Question 1

The first 22 chromosomes contain hundreds of genes in the same positions and sequence.If the code of the gene from one parent is exactly like the code on the same gene from the other parent,the gene pair is:
A) homozygous.
B) heterozygous.
C) monozygotic.
D) dizygotic.

Accepted Answer

Homozygous means having the same alleles (versions of a gene) for a particular gene. If the code of the gene from one parent is exactly like the code on the same gene from the other parent, this means that the individual has two identical alleles for that gene, making them homozygous. Heterozygous individuals have two different alleles for a particular gene. Monozygotic and dizygotic refer to twins, and are not applicable to individual genes.

Question 2

Couples can select the sex of a child by all the following methods EXCEPT:
A) inactivating X or Y sperm before conception.
B) selecting only X eggs for fertilization.
C) aborting XX or XY fetuses.
D) undergoing in vitro fertilization and then inserting only male or female zygotes.

Accepted Answer

Selecting only X eggs for fertilization is not a method used to select the sex of a child. The sex of a child is determined by the sperm (X or Y chromosome) that fertilizes the egg, not by selecting the egg itself, as all human eggs carry an X chromosome.

Question 3

Individual A's 23rd pair of chromosomes is XY.Individual A is:
A) male.
B) female.
C) neither male nor female.
D) both male and female.

Accepted Answer

Individuals with XY chromosomes are biologically male.

Question 4

On the 23rd pair of chromosomes,females have:
A) two X chromosomes.
B) two Y chromosomes.
C) an X chromosome and a Y chromosome.
D) just a Y chromosome.

Accepted Answer

Females have two X chromosomes on their 23rd pair of chromosomes, while males have one X and one Y chromosome on their 23rd pair.

Question 5

Identical twins are also called _____ twins.
A) monozygotic
B) dizygotic
C) zygotic
D) gamete

Accepted Answer

Identical twins are formed from a single fertilized egg that splits into two embryos, resulting in each twin having the exact same genetic material. This process is called monozygotic twinning.

Question 6

Fraternal twins are also called _____ twins.
A) monozygotic
B) dizygotic
C) zygotic
D) gamete

Accepted Answer

Fraternal twins are also known as dizygotic twins which means they are formed from two different sperm and egg cells. Monozygotic twins, on the other hand, come from a single fertilized egg which splits into two embryos, making them genetically identical. Zygotic and gamete are not terms typically used to describe twins.

Question 7

In China,a "one-child" policy cut the birth rate in half.Although the intended goal of reducing poverty was achieved,several unintended consequences were identified.All the following were unintended consequences EXCEPT for:
A) there being far more unmarried men in China than women.
B) millions of newborn girls being placed up for adoption.
C) males living longer than females.
D) increased abortions of female fetuses.

Accepted Answer

The one-child policy did not cause males to live longer than females. The unintended consequences were the sex imbalance with more unmarried men than women, increased abortions of female fetuses due to the cultural preference for male heirs, and millions of newborn girls being placed up for adoption or abandoned.

Question 8

The instructions for making amino acids are on about 3 billion pairs of chemicals called "_____ pairs."
A) couple
B) foundation
C) base
D) copy

Accepted Answer

The instructions for making amino acids are encoded in DNA, which is made up of chemical building blocks called nucleotides. Each nucleotide consists of a sugar, a phosphate group, and a nitrogenous base. There are four types of nitrogenous bases in DNA: adenine, thymine, guanine, and cytosine. These bases pair up with each other (adenine with thymine and guanine with cytosine) and form the rungs of the DNA ladder. Therefore, the instructions for making amino acids are on about 3 billion pairs of nitrogenous bases or "base pairs."

Question 9

James and Jacob are identical twins.They are the result of:
A) one ovum fertilized by one sperm that split into two zygotes.
B) two separate ova that were fertilized by two different sperm.
C) one ovum that was fertilized by two sperm.
D) two ova that were fertilized by one sperm.

Accepted Answer

Identical twins result from one ovum being fertilized by one sperm that splits into two separate zygotes. This is also known as monozygotic twinning.

Question 10

Stacey is in need of an an organ donation.Which organ donor would be the BEST match for Stacey?
A) her grandparent
B) her younger sibling
C) James,her dizygotic twin
D) Samantha,her monozygotic twin

Accepted Answer

Since Samantha is Stacey's monozygotic twin, they have identical DNA and therefore identical HLA (human leukocyte antigen) markers. HLA markers are used to match organ donors and recipients, and having identical HLA markers greatly increases the chances of a successful organ transplant. Therefore, Samantha would be the best match for Stacey.

Question 11

On the 23rd pair of chromosomes,males have:
A) two X chromosomes.
B) two Y chromosomes.
C) an X chromosome and a Y chromosome.
D) just a Y chromosome.

Accepted Answer

The 23rd pair of chromosomes is the sex chromosomes. Males have one X chromosome and one Y chromosome, while females have two X chromosomes. Therefore, option C is the correct choice.

Question 12

Individual A's 23rd pair of chromosomes is XX.Individual A is:
A) male.
B) female.
C) neither male nor female.
D) both male and female.

Accepted Answer

XX chromosomes represent the female sex chromosomes. Therefore, individual A is female.

Question 13

An individual's entire genetic inheritance is called a(n):
A) phenotype.
B) allele.
C) genotype.
D) gamete.

Accepted Answer

An individual's entire genetic inheritance is called genotype. Phenotype refers to an individual's observable physical and behavioral traits, allele refers to one of the possible forms of a gene, and gamete refers to specialized cells that combine during fertilization to form a zygote.

Question 14

Jennifer and Jerry are dizygotic twins.They are the result of:
A) one ovum fertilized by one sperm that split into two zygotes.
B) two separate ova that were fertilized by two different sperm.
C) one ovum that was fertilized by two sperm.
D) two ova that were fertilized by one sperm.

Accepted Answer

Dizygotic (fraternal) twins result from two separate ova being fertilized by two different sperm. This is the most common type of twinning, accounting for approximately two-thirds of all twin births.

Question 15

The first 22 chromosomes contain hundreds of genes in the same positions and sequence.If the code of the gene from one parent differs from the code on the same gene from the other parent,the gene pair is:
A) homozygous.
B) heterozygous.
C) monozygotic.
D) dizygotic.

Accepted Answer

If the code of the gene from one parent differs from the code on the same gene from the other parent, it means the gene pair is heterozygous. Homozygous refers to two identical copies of the same gene, while monozygotic and dizygotic refer to twins and are not relevant to gene pairs.

Question 16

Brad learned in his college biology class that,with respect to the sex chromosomes,the:
A) Y chromosome is larger than the X chromosome and has more genes.
B) X chromosome is larger than the Y chromosome and has more genes.
C) X and Y chromosomes are the same size,but the X chromosome has more genes.
D) X and Y chromosomes are the same size and have the same number of genes.

Accepted Answer

The X chromosome is larger than the Y chromosome and has more genes. The Y chromosome is smaller and contains fewer genes, some of which are important for male development and fertility.

Question 17

Males have one X and one Y on:
A) each sperm.
B) on the 43rd chromosome.
C) the 23rd pair of chromosomes.
D) each stem cell.

Accepted Answer

The sex chromosomes, including the X and Y chromosomes, are located on the 23rd pair of chromosomes, also known as the sex chromosomes pair. Males inherit one X chromosome from their mother and one Y chromosome from their father, giving them a total of one X and one Y chromosome in each of their cells.

Question 18

In 22 of the 23 pairs of chromosomes,both members of the pair are closely matched.Each of these 44 chromosomes is called a(n):
A) allele.
B) gamete.
C) autosome.
D) blastocyst.

Accepted Answer

Autosomes are the 44 chromosomes in a human cell that are not involved in sex determination. They come in pairs, with each member of the pair closely matched. Therefore, option C is the best choice.

Question 19

Melissa and Brandon are having a baby and are hoping for a boy.The baby's sex will be decided by the chromosomes of:
A) Melissa.
B) Brandon.
C) both Melissa and Brandon.
D) neither Melissa nor Brandon.

Accepted Answer

The sex of a baby is determined by the chromosomes contributed by the father, Brandon, in this case. Women carry two X chromosomes (XX), while men carry one X and one Y chromosome (XY). The mother always contributes an X chromosome, while the father can contribute either an X or a Y chromosome. If the father contributes a Y chromosome, the baby will be male (XY).

Question 20

Which of the following women is MOST likely to have dizygotic twins?
A) Pallavi,who is Korean
B) Oluchi,who is Nigerian
C) Mei,who is Chinese
D) Marissa,who is American

Accepted Answer

Research has shown that African women, specifically those of Nigerian descent, have the highest incidence of dizygotic twinning. This may be due to genetic factors as well as environmental and dietary factors.

Quiz 2: The Beginning: From Conception to Birth

The first 22 chromosomes contain hundreds of genes in the same positions and sequence.If the code of the gene from one parent is exactly like the code on the same gene from the other parent,the gene pair is:

Couples can select the sex of a child by all the following methods EXCEPT:

Individual A's 23rd pair of chromosomes is XY.Individual A is:

On the 23rd pair of chromosomes,females have:

Identical twins are also called _____ twins.

Fraternal twins are also called _____ twins.

In China,a "one-child" policy cut the birth rate in half.Although the intended goal of reducing poverty was achieved,several unintended consequences were identified.All the following were unintended consequences EXCEPT for:

The instructions for making amino acids are on about 3 billion pairs of chemicals called "_____ pairs."

James and Jacob are identical twins.They are the result of:

Stacey is in need of an an organ donation.Which organ donor would be the BEST match for Stacey?

On the 23rd pair of chromosomes,males have:

Individual A's 23rd pair of chromosomes is XX.Individual A is:

An individual's entire genetic inheritance is called a(n) :

Jennifer and Jerry are dizygotic twins.They are the result of:

The first 22 chromosomes contain hundreds of genes in the same positions and sequence.If the code of the gene from one parent differs from the code on the same gene from the other parent,the gene pair is:

Brad learned in his college biology class that,with respect to the sex chromosomes,the:

Males have one X and one Y on:

In 22 of the 23 pairs of chromosomes,both members of the pair are closely matched.Each of these 44 chromosomes is called a(n) :

Melissa and Brandon are having a baby and are hoping for a boy.The baby's sex will be decided by the chromosomes of:

Which of the following women is MOST likely to have dizygotic twins?