Question 1

Down syndrome

Accepted Answer

The risk of Down syndrome increases with the mother's age, specifically after age 35.

Answer: D
 Individuals with Down syndrome typically have normal organ and bone development but are mentally impaired to varying degrees.

Answer: E
 Down syndrome is caused by an extra copy of chromosome 21, also known as trisomy 21. It is not related to a monosomy (missing one chromosome) as stated in option E.

Question 2

The process by which chromosomes fail to separate during meiosis is called

Accepted Answer

Nondisjunction is the process during which chromosomes fail to separate during meiosis. This can result in gametes with abnormal chromosome numbers, such as trisomy (an extra chromosome) or monosomy (a missing chromosome), both of which are types of aneuploidy. Polyploidy is a separate phenomenon where an organism has more than two complete sets of chromosomes.

Question 3

If a single nondisjunction occurs during anaphase II of meiosis in a normal male cell from meiosis I, of the resulting sperm,

Accepted Answer

The answer of If a single nondisjunction occurs during anaphase...

Question 4

In Duchenne muscular dystrophy, which protein is directly affected?

Accepted Answer

Duchenne muscular dystrophy is caused by a mutation in the gene encoding dystrophin, a protein that helps strengthen and protect muscle fibers during contraction. The absence or deficiency of dystrophin leads to progressive muscle weakness and loss of function. Myosin and actin are contractile proteins involved in muscle contraction, but they are not directly affected in Duchenne muscular dystrophy. Myoglobin and hemoglobin are oxygen-binding proteins found in muscle and red blood cells, respectively, and are also not directly affected in Duchenne muscular dystrophy.

Question 5

Selecting the Exception Four of the five answers listed below are related conditions in which abnormal numbers of chromosomes are present. Select the EXCEPTION.

Accepted Answer

Diploidy is the normal condition in which a cell has two sets of chromosomes, one set inherited from each parent. Monosomy, aneuploidy, polyploidy, and trisomy are all conditions in which abnormal numbers of chromosomes are present.

Question 6

Down syndrome is a trisomy that involves chromosome number

Accepted Answer

Down syndrome is caused by an extra copy of chromosome 21, resulting in three copies of that chromosome instead of the usual two.

Question 7

Females are less likely to have an X-linked recessive disorder than males because

Accepted Answer

Females have two X chromosomes, so if one X chromosome carries a recessive mutation, the other X chromosome may compensate for it. In males, however, only one X chromosome is present and if it carries a recessive mutation, it will be expressed.

Question 8

If a normal egg is fertilized by a sperm which has an extra chromosome, what will be the chromosomal condition of the zygote?

Accepted Answer

If a normal egg is fertilized by a sperm with an extra chromosome, the resulting zygote will have three copies of the affected chromosome and two copies of all the other chromosomes. This condition is known as trisomy and can result in genetic disorders such as Down syndrome.

Question 9

If a 1n egg is fertilized by a n-l sperm, the resulting zygote will have

Accepted Answer

The answer of If a 1n egg is fertilized by...

Question 10

Turner syndrome is a

Accepted Answer

Turner syndrome is a genetic condition in which a female is missing all or part of one of their X chromosomes, resulting in a monosomy.

Question 11

George is a normal XY boy. Who among the following would essentially have the same Y chromosome as George?

Accepted Answer

The answer of George is a normal XY boy. Who...

Question 12

When is preimplantation diagnosis performed?

Accepted Answer

The answer of When is preimplantation diagnosis performed?
...

Question 13

What percent of plants are polyploids?

Accepted Answer

It is estimated that around 70% of all plant species are polyploids. This is due to the fact that polyploidization can lead to increased genetic variation and adaptation in plants, allowing them to survive and thrive under different environmental conditions. Polyploidy is also a common mechanism of speciation in plants, leading to the evolution of new species.

Question 14

Tanya's son Micah has hemophilia A. Who else in Micah's family definitely has hemophilia A?

Accepted Answer

Hemophilia A is a genetic disorder that is carried on the X chromosome. Since males only have one X chromosome, if they inherit the gene for hemophilia A, they will have the disorder. In this case, it is not possible to determine if Tanya carries the gene because women have two X chromosomes and can be carriers without showing symptoms. However, if Tanya's father (Micah's grandfather) has hemophilia A, he must pass the affected X chromosome to Tanya, who then passes it on to Micah. Therefore, Micah's mother's father (Tanya's father) must have hemophilia A in order for Micah to have the disorder.

Question 15

Selecting the Exception Four of the five answers listed below describe gene make up. Select the EXCEPTION.

Accepted Answer

Phenotype is the observable characteristics of an organism, while genotype, homozygous, heterozygous, and carrier all describe the genetic makeup of an organism.

Question 16

Amniocentesis is

Accepted Answer

Amniocentesis is a prenatal diagnostic procedure that involves the removal of a small amount of amniotic fluid from the sac surrounding the developing fetus. The sampled fluid contains fetal cells that can be used for genetic testing to detect chromosomal mutations and genetic disorders in embryos. It is not a surgical means of repairing deformities, a form of chemotherapy, gene replacement therapy, or all of these.

Question 17

Which of the following prenatal tests can be performed earliest in a pregnancy?

Accepted Answer

The answer of Which of the following prenatal tests can...

Question 18

Ella is a normal XX girl who is red-green colorblind. She is pregnant and the father is Terrick who has normal color vision. What is the probability that - if they have a daughter - the daughter will be red-green colorblind?

Accepted Answer

The answer of Ella is a normal XX girl who...

Question 19

Which of the following chromosomal conditions is treated with testosterone injections?

Accepted Answer

XXY is a condition known as Klinefelter syndrome, which results in low testosterone levels. Testosterone injections can be given as a treatment to increase testosterone levels and alleviate symptoms such as decreased fertility, low energy, and decreased muscle mass. The other conditions listed do not typically require testosterone injections as a treatment.

Question 20

Amniocentesis involves sampling

Accepted Answer

Amniocentesis involves sampling of fetal cells in the amniotic fluid. This is usually done around 16-20 weeks of pregnancy and can be used to diagnose genetic disorders or other fetal abnormalities.

Quiz 9: Patterns of Inheritance