/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 11 There are three major classes of... [FREE SOLUTION] | 91影视

91影视

Log out

Learning Materials

Features

Discover

Chapter 1: Problem 11

There are three major classes of protein filaments that make up the cytoskeleton of a typical animal cell. What are they, and what are the differences in their functions? Which cytoskeletal filaments would be most plentiful in a muscle cell or in an epidermal cell making up the outer layer of the skin? Explain your answers.

Short Answer

Expert verified
Muscle cells have abundant microfilaments for contraction; epidermal cells have abundant intermediate filaments for strength.

Step by step solution

01

Identify the Three Major Cytoskeletal Filaments

The cytoskeleton of a typical animal cell is composed of three main types of protein filaments: microfilaments (actin filaments), microtubules, and intermediate filaments. These filaments provide structural support, facilitate cell movement, and play various roles in intracellular transport.
02

Describe the Functions of Microfilaments

Microfilaments, also known as actin filaments, are the thinnest filaments of the cytoskeleton. They are made of actin proteins and are primarily involved in providing structural support, facilitating cell movement, and enabling muscle contraction by working with myosin.
03

Describe the Functions of Microtubules

Microtubules are the thickest filaments and are composed of tubulin proteins. They help maintain cell shape, provide tracks for intracellular transport, and are involved in cell division by forming the mitotic spindle.
04

Describe the Functions of Intermediate Filaments

Intermediate filaments have a diameter between that of microfilaments and microtubules. They are primarily involved in providing mechanical strength to cells, enhancing their ability to withstand stress, and are crucial for maintaining cell integrity, especially in tissues.
05

Identify the Most Plentiful Filaments in Muscle Cells

In muscle cells, microfilaments are the most abundant because they facilitate muscle contraction. Actin filaments work closely with myosin to execute the contraction process that is essential for muscle function.
06

Identify the Most Plentiful Filaments in Epidermal Cells

In epidermal cells, intermediate filaments, specifically keratin filaments, are the most abundant. They provide strength and structural integrity to the cells, which is vital for the protective role of the skin's outer layer.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with 91影视!

Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Microfilaments
Microfilaments, also known as actin filaments, are one of the three main types of structures that form the cytoskeleton of animal cells. These are the smallest cytoskeletal structures, with a diameter of approximately 7 nm.
Composed of actin proteins, microfilaments are crucial for a variety of cell functions.
  • They play a significant role in maintaining the cell's shape by forming a dense network underneath the plasma membrane.
  • Microfilaments are essential for muscle contractions, a process where they work in tandem with the protein myosin. This function is particularly salient in muscle cells where actin-myosin interactions are vital for muscle movement.
  • Additionally, they are involved in cell motility, aiding in processes such as amoeboid movement and cell division.
In contexts like muscle cells, microfilaments are prevalent due to their role in supporting muscle contractions, emphasizing their critical importance in muscle functionality.
Microtubules
Microtubules are the thickest cytoskeletal filaments, with a staggering diameter of about 25 nm. These structures are made up of tubulin proteins, which form a hollow tube-like filament.
This structural form gives them the strength to perform various cellular functions.
  • One of their primary roles is to maintain cell shape and provide a rigid, structural framework within the cell.
  • They serve as tracks for motor proteins, like kinesin and dynein, to transport organelles, vesicles, and other cellular components.
  • Crucially, microtubules are involved in cell division. They form the mitotic spindle, an apparatus that segregates chromosomes into the daughter cells during mitosis and meiosis.
Microtubules' dynamic nature, characterized by rapid assembly and disassembly, is fundamental to their function in these cellular processes.
Intermediate Filaments
Intermediate filaments are aptly named for being thicker than microfilaments but thinner than microtubules, with diameters around 10 nm. These filaments are comprised of various proteins depending on cell type, such as keratins in epithelial cells.
Their composition provides durability.
  • They are primarily responsible for providing mechanical strength and helping cells withstand stress without damage.
  • The solid nature of intermediate filaments contributes to maintaining cell integrity, especially in tissues subject to mechanical stress, such as the epidermis or neurons.
  • In epithelial cells, like those that form the outer layer of the skin, keratin-rich intermediate filaments are abundantly present. These filaments act as a crucial defensive structure.
In summary, intermediate filaments are integral in tissue resilience and cellular stability, making them indispensable components of the cytoskeletal framework.

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

You have embarked on an ambitious research project: to create life in a test tube. You boil up a rich mixture of yeast extract and amino acids in a flask, along with a sprinkling of the inorganic salts known to be essential for life. You seal the flask and allow it to cool. After several months, the liquid is as clear as ever, and there are no signs of life. A friend suggests that excluding the air was a mistake, since most life as we know it requires oxygen. You repeat the experiment, but this time you leave the flask open to the atmosphere. To your great delight, the liquid becomes cloudy after a few days, and, under the microscope, you see beautiful small cells that are clearly growing and dividing. Does this experiment prove that you managed to generate a novel lifeform? How might you redesign your experiment to allow air into the flask, yet eliminate the possibility that contamination by airborne microorganisms is the explanation for the results? (For a readymade answer, look up the classic experiments of Louis Pasteur.)

Mutations are mistakes in the DNA that change the genetic plan from that of the previous generation. Imagine a shoe factory. Would you expect mistakes (i.e., unintentional changes in copying the shoe design to lead to improvements in the shoes produced? Explain your answer.

Your next-door neighbor has donated \(\$ 100\) in support of cancer research and is horrified to learn that her money is being spent on studying brewer's yeast. How could you put her mind at ease?

Draw to scale the outline of two spherical cells, one a bacterium with a diameter of \(1 \mu \mathrm{m}\), the other an animal cell with a diameter of \(15 \mu \mathrm{m}\). Calculate the volume, surface area, and surface-to-volume ratio for each cell. How would the latter ratio change if you included the internal membranes of the animal cell in the calculation of surface area (assume internal membranes have 15 times the area of the plasma membrane)? (The volume of a sphere is given by \(4 \pi r^{3} / 3\) and its surface by \(4 \pi r^{2},\) where \(r\) is its radius.) Discuss the following hypothesis: "Internal membranes allowed bigger cells to evolve."

By now you should be familiar with the following cell components. Briefly define what they are and what function they provide for cells. A. cytosol B. cytoplasm C. mitochondria D. nucleus E. chloroplasts F. Iysosomes G. chromosomes H. Golgi apparatus I. peroxisomes J. plasma membrane K. endoplasmic reticulum L. cytoskeleton M. ribosome
See all solutions

Recommended explanations on Biology Textbooks

Energy Transfers

Read Explanation

Ecology

Read Explanation

Bioenergetics

Read Explanation

Microbiology

Read Explanation

Substance Exchange

Read Explanation

Chemistry of Life

Read Explanation
View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.