Question 1

Possible future interventions for spinal cord damage include

Accepted Answer

A)  transplanting stem cells. 
B)  promotion of growth-inhibiting chemicals released by oligodendrocytes. 
C)  suppression of growth-inhibiting chemicals released by Schwann cells. 
D)  promotion of the activity of Nogo.

Question 2

Cortical thickening peaks around the age of

Accepted Answer

A)  18 months. 
B)  11-12 years. 
C)  18-25 years. 
D)  45 years.

Question 3

Most cases of Down syndrome are the result of

Accepted Answer

A)  paternal age. 
B)  maternal age. 
C)  multiple codon repeats on the X chromosome. 
D)  the inability to metabolize phenylalanine.

Question 4

During migration,most neurons are guided to their ultimate location by

Accepted Answer

A)  the ventricular zone. 
B)  radial glia. 
C)  oligodendrocytes. 
D)  The formation of synapses.

Question 5

"Extreme skewing" in x-inactivation has been linked with which of the following characteristics in offspring?

Accepted Answer

A)  hemophilia 
B)  colorblindness 
C)  Alzheimer's disease 
D)  sexual orientation

Question 6

At least in mice,aging can be slowed dramatically by

Accepted Answer

A)  increased calories. 
B)  caloric restriction. 
C)  increased exercise. 
D)  sleep deprivation.

Question 7

A recessive gene

Accepted Answer

A)  is never expressed. 
B)  can influence a genotype,but not a phenotype. 
C)  can influence the phenotype of female children,but not male children. 
D)  can influence a phenotype when it occurs in pairs or on the X chromosome.

Question 8

Guidepost cells release chemicals that

Accepted Answer

A)  repel all advancing growth cones. 
B)  attract all advancing growth cones. 
C)  both repel and attract advancing growth cones. 
D)  form cell adhesion molecules.

Question 9

Some researchers have found disorganization of cells in the hippocampus in some schizophrenics.Which of the following is the most likely inference based on this finding?

Accepted Answer

A)  Because the organization of cells occurs before birth,schizophrenia cannot be blamed on childrearing practices. 
B)  There must be a single gene that has caused this error in development. 
C)  The hippocampus must be responsible for the hallucinations some schizophrenics have. 
D)  We can expect that persons with poor prenatal care are more apt to have schizophrenic children.

Question 10

The complete set of instructions for constructing a human being is known as the human

Accepted Answer

A)  genome. 
B)  genotype. 
C)  phenotype. 
D)  chromosome.

Question 11

Rosa Hoekstra and her colleagues (2007,p.372)reported that "individual differences in endorsement onautistic traits show substantial heritability (57%)." Define heritability,and discuss the proper use of the concept and the implications of Hoekstra et al.'s statement.

Accepted Answer

The answer of Rosa Hoekstra and her colleagues (2007,p.372)reported that...

Question 12

Which of the following statements about the genetic makeup of humans is true?

Accepted Answer

A)  Our genetic makeup is very different from every other animal on earth. 
B)  Our genes are what make all humans similar,but it is also our genes that make us all different from each other. 
C)  We share an identical genetic code with old-world apes-it is just the expression of alleles that makes us human and able to speak. 
D)  The DNA of all humans is similar,but the DNA of other animals is different.

Question 13

Forensic scientists prefer which of the following methods for identifying human remains?

Accepted Answer

A)  an analysis of chromosomal DNA inherited from both parents 
B)  an analysis of chromosomal DNA inherited from the mother 
C)  an analysis of mitochondrial DNA inherited from the mother 
D)  an analysis of mitochondrial DNA inherited from the father

Question 14

Which of the following statements about radial glia is true?

Accepted Answer

A)  They degenerate when migration is complete. 
B)  They differentiate into astrocytes. 
C)  They retain the ability to produce daughter cells. 
D)  They differentiate into neurons.

Question 15

You were recently introduced to your roommate's sibling.To your surprise,even though the siblings are the same sex,they look nothing alike.Which of the following is the best explanation of this situation?

Accepted Answer

A)  They must have different parents,as genetic inheritance ensures that they share a significant number of genes. 
B)  Although they started out very similar genetically,their genotypes have changed during development to make them look very different. 
C)  Given the number of different combinations of genes possible during reproduction,it may be that the two siblings don't really share many genes. 
D)  One has expressed only recessive genes,while the other has not.

Question 16

A person's phenotype represents

Accepted Answer

A)  genetic influences,but not environmental influences. 
B)  environmental influences,but not genetic influences. 
C)  neither environmental nor genetic influences. 
D)  an interaction between genetic and environmental influences.

Question 17

We inherit our mitochondrial DNA from

Accepted Answer

A)  our fathers only. 
B)  our mothers only. 
C)  both parents in equal amounts. 
D)  both parents,but about two-thirds from our mother and one-third from our father.

Question 18

An allele that produces a phenotypical trait regardless of whether or not its pair is homozygous or heterozygous is

Accepted Answer

A)  imprinted. 
B)  dominant. 
C)  recessive. 
D)  an SNP.

Question 19

Which of the following processes does not experience a critical window?

Accepted Answer

A)  imprinting 
B)  language 
C)  vision 
D)  mathematical reasoning

Question 20

Nancy and Cliff had four children who did not have cystic fibrosis,but their fifth child was born with the disease.Cystic fibrosis is carried on a recessive gene.Given what you've learned in this chapter,how could this happen?

Accepted Answer

A)  It wasn't until the fifth child that both parents passed on the allele for this illness. 
B)  Recessive genes normally skip a generation,but after the parents had five children,the gene was expressed. 
C)  Their fifth child must have been a boy,which makes it more probable that he would have the illness. 
D)  Their fifth child must have been a girl,which makes it more probable that she would have the illness.

Exam 5: Genetics and the Development of the Human Brain