5. Cell Components

Introduction to the Cytoskeleton

USMLE Step 1 - Lesson 20 - Elements of the Cytoskeleton

Microfilaments and intermediate filaments | Cells | MCAT | Khan Academy

What is the Cytoskeleton?

Which of the following best characterizes an adaptive radiation?

a. Descendant species occupy a large geographic area.
b. A single lineage diversifies rapidly, and descendant species occupy many habitats and ecological roles.
c. Natural selection is particularly intense, because disruptive selection occurs.
d. Species recover after a mass extinction.

Short Video: Flagellum in Sperm

 No. The lysosomes are involved in degradation, and this is not a function shared with the cytoskeleton. 

 No. The cytoskeleton does not have a role in protein synthesis. 

 No. RNA has nothing to do with the functioning of the cytoskeleton. 

 None of the listed responses is correct. 

Consider the function of the cytoskeleton.

Microtubules and microfilaments commonly work with which of the following to perform many of their functions?

Many species of animals on islands are larger than related species on the mainland. Scientists hypothesize that this phenomenon, called island gigantism, evolved in response to the scarcity of competitors and predators on islands. Reduced competition and predation allows species to exploit more resources and frees them from the need to hide in small refuges.

The graph shown here compares the average carapace (shell) length of mainland and island tortoises. Summarize the results, then use the data to predict whether the surface area to volume ratio is higher in mainland or island tortoises. <IMAGE>

 No. Both mitochondria and chloroplasts are found in plant cells. 

 No. This is a feature common to all cells, so it must be found in both animal and plant cells. 

 No. All plant cells and animal cells have at least one Golgi apparatus. 

 No. Plant and animal cells both have rough endoplasmic reticulum. 

Compare and contrast the structures found in animal and plant cells.

Which of the following structures is found in animal cells but not in plant cells?

 No. Actin is a protein that is a major component of microfilaments. 

 No. Pseudopodia are transient cell structures involved in amoeboid movement. 

 No. Mitochondria supply the energy for motion in the cytoskeleton, but they do not cause the motion. 

 No. Tubulin is the major protein component of microtubules. 

Consider how motion is accomplished in the cytoskeleton.

Cilia and flagella move due to the interaction of the cytoskeleton with which of the following?

Microtubules | Cells | MCAT | Khan Academy

What component of the cytoskeletons do motor proteins use to transport vesicles?

Short Video: Sperm Flagellum

Cilia & Flagella

Many species of animals on islands are larger than related species on the mainland. Scientists hypothesize that this phenomenon, called island gigantism, evolved in response to the scarcity of competitors and predators on islands. Reduced competition and predation allows species to exploit more resources and frees them from the need to hide in small refuges.

Which tortoises, mainland or island, need to eat more food per gram of their body mass?

 Intermediate filaments are hollow tubes of protein that provide structural support. 

 No. Microtubules are relatively rigid tubular structures that provide support in the cell. 

 Microtubules are chains of proteins that resist stretching. 

 No. Microfilaments are polymers of the protein actin that are quite strong and resist stretching. 

 Microfilaments are more permanent structures in cells compared to intermediate filaments and microtubules. 

 No. Intermediate filaments are more permanent in their structure than microfilaments and microtubules are in theirs. 

 Plant cells lack a cytoskeleton because they have a rigid cell wall. 

 No. The cytoskeleton is important in many other processes besides maintaining cell shape. 

 Components of the cytoskeleton often mediate the movement of organelles within the cytoplasm. 

Consider the structures and functions of the different types of cytoskeleton.

Which statement about the cytoskeleton is true?

The cytoskeleton | Structure of a cell | Biology | Khan Academy

 No. Basal bodies are made up of components of the cytoskeleton and are not associated with the nucleus. 

 No. Basal bodies are made up of components of the cytoskeleton and are not associated with the mitochondria. 

 No. Basal bodies are made up of components of the cytoskeleton and are not associated with the vacuole. 

 No. Basal bodies are made up of components of the cytoskeleton and are not associated with the Golgi. 

Centrioles are structurally similar to basal bodies.

Basal bodies are most closely associated with which of the following cell components?

Animation: Cilia and Flagella

BioFlix: Cytoskeleton

Cell Organelles 2 Cytoskeleton

In human cells, ___________________ are used to move a cell within its environment while ___________________ are used to move objects in the environment relative to the cell.

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The Explorer's Guide to Biology

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1. Introduction to Biology

2. Chemistry

3. Water

4. Biomolecules

6. The Membrane

7. Energy and Metabolism

8. Respiration

9. Photosynthesis

10. Cell Signaling

11. Cell Division

12. Meiosis

13. Mendelian Genetics

14. DNA Synthesis

15. Gene Expression

16. Regulation of Expression

17. Viruses

18. Biotechnology

19. Genomics

20. Development

21. Evolution by Natural Selection

22. Evolution of Populations

23. Speciation

24. History of Life on Earth

25. Phylogeny

26. Prokaryotes

27. Protists

28. Plants

29. Fungi

30. Overview of Animals

31. Invertebrates

32. Vertebrates

33. Plant Anatomy