BMS100 Past Test Questions
Chapter 20, Spring 2009

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1. The effects of _?_ genes are "masked" (covered) by the effects of dominant genes.
   1. sex-linked
   2. recessive
   3. heterozygous
   4. autosomal
   
   
2. In cases of complete dominance, the dominant phenotype occurs in
   1. individuals with the heterozygous genotype
   2. individuals with the homozygous dominant genotype
   3. both of the above
   4. none of the above
   
   
3. Suppose that two people with normal skin have an albino child. What is the probability that a second child borne to this couple will have the normal phenotype (normal skin color), regardless of the child's genotype?
   1. 25%
   2. 33%
   3. 50%
   4. 67%
   5. 75%
   
   
4. In relation to cystic fibrosis, a "carrier"
   1. has abnormally thick mucus and will pass the "defective" gene to all children
   2. has abnormally thick mucus and may pass the "defective" gene to some children
   3. has normal mucus and will pass the "defective" gene to all children
   4. has normal mucus and may pass a "defective" gene to some children
   5. has normal mucus and cannot pass the "defective" gene to any children
   
   
5. If two carriers of cystic fibrosis (cf) have children together, what outcomes are possible among the children?
   1. thick mucus, respiratory difficulties, etc.
   2. normal mucus but still a carrier of the "cf" gene
   3. normal mucus a not a carrier of the "cf" gene
   4. A and B, but not C, are possible
   5. all of the above are possible
   
   
6. In relation to ABO blood types, controlled by the genes I^A, I^B, and i, there are _?_ possible genotypes and _?_ possible phenotypes.
   1. three / four
   2. four / six
   3. six / four
   4. eight / eight
   
   
7. Which one of the following is true?
   1. "SRY" refers to a part of the Y chromosome that causes an embryo to develop as a male
   2. "X^C" refers to a part of the X chromosome that causes an embryo to develop as a female
   3. both of the above
   4. none of the above
   
   
8. An individual in which the karyotype consists of 44 autosomes and one X chromosome would be
   1. a normal male
   2. a normal female
   3. a female who is color blind but otherwise normal (very rare)
   4. none of the above
   
   
9. Which one of the following is not possible?
   1. a sperm with 22 autosomes and one X chromosome
   2. a sperm with 22 autosomes and one Y chromosome
   3. an ovum ("egg") with 22 autosomes and one X chromosome
   4. an ovum ("egg") with 22 autosomes and one Y chromosome
   
   
10. The X chromosome
    1. is the largest of all chromosomes and contains many important genes
    2. is a mid-size chromosome and contains many important genes
    3. is the smallest of all chromosomes and contains no genes other than those required to cause male development
    4. is the smallest of all chromosomes and contains no genes other than those required to cause female development
    
    
11. Huntington's disease and certain types of dwarfism are caused by autosomal dominant genes. An autosomal dominant gene
    1. will be expressed in all people who have the gene
    2. will affect males and females equally
    3. both of the above
    4. none of the above
    
    
12. If a man and woman, both with normal vision, have a color blind son, then we know that
    1. the father, not the mother, is a carrier of the recessive gene that leads to color blindness
    2. the mother, not the father, is a carrier of the recessive gene that leads to color blindness
    3. both parents are carriers of the recessive gene that leads to color blindness