Answer:
C. Nucleotides
Explanation:
Nucleic acids are macromolecules which are polymers of nucleotides. There are two types of nucleic acids namely: deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). Nucleotides are the building blocks of nucleic acids.
A nucleotide is made up of three components:
- A phosphate group
- A five carbon sugar called pentose sugar. In RNA the sugar is ribose sugar and in DNA the sugar is deoxyribose sugar.
- Nitrogenous bases: There are four different types of bases in DNA: adenine, guanine, cytosine and thymine. In RNA thymine is replaced by uracil. Adenine and guanine are purines whereas cytosine, thymine and uracil are pyrimidines.
Nitrogenous base and sugar together are called nucleoside and when phosphate is also attached then it is called nucleotide.
First comes fertilization, when two gametes combine to form a zygote.
Answer:
Compounds from different organisms are being used widely bu humans for their benefits. Some of the compounds are used as drugs. For example, penicillin is used as a drug or antibiotic. There are many plants which provides humans with other types of medicines and herbal remedies. There are other compounds which are used for cancer treatment. For example, taxol is a compound obtained from trees which are being used as anticancer drugs.
Antibiotic used include kenamycin, ampicillin and tetracycline. This is useful to determine if and which bacteria took up the plasmid as they were supposed to during the process of recombination. Host bacteria are normally killed by these antibiotics. If the recombinant plasmids were taken up by the bacteria, plasmid may have contained a DNA gene for resisting the effects of one or more antibiotics. Host bacteria are placed in a growth medium containing an antibiotic to which they have a resistant gene in their recombinant plasmid DNA survivor. If they havent taken the plasmid they die.
