Textbook Question
Explain why the one-gene:one-enzyme concept is not considered totally accurate today.
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Ch. 13 - Translation and Proteins
Klug10th EditionEssentials of GeneticsISBN: 9780135588789
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Table of contents
- Ch. 1 - Introduction to Genetics16
- Ch. 2 - Mitosis and Meiosis28
- Ch. 3 - Mendelian Genetics37
- Ch. 4 - Modification of Mendelian Ratios53
- Ch. 5 - Sex Determination and Sex Chromosomes32
- Ch. 6 - Chromosome Mutations: Variation in Number and Arrangement37
- Ch. 7 - Linkage and Chromosome Mapping in Eukaryotes36
- Ch. 8 - Genetic Analysis and Mapping in Bacteria and Bacteriophages24
- Ch. 9 - DNA Structure and Analysis38
- Ch. 10 - DNA Replication29
- Ch. 11 - Chromosome Structure and DNA Sequence Organization22
- Ch. 12 - The Genetic Code and Transcription36
- Ch. 13 - Translation and Proteins27
- Ch. 14 - Gene Mutation, DNA Repair, and Transposition34
- Ch. 15 - Regulation of Gene Expression in Bacteria22
- Ch. 16 - Regulation of Gene Expression in Eukaryotes37
- Ch. 17 - Recombinant DNA Technology27
- Ch. 18 - Genomics, Bioinformatics, and Proteomics30
- Ch. 19 - The Genetics of Cancer21
- Ch. 20 - Quantitative Genetics and Multifactorial Traits37
- Ch. 21 - Population and Evolutionary Genetics45
Chapter 13, Problem 14
Assuming that each nucleotide in an mRNA is 0.34 nm long, how many triplet codes can simultaneously occupy the space in a ribosome that is 20 nm in diameter?
Verified step by step guidance1
Understand the problem: We need to find how many triplet codons (each consisting of 3 nucleotides) can fit within the length of the ribosome, which is given as 20 nm in diameter. Each nucleotide is 0.34 nm long, so the total length occupied by a triplet codon is 3 times 0.34 nm.
Calculate the length of one triplet codon by multiplying the length of a single nucleotide by 3: \$3 \times 0.34 \text{ nm}$.
Determine how many such triplet codons can fit into the 20 nm space by dividing the total length of the ribosome (20 nm) by the length of one triplet codon: \(\frac{20 \text{ nm}}{3 \times 0.34 \text{ nm}}\).
Interpret the result as the number of triplet codons that can simultaneously occupy the ribosome space. Since the number of codons must be a whole number, consider whether to round down to the nearest whole number.
Summarize the approach: by dividing the ribosome length by the length of one codon, you find the maximum number of codons that can fit simultaneously in the ribosome.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Structure and Length of mRNA Nucleotides
mRNA is composed of nucleotides arranged linearly, each approximately 0.34 nm in length. This measurement helps determine how much physical space a sequence of nucleotides occupies, which is essential for calculating how many codons fit within a given length.
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06:25
DNA Structure
Triplet Codon Concept in Genetic Code
A triplet codon consists of three consecutive nucleotides in mRNA that encode a specific amino acid during protein synthesis. Understanding that codons are groups of three nucleotides is crucial for relating nucleotide length to the number of codons present.
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11:43The Genetic Code
Physical Constraints of the Ribosome
The ribosome is a molecular machine with a defined size, here given as 20 nm in diameter. Knowing the ribosome's spatial dimensions allows us to estimate how many nucleotides or codons can physically fit inside its active site during translation.
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03:49Ribosome Structure
Related Practice
Textbook Question
Using sickle-cell anemia as an example, describe what is meant by a molecular or genetic disease. What are the similarities and dissimilarities between this type of a disorder and a disease caused by an invading microorganism?
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Textbook Question
List as many different categories of protein functions as you can. Wherever possible, give an example of each category.
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