Answers are provided below each question

1) Genes are segments of DNA that code for the _____.
  A) trait of hair color
  B) synthesis of proteins
  C) muscle contraction
  D) the function of insulin
2) Which of the following is not true of chromosomes?
  A) contain DNA
  B) coated with histones
  C) 46 in mitotic cells
  D) visible at all times
3) The genes for cystic fibrosis are located on chromosome number _____.
  A) 4
  B) 7
  C) 17
  D) 21
4) Huntington disease is associated with chromosome _____.
  A) 4
  B) 7
  C) 17
  D) 21
5) When does the chromosome number reach 92?
  A) never
  B) prophase
  C) before prophase
  D) metaphase
6) Persons with dark skin who produce offspring with the same color have genes that are probably _____.
  A) heterozygous for melanin
  B) different alleles
  C) heterozygous for melanin enzymes
  D) homozygous for melanin enzymes
7) Which organ system is not significantly affected by Cystic fibrosis?
  A) nervous
  B) pulmonary
  C) gastrointestinal
  D) reproductive
8) The term __________ refers to having two different gene alleles.
  A) homozygous
  B) heterozygous
  C) autosomal
  D) karyotype
9) Sickle cell genes are present in _____% of the American population with central African ancestry.
  A) 8
  B) 18
  C) 48
  D) 2
10) The genes for sickle cell anemia are inherited as a form of _____.
  A) heterozygous recessive
  B) autosomal recessive
  C) incomplete dominance
  D) codominance
11) When will a person with sickle cell trait develop symptoms?
  A) every day
  B) under hypoxia
  C) never
  D) exercising
12) The genes for the ABO blood types are _____.
  A) alleles
  B) incomplete dominant
  C) codominant
  D) recessive
13) Persons with blood type B have the _____ agglutinogens (antigen).
  A) A
  B) B
  C) A and B
  D) neither A or B
14) Which blood type could these parents not produce in their children, AO and BB?
  A) B
  B) AB
  C) Rh+
  D) O
15) The final height of a child is determined by _____.
  A) the height of the parents
  B) the height of the grandparents
  C) polygenic inheritance
  D) recessive inheritance
16) Which of the following affects the expression in an individual with a homozygous recessive trait?
  A) the health of the mother
  B) disease in the father
  C) diet
  D) all of these
17) The result of meiosis is to produce _____.
  A) the zygote
  B) 23 chromosomes
  C) 46 chromosomes
  D) oogonia
18) Which term refers to the inheritance of traits that require two genes?
  A) phenotype
  B) genotype
  C) recessive
  D) dominant
19) When a physician questions a patient about their family history, they are gathering evidence to construct a___________.
  A) diagnosis
  B) prognosis
  C) pedigree
  D) Punnett square
20) How is familial hypercholesterolemia usually inherited?
  A) incomplete dominance
  B) codominant
  C) recessive
  D) sex-linked
21) Diseases that display different symptoms and signs for the same disease are displaying ____.
  A) heterogeneity
  B) pleiotropy
  C) penetrance
  D) polygenicity
22) The SRY gene causes expression of ____ chromosome genes.
  A) X
  B) Y
  C) autosome
  D) X or Y
23) Traits only transferred from fathers to their sons are associated with the ___ chromosome.
  A) X
  B) Y
  C) number 13
  D) number 21
24) Which of these conditions is usually not found in females?
  A) blood clotting disorders
  B) acromegaly
  C) muscular dystrophy
  D) Duchenne dystrophy
25) The growth of facial hair is an example of ___________.
  A) sex-linked inheritance
  B) sex-limited trait expression
  C) sex-influenced inheritance
  D) dominant genetics
26) What is the probability of there being a recessive gene in the gametes from a parent who is Aa (assuming "a" is recessive)?
  A) 10%
  B) 25%
  C) 50%
  D) 75%
27) Which offspring result from Aa and aa parents?
  A) all aa
  B) all AA
  C) AA, Aa, Aa, aa
  D) aa, aa, Aa, Aa
28) The inheritance of maleness is caused by a _____ chromosome pattern.
  A) autosomal
  B) Y
  C) XY
  D) XX
29) Which type of condition can only be passed from the father to his sons?
  A) sex linked recessive
  B) sex linked dominant
  C) holandric
  D) autosomal
30) Which of the following is not an X-linked recessive condition?
  A) hemophilia A
  B) color blindness
  C) von Willebrand's
  D) optic atrophy
31) The condition _____ is characterized by a deficiency of plasma thromboplastin component (factor IX).
  A) hepatocarcinoma
  B) microphthalmia
  C) hemophilia B
  D) coloboma iridis
32) Which term is correctly used to describe all Down's person's?
  A) aneuploidy
  B) trisomy 21
  C) polyploidy
  D) translocation
33) Which of the following is associated with Down's syndrome?
  A) XO
  B) XYY
  C) 21, 21, 21
  D) trisomy 22
34) The term for prenatal genetic testing using sloughed-off fetal cells is called ____.
  A) AFP
  B) amniocentesis
  C) chorionic villus sampling
  D) CEA
35) Which of the following is not usually seen in Down's syndrome?
  A) kidney defects
  B) heart defects
  C) skeletal deformities
  D) mental retardation
36) How many genes are believed to constitute the human genome?
  A) one million
  B) ten million
  C) 100,000
  D) 40,000
37) During which meiotic division is the number of chromosomes halved?
  A) during meiosis I
  B) during meiosis II
  C) prior to meiosis I, during the S phase
  D) after meiosis II
38) Choose the recessive human trait from the list that follows.
  A) widow's peak
  B) cheek dimples
  C) hairless forearms
  D) freckles
39) During which phase of meiosis does the phenomenon called crossing-over occur?
  A) prophase I
  B) metaphase I
  C) telophase I
  D) prophase II
40) Homologous chromosomes are separated during _______________.
  A) prophase I
  B) metaphase I
  C) anaphase I
  D) telophase I
41) Which of these does not contribute to genetic variability?
  A) meiosis
  B) crossing-over
  C) having children with a close relative
  D) having children with someone who is not a relative
42) Several variant forms of a gene for a given trait are called ______________.
  A) autosomes
  B) alleles
  C) sex chromosomes
  D) histones
43) A person who can pass either a widow's peak or straight hairline to the next generation is said to be _______________ for the hairline trait.
  A) homozygous
  B) heterozygous
  C) incompletely dominant
  D) recessive
44) If a recessive trait, such as hemophilia, occurs more often in males than in females, it is because the gene for the trait is most likely carried on ________________.
  A) the X chromosome
  B) the Y chromosome
  C) a mutant allele
  D) an autosome
45) If Chris, who carries the gene for cystic fibrosis but does not have the disease, fathers a child with Rhonda, who also carries the cystic fibrosis gene but does not have the disease, what is the likelihood that their first-born will have cystic fibrosis?
  A) 75% chance
  B) 50% chance
  C) 25% chance
  D) 0% chance
46) What is an example of a codominant trait in humans?
  A) sickle cell disease
  B) Huntington disease
  C) ABO blood groups
  D) Tay-Sachs disease
47) Traits that are controlled by one or more genes and influenced by the environment are said to be _________________.
  A) incompletely dominant
  B) multifactorial
  C) polygenic
  D) incompletely penetrant
48) The fact that a woman cannot generally grow a beard is because beard growth is a(n) ________________ trait.
  A) completely penetrant
  B) pleiotropic
  C) sex-limited
  D) sex-influenced
49) The normal chromosome number is referred to as _____________.
  A) euploid
  B) aneuploid
  C) polyploid
  D) tetraploid
50) The last pair of 23 chromosomes is referred to as the _____.
  A) karyotype
  B) autosomes
  C) nondisjunction chromosomes
  D) sex chromosomes
51) In Down's syndrome, there is an extra chromosome number _____.
  A) 19
  B) 20
  C) 21
  D) 22
52) Which chromosomes indicate a normal male fetus?
  A) XX
  B) XXY
  C) XY
  D) XYY


53) All person's with Down's syndrome display profound mental retardation.
  A) True
  B) False
54) The genes of an individual will always be different from those of the parents.
  A) True
  B) False
55) Theoretically, only 23 chromosomes are required to produce a normal human individual.
  A) True
  B) False
56) All humans have two sets of identical homologous chromosomes.
  A) True
  B) False
57) It is impossible to have a genotype for a trait and not have its phenotype.
  A) True
  B) False
58) Brown-eyed parents could not have a blue eyed child.
  A) True
  B) False
59) A person with blood type A will be completely genetically compatible with a transfusion from a donor with type A.
  A) True
  B) False
60) If a child contains a gene that is not found in either parent, then one of them is not the biological parent.
  A) True
  B) False
61) Traits such as skin pigmentation are totally governed by inheritance.
  A) True
  B) False
62) Gene therapy has not been completely successful at this time.
  A) True
  B) False
63) All forms of gene therapy changes cannot be inherited.
  A) True
  B) False
64) Fetal stem cells have no value over mature bone marrow in gene therapy research.
  A) True
  B) False
65) A younger women has a higher risk of a Down's conception than one who is older.
  A) True
  B) False
66) Chorionic villus sampling is less invasive than amniocentesis.
  A) True
  B) False
67) Gene therapy using the liver can be used to prevent heart disease.
  A) True
  B) False
68) Viruses are the usual causes of brain tumors such as gliomas.
  A) True
  B) False
69) The phenomenon of incomplete dominance will result in the meiosis of cells with two forms of a particular gene.
  A) True
  B) False
70) Males always determine the sex of a fetus.
  A) True
  B) False
71) A male with color blindness cannot have a daughter who is color blind because it is X-linked recessive.
  A) True
  B) False
72) It is possible for human cells to have more than 46 chromosomes.
  A) True
  B) False
73) The disintegration of chromosomes during meiosis is called nondisjunction.
  A) True
  B) False
74) Older women carry a greater chance of having a child with trisomy 21 than a younger women.
  A) True
  B) False
75) Persons with Turner's syndrome have male chromosomes but have a female appearance.
  A) True
  B) False
76) Syndromes having abnormal numbers of chromosomes are usually related to defective sperm cells.
  A) True
  B) False
77) Only the sperm have the ability to determine the sex of the offspring.
  A) True
  B) False
78) All genetic abnormalities are inherited.
  A) True
  B) False
79) Sex-linked genes are those associated with chromosomes X or Y.
  A) True
  B) False
80) Males and females have equal chances of inheriting x-linked disorders.
  A) True
  B) False
81) All birth defects are genetic and inherited.
  A) True
  B) False