Question 1

Jason was born with _____.The doctor tells his parents that this genetic disorder occurred because he has an extra copy of chromosome 21.

Accepted Answer

Down syndrome is caused by an extra copy of chromosome 21, which results in developmental delays, characteristic facial features, and potential health complications. Fragile X syndrome is caused by a mutation on the X chromosome and can cause intellectual disabilities, while Klinefelter disease is caused by an extra X chromosome and can lead to infertility and other physical differences in males. Tay-Sachs disease is a rare genetic disorder caused by a deficiency in an enzyme that leads to the accumulation of fatty substances in the brain, resulting in severe neurological damage.

Question 2

In some cases,one gene of a pair always exerts its effects,overriding the potential influence of the other gene.This is the _____ principle.

Accepted Answer

The dominant-recessive genes principle refers to the fact that when one gene in a pair is dominant, it will always exert its effect over the recessive gene, which will not influence the phenotype unless paired with another recessive gene. This principle explains how traits are inherited in a Mendelian fashion. Sex-linked genes refer to genes located on one of the sex chromosomes, genetic imprinting refers to the differential expression of genes depending on whether they were inherited from the mother or the father, and polygenic inheritance involves the influence of multiple genes on a single trait.

Question 3

Which of the following is TRUE of Down syndrome?

Accepted Answer

The answer of Which of the following is TRUE of...

Question 4

_____ genes arethose that make the individual less vulnerable to certain diseases and more likely to live to an older age.

Accepted Answer

Longevity genes are the ones that make an individual less vulnerable to certain diseases and more likely to live longer.

Question 5

Carrie's parents both have brown hair.However,Carrie gets genes for blonde hair from both parents,and as a result she has blonde hair.This indicates that the gene for blonde hair is a:

Accepted Answer

If both parents have brown hair, they most likely carry the dominant gene for brown hair. For Carrie to have blonde hair, she would need to receive two copies of the recessive gene for blonde hair, one from each parent. This suggests that the gene for blonde hair is recessive in this case.

Question 6

Which of the following women has the highest probability of giving birth to a child with Down syndrome?

Accepted Answer

The probability of having a child with Down syndrome increases as the woman's age increases. Jane, at 41 years old, has a higher probability than the other women listed.

Question 7

A mistake by the cellular machinery,or damage from an environmental agent such as radiation,may produce a _____,which is a permanently altered segment of DNA.

Accepted Answer

A mutated gene is a permanently altered segment of DNA that may result from a mistake by the cellular machinery or damage from an environmental agent such as radiation. Susceptibility, vulnerability, and longevity genes do not necessarily refer to altered DNA sequences.

Question 8

Erin is 90 years old.She has relatively good health and is fully mobile.Most of Erin's blood relatives lived to a ripe,old age.Which of the following genes might be responsible for this?

Accepted Answer

Longevity genes are responsible for an individual's ability to live a long, healthy life. Erin's relatively good health and family history of long life suggest that she may have inherited longevity genes. Susceptibility genes are associated with an increased risk of developing certain health conditions, vulnerability genes make individuals susceptible to certain diseases or conditions, and mutated genes are genes with errors in their DNA sequence.

Question 9

Mary's mother has blonde hair and her father has brown hair.Mary has a gene for brown hair and a gene for blonde hair.She has brown hair.This indicates that the gene for brown hair is a:

Accepted Answer

If Mary has brown hair, it means she has inherited a dominant gene for brown hair from one of her parents. The fact that her mother has blonde hair indicates that blonde hair is a recessive gene, as it was not expressed in Mary's phenotype. Therefore, the gene for brown hair must be dominant.

Question 10

Marly describes her friend,Gina,as having blonde hair,green eyes,and fair skin with freckles.Marly has described Gina's:

Accepted Answer

Marly has described Gina's observable physical traits, which is her phenotype. The other options do not fit the given scenario.

Question 11

According to your text,gene-gene interactions have been documented in all of the following EXCEPT:

Accepted Answer

Social referencing is not a condition or trait that is influenced by gene-gene interactions. Alcoholism, asthma, and arthritis have all been reported to have gene-gene interactions.

Question 12

Clark's genotype contains a dominant gene for brown eye color and a recessive gene for blue eye color.According to the dominant-recessive gene principle,which of the following phenotypes is most likely to be observed in Clark?

Accepted Answer

Since Clark has a dominant gene for brown eyes, and brown eyes are the dominant trait, it is most likely that he will display the phenotype of brown eyes.

Question 13

A recessive gene exerts its influence only if:

Accepted Answer

A recessive gene is only expressed if both genes in a pair are recessive. Dominant genes will always mask recessive genes if present in a pair. The strength of a gene is not relevant to whether it is dominant or recessive. Environmental factors may have an impact on gene expression but do not determine whether a gene is dominant or recessive.

Question 14

When a mutated gene is carried on the X chromosome,the result is called:

Accepted Answer

When a mutated gene is carried on the X chromosome, the inheritance pattern is called X-linked inheritance. This is because the X chromosome is one of the two sex chromosomes and is present in both males and females, although in different numbers. As a result, X-linked disorders tend to affect males more frequently than females, since males only have one X chromosome while females have two. Examples of X-linked disorders include hemophilia, color blindness, and Duchenne muscular dystrophy.

Question 15

_____ is the way an individual's genotype is expressed in observable and measurable characteristics.

Accepted Answer

Phenotype is the physical expression of an individual's genotype, which includes observable and measurable characteristics such as height, eye color, and facial features. RNA and DNA are molecular components of genetic information, while stereotype is a preconceived notion about a group of people.

Question 16

Which of the following is an example of chromosomal abnormality that occurs when whole chromosomes do not separate properly during meiosis?

Accepted Answer

Down syndrome is caused by an extra copy of chromosome 21, which typically results from nondisjunction during meiosis. In this type of chromosomal abnormality, whole chromosomes do not separate properly during meiosis, resulting in the production of gametes with either an extra or missing chromosome.

Question 17

Who is MOST likely to develop an X-linked disease?

Accepted Answer

X-linked diseases are caused by mutations on the X chromosome. Since males only have one X chromosome, they are more likely to develop X-linked diseases compared to females who have two X chromosomes.

Question 18

Emma and Anna are identical twins who were adopted by different families a few weeks after birth.Although genetically identical,they grew up with different physical and psychological characteristics.For example,though both inherited a tendency to grow large,Anna was slim and athletic due to the active lifestyle practiced in her adoptive family.This variability can be explained by how:

Accepted Answer

For each genotype, a range of phenotypes can be expressed. This means that even if two individuals have the same genetic makeup, their environment and experiences can lead to different physical and psychological traits being expressed. In the case of the twins, although they were genetically identical, their different adoptive families and environments led to differences in their physical characteristics.

Question 19

Ethel is 50 years old but appears much more aged in appearance.Most of Ethel's relatives don't live past the age of 60.Which of the following genes are responsible for the accelerated aging that is observed in Ethel and her family members?

Accepted Answer

The answer of Ethel is 50 years old but appears...

Question 20

_____ genes are those that make the individual more vulnerable to specific diseases or acceleration of aging.

Accepted Answer

Susceptibility genes are associated with increased vulnerability to certain diseases or disorders, as well as faster aging processes. They may be inherited or acquired through environmental factors. Longevity genes, on the other hand, are associated with extended lifespan and healthy aging, while mutated genes can have various effects depending on the specific mutation. Therefore, the best choice for this question is A) Susceptibility genes.

Quiz 2: Biological Beginnings