BIOL 115 Lecture Notes - Lecture 4: Adherens Junction, Leg, Tight Junction

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pinkgoldfish355

25 Jun 2016

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There are many proteins that regulate growth or shrinkage of mts. In cilium, doublets of mt, connected by dynein proteins and linker proteins that enable it to bend with the movement of dynein. Cell adhesion: cells can interact with the environment. In cell recognition, one cell specifically binds to another cell of a certain type. (can lead to dna exchange, egg/sperm, cell adhesion) In cell adhesion, cells stably bind to each other or the extracellular matrix. Five major types of cell junctions: tight junction. Seals neighbouring cells together in an epithelial sheet to prevent leakage of molecules between them. Separates apical and basolateral membrane domans and their membrane proteins (keeps blood from getting to gut: adherens junction. Joins an actin bundle in one cell to a similar bundle in a neighbouring cell. Adherens junction is the most important and ancient cell-cell junction. Generally form a circumferential belt close to the apical-basolateral boundary. Several cadherins from two different cells bind together.

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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

1)Describe the directions in which the two motor proteins, kinesin and dynein, travel along a microtubule. Which of the two proteins moves materials towards the Golgi and which moves materials away from the Golgi? Lastly, what is the speed of kinesin dependent on?

2)What are microfilaments crucial for? How do they self-assemble? Which end do they prefer to elongate from?

3)Describe what types of filaments are in each of the bands of the sarcomere. As a muscle fiber is shortened, describe what happens to each of the bands in the sarcomere as the Z lines move inwards.

4)Describe the role of calcium ions in muscle contraction.

5)List the various types of actin-binding proteins

6) A. What are 3 functions of the cytoskeleton?

B.What are the three filaments that compose the cytoskeleton, and what are they composed?

7)How do they see the internal structures of cells in the microscope? What do proteins get labeled with?

8)Myosin II action (Figure 9.61) differs from that of kinesin (Figure 9.15) in that one of the kinesin heads is always in contact with a microtubule, whereas both myosin heads become completely detached from the actin filament. How are these differences correlated with the two types of motor activities in which these proteins engage?

9)If a myofibril were pulled so that the sarcomeres increased in length by approximately 50 percent, what effect would you expect this to have on the contractile ability of the myofibril? Why? What effects would this have on the H, A, and I bands?

10)Because cytoplasmic vesicles are seen to move in both directions within an axon, can you conclude that some microtubules are oriented with their plus end facing the axon terminus and others oriented with the opposite polarity? Why or why not?

The vesicles that transport materials from donor membranes to acceptor membranes include:

	1.	COP-II coated vesicles
	2.	COP-III coated vesicles
	3.	COP-I coated vesicles
	4.	Clathrin coated vesicles

2.5 points

QUESTION 11

During skeletal muscle contraction, the roles of ATP include:

	1.	ATP is not required for forming the crossbridges between myosin and actin filaments.
	2.	ATP is utilized as a structural linker to mediate the interaction between myosin and actin filaments
	3.	Hydrolysis of ATP provides energy for myosin head to move along actin filaments and the binding of ATP to myosin head allows the detachment of myosin fromactin filaments.
	4.	ATP binds to actin filaments to drive the power stroke of myosin head.

2.5 points

QUESTION 12

One of the functions of smooth endoplasmic reticulum is

	1.	Synthesizing steroid hormone in the endocrine cells of the gonad and adrenal cortex
	2.	Serves as the starting point of the biosynthetic pathway
	3.	Synthesizing secretory proteins
	4.	Degrading cell debris

2.5 points

QUESTION 13

The function of COP-II coated vesicles is mainly:

	1.	Transporting materials from endosomes to Golgi complex
	2.	Moving materials from the ER to the ERGIC and Golgi complex.
	3.	Transporting materials from Golgi complex back to endoplasmic reticulum.
	4.	Involved in receptor-mediated endocytosis.

2.5 points

QUESTION 14

Which of the following processes is completed in rough endoplasmic reticulum?

	1.	Chaperones help misfolded proteins fold correctly.
	2.	Proteins that target to nucleus are synthesized in rough endoplasmic reticulum.
	3.	O-linked glycosylation occurs in rough endoplasmic reticulum.
	4.	Misfolded proteins are destructed in rough endoplamic reticulum.

2.5 points

QUESTION 15

Kinesin is the motor protein that coorporates with microtubules. It has the following functions:

	1.	It uses GTP as energy source.
	2.	It can hydrolyze ATP and use the energy to drive cargo along microtubules from minus end to plus end.
	3.	It has a globular head that can act as GTPase
	4.	The tail of kinesin is more diverse and binds to cargo

2.5 points

QUESTION 16

For correct segregation and trafficking, lysosomal proteins are tagged in the cis-Golgi with phosphorylated mannose residues, and then the tagged lysosomal enzymes are recruited to clathrin coated vesicles by mannose 6-phosphate receptors.

True

False

2.5 points

QUESTION 17

The process that specialized cells, such macrophages, engulf relatively large particles is:

	1.	Called pinocytosis
	2.	Called phagocytosis
	3.	Mediated by COP-II coated vesicles
	4.	Called autophagy

2.5 points

QUESTION 18

Proteins synthesized on rough endoplasmic reticulum and smooth endoplasmic reticulum are imported co-translationally to their destinations

True

False

2.5 points

QUESTION 19

Treatment of cells with a drug that promotes microtubule disassembly disperses Golgi complex into separate stacks of membrane compartments, suggesting that:

	1.	Golgi complex is made of microtubules.
	2.	Microtubules are important for the organization of Golgi complex.
	3.	Microtubules are transported into Golgi complex
	4.	Golgi complex is composed of tubulin proteins

2.5 points

QUESTION 20

Which of the following is correct about signal sequence of a secretory protein?

	1.	It is an âaddress codesâ for protein trafficking pathways
	2.	It is usually located at the C-terminus.
	3.	It targets the ribosome and the protein that is being synthesized to endoplasmic reticulum.
	4.	It is removed in Golgi complex.

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BIOL 115 Lecture Notes - Lecture 4: Adherens Junction, Leg, Tight Junction

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