Biology A Guide To The Natural World 5th Edition By David Krogh – Test Bank

MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) When two identical alleles for a character are present, the genotype is referred to as: 1) A) heterozygous.
B) dominant.
C) recessive.
D) homozygous.
Answer: D
Explanation: A)
B)
C)
D)
2) What is the basis of codominance?
A) There is only one allele for a gene.
B) Each allele of a gene produces a protein that functions to create a trait.
C) One allele can have many effects on a phenotype.
D) One allele of a gene encodes a protein, and the other allele is nonfunctional.
E) One gene has many alleles.
Answer: B
Explanation: A)
B)
C)
D)
E)
3) In order to track the inheritance of two characters, you would need to do a: 3)
A) true- breeding cross.
B) monohybrid cross.
C) dihybrid cross.
D) trihybrid cross.
Answer: C
Explanation: A)
B)
C) D)
4) In humans, “unattached” earlobes are dominant over “attached” earlobes. Widow’s- peak hairline is 4) dominant over non- widow’s- peak hairline. Use E and e for the earlobe phenotype alleles and W and w for the hairline phenotype alleles. A woman with unattached earlobes and a widow’s peak and a man with attached earlobes and a widow’s peak have a child. The child has attached earlobes and a non- widow’s- peak hairline. What are the genotypes of the parents?
A) EEWW and eeww

B) EEWW and eeWw
C) EeWw and eeww
D) EeWw and eeWw
E) EeWw and EeWW
Answer: D
Explanation: A)
B)
C)
D)
E)
5) Mendel postulated that individuals have genetic elements that exist in pairs, which determine a 5) single phenotype. What do we now know these pairs of elements to be?
A) two alleles of a gene on homologous chromosomes

B) pairs of centromeres
C) two haploid sets of chromosomes
D) pairs of sister chromatids
E) a sperm and an egg
Answer: A
Explanation: A)
B)
C)
D)
E)
6) Before Mendel, people had observed inheritance of dominant and recessive traits by following 6) many generations of plants and animals. What was different about Mendel’s work? A) He followed more generations than anyone else.
B) His results were immediately accepted and applied to other studies.
C) He did both cross- and self- fertilizations.
D) He used a plant that had never been cultivated before.
E) He kept careful count of his results, including mathematical analysis.
Answer: E
Explanation: A)
B)
C)
D)
E)
7) In order to track the inheritance of a single character, you would need to do a: 7)
A) trihybrid cross.
B) dihybrid cross.
C) true- breeding cross.
D) monohybrid cross.
Answer: D
Explanation: A)
B)
C)
D)
8) Characters such as height, weight, and skin color are controlled by many genes acting together. 8) These are examples of: A) codominance.
B) multiple alleles.
C) polygenic inheritance.
D) incomplete dominance.
Answer: C
Explanation: A)
B)
C)
D)
9) The phenotype of an organism can be influenced by: A) both its environment and its genotype.
B) neither its genotype nor its environment.
C) its environment.
D) its genotype.
Answer: A
Explanation: A)
B)
C)
D)
10) In Mendel’s pea plants, yellow seeds are dominant to green seeds. Purple flowers are dominant to 10) white flowers. Use Y and y for the seed color alleles and P and p for the flower color alleles. Flower color and seed color assort independently. If a plant that is heterozygous for both flower color and seed color genes is self- fertilized, what proportion of the offspring will have one of the dominant phenotypes, either the seed color or flower color, but not both?
A) 6/64
B) 6/16
C) 9/32
D) 9/16
E) 6/32 Answer: B
Explanation: A)
B)
C)
D)
E)