Biology I ECA Review Standard 7 Genetics

Biology I ECA Review Standard 7 Genetics

Explain how the genetic information from parents determines the unique characteristics of their offspring.

·  7.1 Distinguish between dominant and recessive alleles and determine the phenotype that would result from the different possible combinations of alleles in an offspring.

·  7.2 Describe dominant, recessive, codominant, sex-linked, incompletely dominant, multiply allelic and polygenic traits and illustrate their inheritance patterns over multiple generations.

·  7.3 Determine the likelihood of the appearance of a specific trait in an offspring given the genetic make-up of the parents.

·  7.4 Explain the process by which a cell copies its DNA and identify factors that can damage DNA and cause changes in its nucleotide sequence.

·  7.5 Explain and demonstrate how inserting, substituting or deleting segments of a DNA molecule can alter a gene, how that gene is then passed to every cell that develops from it and how the results may be beneficial, harmful or have little or no effect on the organism.

Multiple Choice

1.  The curled ears of the American Curl cat are caused by an autosomal dominant allele. What are the chances of a heterozygous female and a homozygous recessive male producing offspring with curled ears?

a.  1 in 4 c. 3 in 4

b.  2 in 4 d. 4 in 4

2.  The allele for attached earlobes (e) is recessive to the allele for unattached earlobes (E). A woman with the genotype (Ee) and a man with the genotype (ee) have a child. What is the probability that the child is heterozygous for attached earlobes?

a.  0% c. 25%

b.  50% d. 75%

3.  Snapdragons, a flowering plant popular with gardeners, can have red,white and pink colored petals. When snapdragons with red petals (RR) are crossed with snapdragons having white (rr) petals, the offspring have pink petals. The pink coloration (Rr) is a phenotype in between the red and white parental phenotypes. What is this kind of inheritance pattern called?

a.  Recessive inheritance c. Bipolar Inheritance

b.  Incomplete Dominance d. Classic Dominance

4.  Which of the following bases is found only in RNA?

a.  Adenine c Gunanine

b.  Thymine d. Uracil e. Cytosine

5.  A mutation occurred in the following, what kind was it? ______

Original sequence: AUG AAG UUU GGC GCA becomes

Altered sequence: AUG AAG UUG GCG CA

6.  The type of mutation that causes the least effect on the make up of a protein is

a.  a point mutation. c. a deletion of a nucleotide.

b.  frameshift mutation. d. an insertion of an extra nucleotide.

7.  A chromosome that has been broken and rejoined in a reversal sequence has undergone

a.  inversion. c. duplication.

b.  deletion. d. translocation.

8.  In Drosophilia, the gene for eye color is on the X chromosome. Red eye color is dominant over white eye color. What would be the result on the progeny?

a.  White eyes c. Pink eyes

b.  Red eyes d. Red and white eyes

9.  A man and woman living in a tropical area where malaria is prevalent and health care is not accessible have seven children. The genotypes of these children are ss, Ss, SS, ss, Ss, Ss, and SS. Top of Form

What must the genotype of both parents be? (Hint: what would be needed to have those kinds of children?)

a. ss x SS b. SS x SS c. Ss x ss d. Ss x Ss e. ss x ss

If that’s their genotype, what kind(s) of gametes (eggs/sperm) can each produce? ______

10.  A chromosome's gene sequence that was ABCDEFG before modification and ABCDLMNOP afterward is an example of

a.  inversion. c. duplication.

b.  deletion. d. translocation.

11.  The type of inheritance shown when a red-flowering plant is crossed with a white-flowering plant and only pink-flowering plants are produced is _____.

a.  inbreeding c. polygenic inheritance

b.  incomplete dominance d. codominance

12.  A human geneticist determined the pedigree shown in the diagram with filled symbols showing the affected individuals. How is this pattern of inheritance described?

a.  Autosomal dominant c. sex-linked recessive

b.  Autosomal recessive d. sex-linked dominant e. none of these

13.  Replication of DNA

a.  produces RNA molecules.

b.  produces only new DNA.

c.  produces two molecules, each of which is half-new and half-old DNA joined lengthwise to each other.

d.  generates excessive DNA, which eventually causes the nucleus to divide.

14.  How many affected females are there in the pedigree?

a.  0 b. 2 c. 4 d. 8

15.  How many normal males are there in the pedigree?

a.  0 b. 3 c. 6 d. 9

Figure 9-1

16.  In Figure 9-1, the replication illustrated here is termed

a.  dominant. c. semiconservative.

b.  recessive. d. conservative.

17.  In step "c" of Figure 9-1, which bonding is the only one that is possible?

a.  A with C c. C with T

b.  G with C d. T with G.

18.  DNA strands serve as which of the following during DNA synthesis?

a.  replicate c. template

b.  substitute d. source of nucleotides

Short Answer Response:

1.  A. Explain why a male with a recessive X-linked trait usually produces no female offspring with the trait.

B.  If a male with a recessive X-linked trait does produce a female offspring with the trait, what are possible genotypes of the mother?

2.  In humans, brown eyes (B) are dominant over blue (b)*. A brown-eyed man marries a blue-eyed woman and they have three children, two of whom are brown-eyed and one of whom is blue-eyed. Draw the Punnett square that illustrates this marriage. What is the man’s genotype? What are the genotypes of the children?

a.  If blue is recessive, what must the woman’s genotype be? ______

b.  If that’s her genotype, what kind(s) of gametes (eggs) can she produce? ______

c.  If the man has brown eyes, but has a blue-eyed child what must his genotype be? (if you don’t understand why, review the testcross problem) ______

d.  If that’s his genotype, what kind(s) of gametes (sperm) can he produce? ______

3. Suppose a person with type A blood and a person with type B blood get married. What are the possible genotypes their children could have?

19.  Top of Form

a.  What possible genotypes can a person be if that person has type A blood?

b.  Which of those genotypes would give rise to the wider variety of genotypes in the children that are produced?

c.  If that’s that person’s genotype, what kind(s) of gametes (eggs/sperm) would that person produce?

d.  What possible genotype(s) can a person be if that person has type B blood?

e.  Which of those genotypes would give rise to the wider variety of genotypes in the children that are produced?

4. Three babes were recently mixed up at your local hospital. The blood types of the parents and babies are shown below. Determine which baby belongs to which parents. Construct a blood type genotype graph to verify your choices.
Parents Parents I Parents II Parents III

A and B A and A AB and O

Baby 1= B Baby 2= O Baby 3= AB

20.  Bottom of Form

Bottom of Form

5. Saguaro cacti are very tall cylindrical plants that usually have two L-shaped arms, one on each side. Suppose you lived in southern Arizona where the Saguaro cactus is common and you happen to have one growing in your yard. Your Saguaro has two arms but one is longer than the other. Now, assume that arm length in these cacti are controlled by a single gene with arms of the same length (A) being dominant to arms of different lengths. What is the genotype of your cactus?

Could one of the parents of your cactus have had a phenotype with arms the same length?

If so, what would have been the genotype of that parent?

Suppose you cross your cactus with that of your neighbor which has arms of the same length. Your great grandchildren (it takes a Saguaro cactus a long time to mature) find that half of the resulting offspring have arms the same length and half have arms of different lengths. What was the genotype of your neighbor's cactus?