Question 1

Which of the following best describes the central dogma of molecular biology?

Accepted Answer

DNA is transcribed into RNA, which is then translated into protein.

Question 2

A DNA sequence 5'-ATG CAT GCA TGC-3' is transcribed and translated. What is the corresponding mRNA sequence?

Accepted Answer

$$5'\ \mathrm{AUG\ CAU\ GCA\ UGC}\ 3'$$

Question 3

Which process occurs in the cytosol and involves tRNA molecules bringing amino acids to the ribosome?

Accepted Answer

Translation

Question 4

A point mutation changes a codon from GAG to GUG in the hemoglobin gene. What type of mutation is this, and what is the likely effect?

Accepted Answer

Missense mutation; glutamic acid is replaced by valine

Question 5

Which of the following mutations is most likely to result in a nonfunctional protein?

Accepted Answer

Nonsense mutation

Question 6

In a cross between two heterozygous mice (Mm x Mm) for a gene where M is dominant for dark fur and m is recessive for light fur, what is the expected phenotypic ratio in the offspring?

Accepted Answer

$$\frac{3}{4}$$ dark, $$\frac{1}{4}$$ light

Question 7

A mutation in the CFTR gene deletes a codon for phenylalanine. What is the most likely consequence for the protein product?

Accepted Answer

The protein is nonfunctional and cannot be inserted into the membrane.

Question 8

Which of the following best explains why most point mutations are considered neutral?

Accepted Answer

They do not change the amino acid sequence due to redundancy in the genetic code.

Question 9

Given the DNA template strand 3'-GGACTCCTTCA-5', what is the corresponding mRNA sequence?

Accepted Answer

$$5'\ \mathrm{CCUGAGGAGAAG}\ 3'$$

Question 10

A mutation changes the DNA sequence from 5'-AAT-3' to 5'-AGT-3'. Using the mRNA codon table, what amino acid change occurs?

Accepted Answer

Asn to Ser

Question 11

Which of the following is the ultimate source of new alleles in a population?

Accepted Answer

Mutation

Question 12

A pedigree shows a trait that appears in every generation and affects both males and females equally. What is the most likely mode of inheritance?

Accepted Answer

Autosomal dominant

Question 13

If a mutation introduces a premature stop codon in the middle of a gene, what is the most likely result?

Accepted Answer

A truncated, likely nonfunctional protein

Question 14

Which of the following best describes a frameshift mutation?

Accepted Answer

A mutation that shifts the reading frame, altering all downstream amino acids

Question 15

A mouse with genotype Bb (B = brown fur, b = white fur) is crossed with a bb mouse. What is the probability that their offspring will have white fur?

Accepted Answer

$$\frac{1}{2}$$

Question 16

Which of the following is NOT a property of life?

Accepted Answer

Ability to photosynthesize

Question 17

Which of the following best explains why the S allele of the hemoglobin gene confers resistance to malaria?

Accepted Answer

It causes red blood cells to sickle, making it harder for malaria parasites to survive.

Question 18

If a DNA sequence is mutated from 5'-TAC-3' to 5'-GAC-3', what is the resulting amino acid change?

Accepted Answer

Tyrosine to Aspartic acid

Question 19

Which of the following is a real-world example of a missense mutation affecting phenotype?

Accepted Answer

The S allele in sickle cell anemia, changing glutamic acid to valine in hemoglobin

Question 20

Which of the following best describes the relationship between genotype and phenotype?

Accepted Answer

Genotype determines the sequence of amino acids in proteins, which in turn determines phenotype.

Information Flow, Mutations, and Mendelian Genetics in General Biology

Guida di studio - Domande di pratica

Study guide - Flashcard