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1st Semester Final Exam
Study Guide
Answers to Questions #56-106
(Genetics & DNA-RNA-Protein Synthesis)
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GENETICS
(CHAPTERS 11,
12-4 & 14)
56. What is heredity?
ANSWER:
Heredity is the passing of traits from
parent to offspring
57. What do you call the genetic
makeup of an organism?
ANSWER:
Genotype
58. What is the outward
appearance of a trait called?
ANSWER:
Phenotype
59. What do the terms homozygous
and heterozygous mean?
Give an example of each genotype.
ANSWER:
Homozygous means the alleles are
the same (Ex: HH, gg)
Heterozygous means the alleles are
different (Ex: Hh, Gg)
60. Who is known as the “Father of
Genetics?”
ANSWER:
Gregor Mendel
61. What term describes when two
alleles affect the phenotype of an
organism by blending together?
ANSWER:
Incomplete Dominance
Ex: Red flowers crossed
with white flowers
make pink flowers.
62. What term describes two alleles
affecting the phenotype of an
organism but without blending?
ANSWER:
Codominance
Ex: Red flowers crossed
with white flowers
make red & white
flowers.
63. What is a trait determined by
more than one pair of alleles or
more than one gene? (Know
examples)
ANSWER:
Polygenic Traits
Examples are hair color, eye color, skin
color & height – they are all
controlled by multiple genes.
64. What do you call traits
determined by three or more alleles?
(Know examples)
ANSWER:
Multiple allelic traits
An example is human blood types –
the three alleles are A, B and O.
65. What genotypes (letters) are
used to represent males and
females?
ANSWER:
Males = XY
Females = XX
66. Who is more likely to inherit a
sex-linked condition – men or
women? EXPLAIN WHY.
ANSWER:
Males – they have only one X
chromosome so they only need to
inherit one copy of the gene rather
than two copies.
67. If chromosomes do not separate
correctly during the process of
meiosis, this is called ____.
ANSWER:
Nondisjunction
68. If chromosomes do not separate
correctly during meiosis, how does this
change the number of chromosomes in
the gametes that form?
ANSWER:
The gametes
either have
extra or
missing
chromosomes
69. Describe the following chromosomal
mutations:
a. Inversion
b. Translocation
ANSWER:
a. Inversion is when part of a chromosome is
reversed or switched around in the wrong
order
b. Translocation is two chromosomes
exchange information when they are not
supposed to
Know your chromosome mutations!
70. What is a carrier – what
genotype is used to describe a
carrier?
ANSWER:
Carriers are individuals who have one
copy of a recessive allele.
They are heterozygous
71. If a trait is sex-linked, who
can never be a carrier for it?
ANSWER:
MALES
72. What do you call a diagram
that allows you to follow or trace a
trait through several generations?
ANSWER:
Pedigree
73. For a pedigree, what do
circles and squares represent?
ANSWER:
Circles = Females
Square = Males
74. For a pedigree, if circles or
squares are half-shaded, these
individuals are ____.
ANSWER:
Carriers
75. What do you call a picture of your
chromosomes that arrange them into
pairs and then orders them by size?
Why are these pictures important?
ANSWER:
- Karyotypes!
- They are important
because it can help
detect genetic
disorders
76. Based on the descriptions below,
identify the correct genetic disorder.
ANSWER:
a. Individual may have both female and male
characteristics because their sex
chromosomes are XXY =
KLINEFELTER’S SYNDROME
b. Individuals have mental retardation, muscle
weakness and short stature because they have
three chromosomes at position twenty-one =
DOWN SYNDROME
76. Based on the descriptions below,
identify the correct genetic disorder.
ANSWER:
c. Individuals have deterioration of brain tissue
in the middle ages because of a dominant
gene =
HUNTINGTON’S DISEASE
d. Females may have developmental or
reproductive issues because they have only
one X chromosome =
TURNER’S SYNDROME
76. Based on the descriptions below,
identify the correct genetic disorder.
ANSWER:
e. Individuals cannot clot their blood because
they have a recessive sex-linked gene=
HEMOPHILIA
77. Name three methods for
genetic screening.
ANSWER:
a) Blood tests (check for presence of proteins)
b) Amniocentesis = extract fluid surrounding
baby and test
c) Chronic Villi Sampling = extract tissue from
placenta and test
78. What is the identification and
manipulation/transfer of genes
from one organism to a different
organism called?
ANSWER:
GENETIC ENGINEERING
79. Name four practical uses of
genetic engineering/DNA technology.
ANSWER:
a) Medicine/vaccines
b) Useful bacteria
c) Food crops (more vitamins/nutrients, help in
growth)
d) Alter plants (resistant to pesticides/insects,
no fertilizer)
DNA, RNA &
PROTEIN
SYNTHESIS
(SECTIONS 12-1
TO 12-4)
80. What does DNA stand for?
ANSWER:
Deoxyribonucleic acid
KNOW THE PARTS OF DNA!!
81. What does RNA stand for?
ANSWER:
Ribonucleic acid
82. Name the 3 parts of a
nucleotide (the “building blocks” of
DNA)
ANSWER:
a. Sugar
b. Phosphate
c. Nitrogen base
83. Name the 4 bases in DNA.
How do they pair up?
ANSWER:
Adenine, guanine, cytosine and
thymine
Adenine pairs to Thymine
Cytosine pairs to Guanine
84. What is the difference between
a purine and a pyrimidine?
ANSWER:
Purines =
two chemical rings
(adenine & guanine)
Pyrimidines =
one chemical ring
(thymine & cytosine)
85. What type of chemical bond
forms between sugars and
phosphates?
ANSWER:
Covalent bond
86. What type of chemical bond
forms between nitrogen bonds?
ANSWER:
Hydrogen bond
87. What is the shape of DNA?
Who are the scientists who
discovered it?
ANSWER:
DNA has a helix shape
(a twisted ladder)
Watson & Crick are the
scientists who discovered it.
88. What is a mutation? Is it
always harmful?
ANSWER:
Mutations are permanent changes in
DNA.
They can be harmful BUT can also be
helpful or have no effect on the
organism.
89. Describe the following gene
mutations:
a. Point mutation
ANSWER:
a. Point mutations mean one base is
substituted for the wrong base
(Ex: Adenine is accidentally put where
Guanine should be) – it may or may not
affect the organism.
89. Describe the following gene
mutations:
b. Frameshift mutation
ANSWER:
Frameshift mutations mean you add or delete one
nucleotide – it moves all the other bases over
one place & changes the entire protein that gets
produced.
90. Why is DNA replication referred
to as “semi-conservative?”
ANSWER:
Replication is called
“semi-conservative”
because whenever new
DNA is made, one
strand is old and one
strand is new.
91. List all the differences between
DNA and RNA.
ANSWER:
DNA
a) Deoxyribose sugar
RNA
a) Ribose sugar
b) ACGT bases
T = thymine
b) ACGU bases
U = uracil
c) double-stranded
helix
c) single-stranded &
no helix
92. Name the function of each type of
RNA:
a. mRNA
b. tRNA
c. rRNA
ANSWER:
a. mRNA = copies the code or “message” of DNA &
sends it out to the ribosome
b. tRNA = carries the amino acid over to the
ribosome (amino acids make up a protein)
c. rRNA = makes up the structure of the ribosome
93. Name the process that will
make RNA from DNA.
ANSWER:
Transcription
94. What is a codon?
ANSWER:
A codon represents
three mRNA
nucleotides that
determines one
amino acid (for the
protein)
95. Using the codon chart, what amino
acid is produced from each codon listed
below?
ANSWER:
ACG = threonine (Thr)
GUG = valine (Val)
UGG = Tryptophan (Trp)
96. Using the codon chart, what codon
is the START codon for all proteins?
What amino acid does this codon code
for?
ANSWER:
AUG is the start codon.
Methionine (Met) is the
amino acid.
97. Using the codon chart, what are the
three STOP codons that tell the cell to
stop making a protein?
ANSWER:
UAA
UAG
UGA
98. Name the process that makes
proteins from RNA.
ANSWER:
Translation
99. What do proteins consist of?
What types of bonds link these
components together to make a
protein?
ANSWER:
Proteins consist of
AMINO ACIDS.
Peptide bonds link amino
acids together.
100. Write the complementary
strand to the strand of DNA shown
under the process of REPLICATION.
A T T C C G T C A A A
T A A G G CA G T T T
*You’re making a matching strand of DNA!
101. Write the complementary
strand to the strand of DNA shown
under the process of
TRANSCRIPTION.
A T T C C G T C A A A
UA A G GC A G UU U
*You’re making a matching strand of RNA!
102. A given piece of DNA contains
20% adenine. How much thymine
should be present
A + T + C + G = 100%
A = T; C = G (base pair rules)
A=20% so…
T=20%
103. A given piece of DNA contains
10% cytosine. How much adenine
should be present?
A + T + C + G = 100%
A = T; C = G (base pair rules)
C=10% so… G=10%
C+G= 20% so… A+T=80%
A=T so… A=40%
104. Label the following piece of DNA. Use
a D for the sugar, P for the phosphates, and
the letter A, C, G, T for the bases. Circle a
nucleotide.
105. From the given strand of
DNA, write the protein that would
result. In order to get full credit
on the test, be sure to include the
mRNA strand, tRNA strand, group
the codons, and circle and link the
amino acids together.
1. Make mRNA by base pairing to DNA
2. Bracket every three bases on mRNA to
show the codons
3. Write in the correct amino acid for each
codon
4. Circle and link together amino acids
starting with “Met” until you reach a
“Stop.” The circled and linked amino acids
represent your protein.
5. Fill in tRNA after writing amino acids by
base pairing to mRNA
6. Bracket tRNA to amino acid to show
anticodons