Answer:
Cell membrane
Explanation:
Cell membrane controls what goes in and out of cells
Water.
Sound travels slowly because the amount of pressure.
Hi,
The rda is designed to be averaged over several days.
- true
(average across a number of days, because body is good at storing based on solid, reliable evidence and observations).
Answer:
A frameshift changes every codon past it. A base substitution only changes one codon.
Explanation:
DNA is comprised of nucleotides (A, C, T, G) that make up amino acids. Every three bases is called a codon and represents an amino acid.
In a frameshift mutation, a nucleotide is either added or deleted from the sequence. This offsets the entire sequence after it because the reading frame shifts. Here's an example:
ACTGCTATCGTCATC
If another T is added in between the first and second codons, then every codon after will be changed.
ACT>T<GCTATCGTCATC
A substitution mutation is usually less severe, as it only alters one codon in the sequence. These occur when one nucleotide is replaced by another one. Here's an example:
ACTGCTATCGTCATC
Let's say the first G is replaced by a T.
ACT>T<CTATCGTCATC
As you can see, none of the other codons changed.
Typically, a frameshift mutation is considered worse than a substitution mutation.
Answer:
e. Red segregated from brown in meiosis I, and straight segregated from curled in meiosis I.
Explanation:
A cross between two flies heterozygous for both genes produced an offspring with the phenotypic ratio of 9:3:3:1. This ratio is expected according to Mendel's law of independent assortment, which states that alleles of the same gene assort independently during gamete formation.
Before meiosis starts in flies, a single diploid cell duplicates its DNA, so each chromosome has 2 sister chromatids that contain the same information.
- During meiosis I, <u>the homologous chromosomes separate</u> into two daughter cells. The chromosome number is reduced by half, but each chromosome has two sister chromatids.
- During meiosis II, <u>the sister chromatids separate</u> and each daughter cell from meiosis I divides into two new daughter cells (to get the total of 4 haploid cells).
In a heterozygous fly, each homologous chromosome contains a different allele, and the sister chromatids are copies that carry the same allele. For that reason, both traits were segregated during meiosis I.
