MCB 252 Final Exam Questions With
Correct Answers
true/false
The two ends of a microtubule that is growing in vitro (with neither end capped)
have different critical concentrations. - ANSWER true
Which proteins are MAPS? - ANSWER proteins that bind the GTP cap and
promote assembly of microtubules
proteins that promote the bending of proto-filaments and promote disassembly
of microtubules
proteins that bind the sides of microtubules and connect to other proteins such
as IFs
true/false
as described in lecture, MT assembly is best described as an equilibrium
reaction rather than a steady state reaction - ANSWER false
MT assembly is a steady state reaction
true/false
dyneins are minus end directed motor proteins - ANSWER true
true/false
dyneins and kinesins are part of the same superfamily of proteins - ANSWER
false
in which of the following time frames do we think that LUCA existed? - ANSWER
3.6 to 4.1 billion years ago
true/false
the progenitor of the AAA ATPase family of proteins existed before the
eubacteria, the archaebacteria, and the eukaryotes diverged from each other -
ANSWER true
organisms such as octopi and cuttlefish that can change color do so by
regulating the activity of: - ANSWER motor proteins
In lecture we talked about an experiment that allow us to figure out the
conformational change associated with the power stroke of dynein. In that
experiment we compared EM micrographs of dynein molecules trapped in the
pre-power stroke conformation with EM micrographs of dynein molecules
, trapped in the post-power stroke conformation. What nucleotide did we use to
trap dynein motors in the pre-power stroke conformation? - ANSWER ADP-Vi
which part of the dynein family members binds the microtubules? - ANSWER the
stalk
Which part of dynein family members contains the ATPase? - ANSWER the head
true/false
in the early part of mitosis, prior to anaphase chromosomes are moved to the
center of the cell; whereas in anaphase the sister chromatids move toward the
spindle poles away from the center of the cell - ANSWER true
the microtubules that attach to the chromosomes at the centromere/kinetochore
attach to what? - ANSWER the outer layer of the kinetochore
true/false
kinetochore microtubules treadmill in M-phase prior to anaphase - ANSWER true
true/false
kinetochore microtubules begin to pull on the sister chromatids prior to
anaphase - ANSWER true
true/false
In a classic adhesion experiment, different types of cells sort in such a way that
cells from internal tissues end up in the middle and cells from more external
tissues end up surrounding the cells that form the internal tissues - ANSWER
true
what specific type of experiment demonstrated that cadherins were sufficient to
mediate cell-cell adhesion? - ANSWER expression of a cadherin gene in cells
that do not normally adhere to each other (or have low adhesion function)
true/false
classic cadherins are primarily thought to engage in homophilic interactions in
dictating cell-cell adhesion - ANSWER true
You are studying one type of classic cadherin. You express that cadherin in a
cell line that normally does not adhere. You connect your gene to two different
promoters, one promoter expresses 5x as much cadherin as the other promoter.
You them perform a cell adhesion assay with a mixture cells some of which
contain the gene expressing the higher level of your cadherin and others which
contain a gene that expresses a lower level of your cadherin. What result do you
expect at the end of your adhesion assay? - ANSWER The cells expressing the
higher level of cadherin will cluster in the middle of a ball and the cells
expressing the lower level will form a layer(s) surrounding the central ball
Correct Answers
true/false
The two ends of a microtubule that is growing in vitro (with neither end capped)
have different critical concentrations. - ANSWER true
Which proteins are MAPS? - ANSWER proteins that bind the GTP cap and
promote assembly of microtubules
proteins that promote the bending of proto-filaments and promote disassembly
of microtubules
proteins that bind the sides of microtubules and connect to other proteins such
as IFs
true/false
as described in lecture, MT assembly is best described as an equilibrium
reaction rather than a steady state reaction - ANSWER false
MT assembly is a steady state reaction
true/false
dyneins are minus end directed motor proteins - ANSWER true
true/false
dyneins and kinesins are part of the same superfamily of proteins - ANSWER
false
in which of the following time frames do we think that LUCA existed? - ANSWER
3.6 to 4.1 billion years ago
true/false
the progenitor of the AAA ATPase family of proteins existed before the
eubacteria, the archaebacteria, and the eukaryotes diverged from each other -
ANSWER true
organisms such as octopi and cuttlefish that can change color do so by
regulating the activity of: - ANSWER motor proteins
In lecture we talked about an experiment that allow us to figure out the
conformational change associated with the power stroke of dynein. In that
experiment we compared EM micrographs of dynein molecules trapped in the
pre-power stroke conformation with EM micrographs of dynein molecules
, trapped in the post-power stroke conformation. What nucleotide did we use to
trap dynein motors in the pre-power stroke conformation? - ANSWER ADP-Vi
which part of the dynein family members binds the microtubules? - ANSWER the
stalk
Which part of dynein family members contains the ATPase? - ANSWER the head
true/false
in the early part of mitosis, prior to anaphase chromosomes are moved to the
center of the cell; whereas in anaphase the sister chromatids move toward the
spindle poles away from the center of the cell - ANSWER true
the microtubules that attach to the chromosomes at the centromere/kinetochore
attach to what? - ANSWER the outer layer of the kinetochore
true/false
kinetochore microtubules treadmill in M-phase prior to anaphase - ANSWER true
true/false
kinetochore microtubules begin to pull on the sister chromatids prior to
anaphase - ANSWER true
true/false
In a classic adhesion experiment, different types of cells sort in such a way that
cells from internal tissues end up in the middle and cells from more external
tissues end up surrounding the cells that form the internal tissues - ANSWER
true
what specific type of experiment demonstrated that cadherins were sufficient to
mediate cell-cell adhesion? - ANSWER expression of a cadherin gene in cells
that do not normally adhere to each other (or have low adhesion function)
true/false
classic cadherins are primarily thought to engage in homophilic interactions in
dictating cell-cell adhesion - ANSWER true
You are studying one type of classic cadherin. You express that cadherin in a
cell line that normally does not adhere. You connect your gene to two different
promoters, one promoter expresses 5x as much cadherin as the other promoter.
You them perform a cell adhesion assay with a mixture cells some of which
contain the gene expressing the higher level of your cadherin and others which
contain a gene that expresses a lower level of your cadherin. What result do you
expect at the end of your adhesion assay? - ANSWER The cells expressing the
higher level of cadherin will cluster in the middle of a ball and the cells
expressing the lower level will form a layer(s) surrounding the central ball
