You have isolated a strain of mutant yeast cells that divides normally at 30°C but cannot enter M phase at 37°C
You have isolated its mitotic cyclin and mitotic Cdk and find that both proteins are produced and can form a normal M-Cdk complex at both temperatures. Which of the following temperature-sensitive mutations could not be responsible for the behavior of this strain of yeast?
(a) inactivation of a protein kinase that acts on the mitotic Cdk kinase
(b) inactivation of an enzyme that ubiquitylates M cyclin
(c) inactivation of a phosphatase that acts on the mitotic Cdk kinase
(d) a decrease in the levels of a transcriptional regulator required for producing sufficient amounts of M cyclin
(b) A cell with a mutation that prevents ubiquitylation of M cyclin could enter mitosis but could not exit mitosis properly.
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Answer the following statements true (T) or false (F)
1. A plant that is dioecious could also have perfect flowers. 2. A bilaterally symmetrical flower has only two equal parts. 3. Plants that are pollinated by insects probably do NOT produce allergy reaction in humans. 4. A dog that is conditioned to salivate in response to a stimulus associated with food will salivate in response to that stimulus even after the food is removed. 5. When body temperature drops below normal, a person starts shivering uncontrollably. This is an example of negative feedback.
The bacterium Bacillus tumefaciens has been harnessed in biotechnology because it can insert a gene from one species of plant into another. This can also occur in nature and is referred to as
A. vestigial transfer. B. homology. C. horizontal gene transfer. D. vertical evolution. E. exon shuffling through endocytosis.
What information is used to calculate the age-specific fertility rate, mx?
A. the net reproductive rate of females B. total number of offspring born to females within a reproductive age class C. the per capita growth rate of all females D. number of female offspring born to females within a reproductive age class E. the average age of first reproduction for females
The logical conclusion that can be drawn from Wilcove's experimental data in the graph above is that
____.
a. songbird nests in a variety of habitats are equally likely to be found by predators b. songbird nests in forest fragments are more likely to be found by predators than those in intact tracts of forest c. songbird nests in forest fragments are less likely to be found by predators than those in intact tracts of forest d. songbird nests in rural areas are more likely to be found by predators than those in suburban areas e. songbirds that nest on the ground are more vulnerable to predators than those that nest in trees or shrubs