Deck 5: Patterns of Inheritance

Question 1

The segregation principle states that in sexually reproducing diploid organisms the two copies of each gene

A)move together as a unit during meiosis.
B)separate from each other during mitosis.
C)will both wind up in either the sperm or egg.
D)must always be the same allele.
E)segregate from each other during meiosis.

Answer 1

E

Question 2

With respect to genetic traits, what is the opposite of recessive?

A)regressive
B)progressive
C)dominant
D)subordinant
E)hybrid

Answer 2

C

Question 3

Sickle cell anemia is an example of what type of inheritance?

A)incomplete dominance
B)complete dominance
C)codominance
D)recessive dominance
E)multiple alleles

Answer 3

A

Question 4

Mendel determined that tall pea plants were dominant to short pea plants. Cross a homozygous short pea plant with a heterozygous tall pea plant. Which of the following is the phenotypic ratio of the offspring?

A)1:0
B)1:1
C)1:2:1
D)3:1
E)4:1

Question 5

Gregor Mendel was successful in his analysis of the genetics of pea plants because

A)he examined and analyzed both the F₁ and F₂ generations.
B)he studied the parental plants to determine their differences.
C)pea plants have genetics different from other organisms.
D)he decided to only look at his results in an objective manner.
E)he studied a trait that had a strange inheritance pattern.

Question 6

Which of the following statements is true?

A)In carriers, the recessive allele causes an intermediate phenotype.
B)With recessive genetic disorders, if both parents are carriers, the offspring will all be affected.
C)In recessive genetic disorders, the mother and/or father of an affected individual must also be affected.
D)With dominant genetic disorders, the mother and/or father of an affected individual must also be affected.
E)The dominant allele is masked in homozygous dominant individuals.

Question 7

The ABO blood type gene is an example of ___________, which means that heterozygotes display two phenotypes at the same time.

A)advanced hybridism
B)fading
C)incomplete dominance
D)codominance
E)cross-fertilization

Question 8

Pedigrees are

A)used by geneticists to determine the sequence of an individual's genes.
B)histories of families with regard to particular genetic traits.
C)used only for dogs, cats, and horses.
D)mutated alleles capable of causing genetic disorders.
E)characteristics that are apparent in an individual.

Question 9

Mendel observed that dominant traits

A)are only expressed in hybrids.
B)were absent in the F₁ generation of pea plants that he used in his experiments.
C)were the only traits seen in the F₂ generation of pea plants in his experiments.
D)are expressed in all plants.
E)are seen in all the F₁ hybrid pea plants in his experiments.

Question 10

The protein responsible for cystic fibrosis is

A)found on the inside of cells.
B)the same in normal individuals and those with cystic fibrosis.
C)responsible for blocking normal fluid transport across the cell membrane.
D)a carcinogen.
E)the result of a normal gene.

Question 11

A gene on the X chromosome is said to be

A)heterozygous.
B)sex limited.
C)x-linked.
D)bipolar.
E)a mutation.

Question 12

Mendel correctly surmised that the 3 dominant:1 recessive phenotypic ratio seen in the F₂ generation pea plants was due to

A)a tendency to have more fertilization events yielding homozygous dominant than homozygous recessive.
B)homozygosity.
C)genotypic selection.
D)random combination of sperm and egg with respect to the allele carried.
E)certain phenotypes having a selective advantage.

Question 13

Consider two traits for an organism, determined by two genes, each of which is governed by at least two alleles. In the case of a dihybrid individual, the gametes formed will be of either the parental type or the recombinant type. Recombinant type gametes are formed because of

A)incomplete dominance.
B)independent assortment.
C)heterozyogosity.
D)the principle of dihybrids.
E)multiple alleles.

Question 14

A person with the genotype XXY will be a ___________ with _________ syndrome and have ________ chromosomes in each cell.

A)male, Turner, 47
B)female, Turner, 45
C)male, Klinefelter, 45
D)female, Klinefelter, 47
E)male, Klinefelter, 47

Question 15

An organism with two copies of the same allele is said to be

A)Homozygous.
B)heterozygous.
C)phenotypic.
D)genotypic.
E)a hybrid.

Question 16

The determination of gene positions on chromosomes is known as

A)gene therapy.
B)gene mutation.
C)gene construction.
D)gene alteration.
E)gene mapping.

Question 17

The genetic makeup of a particular trait in an individual is its

A)dominance.
B)heterozygosity.
C)genotype.
D)phenotype.
E)filial.

Question 18

The physical characteristics of an organism resulting from its genes are known as the organism's

A)alleles.
B)hybrids.
C)recessive characteristics.
D)genotype.
E)phenotype.

Question 19

An allele is

A)the dominant form of a gene.
B)an alternate form of a gene.
C)always recessive.
D)the main factor determining a trait.
E)always one of a pair.

Question 20

Different forms of a gene are known as

A)alleles.
B)hybrids.
C)recessives.
D)genotypes.
E)phenotypes.

Question 21

You learned that the phenotypic ratio of the F₂ generation of a typical test cross was 3:1. The genotypic ratio was 1:2:1. Why is a different ratio seen in a dihybrid cross? What conditions must be met for these parameters to be true?

Question 22

A woman with type A blood just had her first child. The child, like mother, had type A blood. What are all of the possible blood types of the father?

Question 23

The defective protein that actually causes cystic fibrosis is found in

A)blood serum.
B)the mitochondrial membrane.
C)the cell cytoplasm.
D)the nucleus.
E)the cell membrane.

Question 24

Duchenne muscular dystrophy (MD)is inherited from an X-linked recessive allele. What is the probability that a son with Duchenne MD inherited this disease from his biological father?

A)0
B)1/4
C)1/2
D)1/8
E)1/16

Question 25

Explain how females with the chromosome constitution XXX are often fertile with normal intelligence and lead normal lives.

Question 26

Compare and contrast the blending and particulate models of heredity.

Question 27

A young couple already has three children and is expecting a fourth. Through a genetic test, the couple finds out that each of them is a carrier for cystic fibrosis. Upon counseling, they are informed that there is a 1 in 4 chance of their unborn child having cystic fibrosis and a 1 in 2 chance that he/she will be a carrier. Describe how the genetic counselor was able to determine these probabilities. The husband deduces that the child will be born with cystic fibrosis because the other 3 children do not have it. Explain why this reasoning is faulty. How would you handle the situation?

Question 28

Before the 1900s, inheritance was thought to be blended. In other words, a father who was tall and a mother who was short would often have children who were of medium height. Indeed, this is often seen. As another example, a father with dark skin and a mother of lighter skin will often have children who have skin tones intermediate between their parents. How is this explained in light of modern genetics?

Question 29

Why do geneticists find that human genetics are rather hard to study, when compared to experimental organisms such as pea plants or fruit flies?

Question 30

Most cases of red-green colorblindness are inherited as an X-linked recessive characteristic. Which of the following are possible if a woman, who is a carrier for colorblindness, has offspring with a male who is colorblind?

A)All their sons will have normal color vision.
B)All their sons will be colorblind
C)All their daughters will be colorblind.
D)All their daughters will have normal vision.
E)All of the above are possible.

Question 31

Huntington's disease, an often fatal disease of the central nervous system, is inherited from a dominant allele. Furthermore, a person may not show symptoms of the disease until 30 - 50 years of age. Jack and Jill have been married for 40 years and have two children, Joe and Jane. Jack has recently been diagnosed with Huntington's disease. Assuming that Jane does not have the disease, determine the probability that one of the children will eventually have Huntington's. What is the probability that both Joe and Jane will inherit the disease?

Question 32

Contrast Mendel's model of heredity with the blending model. Which one is a better description of the way traits are passed from one generation to the next?

Question 33

Explain the role of the human genome project and modern medicine in helping to find a cure for cystic fibrosis.

Question 34

Tall corn plants (T)are dominant to dwarf plants (tt). Solid green leaves (G)are dominant to leaves with a white tip (gg). A cross between two corn plants yielded the following phenotypes: 51 tall plants with a white tip on their leaves; 43 dwarf plants with solid leaves; 48 dwarf plants with white tips on their leaves; 45 tall plants with solid leaves. What are the genotypes of the parents that produced these plants?

A)TtGg x TtGg
B)TtGg x Ttgg
C)ttGG x TTgg
D)TtGg x ttgg
E)None of the above

Question 35

You have just graduated from college as a business major, but have a special interest in genetics, ever since taking introductory biology with the new Life curriculum. Therefore, you decide to manage a pet store where you can dabble in animal breeding experiments. Your first investigation is with one of your childhood favorites, the guinea pig. When you cross a black guinea pig with a white guinea pig, three of the offspring are black and three are white. When you cross two of the black offspring you get six black and two white offspring. Which phenotype is most likely dominant? How do you know? What are the genotypes of the original parental guinea pigs?

Question 36

Usually, an egg cell from a human female contains

A)one X chromosome and one Y chromosome.
B)one X chromosome.
C)one Y chromosome.
D)two X chromosomes.
E)two Y chromosomes.

Question 37

What is the probability that a person would have cystic fibrosis if one of her parents was homozygous dominant and the other was a carrier for cystic fibrosis?

A)0
B)1:4
C)1:6
D)1:8
E)1:16

Question 38

Describe how you might analyze a pedigree to determine whether a particular condition is recessive or dominant, and X-linked or autosomal. For the sake of this question, ignore conditions such as multiple alleles, incomplete dominance, and other complications.

Question 39

The hairline of some people drops downward near the center of the forehead and forms a distinct point. This condition is known as widow's peak. The alternative phenotype is a continuous hairline that does not drop down. A person with widow's peak always has an affected parent. Explain the inheritance pattern of widow's peak.

Question 40

You are a young M.D. and genetic researcher working in conjunction with the Human Genome Project. The charge of your laboratory is to research cures for genetic diseases. Recently the Centers for Disease Control and Prevention (CDCP)reported several cases of a new genetic disease dubbed the "Liver Quiver Syndrome." Even though little is known about the inheritance pattern of the disease, the abnormal allele(s)cause(s)a defective protein in the membrane structure of the Golgi apparatus. This abnormal protein prevents the processing of a protein that would eventually be secreted from liver cells. Symptoms include a spasm-like condition of the liver. Thus the name "Liver Quiver Syndrome." This disease is almost always fatal, killing most victims by age 50. As a doctor and genetic researcher, discuss the genetic research that must first be completed before a cure can be found.