1. Introduction to Biology

2. Chemistry

3. Water

4. Biomolecules

5. Cell Components

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

34. Vascular Plant Transport

35. Soil

36. Plant Reproduction

37. Plant Sensation and Response

38. Animal Form and Function

39. Digestive System

40. Circulatory System

41. Immune System

42. Osmoregulation and Excretion

43. Endocrine System

44. Animal Reproduction

45. Nervous System

46. Sensory Systems

47. Muscle Systems

48. Ecology

49. Animal Behavior

50. Population Ecology

51. Community Ecology

52. Ecosystems

53. Conservation Biology

[BOOK BIO] CLUTCH

Introduction to the Cytoskeleton

Microfilaments and intermediate filaments | Cells | MCAT | Khan Academy

What is the Cytoskeleton?

How does the hydrolysis of ATP result in the movement of a motor protein along a cytoskeletal filament?

Microtubules often produce movement through their interaction with motor proteins. But in some cases, microtubules move cell components when the length of the microtubule changes. Through a series of experiments, researchers determined that microtubules grow and shorten as tubulin proteins are added or removed from their ends. Other experiments showed that microtubules make up the spindle apparatus that 'pulls' chromosomes toward opposite ends (poles) of a dividing cell. The figures below describe a clever experiment done in 1987 to determine whether a spindle microtubule shortens (depolymerizes) at the end holding a chromosome or at the pole end of a dividing cell. Experimenters labeled the microtubules of a dividing cell from a pig kidney with a yellow fluorescent dye. As shown on the left half of the diagram below, they then marked a region halfway along the microtubules by using a laser to eliminate the fluorescence from that region. They did not mark the other side of the spindle (right side of the figure). <img class="fr-dib" src="https://lightcat-files.s3.amazonaws.com/problem_images/e8703f92447b00dc-1677714421797.jpg" style="width: 300px;">

Short Video: Flagellum in Sperm

The figure below illustrates the results they observed as the chromosomes moved toward the opposite poles of the cell. 
Describe these results. What would you conclude about where the microtubules depolymerize from comparing the length of the microtubules on either side of the mark? How could the experimenters determine whether this is the mechanism of chromosome movement in all cells?<img class="fr-dib" src="https://lightcat-files.s3.amazonaws.com/problem_images/266770e4aee89a70-1677714454648.jpg" style="width: 300px;">

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.

Consider the function of the cytoskeleton.

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

The eukaryotic cytoskeleton is a highly dynamic network of filaments and motor proteins. Which of the following correctly describe activities of these cytoskeletal components? Select True or False for each statement.
T/F Myosin motors walk toward the plus ends of intermediate filaments.
T/F Dynein motors are responsible for the whip-like movement of eukaryotic flagella.
T/F Kinesin motors move vesicles along tracks toward the microtubule-organizing center.
T/F Actin filaments are required for cytoplasmic streaming.

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

USMLE Step 1 - Lesson 20 - Elements of the Cytoskeleton

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

Short Video: Sperm Flagellum

Cilia & Flagella

George Palade's research group used the pulse–chase assay to elucidate the secretory pathway in pancreatic cells. If they had instead performed this assay on muscle cells, where would you expect the labeled proteins to end up during the chase? (Muscle cells consist primarily of actin and myosin filaments and have high energy demands for muscle contraction.)

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

Introduction to the Cytoskeleton Practice 2

BioFlix: Cytoskeleton

Describe two different ways in which cilia can function in organisms.

Cilia are found on cells in almost every organ of the human body, and the malfunction of cilia is involved in several human disorders. During embryological development, for example, cilia generate a leftward flow of fluid that initiates the left-right organization of the body organs. Some individuals with primary ciliary dyskinesia exhibit a condition (situs inversus) in which internal organs such as the heart are on the wrong side of the body. Explain why this reversed arrangement may be a symptom of PCD.

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.

Introduction to the Cytoskeleton Practice 1

Learn the toughest concepts covered in Biology1&2 with step-by-step video tutorials and practice problems by world-class tutors 