Question

1. in some ecosystems, wolves have been eliminated due to their threats to humans. how can the reintroduction of wolves benefit the ecosystem?

a. it can eliminate weak animals from a prey population, thereby decreasing competition for natural resources.
b. it can eliminate the most fit animals among the prey population, which will cause an increase in birth rates of the prey.
c. it can cause the prey population to migrate to other areas, resulting in more prey.
d. it can cause the prey population to better blend in with their environment.

1. what will most likely be the result as humans move into new areas, forests are clear cut and housing developments are built?

a. global temperatures will decrease because trees are removed.
b. many organisms will lose their homes because their habitats have been destroyed.
c. better sanitation in the area will reduce the amount of pollution.
d. the rainfall in the area will increase because there will be increased runoff

1. what activity most contributes to the depletion of the ozone layer?

a. burning fossil fuels
b. release of cfcs
c. deforestation
d. overuse of fertilizers

1. a saltwater plant is placed in freshwater. what will most likely happen to the cells of the plant?

a. the cell wall will prevent water from flowing in or out of the cells.
b. the cells will lose water and shrivel.
c. the cells will gain water and swell.
d. the cells will stay the same size.

1. a student uses a microscope to observe a cell that has a cell wall, a plasma membrane, and circular dna. what kind of cell is this student observing?

a. plant cell c. eukaryotic cell
b. animal cell d. prokaryotic cell
open response: transcribe and translate the following gene:
actattgtacgc
uga|uaa|cau|gcg
stop - stop - histidine -

Explanation:

1. Wolves are apex predators that naturally cull sick, weak prey animals. This strengthens the prey gene pool and reduces overcompetition for limited food/water resources.
2. Clearing forests for housing destroys native organism habitats, displacing or killing local wildlife as they lose their living/feeding spaces.
3. Chlorofluorocarbons (CFCs) break down ozone molecules in the stratosphere, directly causing ozone layer depletion.
4. Saltwater plant cells have a higher internal solute concentration than freshwater. Osmosis will move water into the cells, making them swell.
5. Prokaryotic cells have a cell wall, plasma membrane, and free-floating circular DNA with no membrane-bound nucleus.
6. Transcription: DNA ACTATTGTACGC is converted to mRNA UGA UAA CAU GCG. UGA and UAA are stop codons that terminate translation immediately, followed by CAU (Histidine) and GCG (Alanine) which are not translated due to the early stop signals.

Answer:

1. a. It can eliminate weak animals from a prey population, thereby decreasing competition for natural resources.
2. b. Many organisms will lose their homes because their habitats have been destroyed.
3. b. release of CFCs
4. c. The cells will gain water and swell.
5. d. prokaryotic cell
6. Transcription produces mRNA sequence: $UGA \ UAA \ CAU \ GCG$. Translation stops at the first stop codon ($UGA$), so no full polypeptide chain is produced beyond the immediate termination signal.