Answer:
Answer is C.
Explanation:
For A and B, a base substitution affects one of the three bases that comprise a codon, the DNA/RNA unit that corresponds to a particular amino acid. If one base is substituted, one codon and therefore one amino acid will be affected. Codons have built-in redundancy, so even by changing one base, the new codon sometimes still corresponds to the same amino acid. Therefore, a base substitution at most affects one amino acid, and sometimes doesn't affect it all.
Frameshift mutations cause a lot more trouble. These occur when you have a deletion or insertion that changes the number of bases in your gene. As a result, the "frame" of the codons changes (everything shifts one way or the other by the number of bases added/removed). This affects EVERY codon downstream of the mutation, so you can imagine that such a mutation would have a bigger effect the closer to the start of the gene it occurs. This is why C is correct.
L'utilisation de pesticides je pense...
Answer:
Air pollution will increase due to increased use of fossil fuels and the amount of natural space will decrease as suburban areas increase.
Most bacteria live in a solution that is hypotonic relative to the cytoplasm of the bacteria. This means that the bacterial cell is constantly taking in water. The cell wall of a bacterium is a peptidoglycan polymer that is tightly cross-linked. This would therefore function to:_________-.
A. regulate the flow of most molecules into and out of the bacterial cell.
B. provide a rigid wall that prevents the cell from swelling.
C. provide a rigid wall that prevents the cell from shrinking.
D. confirm a close relationship to plant cells that have a similar structure and live in hypotonic solutions.
E. make all bacteria fairly uniform in metabolic chemistry.
Answer:
B. provide a rigid wall that prevents the cell from swelling.
Explanation:
When organisms are present in hypotonic surroundings, their cells that are in contact with the surroundings tend to gain water. Bacteria present in hypotonic solution would gain water as their cells are hypertonic than the surroundings. The entry of water would increase the volume of cytoplasm and could lead to the bursting of the cell. However, the presence of a cell wall made up of cross-linked peptidoglycan prevents the swelling of the bacterial cell and allow them to survive in hypotonic surroundings.
