Biology 2382B Lecture 9: Damjanovski Section 1 - Cytoskeleton

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magentacrocodile542

16 Aug 2017

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Specific functions (kinesin and dynein function: anterograde/retrograde transport, axoneme (cilia and flagella movement, mitosis (mitotic apparatus) Cell junctions, cell adhesion and the extracellular matrix 921-968. Cytoskeleton intricate network of protein filaments that extend throughout the cytoplasm. Microtubules (made of (cid:533)-tubulin dimers) 25nm. *memorize this slide (networks, vs ropes (pull) vs rods) Cellular trafficking of organelles things inside cell can move. Biological molecules are 3-dimensional (specific size and shape) and take up space!! When we are talking about what is happening in a cell, we have to think about molecules and the fact that they are happening in 3d space. When the textbook shows simplistic diagrams, appreciate that everything is full. There is no empty space inside a cell. 25nm diameter, up to hundreds of m long: microtubule structure can be bigger than the cell, microtubules make up structures such as cilia and flagella (can be huge) If a cell is polymerizing microtubules, it is using (cid:533) dimers.

Related Questions

1. How does the extracellular matrix affect a cell that it surrounds? (Select all that apply.)

	The cell's shape depends in part on the structure and composition of the extracellular matrix.
	The genes that the cell expresses depend in part on the types of proteins in the extracellular matrix.
	The size that the cell grows to depends in part on the polysaccharides in the extracellular matrix.
	The extracellular matrix has no effect on the cells that it surrounds.
	All of these choices are correct.

2. Which of the following enable(s) the movement of cells?

	microtubules
	microfilaments
	intermediate filaments
	microtubules and microfilaments
	microfilaments and intermediate filaments

3. Microtubules increase in length:

	more quickly at one end than the other.
	by growing outward from the centrosome.
	in cycles, following rapid depolymerization.
	if free tubulin dimers are available.
	All of these choices are correct.

4. Dynamic instability is the rapid assembly and disassembly of:

	microfilaments.
	intermediate filaments.
	microtubules.
	both microfilaments and microtubules.

5. Which one of the following is a characteristic shared by integrins and cadherins?

	Both are peripheral membrane proteins.
	Both facilitate the adhesion of cells to extracellular matrix proteins.
	Both are present in adherens junctions, desmosomes, and hemidesmosomes.
	The cytoplasmic domains of both proteins are connected to the cytoskeleton.

6. Cadherin is an example of a(n):

	motor protein.
	intermediate filament protein.
	cell adhesion molecule.
	extracellular matrix protein.

7. Which is the CORRECT order from lesser to greater complexity for the following?

	organs, tissues, cells
	cells, tissues, organs
	tissues, organs, cells
	cells, organs, tissues

pucebear535

not too details, just main points please...

1. What you should know about microtubles

- MT structure, what they are made of

- MT function

- Motor proteins(kinesins&dyneins)

- How kinesins move, coupling to ATP hydrolysis

- Microtubule Organizing Center (MTOC), how MTs are nucleated

- MT dynamics, how it's affected by drugs and MAPs

- dynamic instability and how its linked to GTP/GDP cycle

- cilia/flagella, axoneme structure

- how cilia/flagella move and the role of dynein

-intra-flagellar transport

2. What you should know about actin filaments

- F-actin structure

- F-actin Function

- Motor proteins (myosins)

- Actin dynamics, how it's affected by actin-binding proteins

- the concept of critical concentration

- actin/myosin structure and function in the contezt of muscle

- how muscle contract

- actinomyosin cycle (myosin movement), coupling to ATP hydrolysis

- How cells move and change shape, using actin

3. What you should know about IF

- IF strcuture, what they are made of

- IF function, roles inside and outside cells

- Regulation of nuclear IF in the cell cycle

- be able to compare major features of IF, Actin, and MTs

Bacterial cytoskeleton, that bacteria have proteins that

- polymerize

-affect cell shape, cytokinesis, ect.

- play analogous roles to MT, F-actin

4. what you should know about the cell cycle

- parts of the cell cycle, stages of mitosis

- MPF; how it was identified, what it is made of (cyclin and cdk)

- Universality of cyclin/Cdks (in yeast, frogs, etc.)

-how Cdk activity is regulated (many mechanisms)

- how Cdks function (by phosphorylation)

- how multiple cdks divide their function

- how the spindle is formed and mistakes corrected

- the role of motors and MY dynamics in above

- the tolr of proteolysis in mitotic transitions

- what a checkpoint is

- how checkpoints provide an additional layer of cell cycle regulation in case of damage

pearcrab948

QUESTION 30

The function of centrosome is:

	1.	Microtubule initiation and organization in animal cells
	2.	Organization of thin filaments
	3.	Depolymerization of microtubules
	4.	Organization of intermediate filaments

2.5 points

QUESTION 31

The destinations of proteins synthesized on "free" ribomsomes include:

	1.	Endoplasmic reticulum
	2.	Nucleus
	3.	Mitochondria
	4.	Lysosomes

2.5 points

QUESTION 32

Microtubules can be assembled and disassembled quickly in response to the cellular changes is because:

	1.	Cells synthesize tubulin proteins very fast.
	2.	Cells can turn other cytoskeletal filaments into microtubules
	3.	Microtubules have an instable plus end and microtubules are probably organized by weak non-covalent interactions
	4.	The motor proteins of microtubules can organize the microtubules in response to the cellular changes

2.5 points

QUESTION 33

Both signal recognition particle and a translocon in rough endoplasmic reticulum membrane can recognize and bind to the signal sequence of a secretory protein, so they play the exact same role during protein co-translational translocation.

True

False

2.5 points

QUESTION 34

Rough endoplasmic reticulum is so named is because:

	1.	It has many proteins associated with its surface.
	2.	It has ribosomes associated with its cytosolic surface.
	3.	It is associated with nuclear membrane.
	4.	It has vesicles budding off its surface.

2.5 points

QUESTION 35

The membrane vesicles that transport materials between membrane compartments have a protein coat. The protein coat has similar functions in different vesicles. These functions include:

	1.	Help the enclosed material fold correctly.
	2.	Help degrade the protein in the vesicles
	3.	Maintain the internal pH of the vesicles
	4.	Function as mechanical device to form a vesicle and select the components to be carried by a vesicle.

2.5 points

QUESTION 36

Lysosomes are important for:

	1.	Receptor-mediated endocytosis.
	2.	Breaking down foreign particles brought into the cells by endosomes
	3.	Regulating the process of organelle turnover.
	4.	Protein trafficking between membrane compartments

2.5 points

QUESTION 37

Which of the following is correct about membrane biosynthesis?

	1.	Membranes are synthesized in Golgi Complex.
	2.	Membranes arise from preexisting endoplasmic reticulum membranes.
	3.	Membranes are synthesized on ribosomes.
	4.	Membranes of all organelles have the same composition of proteins and lipids, since they all originate from endoplasmic reticulum.

2.5 points

QUESTION 38

During skeletal muscle contractions, the shortening of the muscle fibers is because of:

		The shortening of the thin and thick myofilaments.
		The shortening of the cytoskeletal filaments.
		The kinesin proteins moving over microtubules.
		The actin and myosin filaments sliding over each other.

2.5 points

QUESTION 39

The assembly and disassembly of microtubules is regulated by rate of growth and shrinkage of the plus end.

True

False

2.5 points

QUESTION 40

The functions of Golgi complex include:

	1.	O-linked oligosaccharides and most of a cellâs complex polysaccharides are assembled in Golgi complex
	2.	Cis Golgi complex sorts proteins
	3.	Trans Golgi complex segregates proteins in different types of vesicles for dilevery.
	4.	N-linked oligosaccharides are further processed in Golgi complex

ochrecoyote721

Biology 2382B Lecture 9: Damjanovski Section 1 - Cytoskeleton

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