CYTOGENETICS - PRELIM Flashcards
In pea plants, the allele for tall stalks (T) is
dominant over the allele for short stalks (t).
Suppose a cross between a tall pea plant and
a short pea plant produces 43 tall offspring
and 47 short offspring. If one of the tall
offspring is crossed with one of the short
offspring, what ratio of genotypes would be
most likely in their offspring?
1Tt :1tt
In forming a chromatin, the double-stranded
DNA must bind with proteins that are rich in
arginine
How many different types of chromosomes
are found in human female lymphocyte?
23
Which involves the removal of a wrong
nucleotide on an unmethylated DNA strand
and its replacement with the correct one?
mismatch repair
In transcription, what is the role of the sigma
factor?
It recognizes the promoter locus, which is
required to identify the site to be transcribed.
If in a diploid organism two different alleles
of a gene are both expressed in a heterozygous individual, the condition is
termed
codominant
An actin-rich “purse string” that draws tight
to separate daughter cells to complete
cytokinesisin cell division is a
cleavage furrow
X-inactivation occurs by addition of () in the
DNA.
methyl groups
Which of the following is characteristic of
the first meiotic division but NOT mitotic
division?
Homologous chromosomes pair
The PO4-end of the DNA is also known as
5’ end
In guinea pigs, short hair is dominant over
long hair. If a short haired SS guinea pig is
crossed with a long haired ss guinea pig,
what is the percent chance that the offspring
is short-haired?
1
Which guides the RNA polymerase as to
what appropriate nucleotide is added to a
growing RNA?
DNA template
The X chromosome of a mother has a
mutated recessive gene for coagulation
factor VIII. This defective coagulation factor
is non-functional and, therefore, causes
hemophilia characterized by difficult-tocontrol bleeding. Which of the following is
INCORRECT regarding this?
A father with the recessive gene is likely to
transmit it to his son
Which of the following best describes the
law of segregation?
During the formation of gametes, the paired
unit factors separate, or segregate, randomly
so that each sex cell receives one or the
other with equal likelihood.
Which is INCORRECT regarding sex
chromosomes?
X-inactivation primarily occurs in the
maternal X chromosome
Which of the following is a faithful copy of
the information encoded in a gene?
mRNA
At what stage of the cell cycle do the
chromosomes become dyads?
interphase
During DNA replication, the DNA
polymerase adds the new nucleotide at the
-OH end
Which feature is the same in the translation
process of prokaryote and eukaryote?
peptide formation by peptidyl transferase
Which is true about the telomere?
It consists of repeated sequence of
TTAGGG.
A gene for corn has two alleles, one for
yellow kernels and one for white kernels.
Cross pollination of yellow corn and white
corn results in ears of corn that have an
approximately even mix of yellow and white
kernels. Which term best describes the
relationship between the two alleles?
Codominance
Which of the following is NOT used to
identify a chromosome?
shape
A recessive gene in female X chromosome
is expressed in the phenotype when the
alleles are
homozygous
Which of the following best describes the
law of independent assortment?
During gamete formation, segregating pairs
of unit factors assort independently of each
other
Meiosis in males starts
at adolescence
The cycle control mechanisms check the
following except
Whether cellular contents are received
equally by each of the daughter cells
Which of the following cells enters the G0
phase and remain there for the life of the
individual?
myocytes
If two genes undergo independent
assortment, which assumption is most likely
true?
The genes are located on different
chromosomes or are far apart on the same
chromosome
These are nucleotide sequences that are
transcribed but are excised from the mRNA
before translation into protein.
introns
If a cell has a diploid number of 36 (2n=36),
how many chromosomes will be present in
each daughter cell at the end of meiosis II?
18
A cross between two pea plants with
genotypes RrYy and RrYy results in an F1
generation that is 25% RRYY, 50% RrYy, and 25% rryy. Which reason most likely
explains why other possible genotypes are
not present?
The loci of the genes are on the same
chromosome and in close proximity with
each other
Human sex cells have () autosomes.
22
Which of the following is a correct pair?
Transcription: nucleus
In a dihybrid cross, if two heterozygotes (for
both genes) are crossed, what will be the
expected phenotypic ratios? (In the
following order: dominant for both traits;
dominant for the first trait recessive for the
second; recessive for the first trait and
dominant for the second; recessive for both
traits)
9:3:3:1
Suppose a white-furred rabbit breeds with a
black-furred rabbit and all of their offspring
have a phenotype of gray fur. What does the
gene for fur color in rabbits appear to be an
example of?
Incomplete Dominance
During meiosis, the X and Y chromosome
pair at the metaphase plate
True
Chromosome Y has similar size and
morphology as chromosome
22
Which characteristic of the genetic code
indicates that an amino acid may be coded
by more than one codon?
degenerate
How many different types of chromosomes
are found in a human male lymphocyte?
24
During which stage of mitosis do
chromosomes divide at the centromeres?
anaphase
This structure is responsible for the accurate
segregation of the replicated chromosome
during mitosis and meiosis.
centromere
A cell with 20 chromosomes undergoes
mitosis. How many daughter cells are
created? () and each daughter cell has ()
chromosomes.
2, 20
Phenotype refers to the () of an individual
actual physical appearance
The Broad Thumb-Hallux syndrome is due
to deletion 16p13.3. This indicates that the
deletion is located at
sub-band 3
Crossing-over may occur between X and Y
chromosomes
True
Which is INCORRECT regarding oogenesis
in human?
It stops at metaphase I.
Which of the following enzymes acts before
the others in DNA replication?
primase
Which is true about G2/M checkpoint?
It ensures that the cell has an adequate size
How many chromatids are there in 2 (two)
bivalents?
8
Obesity is an example of genotype and
environment interacting in order to produce
phenotype
Who shows hemizygous traits?
brother
Which characterizes a chromatid?
It is one of the two identical copies of DNA
making up a duplicated chromosome
Which triplet will be most vulnerable to
UVL?
TTA
