The answer is B.
neutral: OH- = H+
acid: H+ > OH-
base OH- > H+
Out of the following give choices;
a. All DNA strands
contained only the heavy nitrogen isotope.
b. Half of the DNA strands contained only the light nitrogen
isotope.
c. All DNA strands contained both heavy and light nitrogen
isotopes.
d. All DNA strands contained only the lighter nitrogen
isotope.
The answer is b. Meselson–Stahl experiment demonstrated the semi-conservative model of DNA replication.
When DNA is replicated, one strand of the new double
helix strand is the parent's strand while the other is the newly synthesized
one. This made the semiconservative model stand out over the other two, dispersive
and conservative models.
Answer:
Newer
Explanation:
Because it is like when you place a plant and its roots underground and cover it up. You have the newer dirt going over the newest roots and the roots are close to the top
(If you aren't satisfied with that explanation here's another one) :
A hundred years ago dinosaurs existed and then they died and their remains were buried under dirt. However, we know that the fossils aren't anywhere near the top. Over time fossils get buried under layers of dirt the newer ones will be near the top because they haven't had time to be more buried.
Ans.
DNA acts as genetic material in all living organisms that store and transmit genetic information from one to next generation. DNA sequence carries instructions for the expression of genes to make proteins, responsible for different phenotypic characters of individuals.
The DNA, first synthesizes mRNA molecule that carry information for the protein synthesis, in the form of codons and code for a specific polypeptide chain or protein.
The sequence present in DNA determines the amino acid sequence in protein encoded by the DNA. Change in DNA sequence affects gene expression as it leads to change in mRNA sequence, and thus, change in sequence of amino acid of the resulting protein.
The human immunodeficiency virus (HIV) that causes the disease known as aids selectively infects helper T cells (CD4+).
This retrovirus also infects macrophages and dendritic cells. When CD4+ T cell numbers decrease below a critical level (due to the killing of this cells with different mechanisms), cell-mediated immunity is lost. As a result, the body becomes progressively more susceptible to infections, leading to the development of AIDS.
<span> HIV can be transmitted only via body fluids like blood, semen, pre-seminal fluid, rectal fluids, vaginal fluids, and breast milk, which means that people usually get or transmit HIV through sexual behaviours and use of the needle. For HIV infection, these fluids must come in direct contact with a mucous membrane or damaged tissue. Another way is to be directly injected into the bloodstream (from a needle for example).</span>
