Flashcards in Test 5 Deck (230)
Centromeric chromatin binds specific proteinscalled ________ that serve as attachment sites for the microtubules that separate chromosomes during cell division.
A cell must possess ________ in order to respond to the presence of glucocorticoids.
a specific receptor for glucocorticoids
In addition to being regulated by proximal and distal promoter elements, the expression of most genes is regulated by even more distant DNA elements called _____, which typically contain multiple binding sites for sequence-specific transcriptional activators.
Each transcription factor usually has at least two domains that mediate different aspects of their function. What are they?
the DNA-binding domain and the activation domain
DNA methylation is thought to serve as a(n) __________ mark or tag that allows identification of certain DNA regions and allows them to be used differently from other regions.
The enzymes that remove acetyl groups from histones in the chromatin are ________.
What protein is responsible for sequestering cytoplasmic iron atoms for the purpose of protecting cells from the toxic effects of the free metal?
How short must the poly(A) tail get to cause the mRNA to be degraded rapidly?
about 30 adenosine residues
What nucleotide sequence has been identified in the 3' UTR that binds to specific proteins that stabilize mRNA?
When do chromosomes separate during the cell cycle?
Which list has the phases of mitosis in the correct order?
prophase, prometaphase, metaphase, anaphase, telophase, cytokinesis
What causes a cell to enter into the M-phase?
highcyclin concentration which causes high MPF kinase activity.
What enzyme activates Cdk by adding an important phosphate group to the threonine residue at position 161 (Thr 161)?
Cdk-activating kinase (CAK)
When normal cells are subjected to treatments that damage DNA, like ionizing radiation or DNA-altering drugs, what happens?
Their progress through the cell cycle stops while the damage is repaired.
What is responsible for holding sister chromatids together after replication? It serves as a physical bridge that holds the two chromatids together through G2 and into mitosis.
Which of the following organelles is most likely to remain intact during mitosis?
Which of the following is a function of the kinetochore?
move chromosomes along microtubules
Tubulin subunits are added to the plus end and are lost from the minus end of the spindle microtubule during:
What powers a chromosome's movement along a microtubule wall?
motor proteins located in the kinetochore
What is the force-generating mechanism which forms a contractile ring that cuts an animal cell in half during cytokinesis?
the sliding of actin filaments over one another with the aid of myosin
The role of meiosis is to:
reduce the number of chromosome for gamete formation.
Which of the following conditions in humans is usually, but not always, fatal during fetal development?
Someone with Turner syndrome has:
One X chromosome and no Y chromosome.
What is the role of a G protein in a signaling pathway?
G proteins transfer the signals from the receptors to an effector.
Which of the following describe a way that signal transduction amplification is achieved?
Enzyme cascades are activated.
Different G proteins subunits can react with either cAMP, cGMP, or cTMP.
Arrestin binding to GPCRs __________.
prevents further activation of additional G proteins
Which of the following is activated by caspases?
disruption of the cytoskeleton
What happens after insulin binds to the insulin receptor’s α subunits causing the β subunits to dimerize?
autophosphoylation of tyrosine residues occurs.