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Chp 3 Test D

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.

Word Bank (use the following words to make the false statements below true)
offspring      order      Messenger            half            Tall
     
 

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

 

4. 
An organism’s physical appearance is its phenotype.

 

5. 
The sex cells produced by meiosis have twice the number of chromosomes as the parent cells.

 

6. 
Chromosomes carry genes from parents to offspring.

 

7. 
The number of DNA bases forms a genetic code.

 

8. 
Transfer RNA carries coded messages from the nucleus to the cytoplasm.

 

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

9. 
What did Gregor Mendel do to study different characteristics in his genetics experiments?
a.
He ate chocolate covered crickets.
b.
He cross-pollinated plants.
 

10. 
In Mendel’s experiments, what proportion of the plants in the F2 generation had a trait that had been absent in the F1 generation?
a.
none
b.
one fourth
 

11. 
Factors that control traits are called
a.
genes.
b.
purebreds.
 

12. 
Scientists call an organism that has two different alleles for a trait a
a.
hybrid.
b.
trait.
 

13. 
What does the notation TT mean to geneticists?
a.
two dominant alleles
b.
two recessive alleles
 

14. 
What does the notation Tt mean to geneticists?
a.
one dominant allele and one recessive allelle
b.
two dominant alleles
 

15. 
What is probability?
a.
the actual results from a series of events
b.
the likelihood that a particular event will occur
 

16. 
What did Mendel predict was the probability of producing a tall plant from a genetic cross of two hybrid tall plants?
a.
two in four
b.
three in four
 

17. 
What does a Punnett square show?
a.
all the possible outcomes of a genetic cross
b.
only the dominant alleles in a genetic cross
 

18. 
If a homozygous black guinea pig (BB) is crossed with a homozygous white guinea pig (bb), what is the probability that an offspring will have black fur?
a.
25 percent
b.
100 percent
 

19. 
An organism’s physical appearance is its
a.
genotype.
b.
phenotype.
 

20. 
What does codominance mean in genetics?
a.
The alleles are neither dominant nor recessive.
b.
Both alleles are recessive.
 

21. 
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.
 

22. 
Walter Sutton discovered that the sex cells of grasshoppers have exactly
a.
the same number of chromosomes found in the body cells.
b.
half the number of chromosomes found in the body cells.
 

23. 
What happens during meiosis?
a.
Each sex cell loses half of its chromosomes.
b.
Chromosome pairs separate to form new sex cells.
 

24. 
When sex cells combine to produce offspring, each sex cell will contribute
a.
one fourth of the normal number of chromosomes.
b.
half the normal number of chromosomes.
 

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
 

26. 
The order of the bases along a gene determines the order in which
a.
amino acids are put together to form a protein.
b.
chromosomes are arranged in the nucleus.
 

27. 
What does messenger RNA do during protein synthesis?
a.
copies the coded message from the DNA and carries it into the cytoplasm
b.
copies the coded message from the DNA and carries it into the nucleus
 

28. 
What do transfer RNA molecules do during protein synthesis?
a.
copy the coded message from the protein and carry it into the nucleus
b.
carry amino acids and add them to the growing protein
 

29. 
What is a mutation?
a.
any change that is harmful to an organism
b.
any change in a gene or chromosome
 

30. 
A mutation is harmful to an organism if it
a.
changes the phenotype of the organism.
b.
reduces the organism’s chances for survival and reproduction.
 

31. 
Which term refers to physical characteristics that are studied in genetics?
a.
traits
b.
offspring
 

32. 
The different forms of a gene are called
a.
alleles.
b.
factors.
 

33. 
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
 

34. 
What does the notation tt mean to geneticists?
a.
two dominant alleles
b.
two recessive alleles
 

35. 
An organism’s genotype is its
a.
genetic makeup
b.
feather color
c.
physical appearance
d.
stem height
 

36. 
Which nitrogen base in RNA is NOT part of DNA?
a.
adenine
b.
uracil
 

37. 
An organism that has two identical alleles for a trait is
a.
homozygous.
b.
tall.
 

38. 
A heterozygous organism has
a.
three different alleles for a trait.
b.
two different alleles for a trait.
 

Completion
Complete each sentence or statement.

Word Bank
(use these words to fill in the blanks below, yu can check them off as you go!)

order     50      codominance    purebred     dominant    gene       Punnett Square mutation     probability    10     TT      order          Transfer
 

39. 
The offspring of a ____________________ plant will always have the same alleles for a trait as the parent.
 

 

40. 
If a ____________________ allele is present, its trait will appear in the organism.
 

 

41. 
In pea plants, the tall-stem allele and the short-stem allele are different forms of the same ____________________.
 

 

42. 
Mendel used the principles of ____________________ to predict what percent of offspring would show a particular trait.
 

 

43. 
If each of ten events is equally likely to occur, the probability of each individual event occurring is ____________________ percent.
 

 

44. 
A chart used to predict results of genetic crosses is known as a(n) ____________________.
 

 

45. 
In a cross between two hybrid Tt pea plants, ____________________ percent of the offspring will be Tt.
 

 

46. 
Alleles that are neither dominant nor recessive produce an inheritance pattern known as ____________________.
 

 

47. 
If all of the sex cells of an organism have the T allele, the genotype of that organism must be ____________________.
 

 

48. 
The ____________________ of the DNA bases determines which protein will be produced.
 

 

49. 
____________________ RNA adds amino acids to a growing protein.
 

 

50. 
The substitution of one base for another during DNA replication is an example of a(n) ____________________.
 

 



 
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