Paramecium is a single-cell eukaryotic organism that can reproduce by mitotic cell division. Prior to the M phase of the cell cycle, which of the following must occur?
A. The cell must replicate its chromosomes.
B. The cell must first be fertilized.
C. The nucleus must divide.
D. Chromatids must be separated.
E. The nuclear envelope must disintegrate.
A
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Sean has congenital generalized hypertrichosis, an X-linked dominant condition that produces dense hair on the face and upper body. He can pass this trait
A) definitely to a daughter and definitely not to a son. B) definitely to a son and definitely not to a daughter. C) with equal probability to a son or daughter. D) with a probability of 1/2 to a son and 1/4 to a daughter.
What is the free energy change for the inward movement of calcium ions into the bacterial cell?
A cell biologist interested in the transport of calcium ions (Ca2+) across the plasma membrane of bacterial cells made the following measurements on bacterial cells at 25°C: Vm = ?150 mV [Ca2+] outside = 20 mM [Ca2+] inside = 0.4 mM A) +4.6 kcal/mol; an endergonic reaction B) +4.6 kcal/mol; an exergonic reaction C) ?9.2 kcal/mol; an endergonic reaction D) ?9.2 kcal/mol; an exergonic reaction E) +9.2 kcal/mol; an exergonic reaction
A white blood cell (WBC) encounters bacteria in a scrape on the knee of a child who has fallen off of his bicycle. The WBC's job is to take the bacteria inside of itself and destroy the bacteria. If the bacteria cannot be moved across the WBC membrane, how will the WBC most likely take it in?
a. exocytosis b. pinocytosis c. facilitated diffusion d. phagocytosis
According to the above figure, which letter corresponds to the lowest tubular fluid osmolarity under normal conditions?
A. A B. B C. C D. D E. E