Question 1

Which of the following best explains why each individual has two repeat numbers per STR site in their DNA profile?

Accepted Answer

Each STR site is inherited from both parents, one from the mother and one from the father.

Question 2

A DNA profile is considered unique to each person who has ever lived. If the probability of two unrelated individuals having the same DNA profile is $$1 	imes 10$$^{-12}$$, what does this imply about the reliability of DNA evidence in forensic investigations?

Accepted Answer

DNA evidence is reliable enough to be considered unique and can be used to convict beyond reasonable doubt.

Question 3

Gel electrophoresis is used to separate DNA fragments based on their size. Which direction do DNA fragments move during electrophoresis, and why?

Accepted Answer

DNA fragments move toward the positive electrode because DNA is negatively charged.

Question 4

In the context of STR analysis, what does it mean if a suspect is homozygous at a particular STR site?

Accepted Answer

The suspect has the same number of repeats on both chromosomes at that site.

Question 5

A man was exonerated after 17 years in prison when STR analysis showed that DNA from the crime scene did not match his profile. Which principle of genetics does this scenario best illustrate?

Accepted Answer

The uniqueness of individual DNA profiles due to independent assortment and recombination

Question 6

Which of the following is NOT a reason why innocent suspects sometimes plead guilty, according to the study materials?

Accepted Answer

Reliable DNA evidence

Question 7

During the cell cycle, healthy cells only enter mitosis if duplication is needed. Which checkpoint ensures that DNA is properly replicated before mitosis?

Accepted Answer

G2 checkpoint

Question 8

What might lead to uncontrolled cell division, as seen in cancer?

Accepted Answer

Loss of cell cycle control due to mutations in regulatory genes

Question 9

Which of the following best describes the process of signal transduction in cell-cell communication?

Accepted Answer

A molecule exits one cell and binds to a receptor protein on the surface of another cell, triggering a cascade of events inside the receiving cell.

Question 10

A transcription factor (TF) is involved in gene regulation. Which statement is correct regarding TFs?

Accepted Answer

TFs bind to specific DNA sequences and play a role in transcribing DNA to RNA.

Question 11

If a pea plant has the genotype $$Pp$$ for flower color, where $$P is $$dominant (purple) and $$p is $$recessive (white), what will be the phenotype?

Accepted Answer

Purple flowers

Question 12

A carrier for a recessive genetic disorder is heterozygous. What is the genotype of a carrier?

Accepted Answer

$$Aa$$

Question 13

Sexual reproduction leads to genetic variation through three main mechanisms. Which mechanism involves the exchange of genetic material between homologous chromosomes?

Accepted Answer

Cross-over

Question 14

Which inheritance pattern is described when one gene influences several characters?

Accepted Answer

Pleiotropy

Question 15

In polygenic inheritance, which of the following is true?

Accepted Answer

Multiple genes influence a single character.

Question 16

In incomplete dominance, what is the phenotype of a heterozygous individual ($$Rr) if$$ $$RR is $$red and $$rr is $$white?

Accepted Answer

Pink (intermediate trait)

Question 17

A pedigree is used to track genetic traits in a family. Which of the following is NOT a purpose of a pedigree?

Accepted Answer

Determining the DNA sequence of an individual

Question 18

If a cell receives a signal molecule that activates a transcription factor, what is the likely outcome?

Accepted Answer

A specific gene will be transcribed to RNA, leading to new protein synthesis.

Question 19

Which of the following best describes the effect of crossing over during meiosis?

Accepted Answer

It produces recombinant chromosomes containing parts of both original chromosomes.

Question 20

A Punnett square is used to predict the genotype and phenotype of offspring. If two heterozygous parents ($$Aa) $$are crossed, what is the expected ratio of phenotypes for a recessive trait?

Accepted Answer

1 normal : 2 carrier : 1 trait

Genetics, DNA Profiling, and Cell Cycle: Core Concepts for College Biology

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