BuyFindarrow_forward

Biology: The Dynamic Science (Mind...

4th Edition
Peter J. Russell + 2 others
ISBN: 9781305389892

Solutions

Chapter
Section
BuyFindarrow_forward

Biology: The Dynamic Science (Mind...

4th Edition
Peter J. Russell + 2 others
ISBN: 9781305389892
Textbook Problem

The sliding filament contractile mechanism:

a. causes thin filaments on each side of a sarcomere to slide overthick filaments toward the center of the A band, bringing theZ lines closer together.

b. is inhibited by the influx of Ca2+ into the muscle fiber cytosol.

c. lengthens the sarcomere to separate the I regions.

d. depends on the isolation of actin and myosin until acontraction is completed.

e. uses myosin crossbridges to stimulate delivery of Ca2+ to themuscle fiber.

Summary Introduction

Introduction:

The sliding filament model of muscle contraction explains the mechanism by which the muscles contract. According to this concept, the myosin binds to the actin, which depends upon the dynamic interactions between actin and myosin protein filaments within the sarcomeres of the muscle fibers. This creates cross-bridges and slides past one another causing contractions.

Explanation

Justification for the correct answer:

Option (a) states that the sliding filament contractile mechanism causes thin filaments on each side of a sarcomere to slide over thick filaments toward the center of the A-band, bringing the Z lines closer together. This is a true statement as the muscle fiber contracts when thin filaments on each side of a sarcomere slide over the thick filament toward the center of the A-band. This causes the Z lines to come closer and it shortens the sarcomeres thus, leading to contraction of the muscles. Hence, option (a) is correct.

Justification for the incorrect answers:

Option (b) states that the sliding filament contractile mechanism is inhibited by the influx of Ca2+ (calcium ions) into the muscle fiber cytosol. This is not a true statement as it is in contradiction to the actual process. According to the sliding filament contractile mechanism, the electrical potential of the plasma membrane of the skeletal muscle fibers can change in response to a stimulus. This causes an increase in the action potential of the concentration of Ca2+ in the cytosol of the muscle fiber. So, it is an incorrect option.

Option (c) states that the sliding filament contractile mechanism lengthens the sarcomere to separate the I regions...

Still sussing out bartleby?

Check out a sample textbook solution.

See a sample solution

The Solution to Your Study Problems

Bartleby provides explanations to thousands of textbook problems written by our experts, many with advanced degrees!

Get Started

Additional Science Solutions

Find more solutions based on key concepts

Show solutions add

Which is not a stage of mitosis? a. prophase b. metaphase c. interphase d. anaphase

Biology: The Unity and Diversity of Life (MindTap Course List)

What are genomes?

Human Heredity: Principles and Issues (MindTap Course List)

An example of a person in positive nitrogen balance is a pregnant woman. T F

Nutrition: Concepts and Controversies - Standalone book (MindTap Course List)

(Chemical Connections 12C) What is the meaning of the term pheromone?

Introduction to General, Organic and Biochemistry

At an outdoor market, a bunch of bananas attached to the bottom of a vertical spring of force constant 16.0 N/M...

Physics for Scientists and Engineers, Technology Update (No access codes included)