Question 1

Janae and Sean are siblings who come from a family with a history of anxiety.Janae is somewhat anxious but generally takes things in stride.Sean,however,is always concerned about his health,his job,and his family even when there is no reason.Which of the following concepts best explains the difference between Janae and Sean?

Accepted Answer

Multifactorial inheritance suggests that traits such as anxiety are influenced by both genetic and environmental factors. Therefore, Janae and Sean may have inherited the genetic predisposition for anxiety, but Janae is better able to handle it due to other environmental factors, whereas Sean is not. This explains the difference in their levels of anxiety. The other choices, epilogical genetics, dominant and recessive traits, and mitochondrial inheritance, are not relevant in this scenario.

Question 2

Which of the following is associated with the second trimester of pregnancy?

Accepted Answer

Movements of the fetus are typically felt by the mother during the second trimester, around 16-20 weeks.

Additional information:
- A: Formation of a mucus "plug" typically occurs in the first trimester and is a protective barrier for the fetus.
- B: Implantation of the zygote on the uterine wall occurs in the first trimester.
- D: Nausea is often associated with the first trimester and may subside during the second trimester.

Question 3

What is the prognosis for children born with trisomy 13 or 18?

Accepted Answer

Trisomy 13 and 18 are both associated with severe developmental and physical abnormalities. Due to these complications, most children born with these chromosomal disorders do not survive past infancy.

Question 4

The genes that cause sex-linked disorders are found on the

Accepted Answer

Sex-linked disorders are caused by genes found on the sex chromosomes, specifically the X chromosome. The Y chromosome carries very few genes that are not involved in determining male sex characteristics. Therefore, the genes responsible for sex-linked disorders are usually located on the X chromosome.

Question 5

What percent of congenital disorders result from harmful genes or faulty chromosomes?

Accepted Answer

Approximately 30% of congenital disorders are due to genetic factors, including harmful genes or faulty chromosomes.

Question 6

Most sex-linked disorders are caused by which of the following?

Accepted Answer

Most sex-linked disorders are caused by recessive genes located on the X chromosome. This is because males have only one X chromosome, making them more susceptible to inheriting a disorder if it is present on that chromosome. Females, on the other hand, have two X chromosomes, which allows for some compensation if a disorder is present on one of them.

Question 7

Which of the following terms describes physical traits that are influenced by both genes and the environment?

Accepted Answer

Multifactorial traits are influenced by both genetic and environmental factors. Examples include height, weight, and susceptibility to certain diseases. Polygenetic traits are influenced by multiple genes, but not necessarily the environment. Dominant-recessive traits are determined by the specific alleles present in an individual's genotype. Epifactorial is not a commonly used term in genetics.

Question 8

Which of the following individuals has the greatest risk for bearing a child with trisomy 21?

Accepted Answer

Advanced maternal age (over 35 years) increases the risk of trisomy 21. Mrs. Black, who is 45 years old, has the highest risk among the options given.

Question 9

Which of the following is a condition that can cause a baby to grow too rapidly and result in premature labor or an infant that is too large for a vaginal birth?

Accepted Answer

Gestational diabetes can cause a baby to receive too much glucose from the mother, leading to excessive growth and potentially causing premature labor or difficulty with vaginal delivery. Ectopic pregnancy, hypothyroidism, and high blood pressure do not typically result in excessive fetal growth.

Question 10

Which of the following is an autosomal dominant disorder?

Accepted Answer

Huntington's disease is an autosomal dominant disorder, meaning a person only needs to inherit one copy of the mutated gene from either parent to develop the disease. Phenylketonuria, sickle-cell disease, and Tay-Sachs disease are all autosomal recessive disorders, meaning a person must inherit two copies of the mutated gene (one from each parent) to develop the disease.

Question 11

Which of the following happens during the first trimester of pregnancy?

Accepted Answer

The zygote implants itself in the lining of the uterus during the first trimester of pregnancy. Chemical messages are sent to the brain to stop, not start, menstruation when a woman becomes pregnant. A woman can still detect pregnancy using a urine test during the first trimester. The cervix thins and stretches during the last trimester of pregnancy, not the first.

Question 12

What is a trisomy?

Accepted Answer

Trisomy refers to the presence of three copies of a specific autosome (non-sex chromosome) instead of the usual two copies. This can occur due to errors in cell division during meiosis, resulting in the inheritance of an extra chromosome. Examples include Down syndrome (trisomy 21) and Patau syndrome (trisomy 13). Fragile-X syndrome and sex-linked syndromes do not necessarily involve trisomies, and a third pair of chromosomes would not be a relevant answer because humans only have 23 pairs of chromosomes (46 total).

Question 13

Phenylketonuria is an example of which of the following?

Accepted Answer

Phenylketonuria is an autosomal disorder caused by a mutation in the PAH gene located on chromosome 12. It is inherited in an autosomal recessive pattern, meaning that an affected individual must inherit two copies of the mutated gene (one from each parent) to develop the disorder.

Question 14

Which of the following is caused by a gene on the X chromosome?

Accepted Answer

Color blindness is caused by a gene on the X chromosome. The gene is recessive and more common in males because they only have one X chromosome. Females can also inherit color blindness if they inherit the recessive gene from both parents. Tay-Sachs disease is caused by a gene on chromosome 15, PKU is caused by a gene on chromosome 12, and sickle-cell disease is caused by a gene on chromosome 11.

Question 15

Which of the following is typical for individuals who have sex chromosome anomalies?

Accepted Answer

Individuals with sex chromosome anomalies often experience learning difficulties due to the impact of these anomalies on cognitive development.

Question 16

Which of the following is the most common sex-chromosome anomaly?

Accepted Answer

Klinefelter's syndrome is the most common sex-chromosome anomaly, affecting males with an extra X chromosome (XXY).

Question 17

Not long after Gloria found out she was pregnant,she began having pain.When she went to her doctor,she was told that the zygote had implanted in her fallopian tube rather than in her uterus.What type of pregnancy is this?

Accepted Answer

This is an ectopic pregnancy, where the fertilized egg implants outside the uterus, most commonly in the fallopian tube. It is a potentially dangerous condition that requires prompt medical intervention. Choices A, B, and D are not accurate descriptions of this type of pregnancy.

Question 18

Which of these genetic disorders usually does not express symptoms until adulthood?

Accepted Answer

Huntington's disease usually does not express symptoms until adulthood.

Question 19

Reese is anatomically female,but did not develop breasts or menstruate at puberty and needed hormone therapy.With which of the following was Reese most likely born?

Accepted Answer

Turner's syndrome is a genetic disorder that affects females who are missing or partially missing an X chromosome. This can lead to a range of physical and developmental differences, including a lack of breast development and delayed or absent menstruation, as well as requiring hormone therapy to promote physical development. Klinefelter's syndrome and an extra Y chromosome typically involve male development, while Down's syndrome involves chromosomal abnormalities unrelated to sexual development.

Question 20

Samson is taller and has a higher IQ than either of his parents.Which of the following terms would be used to explain this?

Accepted Answer

Multifactorial inheritance refers to traits that are influenced by multiple genes and environmental factors, which can explain why Samson might be taller and have a higher IQ than his parents.

Quiz 3: Prenatal Development and Birth