1.
B
2.
E
3.
A or C
4.
C
5.
B
6.
D
7.
C
8.
C
9.
B
10.
B
11.
A
12.
C
13.
D
14.
C
15.
A
16.
B
17.
D
18.
C
19.
D
20.
D
Test #3 short answer section
1.
What is the most likely result … (3 pts)
Frame
shift (2)
Missense
(2)
Nonsense
translation past deletion (3)
Early
termination of translation (2)
No
effect – homologous gene will express (3)
Decrease/50%
expression of protein product (3)
Defective
protein/enzyme (3)
2.
Given a family with the gene for hemophilia: Mom is a carrier, Dad expresses the trait. They have one daughter, one son. What are the odds for:
The
son expressing? _50% or .5 or
1:1 or 1/2_____________
The
daughter expressing? __same as above____________(1 pt each)
3. Deaf-mutism: given the genes for deaf-mutism are recessive,
explain how a deaf-mute mom and a deaf-mute dad can have normal children. Be
specific re: genotypes. (3 pts) Note
hint in the language…genes ARE
This
is a TWO GENE trait (*not* two alleles!).
If
either gene is homozygous recessive, person is deaf-mute.
Here
father is homozygous recessive for one gene, homozygous dominant for the
other. Mother is homozygous dominant
for the first gene, homozygous recessive for the other. ddEE x DDee
Children
are all fully heterozygous (DdEe), thus don’t express.
4.Give
a specific example of temporal gene regulation in a eukaryotic system.
(2 pts)
Temporal
= time regulated, as in something happens at a particular time in the
organism’s life.
Beta
and gamma hemoglobin activation in fetus; also apoptosis of inter-digit flesh
5. Questions about Translation:
What
is main chemical energy source for translation? ____GTP______(1 pt)
What
components are necessary for assembling “loaded” tRNA’s for use in
translation? Be specific. (2 pts) [half
point each]
Aminoacyl-tRNA
synthetase (1 of 20) or specific assembly enzyme
Proper
amino acid
Proper
tRNA
ATP
What
are the components necessary for translation initiation, listed in order of
use?(3 pts) (half point each, final half point for 1st and last in proper
place)
Must
begin with mRNA
Then,
in no particular order…
Initiation
factor(s)
Charged
(“loaded”) tRNA [for Methionine] [for AUG codon] [with UAC anticodon]
GTP
Small
ribosomal subunit
Must
end with large ribosomal subunit
6.
Pedigree questions: The following pedigrees represent phenotypes
displayed by parents and their offspring.
Answer the possibility Yes or No, and give a 10 word or less
explanation proving your choice. (2 pts each; no credit for just yes/no
answers)
Pedigree
1
Yes/No?
NO
______ Could this trait be inherited
as a simple autosomal recessive?
Reason: No dominant gene in parents or
Son’s don’t express recessive
Yes______
Could this trait be inherited as a simple autosomal dominant?
Reason:
Parents both heterozygous
Yes______ Could this trait be inherited as a
simple X-linked dominant?
Reason: Mom heterozygous
Pedigree
2
Yes/No?
Yes______
Could this trait be inherited as a simple autosomal recessive?
Reason: Mom heterozygous
Yes______
Could this trait be inherited as a simple autosomal dominant?
Reason:
Dad heterozygous
Yes______ Could this trait be inherited as a
simple X-linked recessive?
Reason: Mom heterozygous
NO______ Could this trait be inherited as
mitochondria associated?
Reason: Mom doesn’t express or all children
don’t express
Test
#3 essay questions:
Essay: compare the Mendelian and molecular genetic
explanations for the phenotype and genotype expressions of
PKU. Be sure to include organismal
and biochemical effects. (12 pts)
A diagram might be helpful.
**See
web link for diagrams
Phenotype
– retardation – genotype: acts as Mendelian recessive gene, 1:3 ratio for
heterozygous parent cross (4pts)
Protein
(enzyme) production – same level for homozygous normal, heterozygous,
homozygous affected (4 pts)
Enzyme
activity is incomplete dominant –
Homo normal – 100%
Hetero – 50%
Homo affected – 0% (4pts)
Enzyme
quality is co-dominant
Homo normal – 100% good
Hetero – 50% good, 50% bad
Homo affected – 100% bad (4 pts)
2.
Discuss the Griffith’s experiment and the meaning of his unexpected dead
mice. Be sure your discussion uses only
the concepts understood at the time of the experiment! [1920’s] (8 pts) A simple diagram might be helpful.
Smooth
bacteria – dead mouse
Rough
bacteria – live mouse
Heat
killed smooth bacteria – live mouse (2 pts)
Heat
killed smooth + rough live bacteria – dead mouse (2 pts)
Recovered
live smooth bacteria from dead mouse (2 pts)
“Transforming
factor” (1 pt) in heat-killed smooth
changed
non-virulent rough into virulent smooth (4
pts)
Use
the words/phrases: DNA, Nucleic Acid,
Nucleus, Chromosome (-1 pt)