Genetics

Which of the following has the correct order for gene expression?
A. DNA-transcription-translation
B. DNA-translation-transcription
C. transcription-translation-DNA
D. translation-transcription-DNA

Model organisms generally:
A. are useful because we share a common ancestor
B. have longer life cycles
C. have fewer offspring
D. are not useful because our cell structure is so dissimilar
E. all of the above

Which of the following is FALSE when describing the source of genetic variation?
a. the many differences observed in organisms are the result of differences in their genes
b. recombination often results in different genetic combinations
c. mutations are heritable changes that can occur spontaneously or be induced
d. natural selection, as described by Darwin, results in changing allele frequencies based on the allele proportion in a population, rather than their selective advantage
e. they are all true

Which of the following parent breeders will ONLY produce heterozygous offspring when crossed:
A. homozygous dominant x heterozygous
B. heterozygous x homozygous recessive
C. homozygous dominant x homozygous recessive
D. heterozygous x heterozygous

Some cells may enter G_0. Cells in G₀
A. are quiescent and non-dividing
B. are duplicating DNA I preparation for S phase
C. are growing up where they can enter G₂
D. are becoming cancerous

Which of the following is correct reguarding a chromosomes "p" and "q" arm?
A. they always meet in the physical center of the chromosome
B. if an arm is shorter, it will be the p arm
C. the p arm is always shorter
D. p stands for prolonged and q stands for quaint
E. two of the above

When Mendel crossed a strain of tall pea plants with a strain of short pea plants, he observed that all of the plants in the F1 generation were tall. This suggests that
A. the tall trait was controlled by a dominant factor
B. both traits were controlled by a recessive factor
C. the strain of short plants was not capable of pollinating the strain of tall plants
D. the short trait was controlled by a dominant factor

During anaphase of mitosis:
A. the centromeres replicate
B. the chromosome replicates
C. the sister chromatids separate from each other
D. a & d
E. b & d
F. the homologous chromosomes separate from each other

A genetic cross performed many times produces 798 long-stemmed plants and 266 short-stemmed plants. the probability of obtaining a short-stemmed plant in the cross is:
A. 798:266
B. 266:1,064
C. 798:1,064
D. 266:798

To determine the genotype of an individual that shows a dominant phenotype, you would cross that individual with:
A. homozygous recessive
B. heterozygous dominant
C. heterozygous recessive
D. homozygous dominant

The protienaceous complex that forms between chromosomes during prophase is called
A. the chiasma
B. the kinetochore
C. collagen
D. the synaptonemal complex

The australian ant Myrmecia pilosula, called the "bulldog ant" because of it's viciousness, is actually several species of ants, one of which is diploid and has 24 chromosomes. How many chromatids are in a cell in prophase of mitosis?
A. 12
B. 60
C. 36
D. 48
E. 24

Given an individual who is heterozygous at 5 loci on 5 different chromosomes, how many different gametic genotypes are possible?
A. 25
B. 10
C. 32
D. 16

When studying an inherited phenomenon, a geneticist discovers a phenotypic ratio 9:3:3:1 among off-spring of a given mating. A possible explanation for this is a two-locus system that exhibits:
A. linkage
B. pleiotropy
C. independent assortment
D. epistasis

If 83 individuals are homozygous for the recessive trait, eyeless, and 67 of those individuals are eyeless, then this is an example of
A. pleiotropy
B. incomplete dominance
C. incomplete penetrance
D. expressivity

List the three compounds of a nucleotide

In mammals, the locus on the Y chromosome that is necessary for a zygote to become male is

a. the sex-determining region Y

b. the ovary suppression factor

c. the histocompatibility Y-antigen

d. the ZFY gene

e. none of the above

the statistical test that is used to compare an observed distribution to an expected distribution is

a. a t-test

b. analysis of variance

c. means

d. chi-square test

e. two of these

Assume that a prophase I somatic cell nucleus in Geospiza fortis (a medium ground finch) female contains 18 picograms of DNA. How much DNA would be expected in a G1 interphase cell of a female? How much DNA is in each gamete after telophase II is complete?

a. 9 picograms/9 picograms

b. 9 picograms/18 picograms

c. 18 picograms/9 picograms

d. 18 picograms/ 18 picograms

e. 9 picograms/4.5 picograms

f. not enough information to answer

Typical ratios resulting from epistatic interactions in dihybrid crosses would be _________.
a. 9:3:3:1, 1:2:1

b. 1:1:1:1, 2:4:6:4:2

c. 9:3:4, 9:7

d. 1:2:2:4:1:2:1:2:1

e. 3:1, 1:1

f. two of these

The chromosome theory of inheritance states that:
a. genes are located on chromosomes

b. chromosomes replicate before cell division

c. different chromosomes assort independently

d. chromosomes consist of DNA

e. alleles of a gene segregate during cell division

List the stages of the scientific method in order:

A heterozygous fly with a wildtype phenotype is testcrossed and the following progeny are produced: groucho- 518; rough- 471; groucho-rough- 6; wildtype- 5. Which flies are non recombinants? (actual mutations)
a. groucho

b. wildtype

c. rough

d. groucho, rough

e. c & d

f. a & b

e. a & c

In a transformation experiment in which the a+b+ strain is the donor to the ab strain, the following transformant were recovered: a+b= 50, ab+= 50, a+b+= 100. What is the frequency that b is cotransformed with a>
a. 33%

b. 50%

c. 25%

d. 66%

e. too far apart to calculate

The bacteria of Avery et al. (1944) were transformed by a substance that was inactivated by:
a. 32P

b. 35S

c. polymerase

d. RNase

e. DNase

Based on the Watson-Crick double-helix model:
A. if you know the content of one nitrogenoous base (e.g, A) then you know the content of the other three (e.g, T, G, and C)
B. for every A there must be a G
C. two of these
D. A-T nitrogen base bonds are formed from 3 hydrogen bonds
E. nitrogenous bases of antiparallel are paired by covalent bonds

E. coli are cultured in 15N-containing media for many generations and transferred to 14N-contained media. After exactly 2 rounds of replication in the second media, the DNA is extracted without any breakage and density gradient centrifugation is performed.

If DNA replicated in a conservative manner, you would expect to see _____ after 3 generations.
a. all light bands

b. one heavy/light band and one light band

c. one heavy band and one light band

d. one heavy band and one heavy/light band

e. one heavy/light band

E. coli are cultured in 15N-containing media for many generations and transferred to 14N-contained media. After exactly 2 rounds of replication in the
second media, the DNA is extracted without any breakage and density gradient centrifugation is performed.

if DNA replicated in a semi-conservative manner, you would expect to see _____ after 3 generations.

a. all light bands

b. one heavy/light band and one light band

c. one heavy band and one light band

d. one heavy band and one heavy/light band

e. one heavy/light band

E. coli are cultured in 15N-containing media for many generations and transferred to 14N-contained media. After exactly 2 rounds of replication in the second media, the DNA is extracted without any breakage and density gradient centrifugation is performed.

After 3 generations, what did Matthew Meselson and Franklin Stahl find experimentally in 1958?

a. all light bands

b. one heavy/light band and one light band

c. one heavy band and one light band

d. one heavy band and one heavy/light band

e. one heavy/light band

Molecule %A %G %T %C %U
A 26 24 0 24 26
B 21 40 21 18 0
C 33 17 33 17 0
D 33 33 17 17 0
E 15 40 10 20 15

Which of the molecules is RNA?

Molecule %A %G %T %C %U
A 26 24 0 24 26
B 33 33 17 17 0
C 15 40 10 20 15
D 21 40 21 18 0
E 33 17 33 17 0

Which of the molecule(s) is double stranded DNA?

Molecule %A %G %T %C %U
A 26 24 0 24 26
B 33 17 33 17 0
C 21 40 21 18 0
D 33 33 17 17 0
E 15 40 10 20 15
Which of the molecules cannot exist?

3 different rII deletions (labeled #1-3) of phage T4 were tested for recombination by co-infecting E. coli. The following results occurred:
# 1 2 3 A
1 X O X
2 O X X X
3 X X X
A X
X- no growth O= growth

Of mutants 1,2,3 list all that have overlapping mutations:

3 different rII deletions (labeled #1-3) of phage T4 were tested for recombination by co-infecting E. coli. The following results occurred:
# 1 2 3 A
1 X O X
2 O X X X
3 X X X
A X
X- no growth O= growth

Based on the graph, would mutant A grow or not grow with mutant #1?

How is the function of histones related to the amino acid compositions?
A. they are highly hydrophobic so they have a tendency to interact with DNA
B. they are highly hydrophilic so they have a tendency to interact with DNA
C. they are positively charged so they interact with negatively charged DNA
D. they are negatively charged so they interact with positively charged DNA
E. two of the above

Bacterial cells are always haploid unless
A. they are infected with a transforming phage that has been incubated with bacteria from the same strand
B. the F factor is removed from the chromosome, taking chromosomal genes with it, and the cell then transfers its F plasmid to another cell
C. they are simultaneously infected by the two Hfr strains
D. None of the above. they are always haploid

Structures located at the ends of eukaryotic chromosomes are called:
a. centromere

b. telomerases

c. recessive mutations

d. telomeres

e. permissive mutations

RNA differs from DNA in all of the following ways except
a. the 5'-3' orientation of the polynucleotide strand

b. DNA is double stranded, while RNA is single stranded

c. the sugar in DNA nucleotides is deoxyribose, the sugar in RNA nucleotides are ribose

d. DNA has the pyrimidine base pair thymine, and RNA has the pyrimidine base pair uracil

If two DNA strands of identical length were analyzed, which of the following statements would be true of their Tm or melting temperature, or temperature required to denature ("unzip") the strands>
a. DNA with a high GC content must have a lower Tm

b. all DNA strands of equal length have equal melting temperatures

c. DNA with a low AT content would melt more slowly

d. DNA with low GC content would have a lower Tm

Viral chromosomes exist in a variety of structures and can be made up of the following:
a. protein or lipid coding sequences

b. DNA only

c. DNA or RNA

d. RNA only

e. DNA, RNA, or protein

Xeroderma pigmentosum is a disease that inactivates:
a. the X-ray repair system

b. the UV repair system

c. the DNA replication system

d. two of these choices

e. All of the above

An operon is a group of structural polycistronic genes that:
a. encode separate parts of a single protein

b. only function in the presence of the F factor

c. function only in the presence of DNA damage

d. are under the control of a single promoter

e. None of the above

The insulin molecule is composed of two polypeptide chains, one consisting of 20 amino acids and the other consisting of 31. what is the minimum number of base pairs of DNA required to code for this molecule?
a. 20

b. 40

c. 60

d. 100

e. 153

The DNA code for glutamic acid is CTC or CTT. The code for valine is CAA or CAT. In sickle cell hemoglobin, valine is present instead of glutamic acid. Assuming a single base pair substitution has occurred, what is the mRNA code in the affected mutant?
a. CUU

b. GAA

c. GAG

d. GUA

e. GUU

A synthetic mRNA molecule is made by using only two types of nucleotide, containing adenine and cytosine. How many different codons would it contain?
a. 2

b. 4

c. 6

d. 8

e. 12

When RNA is being made, the RNA base ________ always pairs with the base ________ in DNA.

a. U...T

b. T...G

c. U...A

d. A...U

e. T...A

Bacteria and mammalian cells distinguish the template strand from the nascent strand during mismatch repair by:
a. 5'-3' polarity

b. 3'-5' polarity

c. methylation of the newly synthesized strand

d. methylation of the template strand

e. two of the above

In the absence of external mutagens(no chemicals, no radiation), what is the most common type of DNA damage?
a. depurination

b. free radical formation

c. UV light

d. tatomeric shifts

e. secret government mutator ray gun

Two patients have mutated phenylalanine pathway. The first patient has a defective phenylalanine hydroxylase enzyme resulting in phenylketonuria (PKU). The second patient has a defective homogentisate oxidase enzyme resulting in alcaptonuria. For both patients, identify the "major class of mutation" and the type of inheritance pattern you would expect for these two defective enzymes.

a. gain of function mutation, dominant inheritance

b. loss of function mutation, dominant inheritance

c. gain of function mutation, recessive inheritance

d. loss of function mutation, recessive inheritance

e. hydrogen bonds

The role of an enhancer in eukaryotic gene regulation is to:
a. increase the replication of a specific gene

b. increase the transcription of a specific gene

c. increase the half-life of a specific polypeptide

d. increase the half-life of a specific mRNA

e. increase the translation of a specific mRNA

In splicing the primary transcript to for the functional RNA, which of the following components are used directly in the spliceosome?
a. sigma factor

b. TGII-D

c. snRNPs

d. 16S rRNA

e. TFIII-A

A branched biochemical pathway in bacterium synthesized two related essential amino acids D and F. A mutant defective for enzyme 2 grows on minimal media plus:
a. A alone

b. B alone

c. C alone

d. E alone

e. none of the above, both A and B are required

What genetic phenomenon explains the following paradox: There are 64 possible codons, but only 30-40 tRNA types.
a. non-redundancy

b. commaless code

c. wobble

d. petidyl transferase

e. translocation

During translation of the protein, how will the initiation codon be recognized?
A. the first three nucleotides at the 5' end will be used as a start codon
B. the small ribosomal sub-unit will scan from the 5' end to the first start codon
C. the mRNA will have only one codon that can be recognized by a methionine tRNA
D. the 16S rRNA with form basepairs with a sequence near the start codon
E. small nuclear RNAs will recognize a consensus sequence at the start codon

Eukaryotic mRNA undergoes extensive modification before it is released form the nucleus and translated. List the three main ways mRNA is post-transcriptionally modified.

Process of unregulated cell division; loss of controlled growth

Loss of ________ is when the cells stop growing (effects movement and replication) when touched

Cancer is a ________ disease

All tissue is produced by

The accumulated population of cells that changes their gene expression to gene specific to their tissue type

Cancer that is surgically removed

Cancer that can invade other tissue

As most cells differentiate, they lose the ability to proliferate- hang out in G₀ and have a finite lifespan

Cancer cells can divide without _________- never express the genes which turn them "quiescent"

List the 3 checkpoints that control the cell cycle

-Checkpoint that makes the decision about whether the cell should divide and enter S
-Some cells never pass this point and are said to be in G₀

Checkpoint that leads to mitosis

Checkpoint that occurs during metaphase and triggers the exit process of the M phase and entry to the G₁ phase

-Viral cells
-Stimulate cell proliferation-hit accelerator

Cells that can inhibit cell growth- brakes off

Growth factor- modify protein- can activate signal pathway even if there is no signal

-Can fuse cancer cells with normal cells and cancer stops- normal cell suppresses growth

List 3 examples of tumor suppressor genes

-Replicative senescence
-Normal cells off, cancer on
-Strategy in cancer treatment; inhibit it's activity

Cancer does not happen all at once, it take ___ steps; decades over lifetime

Four methods of developing cancer

Type of extracellular inheritance in which DNA contained in the mitochondria of chloroplasts determines certain phenotypic characteristics of an organisms off-spring

Type of extracellular inheritance resulting from the symbiotic or parasitic association of a microorganism

Type of extracellular inheritance on the phenotype, whereby nuclear gene products are stored in the the egg and then transmitted to offspring from the female parent in the cytoplasm of the ovule

-affects chloroplast
-mitochondrial mutations
-mitochondrial-based disorders in humans

-Coexist in symbiotic relationship and passed in maternal cytoplasm
-Cytoplasmically transmitted phenotypes due to an invading organism

-Implies that an offspring's phenotype is under the control of nuclear gene products present in the egg
-Proteins and/or mRNA deposited in oocyte before fertilization

For maternal effect genes, the phenotype of the ___________ and not that of the embryo determines the phenotype of the off-spring

-The study of inherited changes in phenotype(appearance) or gene expression caused by mechanisms other than changes in the underlying DNA sequence

-The overall epigenetic state of a cell

Modification of certain genes, but not the basic structure of DNA

Chromosomes are pulled apart and segregated and different cells receive different information

During prophase of mitosis crossing-over occurs; is necessary for diversity

Causes over-expression of gene
-dominant

-Recessive because gene is broken, function broken

This is a generic diagram of __________.
Which nucleotides are this type?

This is a generic diagram of _________.
Which nucleotides are this type?

If mutated, which enzyme would cause Okazaki fragments to accumulate?

If mutated, which enzyme would cause no initiation of DNA synthesis because polymerase III can't get started?

If mutated, which enzyme would cause RNA to remain in DNA?

If mutated, which enzyme would cause DNA to reanneal quickly after being "unzippered"?

If mutated, which enzyme would cause no replication forks to ever form due to the DNA remaining double stranded?

What specific aspect of replication would be hindered if a cell could not produce dNTPs? Why?

Since our DNA strands run antiparallel to each other in helix, how can you determine which strand has polarity? To which end does polymerase add to the next nucleotide and why?

list 3 differences between organization, expression, or control of expression between prokaryotic and eukaryotic genes.

Describe the function and general nature of promoters. How do they influence transcription?

What is meant by alternative splicing?

Under what conditions might one have an amino acid substitution in a protein that does not result in an altered phenotype?

What are GTFs and what do they do?