Question 1

Dizygotic (DZ) twins run in families.

Accepted Answer

Dizygotic twins, also known as fraternal twins, can run in families because they result from two separate eggs being fertilized by two separate sperm. Factors such as genetics and maternal age can increase the likelihood of having DZ twins.

Question 2

Sebaceous glands cause a developing organism to grow arms or wings, skin or scales.

Accepted Answer

Sebaceous glands are responsible for producing and secreting sebum, an oily substance that helps moisturize and protect the skin and hair follicles. They do not have any role in determining the development of limbs or skin features like wings or scales. These traits are determined by genetic and environmental factors during embryonic development.

Question 3

Amniocentesis is a procedure used in abortion.

Accepted Answer

Amniocentesis is a prenatal test used to diagnose genetic abnormalities and other conditions in the fetus. It involves taking a sample of the amniotic fluid surrounding the fetus and analyzing the DNA. Amniocentesis is not a procedure used in abortion, although it may be recommended in some cases where there are concerns about the health of the fetus.

Question 4

Children suffering from Huntington's disease (HD) can be placed on a diet that is low in phenylalanine within three to six weeks of birth. Following this diet helps them achieve normal development.

Accepted Answer

Huntington's disease is not related to phenylalanine levels; it is a genetic disorder caused by a mutation in the HTT gene. The diet mentioned is for phenylketonuria (PKU), a different condition.

Question 5

When children who are reared by adoptive parents are similar to their natural parents in a trait, a powerful argument is made for a genetic role in the appearance of that trait.

Accepted Answer

This suggests that the trait is inherited genetically, as the child shares it with biological parents despite being raised in a different environment.

Question 6

The probability of having a child with Down's syndrome increases with the age of the parents.

Accepted Answer

This is true. The risk of having a child with Down's syndrome increases with the age of both the mother and the father, but the risk is higher for mothers who are 35 years or older at the time of their child's birth.

Question 7

In amniocentesis, the health professional uses a syringe to suck out some threadlike projections called villi from the outer membrane that envelops the amniotic sac and fetus.

Accepted Answer

Amniocentesis involves extracting amniotic fluid from the amniotic sac, not villi. The procedure that involves sampling villi is called chorionic villus sampling (CVS).

Question 8

Individuals with Klinefelter syndrome produce:

Accepted Answer

Individuals with Klinefelter syndrome have an extra X chromosome, resulting in XXY genotype. This can lead to reduced levels of testosterone production, leading to symptoms such as reduced facial and body hair, decreased muscle mass, and infertility. They do not produce less estrogen or adenine/thymine than normal males.

Question 9

Ultrasound is used to guide the syringe in amniocentesis and chorionic villus sampling (CVS) by determining the position of the fetus.

Accepted Answer

Ultrasound imaging is used during amniocentesis and CVS to accurately locate the fetus and placenta, ensuring the safe insertion of the needle.

Question 10

Amniocentesis was once routinely recommended for women who become pregnant past the age of 40.

Accepted Answer

Amniocentesis was commonly recommended for older pregnant women due to the increased risk of chromosomal abnormalities like Down syndrome, which are more prevalent with advanced maternal age.

Question 11

Meiosis is responsible for the production of sperm and ova.

Accepted Answer

Meiosis is a type of cell division that produces haploid cells with half the number of chromosomes as the parent cell. In humans, meiosis is responsible for the production of sperm and ova (eggs), which are used in sexual reproduction to create genetically diverse offspring.

Question 12

Color blindness is a sex-linked abnormality.

Accepted Answer

Color blindness is caused by a recessive gene located on the X chromosome. Since males have only one X chromosome, they are more likely to inherit the gene and develop color blindness. Females, on the other hand, have two X chromosomes, so they would need to inherit two copies of the gene (one from each parent) to be color blind. Therefore, color blindness is more common among males than females and is considered a sex-linked abnormality.

Question 13

Most victims of _____ die of respiratory infections in their 20s.

Accepted Answer

Cystic fibrosis is a genetic disorder that mainly affects the lungs and digestive system. Most people with cystic fibrosis die of respiratory infections, typically in their 20s. Tay-Sachs disease is a rare genetic disorder that affects the nervous system and is typically fatal in early childhood. Turner and Klinefelter syndromes are genetic disorders that affect sexual development and do not typically result in early death.

Question 14

Twenty-year-old Jack is extremely tall and has very thick facial hair. Most of his male secondary sex characteristics are also more pronounced than men of his age. In this scenario, Jack is most likely:

Accepted Answer

Jack's symptoms suggest he is an XYY male, a condition associated with an extra Y chromosome, which can lead to taller stature and more pronounced male secondary sex characteristics.

Question 15

Monozygotic (MZ) twins are known as fraternal twins.

Accepted Answer

Monozygotic (MZ) twins are known as identical twins, not fraternal twins. Fraternal twins are dizygotic (DZ) twins.

Question 16

Adoption studies in which children are separated from their natural parents at an early age and reared by adoptive parents provide special opportunities for sorting out nature and nurture.

Accepted Answer

Adoption studies help researchers understand the influence of genetics (nature) and environment (nurture) by comparing adopted children to their biological and adoptive parents.

Question 17

Children that suffer from phenylketonuria (PKU) can be cured by placing them on diets high in the enzyme phenylalanine.

Accepted Answer

Phenylketonuria (PKU) is managed by a diet low in phenylalanine, not high, to prevent harmful buildup in the body.

Question 18

Typical human cells contain 50 chromosomes organized into 25 pairs.

Accepted Answer

Typical human cells contain 46 chromosomes organized into 23 pairs.

Question 19

Neural tube defects cause an elevation in the alpha-fetoprotein (AFP) level in the mother's blood.

Accepted Answer

Neural tube defects, such as spina bifida and anencephaly, can cause an elevation in the alpha-fetoprotein (AFP) level in the mother's blood. AFP is a protein produced by the fetus that can pass into the mother's blood. Abnormally high levels of AFP can indicate a neural tube defect or other fetal abnormality.

Question 20

Chorionic villus sampling (CVS) is similar to amniocentesis but is carried out between the 14th and 16th week of pregnancy.

Accepted Answer

Chorionic villus sampling (CVS) is typically performed earlier, between the 10th and 13th weeks of pregnancy, not between the 14th and 16th weeks like amniocentesis.

Quiz 2: Heredity