A mutation in the laci gene that makes the repressor unable to bind lactose will result in:
A: increased synthesis of b-galactocidase only when glucose is low.
B: repression of b-galactocidase synthesis under all growth conditions.
C: constitutive (constant) synthesis of some b-galactocidase.
D: all of the above
Answer: B: repression of b-galactocidase synthesis under all growth conditions.
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Typically pathogenic Neisseria gonorrheae
A. secretes transferrin. B. destroys IgA. C. destroys IgM. D. is very immunogenic.
Rats learning to press a lever to receive food is an example of
A. avoidance. B. operant conditioning. C. habituation. D. classical conditioning. E. negative reinforcement.
The portion of the nervous system that is responsible for both increasing heart rate and increasing movement of the
intestines is the ____.
a. peripheral nervous system b. sympathetic nervous system c. parasympathetic nervous system d. somatic nervous system e. interaction between the somatic and autonomic nervous systems
The accompanying figure shows how levels of a microRNA called miR-320b change with age in the prefrontal cortex of the brains of humans, chimps, and macaques (African monkeys)
This may be important for understanding the genetic features that make us human, because microRNAs ________. A) are found only in primates B) are translated into short polypeptides C) influence gene expression by binding to messenger RNAs D) are transcribed from "selfish DNA" sequences such as Alu elements E) are known to increase neuronal connectivity and therefore intelligence