Answer:
Directional selection
Explanation:
Directional selection is a type of natural selection that favors one extreme phenotype of a genetic trait due to its survival and reproductive advantage to the individuals over another extreme phenotype and the intermediate phenotype.
In the given example, the thick-leaved plants are better adapted to a drier climate due to reduced water loss. Directional selection favored the plants with thick leaves which in turn produced more progeny. Over the generations, the population evolved into the one having more number of thick-leaved plants.
Answer:
The correct answer is "They lack an independent metabolism"
Explanation:
Viruses are usually active/alive in a living environment and become inactive in non-living environment; these is because they rely on the metabolic activities of the invaded living environment/cell. This property is a sharp contrast to normal living cells that are able to metabolize different substances independently using several organelles.
Now it is clear that genes are what carry our traits through generations and that genes are made of deoxyribonucleic acid (DNA). But genes themselves don't do the actual work. Rather, they serve as instruction books for making functional molecules such as ribonucleic acid (RNA) and proteins, which perform the chemical reactions in our bodies.Proteins do many other things, too. They provide the body's main building materials, forming the cell's architecture and structural components. But one thing proteins can't do is make copies of themselves. When a cell needs more proteins, it uses the manufacturing instructions coded in DNA.The DNA code of a gene—the sequence of its individual DNA building blocks, labeled A (adenine), T (thymine), C (cytosine) and G (guanine) and collectively called nucleotides— spells out the exact order of a protein's building blocks, amino acids.
Occasionally, there is a kind of typographical error in a gene's DNA sequence. This mistake— which can be a change, gap or duplication—is called a mutation.
Answer:
The importance of the AUG and UGA bases lies in the fact that the first one is a start codon and the second one is a stop codon, respectively (option a).
Explanation:
Codons or triplets are sequences of three nitrogenous bases, in the mRNA, that determine the synthesis of a specific amino acid.
- <em>AUG </em><em>is called the </em><em>initiation or start codon</em><em>, and is usually at the beginning of a peptide synthesis, in addition to encoding the amino acid methionine.
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- <em>UGA</em><em> is a</em><em> termination or stop codon</em><em> found at the end of a petid chain when it is complete. UAA and UAG codons are also STOP or termination codons and, together with UGA, do not code for amino acids.</em>
The biological importance of start and stop codons is to initiate the synthesis of a protein and to stop the addition of amino acids when their size is adequate.
