Question

8 what initiates dna replication by unwinding the double helix?
a dna polymerase
b okazaki fragments
c helicase
d ligase
9 which of the following correctly describes the structure of dna?
a coiled structure without nucleotides
b triple-stranded helix
c double-stranded helix
d single-stranded helix
10 what real-world application exemplifies the use of genetic engineering to combat vitamin a deficiency?
a creation of genetically modified mosquitoes
b production of biodegradable plastics
c development of golden rice with enhanced nutritional value
d enhancement of crop resistance
11 what does aneuploidy refer to in genetics?
a a condition where chromosomes are perfectly paired
b a type of mutation that occurs in the dna sequence
c a genetic disorder caused by environmental factors
d a chromosomal aberration characterized by an abnormal number of chromosomes in a cell
12 in mendelian genetics, what happens during the law of segregation?
a traits from different parents assort independently.
b parents pass all of their traits to their offspring.
c parents pass half of their traits to their offspring; the child will receive one allele from their father and one from their mother for a given trait.
d different traits do not depend on each other.
13 how do chromosomal aberrations typically impact individuals?
a lead to behavioral tendencies
b affect physical characteristics, intellectual abilities, and overall health
c no impact on health
d only affect physical appearance
14 which syndrome is caused by a deletion in a small segment of chromosome 22?
a huntingtons disease
b digeorge syndrome
c cystic fibrosis
d downs syndrome

Explanation:

• Question 8: DNA replication is initiated by helicase, which unwinds the double helix. DNA polymerase synthesizes new DNA strands, Okazaki fragments are short DNA segments on the lagging strand, and ligase joins DNA fragments.
• Question 9: DNA has a double - stranded helix structure. It is made of nucleotides. A triple - stranded helix is not the typical structure of DNA, and a single - stranded helix is not the correct description for DNA's usual form.
• Question 10: Golden Rice is genetically engineered to combat Vitamin A deficiency. Genetically modified mosquitoes are for disease control (e.g., malaria), biodegradable plastics are about environmental sustainability, and enhanced crop resistance is about pests/diseases.
• Question 11: Aneuploidy is a chromosomal aberration with an abnormal number of chromosomes. Perfectly paired chromosomes are normal (euploidy in some cases), it's not a DNA - sequence mutation (that would be a point mutation etc.), and it's not caused by environmental factors in the sense of being an environmental - induced genetic disorder (it's a chromosomal number issue).
• Question 12: In Mendelian genetics, during the Law of Segregation, parents pass half of their traits (alleles) to offspring. Traits assorting independently is the Law of Independent Assortment, parents do not pass all traits, and different traits not depending on each other is also related to independent assortment.
• Question 13: Chromosomal aberrations typically affect physical characteristics, intellectual abilities, and overall health. They can have impacts on health (so “no impact on health” is wrong), and it's not just about physical appearance or behavioral tendencies (though they can have some behavioral aspects in some cases, the most comprehensive answer is about multiple aspects including physical, intellectual, and overall health).
• Question 14: DiGeorge syndrome is caused by a deletion in a small segment of chromosome 22. Huntington's disease is caused by a trinucleotide repeat expansion in the HTT gene, Cystic fibrosis is due to mutations in the CFTR gene, and Down syndrome is due to an extra copy of chromosome 21.

Answer:

• Question 8: C. Helicase
• Question 9: C. Double - stranded helix
• Question 10: C. Development of Golden Rice with enhanced nutritional value
• Question 11: D. A chromosomal aberration characterized by an abnormal number of chromosomes in a cell
• Question 12: C. Parents pass half of their traits to their offspring; the child will receive one allele from their father and one from their mother for a given trait
• Question 13: B. Affect physical characteristics, intellectual abilities, and overall health
• Question 14: B. DiGeorge syndrome