DNA is made up of molecules called nucleotides. Each nucleotide contains a phosphate group, a sugar<span> group, and a </span>nitrogen base<span>. The four types of nitrogen bases are </span>adenine<span> (A), </span>thymine (T), guanine (G) and cytosine<span> (C). The order of these bases is what determines DNA's instructions, or genetic code.</span>
Answer:
Ligand-receptor interaction is the first interaction that triggers cell signalling.
Explanation:
Ligands are the hormones, drugs or neurotransmitters that specifically bind with receptors present in cell surface to initiate cell signalling. Ligand binding to the receptor is reversible. Binding of the ligand to the receptor can activate or inactivate receptor. Activation may lead to cell signalling pathways. Inside cells, there are secondary molecules which on activation starts a cascade of reactions. which in-turn regulate the function of the ligand molecule.
Best Choice:
Ligand-receptor interaction is the first interaction that triggers cell signalling.
Answer:
1) metals; left
2)sodium: alkali metals calcium: alkaline earth
Explanation:
Answer:
Different type of mutation cause phenotypic change by addition,deletion or substitution of amino acids in an open reading frame of mRNA.
Explanation:
Mutation can be defined as alteration in nucleotide sequence of target DNA molecule.Which force the mutated DNA to undergo phenotypic change resulting in the formation of abnormal protein or disease causing protein.
Foe example When the β6 glutamic acid of hemoglobin is replaced by amino acid valine it result in the sickling of red blood cells that ultimately leads to the development of sickle cell anemia, a life threatening disease.
Answer:
DNA or protein can be used as a ''molecular clock'' that tells how long it has been since two species have diverged from a common ancestor. The fossil record is usually derived from sedimentary rocks laid down millions of years ago.