Table of contents

1. Introduction to Anatomy & Physiology5h 43m
2. Cell Chemistry & Cell Components12h 36m
3. Energy & Cell Processes10h 6m
4. Tissues & Histology10h 3m
5. Integumentary System2h 20m
6. Bones & Skeletal Tissue2h 16m
7. The Skeletal System2h 35m
8. Joints2h 17m
9. Muscle Tissue2h 33m
10. Muscles1h 11m
11. Nervous Tissue and Nervous System1h 35m
12. The Central Nervous System1h 6m
- Introduction to the Central Nervous System
  18m
- The Cerebrum
  48m
13. The Peripheral Nervous System1h 26m
14. The Autonomic Nervous System1h 38m
15. The Special Senses2h 41m
16. The Endocrine System2h 48m
17. The Blood3h 22m
18. The Heart3h 42m
19. The Blood Vessels3h 35m
20. The Lymphatic System3h 16m
21. The Immune System14h 37m
22. The Respiratory System3h 20m
23. The Digestive System2h 5m
24. Metabolism and Nutrition4h 0m
25. The Urinary System2h 39m
26. Fluid and Electrolyte Balance, Acid Base Balance37m
27. The Reproductive System2h 5m
28. Human Development1h 21m
29. Heredity3h 32m

3. Energy & Cell Processes

Steps of Transcription

Anatomy & Physiology

3. Energy & Cell Processes

Steps of Transcription

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Problem 14

Textbook Question

If you wanted to use αα-amanitin to shut down 95 percent of transcription by RNA polymerase II, roughly what concentration of αα-amanitin would you use? Note that the scale on the x-axis of the graph in Question 13 is logarithmic rather than linear, so that each tick mark shows a tenfold higher concentration.

Verified step by step guidance

Examine the graph to understand the relationship between the concentration of α-amanitin and the percent polymerase activity.

Identify the y-axis value that corresponds to 5% polymerase activity, as shutting down 95% of transcription means only 5% activity remains.

Locate the point on the graph where the y-axis value is 5%.

Trace vertically down from this point to intersect the x-axis, which represents the concentration of α-amanitin.

Read the concentration value on the x-axis at this intersection point to determine the required concentration of α-amanitin.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

α-amanitin

α-amanitin is a cyclic peptide toxin derived from the Amanita phalloides mushroom, known for its ability to inhibit RNA polymerase II. This enzyme is crucial for synthesizing mRNA in eukaryotic cells. Understanding the concentration of α-amanitin required to inhibit transcription is essential for studying gene expression and the effects of transcriptional regulation.

Transcription Inhibition

Transcription inhibition refers to the process of blocking the synthesis of RNA from a DNA template. In the context of α-amanitin, it specifically targets RNA polymerase II, leading to a decrease in mRNA production. This concept is vital for understanding how certain compounds can regulate gene expression and the implications for cellular function and development.

Logarithmic Scale

A logarithmic scale is a nonlinear scale used for a large range of values, where each tick mark represents a tenfold increase in value. In the provided graph, the x-axis is logarithmic, which affects how concentrations of α-amanitin are interpreted. Understanding this scale is crucial for accurately determining the concentration needed to achieve a specific level of transcription inhibition, such as 95 percent.