TEST TWO Various Questions Flashcards
A diploid cell has_______ the number of chromosomes as
a haploid cell.
Twice
An organism’s traits are determined by the specific
combination of inherited _____.
genes
The first level of DNA organization in a eukaryotic cell is
maintained by which molecule?
Histones
Identical copies of chromatin held together by cohesin at
the centromere are called _____.
sister chromatids
Chromosomes are duplicated during what stage of the
cell cycle?
S phase
The mitotic spindles arise from which cell structure?
Centrosome
Attachment of the mitotic spindle fibers to the
kinetochores is a characteristic of which stage of
mitosis?
Metaphase
Separation of the sister chromatids is a characteristic of
which stage of mitosis?
Anaphase
The chromosomes become visible under a light
microscope during which stage of mitosis?
Prophase
- The fusing of Golgi vesicles at the metaphase plate of
dividing plant cells forms what structure?
Cell plate
At which of the cell-cycle checkpoints do external forces
have the greatest influence?
G1
What is the main prerequisite for clearance at the G2
checkpoint?
Accurate and complete DNA replication
If the M checkpoint is not cleared, what stage of mitosis
will be blocked?
Anaphase
Which protein is a positive regulator that
phosphorylates other proteins when activated?
cyclin-dependent kinase (Cdk)
Many of the negative regulator proteins of the cell cycle
were discovered in what type of cells?
cancer cells
Which negative regulatory molecule can trigger cell
suicide (apoptosis) if vital cell cycle events do not occur?
p53
__________ are changes to the order of nucleotides in a
segment of DNA that codes for a protein.
Gene mutations
A gene that codes for a positive cell-cycle regulator is
called a(n) _____.
proto-oncogene
A mutated gene that codes for an altered version of Cdk
that is active in the absence of cyclin is a(n) _____.
oncogene
Which eukaryotic cell-cycle event is missing in binary
fission?
karyonesis
FtsZ proteins direct the formation of a _______ that will
eventually form the new cell walls of the daughter cells.
septum
Meiosis usually produces ________ daughter cells.
Four haploid
What structure is most important in forming the tetrads?
synaptonemal complex
At which stage of meiosis are sister chromatids separated
from each other?
Anaphase II
At metaphase I, homologous chromosomes are
connected only at what structures?
chiasmata
What phase of mitotic interphase is missing from
meiotic interkinesis?
S phase
The part of meiosis that is similar to mitosis is ________.
Meiosis II
Which statement best describes the genetic content of
the two daughter cells in prophase II of meiosis?
Haploid with two copies of each gene
How do telophase I and telophase II differ during
meiosis in animal cells?
Cells remain diploid at the end of telophase I, but
are haploid at the end of telophase II.
- Which type of life cycle has both a haploid and diploid
multicellular stage?
Alternation of generations
What is the ploidy of the most conspicuous form of most
fungi?
haploid
Imagine you are performing a cross involving seed color
in garden pea plants. What F1 offspring would you expect
if you cross true-breeding parents with green seeds and
yellow seeds? Yellow seed color is dominant over green.
100% yellow
A recessive trait will be observed in individuals that are
________ for that trait.
Homozygous
If black and white true-breeding mice are mated and the
result is all gray offspring, what inheritance pattern
would this be indicative of?
Incomplete dominance
A farmer raises black and white chickens. To his
surprise, when the first generation of eggs hatch all the
chickens are black with white speckles throughout their
feathers. What should the farmer expect when the eggs
laid after interbreeding the speckled chickens hatch?
All offspring will be speckled
The first suggestion that chromosomes may physically
exchange segments came from the microscopic
identification of ________.
Chiasmata
Which recombination frequency corresponds to
independent assortment and the absence of linkage?
.50
Which recombination frequency corresponds to perfect
linkage and violates the law of independent assortment?
0
Which of the following codes describes position 12 on the
long arm of chromosome 13?
13q12
In agriculture, polyploid crops (like coffee, strawberries,
or bananas) tend to produce ________.
Larger yields
The genotype XXY corresponds to
Klinefelter syndrome
Abnormalities in the number of X chromosomes tends
to have milder phenotypic effects than the same
abnormalities in autosomes because of ________.
X inactivation
By definition, a pericentric inversion includes the
________.
centromere
How many nucleotides are in 12 mRNA codons?
36
The -10 and -35 regions of prokaryotic promoters are
called consensus sequences because ________.
Similar in all bacterial species
Which feature of promoters can be found in both
prokaryotes and eukaryotes?
TATA box
How do enhancers and promoters differ?
Enhancers increase the efficiency of gene
expression, but are not essential for transcription.
Promoter recognition is essential to transcription
initiation.
The RNA components of ribosomes are synthesized in
the ________.
nucleolus
