Can someone please help

mestny [16]

Answer:

0.5 or 50% = 2/4 First box on the bottom

5 0

3 years ago

A host cell infected by a virus will activate the adaptive immune response through _______. (Select all that apply) Dendritic ce

Inga [223]

Answer:

Cytotoxic T cell

Helper T cell

Explanation:

Adaptive immune system is a part of the immune system initiated only when there is an attack by a pathogen or foreign substance. The adaptive immune system is beckoned on when the infection is insurmountable for the body's first line of immunity, which is the innate immune system.

The adaptive immune response is triggered by the white blood cells called LYMPHOCYTES. Lymphocytes consists of T cells and B cells. T cells are either cytotoxic or helper T cells. The cytotoxic T cells kills the cells infected with the virus while the Helper T cells activate every other cell involved in the immune process.

4 0

3 years ago

Semiconservative replication specifically means that

tigry1 [53]

Answer by YourHope:

Hi! :)

Semiconservative replication specifically means that

D) The molecule is a double helix!

:)

5 0

3 years ago

Read 2 more answers

The intermediate disturbance hypothesis predicts that species diversity will be ______when the frequency and/or intensity of dis

alukav5142 [94]

The intermediate disturbance hypothesis predicts that species diversity will be highest when the frequency and/or intensity of disturbances are intermediate

Explanation:

The diversity of the species is maximised at an intermediate near of anthropogenic as well as natural disturbances. As the competitively inferior disturbances are being tolerated for species disturbance and are termed to be dominant. Co exist of the sensitive species when the disturbance are either frequent or rare, which possess the reduced level of the disturbances. the productivity is predicted as very less due to competitive exclusion. As the disturbances increases productivity becomes less as most of them unable to sustain the regular destructive occurrence. So with the intermediate disturbances productivity is high as the rapid colonizers and dominant competitors are able to coexist.

5 0

4 years ago

What proportion of DNA molecules will contain any radioactivity after two rounds of replication?

Vladimir [108]

Answer: After two rounds of replication half of DNA molecules will contain one strand with radioactive nitrogen. And the other half will contain two strands with radioactive nitrogen.

Explanation:

In semi-conservative replication, two DNA molecules are created, each consisting of one strand of the original DNA and one new complementary strand. In other words, the DNA is formed from one old strand and one new strand. And the existing strands serve as a complementary mould to the new ones.

Meselson-Stahl's experiment involves growing the bacterium Escherichia coli in a medium containing radioactive nitrogen. Watson and Crick had predicted that DNA replication was semi-conservative, if so the DNA extracted from the bacteria would be somewhere in between the DNA extracted from the "normal" nitrogen medium and the radioactive nitrogen medium.

DNA replication, which occurs only once in each cell generation, requires many "building blocks", enzymes, and a great deal of energy in the form of ATP. The nucleotides, which are the building blocks of DNA, have to be assembled and available in the nucleus along with the energy to bind them together. Each nucleotide consists of three parts: a nitrogen-containing ring structure called a nitrogen base, a five-carbon sugar, and at least one phosphate group.

Through the action of DNA polymerase during replication, new nucleotides bind to the corresponding nucleotide of the original chain (A to T, C to G).

Since the DNA strands are anti-parallel, and replication proceeds only in the 5' to 3' direction on both strands, one strand will form a continuous copy, while the other will form a series of short fragments known as Okazaki fragments. The chain that is synthesized continuously is known as the forward chain and the chain that is synthesized in fragments is known as the backward chain.

Then, since replication is semi-conservative, the new strand will have nucleotides with "normal" nitrogen while the new strand created from that same DNA molecule will incorporate nucleotides with radioactive nitrogen. So, after two rounds of replication half of DNA molecules will contain one strand with radioactive nitrogen. And the other half will contain two strands with radioactive nitrogen.

7 0

3 years ago