Table of contents

1. Introduction to Biology2h 42m
2. Chemistry3h 37m
3. Water1h 26m
4. Biomolecules2h 23m
5. Cell Components2h 26m
6. The Membrane2h 31m
7. Energy and Metabolism2h 0m
8. Respiration2h 40m
9. Photosynthesis2h 49m
10. Cell Signaling59m
11. Cell Division2h 47m
12. Meiosis2h 0m
13. Mendelian Genetics4h 44m
14. DNA Synthesis2h 27m
15. Gene Expression3h 6m
16. Regulation of Expression3h 31m
17. Viruses37m
- Viruses
  37m
18. Biotechnology2h 58m
19. Genomics17m
- Genomes
  17m
20. Development1h 5m
21. Evolution3h 1m
22. Evolution of Populations3h 53m
23. Speciation1h 37m
24. History of Life on Earth2h 6m
25. Phylogeny2h 31m
26. Prokaryotes4h 59m
27. Protists1h 12m
28. Plants1h 22m
29. Fungi36m
- Fungi
  19m
- Fungi Reproduction
  17m
30. Overview of Animals34m
- Overview of Animals
  34m
31. Invertebrates1h 2m
32. Vertebrates50m
33. Plant Anatomy1h 3m
34. Vascular Plant Transport1h 2m
- Water Potential
  1h 2m
35. Soil37m
- Soil and Nutrients
  20m
- Nitrogen Fixation
  16m
36. Plant Reproduction47m
- Flowers
  33m
- Seeds
  14m
37. Plant Sensation and Response1h 9m
38. Animal Form and Function1h 19m
39. Digestive System1h 10m
- Digestion
  1h 3m
- Blood Sugar Homeostasis
  7m
40. Circulatory System1h 49m
41. Immune System1h 12m
42. Osmoregulation and Excretion50m
- Osmoregulation and Excretion
  50m
43. Endocrine System1h 4m
- Endocrine System
  1h 4m
44. Animal Reproduction1h 2m
- Animal Reproduction
  1h 2m
45. Nervous System1h 55m
- Neurons and Action Potentials
  1h 8m
- Central and Peripheral Nervous System
  46m
46. Sensory Systems46m
- Sensory System
  46m
47. Muscle Systems23m
- Musculoskeletal System
  23m
48. Ecology3h 11m
49. Animal Behavior28m
- Animal Behavior
  28m
50. Population Ecology3h 41m
51. Community Ecology2h 46m
52. Ecosystems2h 36m
53. Conservation Biology24m
- Conservation Biology
  24m

45. Nervous System

Neurons and Action Potentials

General Biology

45. Nervous System

Neurons and Action Potentials

Previous problemNext problem

2:53 minutes

Problem 8

Textbook Question

A proposal to test an SSRI in a large number of individuals with depression was submitted to the FDA. Through random assignments, half of the patients would be controls, receiving nothing at all, and half the patients would receive the drug in pill form. Patients in both groups would note changes in their own mood in a daily journal. What flaw(s) do you note in this experimental design?

Verified step by step guidance

Identify the purpose of the experiment: The goal is to test the effectiveness of an SSRI (Selective Serotonin Reuptake Inhibitor) in treating depression. This requires a well-designed experiment to ensure valid and reliable results.

Recognize the importance of a control group: While the experiment includes a control group, the flaw lies in the fact that the control group receives 'nothing at all.' This can lead to biased results because the placebo effect is not accounted for. A proper control group should receive a placebo pill that looks identical to the SSRI pill but contains no active drug.

Evaluate the method of data collection: Patients are asked to note changes in their mood in a daily journal. This self-reporting method can introduce subjective bias, as individuals may interpret their mood changes differently or inconsistently. A more objective measure, such as standardized mood assessment scales administered by professionals, should be included.

Consider random assignment: Random assignment is correctly used to divide patients into groups, which helps reduce selection bias. However, the experimental design should also ensure that participants and researchers are blinded to group assignments (double-blind study) to prevent bias in treatment administration and data interpretation.

Address sample size and diversity: The proposal mentions a 'large number of individuals,' but it does not specify whether the sample is representative of the population with depression. Ensure that the sample includes diverse demographics (age, gender, ethnicity, etc.) to make the findings generalizable.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above

Video duration:

Play a video:

Was this helpful?

Key Concepts

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

Control Group

A control group is essential in experimental design as it serves as a baseline to compare the effects of the treatment. In this case, the control group receives no treatment, allowing researchers to determine if changes in mood are due to the SSRI or other factors. Properly establishing a control group helps eliminate bias and ensures that the results are attributable to the drug being tested.

Random Assignment

Random assignment is a technique used to ensure that each participant has an equal chance of being placed in either the experimental or control group. This process minimizes selection bias and helps ensure that the groups are comparable at the start of the experiment. In this study, random assignment is crucial for validating the findings and ensuring that any observed effects are due to the SSRI rather than pre-existing differences between participants.

Self-Reporting Bias

Self-reporting bias occurs when participants provide subjective assessments of their mood, which can be influenced by their expectations or beliefs about the treatment. In this study, relying on patients to note changes in their mood in a journal may lead to skewed data, as those receiving the SSRI might report more positive changes simply because they expect the drug to work. This bias can compromise the validity of the study's conclusions.

Watch next

Master Nervous System with a bite sized video explanation from Jason

Start learning

Related Videos

Related Practice

Textbook Question

Explain the difference between a ligand-gated K⁺ channel and a voltage-gated K⁺ channel.

987

views

Textbook Question

Suppose a particular neurotransmitter causes an IPSP in postsynaptic cell X and an EPSP in postsynaptic cell Y. A likely explanation is that

a. The threshold value in the postsynaptic membrane is different for cell X and cell Y

b. The axon of cell X is myelinated, but that of cell Y is not

c. Only cell Y produces an enzyme that terminates the activity of the neurotransmitter

d. Cells X and Y express different receptor molecules for this particular neurotransmitter

1106

views

Textbook Question

Describe the role of summation in postsynaptic cells.

834

views

Textbook Question

Anesthetics block pain by blocking the transmission of nerve signals. Which of these three chemicals might work as anesthetics? (Choose all that apply and explain your selections.)

a. A chemical that prevents the opening of voltage-gated Na⁺ channels in membranes

b. A chemical that inhibits the enzymes that degrade neurotransmitters

c. A chemical that blocks neurotransmitter receptors

877

views

Textbook Question

Using microelectrodes, a researcher recorded nerve signals in four neurons in the brain of a snail, called A, B, C, and D in the table below. A, B, and C can all transmit signals to D. In three experiments, the animal was stimulated in different ways. The number of nerve signals transmitted per second by each of the cells is recorded in the table. Write a short paragraph explaining the different results of the three experiments.

1090

views

Textbook Question

Explain why drugs that prevent neurotransmitters from being taken back up by a presynaptic neuron have dramatic effects on the activity of postsynaptic neurons.

822

views

Textbook Question

Certain species of frogs in the genus Phyllobates have a powerful defensive adaptation—their skin can secrete a milky fluid that contains an extremely toxic compound called batrachotoxin (BTX). These frogs, which are found in Colombia, are known as poison dart frogs because some indigenous Colombian hunters coat the tips of their blowgun darts with the frogs' skin secretions. An animal hit by one of these darts dies quickly.

What is the mechanism of action of BTX? The graph here shows the effect of BTX on the membrane potential of a squid giant axon.

Which of the following is the most likely explanation for the effect of BTX on the squid giant axon?

a. Inactivation of Na⁺/K⁺-ATPase

b. Closing of sodium channels

c. Opening of sodium channels

d. Opening of potassium channels

778

views

Textbook Question

What is the mechanism of action of BTX?

Identify a research technique that could be used to discover how BTX affects specific membrane proteins.

Based on the graph in Question 11, what would you expect this technique to show?

556

views

Show more practices

Download the Mobile app

Privacy

Do not sell my personal information

Accessibility

Patent notice

Sitemap