Question 1

Which life cycle is characterized by having both a multicellular haploid and a multicellular diploid stage?

Accepted Answer

Plants and some algae

Question 2

During which stage of meiosis does crossing over occur, and what is its significance?

Accepted Answer

Prophase I; it increases genetic variation by exchanging DNA between homologous chromosomes

Question 3

A human cell with 46 chromosomes undergoes meiosis. How many chromosomes will each resulting gamete contain?

Accepted Answer

$$23$$

Question 4

Which of the following best explains why siblings from the same parents can look very different from each other?

Accepted Answer

Crossing over, independent assortment, and random fertilization

Question 5

According to Mendel’s law of segregation, what happens to alleles during gamete formation?

Accepted Answer

Alleles for a trait separate so that each gamete receives only one allele

Question 6

A woman who is a carrier for hemophilia (an X-linked recessive disorder) has children with a normal male. What is the probability that their son will have hemophilia?

Accepted Answer

$$50\%$$

Question 7

If a DNA sample contains $$30\%$$ adenine, what percentage of guanine does it contain?

Accepted Answer

$$20\%$$

Question 8

Which enzyme is responsible for unwinding the DNA double helix during replication?

Accepted Answer

Helicase

Question 9

What is the function of Okazaki fragments during DNA replication?

Accepted Answer

They are short DNA segments synthesized on the lagging strand

Question 10

Given the DNA template strand $$3'-TACGGTACG-5'$$, what is the sequence of the resulting mRNA?

Accepted Answer

$$5'-AUGCCAUGC-3'$$

Question 11

A point mutation changes a codon from UAU (tyrosine) to UAA. What type of mutation is this?

Accepted Answer

Nonsense mutation

Question 12

Which of the following is an example of polygenic inheritance?

Accepted Answer

Human height

Question 13

In the pedigree shown, two unaffected parents have an affected child. What is the most likely mode of inheritance?

Accepted Answer

Autosomal recessive

Question 14

Which of the following best describes the role of the signal peptide in protein synthesis?

Accepted Answer

It directs the ribosome to the endoplasmic reticulum

Question 15

Which chromosomal alteration is most likely to result in a genetic disorder such as Down syndrome?

Accepted Answer

Trisomy

Question 16

Which process is responsible for the removal of introns from pre-mRNA in eukaryotes?

Accepted Answer

RNA splicing

Question 17

A calico cat is almost always female because:

Accepted Answer

Males have only one X chromosome and cannot be mosaics for X-linked traits

Question 18

Which of the following is true about mitochondrial inheritance?

Accepted Answer

It is inherited only from the mother

Question 19

If the recombination frequency between two genes is $$10\%$$, what does this indicate about their physical relationship on a chromosome?

Accepted Answer

They are relatively close together

Question 20

Which of the following best describes the semi-conservative model of DNA replication?

Accepted Answer

Each new DNA molecule consists of one parental and one new strand

Meiosis, Genetics, and DNA: Study Guide for BIOL 1201 Exam 3

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