Question 1

What is the cause of Down syndrome?
A)an extra chromosome on the 21ˢᵗ pair
B)an extra X chromosome on the 23ʳᵈ pair
C)neurotransmitter excesses
D)neurotransmitter deficiencies

Accepted Answer

Down syndrome is caused by the presence of an extra chromosome on the 21st pair, resulting in a total of three copies of chromosome 21 instead of two. This extra genetic material causes the typical physical and cognitive characteristics associated with Down syndrome.

Question 2

Silvia has blond hair,even though her mother and father each have brown hair.What do we know about Sylvia's parents?
A)At least one of her parents has a recessive gene for blond hair.
B)Each of her parents must have one recessive gene for blond hair colour.
C)Each of her parents must have one dominant gene for blond hair.
D)Neither of her parents has a gene for blond hair.

Accepted Answer

In this scenario, the trait for blond hair is likely recessive, meaning that both parents must carry at least one copy of the recessive gene that causes blond hair in order for their child to express the trait. This explains why Sylvia can have blond hair even though her parents both have brown hair. Therefore, Choice B is the correct option.

Question 3

Ryan has cystic fibrosis.This means that his mother is a carrier for the cystic fibrosis gene,while his father:
A)is also a carrier.
B)is not a carrier.
C)does not have a cystic fibrosis gene.
D)has two cystic fibrosis genes.

Accepted Answer

The answer of Ryan has cystic fibrosis.This means that his...

Question 4

Conjoined twins are:
A)monozygotic twins.
B)fraternal twins.
C)dizygotic twins.
D)nonidentical twins.

Accepted Answer

Conjoined twins are monozygotic twins that develop from a single fertilized egg that fails to separate completely into two individuals. It is also known as Siamese twins.

Question 5

__________________ develop when two eggs each get fertilized by two different sperm,resulting in two zygotes in the uterus at the same time.
A)Monozygotic twins
B)Fraternal twins
C)Dizygotic twins
D)Wombmates

Accepted Answer

Dizygotic twins, also known as fraternal twins, develop when two eggs are released during ovulation and are fertilized by two different sperm. This results in two zygotes in the uterus at the same time. Monozygotic twins, on the other hand, develop from a single fertilized egg that splits into two embryos. "Wombmates" is not a scientific term used to describe twins.

Question 6

The union of the ovum and sperm is called:
A)fertilization.
B)the fetal period.
C)a zygote.
D)an embryo.

Accepted Answer

Fertilization is the process in which the sperm and ovum unite to form a zygote, marking the beginning of a new human life. The zygote undergoes rapid cell division and becomes an embryo before developing into a fetus during the fetal period.

Question 7

At fertilization,the chromosomes from the father's sperm unite with the chromosomes from the mother's egg,creating a new cell called a/an:
A)embryo.
B)zygote.
C)genome.
D)blastocyst.

Accepted Answer

At fertilization, the sperm and egg fuse together to form a zygote, which is the first cell of a new organism. The other options (embryo, genome, blastocyst) are stages of development that occur after fertilization.

Question 8

Tinotenda and Tinashe Mufuka are ___________ twins.
A)nonidentical
B)dizygotic
C)fraternal
D)conjoined

Accepted Answer

The answer of Tinotenda and Tinashe Mufuka are ___________ twins.
A)nonidentical
B)dizygotic
C)fraternal
D)conjoined...

Question 9

Tinotenda and Tinashe Mufuka share a:
A)body from the waist down.
B)liver.
C)heart.
D)upper torso.

Accepted Answer

The answer of Tinotenda and Tinashe Mufuka share a:
A)body from...

Question 10

Diseases carried by recessive genes are inherited when:
A)a child inherits two recessive genes,one from each parent.
B)a child inherits two dominant genes,one from each parent.
C)a child inherits a dominant gene from one parent and a recessive gene from the other parent.
D)when the child doesn't inherit any genes from one parent.

Accepted Answer

Diseases carried by recessive genes are only expressed if an individual inherits two copies of the recessive gene, one from each parent. This means that both parents must be carriers of the recessive gene, and the offspring has a 25% chance of inheriting two copies of the gene and thus expressing the disease. The other choices do not accurately represent the inheritance patterns of recessive diseases.

Question 11

Marisa is at a point in her pregnancy when the zygote is moving down her uterus,and the placenta and umbilical cord are beginning to form.Which period of prenatal development is Marisa currently experiencing?
A)fetal
B)embryonic
C)placental
D)germinal

Accepted Answer

The answer of Marisa is at a point in her...

Question 12

Twins Tinashe and Tinatenda Mufuka received life-saving surgery and medical care from:
A)St.Jude's Children's Hospital in Montreal.
B)the Zimbabwe Red Cross International Hospital.
C)the Hospital for Sick Children in Toronto.
D)the Mayo Clinic in Boston,Massachusetts.

Accepted Answer

The Hospital for Sick Children in Toronto is known for providing high-quality medical care to children, and it is therefore likely that they would have provided the necessary surgery and medical care to treat the twins' life-threatening condition. St. Jude's Children's Hospital in Montreal and the Mayo Clinic in Boston are also renowned hospitals, but there is no information to suggest that the twins were treated there. The Zimbabwe Red Cross International Hospital is a fictitious hospital and does not exist.

Question 13

In ________ syndrome,the 21ˢᵗ pair of chromosomes contains an extra chromosome resulting in symptoms such as large,round eyes,larger tongue,and developmental delay.
A)PKU
B)Down
C)Klinefelter's
D)Turner's

Accepted Answer

The description matches the symptoms of Down syndrome, which is caused by an extra copy of chromosome 21. PKU is caused by an enzyme deficiency, Klinefelter's syndrome involves extra X chromosomes in males, and Turner's syndrome involves missing X chromosomes in females.

Question 14

The germinal period:
A)occurs during the first 2 weeks after fertilization.
B)occurs from 2 to 8 weeks after fertilization.
C)occurs from approximately 8 weeks after fertilization to birth.
D)occurs from 7 to 10 weeks after fertilization

Accepted Answer

The germinal period occurs during the first 2 weeks after fertilization, when the fertilized egg travels down the fallopian tube and implants in the uterine lining. During this period, cells begin to differentiate and organize into the embryonic disc, which will eventually become the fetus.

Question 15

Which of the following describes the way in which monozygotic twins occur?
A)The mother's body releases multiple eggs,two or more of which are fertilized.
B)The mother's body releases one egg,conceives,and then releases another egg in a later ovulation cycle.
C)The egg is fertilized by a single sperm and then splits completely into two separate zygotes.
D)The mother uses fertility drugs.

Accepted Answer

Monozygotic twins occur when a single fertilized egg splits into two separate zygotes. This results in two embryos with almost identical genetic material.

Question 16

A gene that only influences the expression of a trait when paired with an identical gene is called:
A)recessive.
B)mutated.
C)recombinant.
D)dominant.

Accepted Answer

A recessive gene is one that only affects the phenotype of an individual when there are two copies of that recessive gene. In other words, if a person inherits one copy of the gene from one parent and a different copy from the other parent, the dominant gene will be expressed in the phenotype instead of the recessive gene. The recessive gene will only be expressed if there are two copies of it, one from each parent.

Question 17

The recent finding that monozygotic twins may actually have some genetic differences:
A)supports the idea that identical twins are 100 percent alike in terms of their DNA.
B)supports the idea that fraternal twins are more genetically similar than identical twins.
C)challenges the assumption that differences between identical are due only to environmental differences.
D)challenges the assumption that conjoined twins only occur in dizygotic twins.

Accepted Answer

The recent finding challenges the assumption that differences between identical twins are due only to environmental differences, suggesting that there may be some genetic differences as well. It does not support the idea that identical twins are 100 percent alike in terms of DNA or that fraternal twins are more genetically similar than identical twins. The finding has no relation to conjoined twins.

Question 18

In the process of fertilization,the ________ and _________ unite,resulting in a single cell.
A)sperm; ovum
B)zygote; sperm
C)embryo; zygote
D)ovum; fetus

Accepted Answer

During fertilization, the sperm and ovum unite to form a zygote, which is a single cell.

Question 19

Mary and Juan are twins who developed from two separate fertilized ova that were fertilized by two different sperm.What type of twins are they?
A)monozygotic
B)maternal
C)dizygotic
D)wombmates

Accepted Answer

Mary and Juan are dizygotic twins because they were fertilized from two separate ova and two different sperm. Dizygotic twins are also known as fraternal twins. Monozygotic twins, on the other hand, develop from a single fertilized ovum that splits into two embryos. Maternal and wombmates are not types of twins.

Question 20

Ovum is a term used to describe the:
A)female sex cell or egg.
B)male sex cell.
C)developing organism from conception to the end of the second week after fertilization.
D)developing organism from two to eight weeks after fertilization.

Accepted Answer

Ovum refers specifically to the female sex cell or egg.

Quiz 8: Development Across the Life Span

What is the cause of Down syndrome?

Silvia has blond hair,even though her mother and father each have brown hair.What do we know about Sylvia's parents?

Ryan has cystic fibrosis.This means that his mother is a carrier for the cystic fibrosis gene,while his father:

Conjoined twins are:

__________________ develop when two eggs each get fertilized by two different sperm,resulting in two zygotes in the uterus at the same time.

The union of the ovum and sperm is called:

At fertilization,the chromosomes from the father's sperm unite with the chromosomes from the mother's egg,creating a new cell called a/an:

Tinotenda and Tinashe Mufuka are ___________ twins.

Tinotenda and Tinashe Mufuka share a:

Diseases carried by recessive genes are inherited when:

Marisa is at a point in her pregnancy when the zygote is moving down her uterus,and the placenta and umbilical cord are beginning to form.Which period of prenatal development is Marisa currently experiencing?

Twins Tinashe and Tinatenda Mufuka received life-saving surgery and medical care from:

In ________ syndrome,the 21ˢᵗ pair of chromosomes contains an extra chromosome resulting in symptoms such as large,round eyes,larger tongue,and developmental delay.

The germinal period:

Which of the following describes the way in which monozygotic twins occur?

A gene that only influences the expression of a trait when paired with an identical gene is called:

The recent finding that monozygotic twins may actually have some genetic differences:

In the process of fertilization,the and _ unite,resulting in a single cell.

Mary and Juan are twins who developed from two separate fertilized ova that were fertilized by two different sperm.What type of twins are they?

Ovum is a term used to describe the: