Question 1

There are 46 of these in the nuclei of human cells;they are composed of deoxyribonucleic acid.
A)Teratogens
B)Zygotes
C)Chromosomes
D)Genes

Accepted Answer

Chromosomes are composed of DNA and are found in the nuclei of human cells. There are 46 chromosomes in human cells, except for gametes (egg and sperm cells) which only have 23 chromosomes. Teratogens are substances or agents that can disrupt fetal development, zygotes are fertilized egg cells, and genes are segments of DNA that code for specific traits.

Question 2

Ms.Dawson recently gave birth to twins,a girl and a boy.Which of the following statements about them must be true?
A)They share 100 per cent of their genes.
B)They are monozygotic.
C)They are dizygotic.
D)They originated from a single zygote.

Accepted Answer

Since the twins are a girl and a boy, they cannot be monozygotic (identical) as monozygotic twins come from a single fertilized egg that divides into two embryos, both of which are the same sex. Therefore, the twins must be dizygotic (fraternal) which means they developed from two separate eggs fertilized by two separate sperm. As a result, they share approximately 50% of their genes, just like any other full siblings.

Question 3

When she was pregnant with Joey,Joey's mother had a poor diet because food was in short supply in her war-torn country.The war ended after Joey was born,and his middle-class mother was able to provide him with adequate nutritious food throughout his childhood.Which of the following outcomes is the most likely for Joey?
A)Joey may show few,if any,long term negative effects from his prenatal deprivation.
B)Joey will probably experience serious long-term cognitive deficits.
C)Joey will probably experience serious long-term emotional deficits,but not cognitive problems.
D)Joey is at greater risk of serious ongoing health problems than youngsters who have adequate prenatal nutrition.

Accepted Answer

While poor prenatal nutrition can have negative effects on a child's development, the fact that Joey's mother was able to provide him with adequate nutrition throughout his childhood suggests that any negative effects would likely be minimal or non-existent. Additionally, the fact that the war ended after Joey was born likely meant that he was not exposed to ongoing stress or trauma that could exacerbate any prenatal effects. Therefore, it is most likely that Joey will show few, if any, long-term negative effects from his prenatal deprivation.

Question 4

Myelinization is the process which involves
A)neurons migrating to the temporal lobes.
B)separating the left and right hemispheres of the cortex.
C)coating the axon with a fatty sheath that improves conduction of electrical impulses.
D)development of the nuclei of the brain.

Accepted Answer

Myelinization is the process of creating a fatty sheath around axons, which helps to improve the speed of transmission of electrical impulses through the nervous system. This process is crucial for the proper functioning of the nervous system and plays a role in the development of motor skills, memory, and cognition.

Question 5

Brown eye-color alleles are dominant over blue eye-color alleles,which are recessive.Jenna has brown eyes.Her husband,Bill,has blue eyes.Jenna and Bill are the biological parents of James,who has blue eyes.Jenna would be described as ____________ of the allele for blue eyes.
A)having the phenotype
B)being a regulator
C)having the genotype
D)being a carrier

Accepted Answer

Since Jenna has brown eyes but has a child with blue eyes with Bill (who has blue eyes and thus carries two recessive alleles), Jenna must carry one dominant allele for brown eyes and one recessive allele for blue eyes. This makes her a carrier of the allele for blue eyes.

Question 6

Which of the following is an accurate description of the long-term effects of chronic stress on the body?
A)The ability of the immune system to fight infection and ward off disease is compromised.
B)There are no effects on the immune system,and only short term effects on the cardiovascular system.
C)There are no effects on the cardiovascular system,but long term effects on the skeletal muscles.
D)There are no lasting effects on the body - when the stress ends all physical systems return to normal.

Accepted Answer

Chronic stress can weaken the immune system over time, making it harder for the body to fight off infections and diseases. This can lead to an increased risk of illnesses and infections, as well as a slower recovery time. Additionally, chronic stress can have long-term effects on the cardiovascular system, including high blood pressure, heart disease, and stroke. It can also cause muscle tension and pain, as well as contribute to the development of anxiety and depression.

Question 7

Recessive,defective gene alleles can cause hereditary disorders.It is estimated that most people carry ______________ recessive,defective alleles in their genotypes.
A)zero
B)three to five
C)hundreds of
D)thousands of

Accepted Answer

It is estimated that most people carry three to five recessive,defective alleles in their genotypes, which are usually harmless because they are paired with a dominant, non-defective allele. However, if both parents carry the same recessive, defective allele, there is a chance that their offspring may inherit two copies of the defective gene and develop the associated disorder.

Question 8

In one study,young rats exposed to stress vocalized their anxiety.Their mothers,alerted to this distress,responded with diligent caregiving behavior that altered the development of the hippocampus.Which of the following processes or principles does this example demonstrate?
A)Dominant-recessive gene relationships
B)Active gene effects
C)The role of regulator genes in behavior genetics
D)Epigenesis

Accepted Answer

This example demonstrates epigenesis, which refers to changes in gene expression that are caused by environmental factors such as stress. The stress experienced by the young rats altered the development of the hippocampus, which is a brain region involved in regulating stress responses. This alteration was likely caused by epigenetic changes to the genes involved in hippocampal development, rather than changes in the DNA sequence itself.

Question 9

Which of the following statements is true about the effects of teratogens on the developing fetus?
A)Any given teratogen usually has the same effect regardless of when in prenatal development exposure occurs.
B)The kind of damage done depends on the stage of development during exposure.
C)A teratogen will usually have the same effect regardless of how much exposure the fetus has to that teratogen.
D)Ancient Greeks believed in teratogens,but modern science has been unable to identify any.

Accepted Answer

The kind of damage done by a teratogen depends on the stage of development during exposure. Different teratogens affect different organs and systems depending on the timing of exposure. For example, a teratogen that affects the development of the brain may have a different effect if exposure occurs during the first trimester as opposed to the third trimester.

Question 10

The epigenome is the full set of factors,from the cell to the outside world,that controls the expression of
A)hereditary material.
B)recessive genes.
C)the zygote.
D)histones.

Accepted Answer

The epigenome controls the expression of hereditary material, which refers to the genes that have been passed down from parent to offspring. The epigenome acts like a switch that can turn genes on or off, or increase or decrease their expression. It is influenced by a variety of factors, including environmental conditions and the activities of other parts of the cell. Recessive genes are a type of gene that is only expressed when an individual inherits two copies of the gene, one from each parent. The zygote is the first cell that forms when an egg is fertilized by a sperm, and the epigenome plays a role in determining which genes are expressed in the developing embryo. Histones are proteins that help to package DNA in the cell nucleus, and modifications to histones can affect how tightly or loosely the DNA is packed, which in turn can influence gene expression. However, they are just one of many factors that make up the epigenome.

Question 11

Which of the following is the best example of neuroplasticity?
A)Cells from the hippocampus are instrumental in encoding memories.
B)The 3-year-old's brain is approximately three-fourths of its adult size.
C)Fetal brains grow quickly,increasing in weight over the course of pregnancy.
D)Neurons that are transplanted from the auditory cortex to the visual cortex begin to perceive light.

Accepted Answer

Neuroplasticity refers to the brain's ability to adapt and reorganize itself in response to experiences. The example D shows neuroplasticity because neurons from one area of the brain (auditory cortex) are able to adapt and function in a different area (visual cortex) that has a different function. This demonstrates how the brain can change and adapt to new situations.

Question 12

In one animal study of the influence of genes on behavior,offspring of rats with genes for low stress reactivity were reared by unrelated mother rats with genes for high stress reactivity.This is an example of
A)a survey study.
B)a cross-fostering study.
C)a longitudinal study.
D)a comparative study.

Accepted Answer

This is a cross-fostering study, as the offspring are being raised by mothers with different genetic traits than their biological mothers.

Question 13

Neurons communicate with each other
A)by means of chemicals that are present in the spaces between them.
B)by means of dendrites touching other dendrites.
C)by means of electrical impulses that radiate out of the myelin sheath.
D)by means of connections with glial cells.

Accepted Answer

Neurons communicate with each other through neurotransmitters, which are chemicals that are released from the axon terminal of one neuron and bind to receptors on the dendrites or cell body of another neuron. This communication occurs in the synaptic cleft, the space between the two neurons.

Question 14

Brown eye-color alleles are dominant over blue eye-color alleles,which are recessive.Jenna has brown eyes.Her husband,Bill,has blue eyes.Jenna and Bill are the biological parents of James,who has blue eyes.What eye-color gene alleles must Jenna have?
A)Bb (one brown and one blue allele)
B)BB (two brown alleles)
C)bb (two blue alleles)
D)BBB (three brown alleles)

Accepted Answer

Since James has blue eyes and blue eye-color alleles are recessive, he must have received a blue allele from each parent. Jenna, having brown eyes but passing on a blue allele to James, must be heterozygous (Bb).

Question 15

If you look at the karyotypes of person A and person B and discover that they look alike,what can you infer is the same about these two people?
A)Their parents
B)Their sex
C)Their height
D)Their blood type

Accepted Answer

Karyotypes show the number and appearance of chromosomes in an individual's cells. The similarity in karyotypes between person A and person B indicates that they have the same number and appearance of sex chromosomes, which means they are both likely male or female. Therefore, the correct inference is that they have the same sex. Since karyotypes do not show information about parents, height, or blood type, these options are not valid.

Question 16

Most postnatal brain growth depends upon the proliferation of
A)synapses.
B)myelination.
C)neurotransmitters.
D)glial cells.

Accepted Answer

The proliferation of synapses, known as synaptogenesis, is a major contributor to postnatal brain growth, as it increases the number of connections between neurons.

Question 17

One epigenetic change that can affect the expression of a gene is methylation,which is
A)the subtraction of an organic molecule from DNA
B)the addition of an organic molecule to DNA
C)the addition of RNA to DNA
D)the effect of hormones on DNA

Accepted Answer

Methylation is the addition of a methyl group (an organic molecule containing one carbon and three hydrogen atoms) to DNA. This can inhibit the expression of genes by preventing access of transcription factors and RNA polymerase to the DNA.

Question 18

Which of the following is true with respect to the impact of nurture on the fetus' developing brain?
A)Fetal brain development is almost totally dependent upon the fetus' genetic inheritance because it has no environmental experience in the womb.
B)The development of the lower,primitive areas of the brain depend upon nature but the higher levels depend upon nurture.
C)Mothers can advance the fetus' intelligence significantly by speaking out loud in foreign languages during pregnancy.
D)The establishment of some synaptic connections in the fetal brain depends upon environmental input,like sound.

Accepted Answer

Studies have shown that environmental input, such as sound, can have an impact on the establishment of some synaptic connections in the fetal brain. While genetics do play a role in fetal brain development, nurture also has an influence, particularly in the formation of these neural connections. Speaking in a foreign language during pregnancy has not been shown to significantly advance a fetus' intelligence. Therefore, option D is the correct choice.

Question 19

The hypothalamic-pituitary-adrenal axis (HPA axis)plays a significant role in
A)the human response to stress.
B)X-linked recessive diseases.
C)determining the sex of a fetus.
D)determining eye color.

Accepted Answer

The hypothalamic-pituitary-adrenal axis (HPA axis) is involved in regulating the body's response to stress. This includes the release of cortisol from the adrenal glands, which helps the body cope with stress.

Question 20

Sally,age 28,recently married John,age 45.They would like to have a child,but they are concerned that they may be at high risk to have a child with a chromosomal abnormality,like Down syndrome,because of John's age.What is their genetic counselor likely to tell them?
A)They are at higher than average risk for some chromosomal disorders because of John's age,but not for Down syndrome.
B)They are at higher than average risk for chromosomal disorders of all sorts because of John's age.
C)There is no relationship between parents' age and chromosomal disorders in their offspring.
D)The risk of any chromosomal disorder in a child is only related to the mother's age,not to the father's age.

Accepted Answer

Advanced paternal age has been associated with an increased risk of chromosomal abnormalities, including Down syndrome, in offspring. While the risk is still relatively low overall, it is higher than the risk for younger fathers. Therefore, their genetic counselor is likely to tell them that they are at higher than average risk for chromosomal disorders of all sorts because of John's age.

Quiz 2: Genetics, epigenetics, and the Brain: the Fundamentals of Behavioral Development

There are 46 of these in the nuclei of human cells;they are composed of deoxyribonucleic acid.

Ms.Dawson recently gave birth to twins,a girl and a boy.Which of the following statements about them must be true?

Myelinization is the process which involves

Brown eye-color alleles are dominant over blue eye-color alleles,which are recessive.Jenna has brown eyes.Her husband,Bill,has blue eyes.Jenna and Bill are the biological parents of James,who has blue eyes.Jenna would be described as ____________ of the allele for blue eyes.

Which of the following is an accurate description of the long-term effects of chronic stress on the body?

Recessive,defective gene alleles can cause hereditary disorders.It is estimated that most people carry ______________ recessive,defective alleles in their genotypes.

In one study,young rats exposed to stress vocalized their anxiety.Their mothers,alerted to this distress,responded with diligent caregiving behavior that altered the development of the hippocampus.Which of the following processes or principles does this example demonstrate?

Which of the following statements is true about the effects of teratogens on the developing fetus?

The epigenome is the full set of factors,from the cell to the outside world,that controls the expression of

Which of the following is the best example of neuroplasticity?

In one animal study of the influence of genes on behavior,offspring of rats with genes for low stress reactivity were reared by unrelated mother rats with genes for high stress reactivity.This is an example of

Neurons communicate with each other

Brown eye-color alleles are dominant over blue eye-color alleles,which are recessive.Jenna has brown eyes.Her husband,Bill,has blue eyes.Jenna and Bill are the biological parents of James,who has blue eyes.What eye-color gene alleles must Jenna have?

If you look at the karyotypes of person A and person B and discover that they look alike,what can you infer is the same about these two people?

Most postnatal brain growth depends upon the proliferation of

One epigenetic change that can affect the expression of a gene is methylation,which is

Which of the following is true with respect to the impact of nurture on the fetus' developing brain?

The hypothalamic-pituitary-adrenal axis (HPA axis) plays a significant role in

Sally,age 28,recently married John,age 45.They would like to have a child,but they are concerned that they may be at high risk to have a child with a chromosomal abnormality,like Down syndrome,because of John's age.What is their genetic counselor likely to tell them?