunction event must have occurred in the human ancestor, increasing the overall ploidy.
• C)The loss of a chromosome is due to a deletion event in the human ancestor.
• D)C2 must have undergone an inversion with C4.
• E)There is not enough information to speculate.

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Definitions:

Triglyceride

A molecule made of three fatty acids esterified to glycerol, serving as the primary form of fat storage in animals and plants.

Complex Lipid

Any of a group of lipids that combine with other types of molecules, such as carbohydrates or proteins, forming structures essential for living organisms.

Simple Lipids

Lipids that consist of fatty acids esterified with glycerol, including fats and oils, which serve as energy storage molecules in living organisms.

Esterification

A chemical reaction that forms an ester through the reaction of a carboxylic acid and an alcohol.