Textbook Question
A hypothetical poison prevents transcription factors from binding to the gene for tubulin proteins. What impact would this have on mitosis, and why?
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Ch. 3 The Cell
Amerman3rd EditionHuman Anatomy & PhysiologyISBN: 9780138247201, 9780138247928, 9780138201814
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Table of contents
- Ch. 1 Introduction to Anatomy and Physiology24
- Ch. 2 The Chemistry of Life37
- Ch. 3 The Cell54
- Ch. 4 Histology46
- Ch. 5 The Integumentary System30
- Ch. 6 Bones and Bone Tissue36
- Ch. 7 The Skeletal System40
- Ch. 8 Articulations19
- Ch. 9 The Muscular System35
- Ch. 10 Muscle Tissue and Physiology29
- Ch. 11 Introduction to the Nervous System and Nervous Tissue28
- Ch. 12 The Central Nervous System41
- Ch. 13 The Peripheral Nervous System41
- Ch. 14 The Autonomic Nervous System and Homeostasis31
- Ch. 15 The Special Senses39
- Ch. 16 The Endocrine System42
- Ch. 17 The Cardiovascular System I: The Heart28
- Ch. 18 The Cardiovascular System II: The Blood Vessels43
- Ch. 19 Blood32
- Ch. 20 The Lymphatic System and Immunity41
- Ch. 21 The Respiratory System27
- Ch. 22 The Digestive System27
- Ch. 23 Metabolism and Nutrition7
- Ch. 24 The Urinary System39
- Ch. 25 Fluid, Electrolyte, and Acid-Base Homeostasis39
- Ch. 26 The Reproductive System10
- Ch. 27 Development and Heredity5
Amerman3rd EditionHuman Anatomy & PhysiologyISBN: 9780138247201, 9780138247928, 9780138201814Not the one you use?Change textbook
Chapter 3, Problem L3A2
A popular science fiction program once had an episode that featured an 'intron virus' that 'turned on' the introns in the genes, causing the synthesis of abnormal proteins. The episode may have been entertaining, but its premise had a large flaw about the nature of introns. What was the flaw?
Verified step by step guidance1
Understand the role of introns in gene expression: Introns are non-coding sequences within a gene that are removed during RNA splicing. They do not directly code for proteins, as they are excised from the pre-mRNA before translation.
Clarify the concept of RNA splicing: During transcription, a gene produces pre-mRNA, which contains both exons (coding regions) and introns (non-coding regions). The introns are removed by spliceosomes, leaving only the exons to form the mature mRNA that is translated into a protein.
Identify the flaw in the premise: The idea that introns could be 'turned on' to synthesize abnormal proteins is flawed because introns do not contain coding sequences for proteins. They are regulatory or non-functional sequences that are not translated into proteins under normal circumstances.
Explain why abnormal protein synthesis would not occur: Since introns are removed during RNA processing, they do not contribute to the sequence of the mature mRNA. Therefore, they cannot directly influence the synthesis of proteins, whether normal or abnormal.
Conclude with the scientific basis: The episode's premise misunderstands the fundamental biology of gene expression. Introns are not functional coding units, and their activation would not lead to protein synthesis, as proteins are derived only from the coding exons in the mature mRNA.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Introns
Introns are non-coding sequences of DNA that are found within genes. They are transcribed into precursor mRNA but are removed during RNA splicing before translation into proteins. Understanding the role of introns is crucial, as they do not directly code for proteins but can influence gene expression and the regulation of alternative splicing.
Recommended video:
08:44
2) RNA Splicing Creates Mature mRNA
Gene Expression Regulation
Gene expression regulation refers to the mechanisms that control the timing and amount of gene product (protein) produced in a cell. This process involves various elements, including enhancers, silencers, and transcription factors, which interact with both coding and non-coding regions of DNA, including introns, to modulate gene activity rather than simply 'turning on' introns.
Recommended video:
04:02Types of Genes Regulating Cell Growth
Protein Synthesis
Protein synthesis is the biological process through which cells generate new proteins, involving transcription of DNA to mRNA and translation of mRNA to amino acid chains. The premise of the episode incorrectly suggests that activating introns directly leads to abnormal protein synthesis, overlooking the complex regulatory mechanisms that govern how proteins are made from coding sequences.
Recommended video:
02:50Proteins
Related Practice
Textbook Question
Epithelial cells of the kidneys have pumps that drive the transcellular transport of sodium ions.
The movement of sodium ions drives the transcellular transport of water. Explain why water follows sodium. (Connects to Chapter 3)
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Textbook Question
Which of the following best describes the arrangement of the main component of the plasma membrane?
a. A monolayer of phospholipids with the phosphate heads facing the cytosol and the fatty acid tails facing the extracellular fluid
b. A bilayer of phospholipids with the phosphate heads facing the cytosol and extracellular fluid, and the fatty acid tails facing one another
c. A bilayer of phospholipids with the phosphate heads of one layer facing the fatty acid tails of the other
d. A bilayer of phospholipids with a layer of triglycerides sandwiched in the middle
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Textbook Question
Write a single sentence, using no more than 25 words, to summarize each of the following cellular processes:
Primary active transport
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Textbook Question
Write a single sentence, using no more than 25 words, to summarize each of the following cellular processes:
DNA synthesis
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Textbook Question
Write a single sentence, using no more than 25 words, to summarize each of the following cellular processes:
Mitosis