Question

reading? read the following sections. once you have completed the reading answer the questions below. holt mcdougal biology chapter 8 section 4 pages 226 - 228 1. summarize the central dogma of molecular biology. 2. how do dna and rna differ? 3. what is the role of messenger rna in transcription? 4. why does transcription take place in the nucleus of the cell? holt mcdougal biology chapter 8 section 5 pages 229 - 233 5. how many nucleotides make up a codon? 6. what is the role of messenger rna in translation?

Explanation:

1. The central dogma of molecular biology describes the two - step process, transcription and translation, by which the information in genes flows into proteins: DNA → RNA → protein.
2. DNA is double - stranded, has deoxyribose sugar, and thymine as a base. RNA is single - stranded, has ribose sugar, and uracil instead of thymine.
3. In transcription, messenger RNA (mRNA) is synthesized from a DNA template. It carries the genetic information from DNA in the nucleus to the ribosomes in the cytoplasm for protein synthesis.
4. Transcription takes place in the nucleus because DNA is located in the nucleus. The enzymes and factors required for transcription are also present in the nucleus.
5. Three nucleotides make up a codon. Each codon codes for a specific amino acid or a start/stop signal during translation.
6. In translation, messenger RNA serves as a template. Ribosomes read the sequence of codons on the mRNA and assemble the corresponding amino acids in the correct order to form a polypeptide chain.

Answer:

1. The central dogma is DNA → RNA → protein via transcription and translation.
2. DNA is double - stranded with deoxyribose and thymine; RNA is single - stranded with ribose and uracil.
3. It carries genetic info from DNA in nucleus to ribosomes for protein synthesis.
4. Because DNA is in the nucleus and transcription enzymes are there.
5. Three nucleotides.
6. It serves as a template for ribosomes to assemble amino acids.