What is the definition of a ribozyme?
a. a compound responsible for absorption of the sun's UV light
b. a protective vesicle or enclosure for various molecules
c. tRNA associated with an amino acid
d. a molecule in early life-forms responsible for maintenance of cellular information
e. a catalytic RNA molecule
Ans: e. a catalytic RNA molecule
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Where are neurotransmitter receptors located?
A) the nuclear membrane B) the nodes of Ranvier C) the postsynaptic membrane D) synaptic vesicle membranes E) the myelin sheath
When two allelic variants are expressed equally, they are said to be
A) exclusive. B) uncommitted. C) repressed. D) codominant.
English ivy (Hedera helix) and wintercreeper (Euonymus fortunei) are not closely related, yet both have aerial rootlets that allow them to climb up and stick to bark on trees. What type of evolution is this?
A. Analogous. B. Convergent. C. Radial. D. Bivalent. E. Both analogous and convergent.
Answer the following statements true (T) or false (F)
1. In a commensal relationship between a phoretic species and its "host", the phoretic species is not affected. 2. Humans exert top-down pressures on white-tail deer. 3. Resource partitioning enables species that are better competitors to exclude similar species from a community. 4. Secondary metabolites originally meant to defend a plant can become essential compounds for some herbivores.