REVIEW GUIDE (Chapter 5, sections 1 - 2)
Name
KEY
Class
Section 1: Reviewing Key Concepts
1. (a) Identifying: Identify three patterns of inheritance in humans. Give an example of a trait
that follows each pattern.
Single genes with two alleles – widow’s peak; single genes with multiple alleles –
blood type; multiple genes – skin color
(b) Summarizing: How many human blood types are there? Summarize how blood type is
inherited.
Four – A, B, AB, and O; the alleles for A and B are codominant and the allele for type
O is recessive. Type A blood results from two A alleles or one A and one i; type B
results from two B alleles or one B and one i; type AB is from on A and one B; type O
is from two i alleles.
(c) Drawing Conclusions: Aaron has blood type O. Can either of his parents have blood type
AB? Explain your answer.
No; blood type AB has the genotype IAIB, while blood type O has the genotype ii.
Each of his parents passed on an i allele, so neither could have blood type AB.
2.
(a) Reviewing: What are the functions of the sex chromosomes?
to carry genes that determine whether a person is male or female, and to carry other
traits.
(b) Comparing And Contrasting: Contrast the sex chromosomes found in human females and
human males.
The Y chromosome is much smaller than the X chromosome. Females have two X
chromosomes, and males have an X and a Y chromosome.
(c) Relating Cause and Effect: Explain how red-green colorblindness is inherited. Why is the
condition more common in males than in females?
Red-green colorblindness is determined by a recessive allele on the X chromosome.
The condition is more common in males.
3. (a) Reviewing: Are a person’s characteristics determined only by genes? Explain.
No; genes and the environment interact to determine many of a person’s
characteristics.
(b) Applying Concepts: Explain what factors might work together to enable a great soccer player
to kick a ball a long distance.
Athletic build and coordination may be inherited abilities that work together with
environmental factors of practice like instruction, and exercises to strengthen.
Section 1 practice quiz
1. You are told that one of a child’s parents has type A blood while the other parent has type B
blood. The child’s blood type:
a. could be A, B, AB, or O.
b. could be A or B only.
c. Must be AB.
d. Could be AB or O only.
e.
2. Which combination of sex chromosomes results in a male child?
a. XX
b. YY
c. XY
d. YO
3. What is the relationship between genes and the environment?
a. The environment has no effect on genes.
b. The environment determines which traits a person inherits.
c. The environment only affects a person’s genotype, while genes only affect a person’s
phenotype.
d. Many of a person’s characteristics are determined by their interaction between genes
and the environment.
Section 2: Reviewing Key Concepts
1. (a) Identifying: Identify the two major causes of genetic disorders in humans.
Mutations in DNA or changes in the overall structure or number of chromosomes
(b) Explaining: Which of those two major causes is responsible for Down syndrome?
a change in the overall number of chromosomes
(c) Describing: How are the cells of a person with Down syndrome different from those of a
person without the disorder?
Each of the cells has three copies of chromosome 21; normal cells have two copies
2. (a) Defining: What is a pedigree?
A chart that tracks which members of a family have a particular trait
(b) Inferring: Why are pedigrees helpful in understanding genetic disorders?
It allows scientists and genetic counselors to infer how a genetic disorder is passed
from one generation to the next.
(c) Applying Concepts: Sam has hemophilia. Sam’s brother, mother, and father do not have
hemophilia. Draw a pedigree showing who has the disorder and who is a
carrier.
3. (a) Reviewing: What is a karyotype?
A picture of all the chromosomes in a cell, arranged in pairs
(b) Inferring: Would a karyotype reveal the presence of sickle-cell disease? Why or why not?
No; sickle-cell disease is not related to the number of chromosomes in a cell.
Section 2: practice quiz
1. Hemophilia is caused by a(n)
a. recessive allele on the X chromosome
b. extra chromosome
c. codominant allele
d. a mutation in which three bases are removed from a molecule
2. One important tool that geneticists use to trace the inheritance traits through several generations of
a family is a
a. pedigree
b. Punnett square
c. karyotype
d. phenotype
3. A picture of all the cell’s chromosomes is a
a. pedigree
b. genome
c. karyotype
d. genotype
Section 3: Reviewing Key Concepts
1. (a) Listing: List three methods that scientists can use to develop organisms with desirable traits.
Selective breeding, cloning, and genetic engineering
(b) Describing: Briefly describe each method.
Selective breeding – crossing two individuals to get certain characteristics.
Cloning – producing an organism with the same genes as another organism
Genetic Engineering – transferring genes from one organism into the DNA of
another
(c) Applying Concepts: Lupita has a houseplant. Which method would be the best way of
producing a similar plant for a friend? Explain your answer.
Cloning; many houseplants can be cloned by cutting the stem
from one plant and putting the stem in soil.
2. (a) Defining: What is a genome?
All the DNA in one cell of an organism
(b) Explaining: What is the Human Genome Project?
A research study with the goal of identifying the DNA sequence of every gene
in the human genome
(c) Relating Cause and Effect: How might knowledge gained from the Human Genome Project
be used in gene therapy?
Scientists may eventually be able to insert copies of the
normal gene into the genes of people with a genetic
disorder.
Section 3: practice quiz
1. Which form of selective breeding involves crossing parents with the same or similar sets of
alleles?
a. Cloning
b. hybridization
c. inbreeding
d. genetic engineering
2. Genes from one organism may be transferred into the DNA of another in the process called:
a. selective breeding
b. inbreeding
c. cloning
d. genetic engineering
3. A genome is
a. All the DNA in one organism
b. All the DNA in one cell of an organism
c. A group of scientists
d. A small ring of DNA
All 3 sections put together: practice quiz
1. A human trait that is controlled by a single gene with multiple alleles is
a. dimples
b. blood type
c. height
d. skin color
2. A sex-linked disorder is
a. Cystic fibrosis
c. hemophilia
b. sickle-cell disease
d. Down syndrome
3. Which of the following would most likely be used to diagnose Down syndrome
a. a karyotype
b. a pedigree
c. a blood-clotting test
d. a Punnett square
4. Inserting a human gene into a bacterial plasmid is an example of
a. Inbreeding
b. selective breeding
c. DNA fingerprinting
d. genetic engineering
5. An organism that has the same genes as the organism from which it was produced is called a
a. clone
b. hybrid
c. genome
d. pedigree
Use the pedigree below to answer questions 6 and 7.
6. Which of the following is true for the first
generation?
a. Both the man and the woman have sicklecell disease
b. Both the man and the woman are carriers of
sickle-cell disease.
c. Only the woman is a carrier of sickle-cell
disease.
d. Only the man is a carrier of sickle-cell
e.
disease.
7. How many people in the second generation
have sickle-cell disease?
a. none
b. one person
b. two people
d. three people
8. Which statement is true about the third
generation?
a. no one has sickle –cell disease
b. everyone has sickle cell disease
c. everyone has at least one allele for
sickle-cell disease.
d. no one has any alleles for sickle-cell
disease.
Advances in Genetics (this is from section 3)
Understanding Main Ideas
1. What are two types of selective breeding, and how do they compare?
Inbreeding involves crossing two individuals with identical or similar sets of alleles, and
offspring have alleles that are very similar to those of their parents. Hybridization is crossing
two genetically different individuals so offspring will have the best traits of both parents.
2. What is cloning?
producing offspring that are genetically identical to the parent organism
3. How are bacteria used in genetic engineering?
Scientists can insert a gene that encodes a desired protein into the plasmid of a bacterium. As a
result, the bacterium produces the protein the gene codes for.
4. How could gene therapy someday be used to treat genetic disorders?
Scientists insert working copies of a gene directly into the cells of a person with a genetic
disorder so the cells can produce the protein the person is lacking.
5. What is the Human Genome Project?
A project to identify the DNA sequence of every gene in the human genome
Key Terms
Use the clues to identify Key Terms from the chapter. Write the terms on the lines.
6. A person with one recessive and one dominant allele for a trait ____carrier________________
7. An organism that is genetically identical to the organism from which it was produced ___clone_________
8. All the DNA in one cell of an organism ____genome____________________
9. Breeders cross two genetically different organisms ____hybridization____________________
10. Breeders cross two genetically similar organisms ___inbreeding_____________________
11. A picture of all the chromosomes in a cell ___karyotype_____________________
12. A chart that tracks which family members have a certain trait ___pedigree_____________________
If the statement is true, write true. If it is false, change the underlined word or words to make the
statement true.
(13)
true
A widow’s peak is a human trait that is controlled by a single gene.
(14)
female
A male inherits two X chromosomes.
(15)
pedigree
A karyotype tracks which members of a family have a trait.
(16)
inbreeding
Hybridization is the crossing of two genetically similar organisms.
(17)
true
A genome is all the DNA in one cell of an organism.
Applying Skills
Use the Punnett square to answer Questions 18–20. This
Punnet square shows how muscular dystrophy, a
sex-linked recessive disorder, is inherited.
(18) Interpreting Data: What is the probability that a daughter of these parents will have muscular
dystrophy? Explain your answer.
0%; the father cannot contribute a recessive allele for muscular dystrophy, so it is not
possible for a daughter to receive two X chromosomes with the recessive allele.
(19) Interpreting Data: What is the probability that a son of these parents will have muscular dystrophy?
Explain your answer.
50%; the mother is a carrier of muscular dystrophy, so one of her X chromosomes has the allele for
normal health and the other X chromosome has the allele for muscular dystrophy.
(20) Inferring: Is it possible for a woman to have muscular dystrophy? Why or why not?
Yes, if her father has it and her mother is a carrier. It’s a recessive disorder, so she would have to
inherit the allele for muscular dystrophy on the X chromosomes of both of her parents.
(21) Problem Solving: A woman with normal color vision has a colorblind daughter. What are the
genotypes and phenotypes of both parents?
The mother’s genotype is XCXc and the father’s genotype is XcY.
Extra question: Is muscular dystrophy sex-linked?
YES
(22) Calculating: If a mother is a carrier of hemophilia and the father does not have hemophilia, what is
the probability that their son will have the trait? Explain your answer.
50%; The father does not have the allele for hemophilia on his X chromosome, so he doenss’t
contribute the trait. If the mother is a carrier of hemophilia, one of her X chromosomes has the
allele for normal clotting and the other X chromosome has the allele for hemophilia. The son has a
50% chance of inheriting an X chromosome that carries the allele for hemophilia and therefore of
having hemophilia.
(23) Interpreting Diagrams: The allele for cystic fibrosis is recessive. Identify which members of the
family in the pedigree have cystic fibrosis and which are carriers.
24.
Is cystic fibrosis sex-linked? Why or why not?
NO; In the above pedigree, the father is a carrier. If the disorder was sex-linked the
male could not be a carrier because the allele would be on the X chromosome. If he
had the allele for the disorder, he would have the disorder.