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Genetics Chp 3 & 4 KD

Modified True/False
Indicate whether the sentence or statement is true or false.  If false, change the identified word or phrase to make the sentence or statement true.
 

1. 

When Mendel crossed purebred short plants with purebred tall plants, all of the offspring were short.

 

2. 

A hybrid is the offspring of parents that have different alleles for a trait.

 

3. 

A pea plant that is heterozygous for tall stems has the alleles Tt.

 

4. 

A Punnett square shows all the possible combinations of alleles in parents.

 

5. 

An organism’s physical appearance is its phenotype.

 

6. 

The sex cells produced by meiosis have twice the number of chromosomes as the parent cells.

 

7. 

Chromosomes carry genes from parents to offspring.

 

8. 

Transfer RNA carries coded messages from the nucleus to the cytoplasm.

 

9. 

A mutation in a sex cell can be passed to offspring.

 

10. 

A person’s environment can affect his or her genotype for certain traits, such as height.

 

11. 

A male is represented by a square in a pedigree.

 

12. 

A genetic disorder in which an abnormal form of hemoglobin is produced is hemophilia.

 

13. 

A doctor can look at the chromosomes of a cell in a karyotype.

 

14. 

The technique called cloning produces an organism that is genetically identical to its parent.

 

15. 

Except for identical twins, all people have the same DNA.

 

Multiple Choice
Identify the letter of the choice that best completes the statement or answers the question.
 

16. 

What did Gregor Mendel do to study different characteristics in his genetics experiments?
a.
He studied only asexual animals.
b.
He studied only self-pollinating plants.
c.
He cross-pollinated plants.
d.
He cross-pollinated animals.
 

17. 

Factors that control traits are called
a.
genes.
b.
purebreds.
c.
recessives.
d.
parents.
 

18. 

What does the notation TT mean to geneticists?
a.
two dominant alleles
b.
two recessive alleles
c.
at least one dominant allele
d.
one dominant and one recessive allelle
 

19. 

What is probability?
a.
the actual results from a series of events
b.
the likelihood that a particular event will occur
c.
the way the results of one event affect the next event
d.
the number of times a coin lands heads up
 

20. 

What did Mendel predict was the probability of producing a tall plant from a genetic cross of two hybrid tall plants?
a.
one in four
b.
two in four
c.
three in four
d.
four in four
 

21. 

What does a Punnett square show?
a.
all the possible outcomes of a genetic cross
b.
only the dominant alleles in a genetic cross
c.
only the recessive alleles in a genetic cross
d.
all of Mendel’s discoveries about genetic crosses
 

22. 

What does codominance mean in genetics?
a.
Both alleles are dominant.
b.
Both alleles are recessive.
c.
The alleles are neither dominant nor recessive.
d.
Each allele is both dominant and recessive.
 

23. 

What is the chromosome theory of inheritance?
a.
Chromosomes are carried from parents to offspring on hybrids.
b.
Genes are carried from parents to offspring on chromosomes.
c.
Hybrid pairs of chromosomes combine to form offspring.
d.
Codominant genes combine to form new hybrids.
 

24. 

What happens during meiosis?
a.
Each sex cell loses half of its chromosomes.
b.
Chromosome pairs separate to form new sex cells.
c.
Each sex cell copies itself to form four new chromosomes.
d.
Chromosome pairs remain together when new sex cells are formed.
 

25. 

What is the genetic code?
a.
the order of nitrogen bases along a gene
b.
the number of nitrogen bases in a DNA molecule
c.
the order of amino acids in a protein
d.
the number of guanine and cytosine bases in a chromosome
 

26. 

What is a mutation?
a.
any change that is harmful to an organism
b.
any change in a gene or chromosome
c.
any change that is helpful to an organism
d.
any change in the phenotype of a cell
 

27. 

The different forms of a gene are called
a.
alleles.
b.
factors.
c.
masks.
d.
traits.
 

28. 

Where does protein synthesis take place?
a.
in the ribosomes in the nucleus of the cell
b.
on the ribosomes in the cytoplasm of the cell
c.
in the chromosomes in the nucleus of the cell
d.
on the chromosomes in the cytoplasm of the cell
 

29. 

An organism’s genotype is its
a.
genetic makeup
b.
feather color
c.
physical appearance
d.
stem height
 

30. 

Which nitrogen base in RNA is NOT part of DNA?
a.
adenine
b.
guanine
c.
cytosine
d.
uracil
 

31. 

Which of these traits is controlled by a gene with multiple alleles?
a.
straight hairline
b.
smile dimples
c.
widow’s peak
d.
blood type
 

32. 

Why does height in humans have such a wide variety of phenotypes?
a.
Height is controlled by at least four genes.
b.
The gene for height has only two alleles.
c.
Height is controlled by sex-linked genes.
d.
Height is controlled by a recessive allele.
 

33. 

What controls variations in skin color among humans?
a.
a person’s diet
b.
at least three genes
c.
multiple alleles of a single gene
d.
two alleles of a single gene
 

34. 

What factors can affect a person’s height?
a.
genes only
b.
environmental factors only
c.
both genes and environmental factors
d.
the sex chromosomes a person inherits
 

35. 

Which combination of sex chromosomes results in a male human being?
a.
XX
b.
YY
c.
XY
d.
either XX or YY
 

36. 

Why are sex-linked traits more common in males than in females?
a.
All alleles on the X chromosome are dominant.
b.
All alleles on the Y chromosome are recessive.
c.
A recessive allele on the X chromosome will always produce the trait in a male.
d.
Any allele on the Y chromosome will be codominant with the matching allele on the X chromosome.
 

37. 

What is a pedigree?
a.
a chart that tracks which members of a family have a particular trait
b.
a geneticist who studies the inheritance of traits in humans
c.
a picture of all of the chromosomes in a cell
d.
an allele passed from parent to child on a sex chromosome
 

38. 

Which genetic disorder causes the body to produce unusually thick mucus in the lungs and intestines?
a.
hemophilia
b.
Down syndrome
c.
cystic fibrosis
d.
sickle-cell disease
 

39. 

What is a karyotype?
a.
blood from a newborn baby
b.
a picture of a baby before it is born
c.
a picture of the chromosomes in a cell
d.
fluid that surrounds a baby before it is born
 

40. 

How can genetic counselors predict genetic disorders?
a.
by studying karyotypes and pedigree charts
b.
by taking pictures of a baby before it is born
c.
by exploring new methods of genetic engineering
d.
by eliminating codominant alleles in the parents
 

41. 

Cloning results in two organisms that are
a.
both adult mammals.
b.
produced from cuttings.
c.
genetically similar.
d.
genetically identical.
 

42. 

Which of these is an example of the benefits of genetic engineering?
a.
cross-breeding to create disease-resistant crops
b.
creating human insulin to treat people with diabetes
c.
analyzing karyotypes and pedigree charts
d.
growing a new plant from a cutting
 

43. 

No two people have the same DNA, except for
a.
crime suspects.
b.
brothers.
c.
sisters.
d.
identical twins.
 

44. 

One parent of a child has type A blood and the other has type B blood. What is the child’s blood type?
a.
Type A
b.
Type B
c.
Type AB
d.
Type O
 

45. 

Sex-linked genes are genes on
a.
the X chromosome only.
b.
the Y chromosome only.
c.
the X and Y chromosomes.
d.
all 23 pairs of chromosomes.
 

46. 

Which form of selective breeding crosses genetically different individuals in an attempt to keep the best traits of both parents?
a.
genetic engineering
b.
inbreeding
c.
hybridization
d.
cloning
 

47. 

Which form of selective breeding crosses parents with the same or similar sets of alleles?
a.
fertilization
b.
inbreeding
c.
hybridization
d.
cloning
 

48. 

What must occur for a girl to be colorblind?
a.
Each parent must be colorblind.
b.
Each parent must have the dominant allele for colorblindness.
c.
Each parent must have the recessive allele for colorblindness.
d.
Each parent must have two codominant alleles for colorblindness.
 

49. 

Hemophilia is caused by a(n)
a.
recessive allele on the X chromosome.
b.
extra chromosome.
c.
dominant allele.
d.
codominant allele.
 

50. 

Down syndrome most often occurs when
a.
a person inherits a recessive allele.
b.
chromosomes fail to separate properly during meiosis.
c.
sickle-shaped cells become stuck in blood vessels.
d.
blood fails to clot properly.
 



 
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