Vacuole. Amoeba is a unicellular organism formerly grouped under Kingdom Protista. Amoeba in freshwater need contractile vacuole to control input and output of water. (osmosis). Without this structure, ameboid cells will be filled with water and eventually burst.
Caused by sexual contact are more difficult to treat..
Answer:
The correct answer is: C. third nucleotide position.
Explanation:
- Genes located on the chromosomes encodes for proteins.
- A Gene is made up of a Deoxyribonucleotide (DNA) sequence which is transcribed into the messenger Ribonucleotide (mRNA) sequence by the help of RNA polymerase.
- This mRNA sequence is further translated into the amino acid sequence, that folds to form the functional protein, by the help of the Ribosome.
- The Ribosome reads the mRNA sequence in the form of triplets (three nucleotide together) and each such triplet nucleotide codes for an amino acid.
- Each such triplet nucleotide is known as a Codon.
- The Genetic Code is a table which represents the amino acid encoded by each codon.
- However, the Genetic Code is degenerate in nature. This means that one amino acid can be coded by more than one codon.
- This is because, among the the three nucleotide positions in a codon only the first two determine the specificity of the amino acid while the third nucleotide, also called the wobble nucleotide, is not specific. Presence of any nucleotide in the third position of the codon will not alter the amino acid encoded by the codon.
- In the given question, organisms producing homologous protein have similar amino acid sequence but they vary in the corresponding nucleotide sequence of the gene which codes for the homologous protein.
- This is because at the nucleotide level the variation lies in the wobble nucleotide position that occupies the third position in the codon.
The Precambrian eon is separated from the Phanerozoic eon in the fossil record because of the sudden appearance of organisms.
Explanation:
Precambrian eon is the initial existence on earth that can be predicted by the study of rocks and remaining of fossils. It has been seen as the existence of skeleton in this era, before this era no such things has been observed, even the development of sexual reproduction.
The Phanerozoic era comes after the Precambrian era, more advanced kinds of fossils of animals had been observed in this era. Phanerozoic era period of life on earth. Large organisms sudden appearance are seen in the Phanerozoic era i.e. First dinosaurs, mammals, fishes, angiosperms,first vertebrates etc.
