Q: A DNA sequence is transcribed to mRNA. If the DNA template strand is $$5'\text{-}ATGCGTACG\text{-}3'$$, what is the mRNA sequence produced?

$$5'\text{-}UACGCAUGU\text{-}3'$$

Question 1

Which chemical bond is primarily responsible for the mechanical strength and stability of hair fibers?

Accepted Answer

Disulfide bonds

Question 2

A patient’s DNA sequence for insulin contains the following mutation: the codon $$\mathrm{GAG} is $$changed to $$\mathrm{GTG}. $$What type of mutation is this?

Accepted Answer

Missense mutation

Question 3

Which of the following treatments is most likely to permanently reshape hair by altering its internal chemical structure?

Accepted Answer

Perming solutions that break and reform disulfide bonds

Question 4

A DNA sequence is transcribed to mRNA. If the DNA template strand is $$5'	ext{-}ATGCGTACG	ext{-}3'$$, what is the mRNA sequence produced?

Accepted Answer

$$5'	ext{-}UACGCAUGU	ext{-}3'$$

Question 5

Which environmental factor is most likely to cause hair to return to its natural curl pattern after heat styling?

Accepted Answer

Exposure to high humidity

Question 6

In the sickle cell anemia case study, what type of mutation leads to the production of sickle-shaped red blood cells?

Accepted Answer

A missense mutation substituting valine for glutamic acid

Question 7

Which of the following sequences would NOT result in a change to the reading frame of an mRNA sequence?

Accepted Answer

AGGACCGGUGGCCGAUAAA

Question 8

Why do disulfide bonds contribute more to hair strength than hydrogen bonds?

Accepted Answer

Disulfide bonds are stronger covalent bonds, while hydrogen bonds are weaker and easily broken by water.

Question 9

A mutation changes the DNA codon $$\mathrm{TAC} to$$ $$\mathrm{TAG}. $$What is the effect on the protein sequence?

Accepted Answer

A nonsense mutation introducing a stop codon

Question 10

Which of the following best explains why hair from individuals of East Asian populations tends to be straighter and thicker than hair from other populations?

Accepted Answer

Distinct follicle shape and keratin composition

Question 11

A patient’s insulin gene has a mutation that changes the codon $$\mathrm{GAA} to$$ $$\mathrm{GAG}. $$What is the effect of this mutation?

Accepted Answer

Silent mutation

Question 12

Which process is responsible for converting DNA information into mRNA?

Accepted Answer

Transcription

Question 13

A protein mutation changes the amino acid sequence from $$\mathrm{Glu} to$$ $$\mathrm{Val} at a $$critical position. What is the most likely effect on the protein’s tertiary structure?

Accepted Answer

Disruption of hydrogen bonding and increased hydrophobic interactions

Question 14

Which of the following is a real-world example of a missense mutation causing a disease?

Accepted Answer

Sickle cell anemia caused by a substitution of valine for glutamic acid in hemoglobin

Question 15

Which of the following best describes the role of keratin in hair structure?

Accepted Answer

Keratin is a protein that forms disulfide bonds, providing strength and shape to hair

Question 16

A DNA sequence undergoes a mutation where a single nucleotide is deleted. What is the most likely consequence?

Accepted Answer

Frameshift mutation

Question 17

Which of the following statements about hair porosity is correct?

Accepted Answer

Low-porosity hair is more resistant to chemical damage

Question 18

Which of the following is the correct sequence of events in gene expression?

Accepted Answer

Replication → Transcription → Translation

Question 19

A mutation in the promoter region of a gene most likely affects which process?

Accepted Answer

Transcription initiation

Question 20

Which of the following best explains why hair texture varies widely among different populations?

Accepted Answer

Differences in the number and arrangement of disulfide bonds and follicle shape

Protein Structure, Genetic Mutations, and Hair Texture: A Study Guide

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