30 points! When is gene expression blocked in the lac operon system?

The repressor protein destroys the genes required to produce enzymes.

The repressor protein blocks the genes from making mRNA.

Lactose binds to the repressor and changes its shape.

RNA polymerase begins transcribing the genes.

Which of the following examples can cause gene flow between populations? a. an increase in predators to a population of zebra b. a volcanic eruption that kills half of a population of mice c. bird droppings that contain seeds from a different location d. a person that sprays a toxin on a group of mosquitoes

Look at the images of different rocks. which rocks have a fine-grained texture? check all that apply. 1 2 3 4 5

In a classic experiment using pea shape, mendel conducted two separate genetic crosses. in the first cross the parent plants were “true breeding” for pea shape; one had round peas ( r )and the other had wrinkled (r). the first cross produced a filial 1 generation of all round peas. in the second cross, mendel bred plants from the filial 1 generation. this cross produced different results. out of approximately 1000 plants, about 75% were round and 25% were wrinkled.