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Genetics
Final Review: Questions from exams 1 & 2
112
Biology
05/09/2010

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Term
Much is known about early Greek thinking regarding heredity and variation. What two notable Greeks provided early speculations on the nature of human genetics?
Definition
Hippocrates and Aristotle
Term
The branch of genetics which refers to the passage of genetic traits from one generation to the next is referred to:
Definition
transmission genetics
Term
Why was the ability to observe cells with a microscope crucial to the foundation of modern genetics?
Definition
Microscopes allowed the observation of chromosomes in the nucleus, and dividing in cell division
Term
The contribution of James Watson and Francis Crick to modern genetics was to
Definition
describe the structure of DNA
Term
A diploid somatic cell from a rat has a total of 42 chromosomes. As in humans, sex chromosomes determine sex: XX in females and XY in males.
What is the total number of DNA molecules in a rat cell in G2?
Definition
84
Term
A diploid somatic cell from a rat has a total of 42 chromosomes. As in humans, sex chromosomes determine sex: XX in females and XY in males.
What is the total number of telomeres in a rat cell in G2?
Definition
168
Term
A diploid somatic cell from a rat has a total of 42 chromosomes. As in humans, sex chromosomes determine sex: XX in females and XY in males.
What is the total number of chromosomes in a polar body cell from a rat?
Definition
21
Term
A dividing eukaryotic cell is treated with a drug that inhibits the molecular motors associated with kinetochores. At which cell stage would it stop?
Definition
M (anaphase)
Term
In a healthy male, how many sperm cells would be expected to be formed from
a) 400 primary spermatocytes?
b) 400 secondary spermatocytes?
Definition
a) 1600
b) 800
Term
In a healthy female, how many secondary oocytes would be expected to form from 100 primary oocytes? How many first polar bodies?
Definition
100,100
Term
What is the outcome of synapsis, a significant event in meiosis?
Definition
Chiasma segregation
Term
During interphase of the cell cycle, mitosis or meiosis,
Definition
DNA content essentially doubles
Term
What types of ratios are likely to occur in crosses when dealing with a single gene pair?
Definition
3:1
1:1
1:2:1
Term
Apply the product law to a coin-flip situation. What is the probability that on three flips of a coin, heads will occur on all three flips?
Definition
1/8
Term
The fundamental Mendelian process which involves the separation of contrasting genetic elements at the same locus would be called
Definition
segregation
Term
This organism with such genotype;
Aa BB CC Dd EE
Definition
is dihybrid
Term
Name the single individual whose work in the mid-19th century contributed to our understanding of the particulate nature of inheritance as well as basic genetic transmission patterns. With what organism did this person work?
Definition
Gregor Mendel, Psium sativum
Term
An allele is
Definition
an alternate form of a gene
Term
In Drosophila, sex is determined by a balance between the number of haploid sets of autosomes and the number of
Definition
X chromosomes
Term
In humans, the genetic basis for determining the sex "male" is accomplished by the presence of
Definition
a portion of the Y chromosome
Term
Klinefelter syndrome in humans, which leads to underdeveloped testes and sterility is caused by which chromosomal condition?
Definition
47; XXY
Term
Red-Green color blindness is X-linked recessive. A woman with normal color vision has a father who is color-blind. The woman has a child with a man with normal color vision. Which phenotype is NOT expected?
Definition
color-blind female
Term
Red-green color blindness is X-linked recessive. MN blood type is determined by an autosomal gene with two codominant alleles, L^M and L^N. A woman whose father was color-blind has type MN blood. She is going to have a child with a man who has normal color vision and type MN blood. What is the probability the child will be a boy with normal color vision and type M blood?
Definition
1/16
Term
In a germ-line cell from a female grasshopper (XX-XO sex determination system), when do the homologous X chromosomes segregate?
Definition
meiosis I, anaphase
Term
In a germ-line cell from a human male that is dividing, when do the X and Y chromosomes segregate?
Definition
meiosis I, anaphase
Term
A eukaryotic diploid cell from an organism with the ZZ-ZW sex determination system has two pairs of autosomes and a pair of sex chromosomes, Z and W:
The individual from which the cell came is
Definition
female
Term
A eukaryotic diploid cell from an organism with the ZZ-ZW sex determination system has two pairs of autosomes and a pair of sex chromosomes, Z and W:
What is the probability of a gemete from this individual that has the following genotype: alleles A and b, chromosome Z?
Definition
1/8
Term
A eukaryotic diploid cell from an organism with the ZZ-ZW sex determination system has two pairs of autosomes and a pair of sex chromosomes, Z and W:
Assume A and B are dominant alleles. If this individual was crossed to an individual of genotype AaBb, what is the probability of a female offspring with two dominant traits given by alleles A and B?
Definition
9/32
Term
A Barr body is
Definition
an inactivated X chromosomes, visible in the nucleus of a cell from a female mammal
Term
A person has the genotype XY, but develops female. What is a possible explanation?
Definition
androgen insensitivity syndrome

mutation in SRY
Term
With incomplete dominance, a likely ratio resulting from a monohybrid cross would be
Definition
1:2:1
Term
A situation where there are multiple alternative forms of a given gene would be called
Definition
multiple alleles
Term
A condition in which one gene pair masks the expression of a non-allelic gene pair is called
Definition
epistasis
Term
Hemizygosity would most likely be associated with which of the following?
Definition
sex linked inheritance
Term
Because of the mechanism of sex determination, males of many species can be neither homozygous or heterozygous. Such males are said to be
Definition
hemizygous
Term
interactions among the human ABO blood group alleles involve
Definition
co-dominance and epistasis
Term
Multi-factorial traits are influence by
Definition
multiple genes and environment
Term
If the characteristic followed in the pedigree is autosomal recessive, what is III-1's genotype? (picture on overhead)
Definition
definitely heterozygous
Term
If a cell has 8 chromosomes at metaphase of mitosis, how many chromosomes will it have during anaphase?
Definition
16
Term
Which of the following organisms does NOT reproduce cells by mitosis and cytokinesis?
Definition
bacterium
Term
What are enzymes called that control the activities of other proteins by phosphorylating them?
Definition
protein kinases
Term
The MPF protein complex turns itself off by
Definition
activating an enzyme that destroys cyclin
Term
Which of the following is the term for a human cell that contains 22 pairs of autosomes and two X chromosomes?
Definition
a female somatic cell
Term
How does the sexual life cycle increase the genetic variation in a species?
Definition
by allowing independent assortment of chromosomes

by allowing random fertilization

by allowing crossing over
Term
You are genetically unique. This is at least in part a result of
Definition
random fertilization

genetic recombination

independent assortment of chromosomes
Term
What was the most significant result Gregor Mendel drew from his experiments with pea plants?
Definition
traits are inherited in discrete units, and are not the result of "blending"
Term
A couple who are both carriers of the gene for systic fibrosis have two children who have cystic fibrosis. What is the probability that their next child will have cystic fibrosis?
Definition
25%
Term
Huntington's disease is caused by a dominant allele. If one of your parents has the disease, what is the probability that you, too, will have the disease?
Definition
1/2
Term
Crossing over or recombination cannot take place between X and Y chromosomes except at the
Definition
pseudoautosomal regions
Term
When 2 genes control 1 characteristic with multiple phenotypes, this is called:
Definition
epistasis
Term
Codominant alleles are expressed in individuals that are:
Definition
heterozygous
Term
Mitochondrial DNA was followed to identify the Romanovs, the Russion Royal family killed in the revolution. Why was mitochondrial DNA followed?
Definition
it's inheritance is easy to follow because it is inherited only from the mother
Term
Cytoplasmic inheritance is due to
Definition
mitochondrial and chloroplast genes
Term
If a typical somatic cell has 32 chromosomes, how many chromosomes are expected in each gamete of that organism?
Definition
16
Term
Red-green color blindness is X-linked recessive. A woman with normal color vision has a father who is color-blind. The woman has a child with a man with normal color vision. Which phenotype is NOT expected?
Definition
color-blind female
Term
A condition in which one gene pair masks the expression of a non-allelic gene pair is called
Definition
epistasis
Term
Linked genes
Definition
co-segregate
Term
Genetic distances within a given linkage group
Definition
cannot exceed 100cM

are dependent upon crossover frequencies between paired, non-sister chromatids

are measured in centiMorgans
Term
When two genes fail to assort independently the term normally applied is
Definition
linkage
Term
Assume that a cross is made between AaBb and aabb plants and all the offspring are either AaBb or aabb. These results are consistant with the following circumstance
Definition
complete linkage
Term
Assume that a cross is made between AaBb and aabb plants and the offspring fall into approximately equal numbers of the following groups: AaBb, Aabb, aaBb, aabb. These results are consistent with the following circumstance
Definition
independent assortment
Term
Somatic cell hybridization
Definition
used to localize genes on specific chromosomes

is based on fusion of 2 different lines of cells

hybrid cells will not keep all the chromosomes and will lose them randomly
Term
Assume that a cross is made between AaBb and aabb plants and the offspring occur in the following numbers: 106 AaBb, 48 aaBb, 94 aabb. These results are consistent with the following circumstance
Definition
linkage with 50% crossing over
Term
During interphase of the cell cycle, mitosis or meiosis
Definition
DNA content essentially doubles
Term
A bacterial cell transfers chromosomal genes to F- cells, but rarely causes them to become F'. The bacterial cell is
Definition
Hfr
Term
The E. coli genome contains roughly
Definition
5,000,000 nucleotide pairs and 5000 genes
Term
leu- bacteria are mixed in a flask with leu+ bacteria, and soon all bacteria are leu+. However, if the leu- cells are on one side of a u-tube and the leu+ cells are on the other, the leu- cells do not become prototrophic. This suggests
Definition
conjugation
Term
Two different strains of a mutant phage infect a single bacterium. One phage strain is d- and the other e-. Some of the progeny are d+e+ and some are d-e-. What genetic phenomenon does this demonstrate?
Definition
recombination
Term
What does the enzyme reverse transcriptase do?
Definition
it makes a DNA molecule using RNA as a template
Term
Bananas do not have seeds because
Definition
it is a triploid and can not produce viable gametes
Term
AIDS is caused by a
Definition
retrovirus
Term
Name two forms of recombination in bacteria
Definition
conjugation and transduction
Term
Bacteriophage engage in two interactive cycles with bacteria. What are these cycles?
Definition
lytic and lysogenic
Term
A bacteriophage which is capable of entering either a lytic or lysogenic cycle is called a
Definition
temperate bacteriophage
Term
Transduction is a form of recombination in bacteria which involves
Definition
bacteriophage
Term
The clearing made by bacteriophage in a "lawn" of bacteria on an agar plate is called a
Definition
plaque
Term
Name the general category into which double-stranded circular extrachromosomal DNA elements such as F factors, ColE1, and R would fall
Definition
plasmid
Term
The process of sexduction means
Definition
transfer of a gene from one bacteria to another bacteria

the F' is involved in bacterial gene transfer

the bacteria receiving the gene become merozygotes (having 2 copies of same gene)
Term
Gene deletion is always bad because
Definition
it causes imbalance in amount of gene product

it can cause pseudo dominance

it can cause haplodeficiency (or haplo-insufficiency)
Term
______ can cause genes to move from one linkage group to another.
Definition
translocations
Term
The inheritance of both chromosomes from the same parent is a condition called
Definition
uniparental disomy
Term
When an organism gains or loses one or more chromosomes but not a complete haploid set, the condition is known as
Definition
aneuploidy
Term
The condition known as cri-du-chat syndrome in humans as a genetic constitution designated as
Definition
46, 5p-
Term
While the most frequent forms of Down syndrom are caused by random error, nondisjunction of chromosome 21, down syndrome occasionally runs in families. The cause of this form of familial Down syndrome is
Definition
a translocation between chromosome 21 and a member of the D chromosome group
Term
Robertsonian translocation
Definition
is due to exchange of a short arm of one chromosome with the long arm of another one

is responsible for the formation of the long chromosome 2 in human beings
Term
Which of the following are aneuploid?
monosomy
trisomy
tetrasomy
nullisomy
Definition
all are aneuploidy
Term
A genomic condition which may be responsible for some forms of fragile X syndrome as well as Huntington disease involves
Definition
various lengths of trinucleotide repeats
Term
Recently, a gene located on chromosome 3 in humans, FHIT has been shown to be associated with the significant human malady known as
Definition
cancer
Term
A DNA sample is tested for base composition. Which choice is one of the expected results?
Definition
50% purines, 50% pyrimidines
Term
If a DNA molecule is 30% cytosine (C), which is the percent guanine (G)?
Definition
30%
Term
If a DNA molecule of 50 base pairs contains 15 cytosine bases (C), how many thymine bases will it have?
Definition
35
Term
The basic structure of a nucleotide includes the following components
Definition
base, sugar, phosphate
Term
The classic Hershey and Chase (1952) experiment which offered evidence in support of DNA being the genetic material in bacteriophage made use of the following labeled components
Definition
phosphorus and sulfur
Term
Reverse transcriptase is an enzyme found in association with retroviral activity. It has the property of
Definition
synthesis of DNA from an RNA template
Term
What are the two major components of the Tobacco Mosaic Virus
Definition
RNA and protein
Term
Considering the structure of double stranded DNA, what kinds of bonds hold one complementary strand to the other?
Definition
hydrogen
Term
Transcriptionally active genes are sensitive to _______, indicating that chromatin structure is _______ during transcription.
Definition
DNAase
exposed
Term
Transposition can involve exchange of DNA sequences and recombination, which often leads to DNA
Definition
rearrangements
Term
For a chromosome to be functioning, it must have some of the following elements
Definition
a centromere
2 telomeres
at lease some few genes
an origin of replication
Term
The enzyme telomerase is involved in
Definition
synthesis of telomeres
Term
Which of the following DNA classes codes for protein?
Definition
unique sequence DNA
Term
Fossil DNA
Definition
is found in humans

is a non-functioning DNA sequence
Term
Transposable elements have some shared characteristics:
Definition
all have flanking direct repeat on their 2 ends

most have terminal inverted repeat

all have transposase
Term
Which of the following statements is NOT true for all E. coli DNA polymerases?
Definition
they possess 5' to 3' exonuclease activity
Term
The holliday model refers to ______ and involves _______.
Definition
branch migration; homologous recombination
Term
Requirements for DNA replication are:
Definition
a single strand DNA or template
raw materials (dNTPs)
DNA-polymerase
Term
What do initiation proteins do?
Definition
help the DNA-polymerase to get activated
helps with unwinding by helicase
bind to replicaiton origin and CAUSE a short section of DNA to unwind
sticks to the single stranded DNA and stop them from binding together again
Term
Direction of DNA-synthesis and elongation is
Definition
5' to 3' direction
Term
When considering the initiation of transcription one often finds consensus sequences located in the region of the DNA where RNA polymerases bind. Which are common consensus sequences?
Definition
CAAT; TATA
Term
What is the name given to the three bases in a messenger RNA which bind to the anticodon of tRNA to specify an amino acid placement in a protein?
Definition
codon
Term
The genetic code is fairly consistent among all organisms. The term often used to such consistency in the code is
Definition
universal
Term
Which of the following two terms relates most closely to split genes?
Definition
introns, exons