Practice Questions

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#Question id: 1075

The clustered, regularly interspaced short palindromic repeats (CRISPR) system in bacterial cells has been called the “immune” system of bacteria. CRISPR protect bacteria from a repeat infection from the same phage because bacterial cells

#Unit 4. Cell Communication and Cell Signaling

recognize proteins on the surface of the phage and secrete enzymes that digest the phage.
recognize proteins on the surface of the phage and secrete proteins that block the binding of the phage.
integrate fragments from the phage DNA in their own chromosomes and target for destruction any DNA that contains the same fragments in the future.
modify the attachment sites for the phages so that new infections cannot take place.

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#Question id: 33107

#Unit 1. Molecules and their Interaction Relevant to Biology

Figure given best describes

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#Question id: 4620

#Unit 11. Evolution and Behavior

The upper forelimbs of humans and bats have fairly similar skeletal structures, whereas the corresponding bones in whales have very different shapes and proportions. However, genetic data suggest that all three kinds of organisms diverged from a common ancestor at about the same time. Which of the following is the most likely explanation for these data?

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#Question id: 19742

#Unit 3. Fundamental Processes

Match the following

Organism	Size of RNA component
A) Tetrahymena	i) 451 bases long
B) Humans	ii) 1.3 kb in yeast
C) Yeast	iii) 159 bases long

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#Question id: 11025

#Unit 7. System Physiology – Animal

Listed below are the hydrostatic and oncotic pressures within a microcirculatory bed:

Plasma colloid osmotic pressure = 25 mm Hg

Capillary hydrostatic pressure = 25 mm Hg

Venous hydrostatic pressure = 5 mm Hg

Arterial pressure = 80 mm Hg

Interstitial fluid hydrostatic pressure = −5 mm Hg

Interstitial colloid osmotic pressure = 10 mm Hg

Capillary filtration coefficient = 10 ml/min/mm Hg

What is the rate of net fluid movement across the capillary wall?

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#Question id: 14685

#Unit 4. Cell Communication and Cell Signaling

In dark-adapted rod cells, a high level of cGMP keeps cGMP-gated nonselective cation channels open, leading to hyperpolarization of the plasma membrane and neurotransmitter release.

B - Light absorption generates activated rhodopsin, R*, which binds inactive, GDP-bound Gαt protein and mediates the exchange of GDP for GTP .

C- The free Gαt∙GTP activates PDE by binding to its inhibitory γ subunits and dissociating them from the catalytic α and β subunits . Relieved of their inhibition, the α and β subunits of PDE hydrolyze GMP to cGMP .

D- The resulting decrease in cytosolic cGMP leads to dissociation of cGMP from the cation channels in the plasma membrane and the closing of those channels .

E- The membrane then becomes transiently hyperpolarized, and neurotransmitter release is reduced.