Biology 2382B Lecture Notes - Lecture 21: Rigor Mortis, Atp Hydrolysis, Immunoglobulin Light Chain

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orangealligator209

23 Mar 2016

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Type 2 myosin (dimer) forms thick filament involved in contraction. 1 does not form a dimer 0 binds to membranes. Ex microvilli likely myosin 1 holding actin to pm. Whether myosin will move depends on atp avaliability. Because bound to membrane can be incolced in things called endocytosis. Myosin 5 most organelle transport variable tails. 1 1 heavy chain that binds to membranes, holds things in place, way membrane can be linked to cytoskeleton, can move to + end but doesn"t have to. 2 2 heavy chains, heads of heavy chains bind to actin, the tails bind to other filaments to form thick filament (like kinesin 5) 5 move vesicles around in cell, can bind to diff cargos (tail end variable), moves to + end. Light chains important in regulating how fast myosin moves. Light chains work tog with neck region (towards head of myosin) Different light chains fit on to neck.

Related Questions

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.

apricotgrasshopper117

1.A researcher alters the DNA-binding domain of a glucocorticoid receptor to that of an estrogen receptor. How would the cells respond to exposure to glucocorticoids?

a. They would bind estrogen, and initiate estrogen-dependent synthesis

b. They would bind glucocorticoids, and initiate testosterone-dependent synthesis

c. They would bind estrogen, and initiate testosterone-dependent synthesis

d. They would bind glucocorticoids, and initiate estrogen-dependent synthesis

e. They would bind neither hormone

2. All of the following statements about mitochondria are valid except:

a. The outer membrane of the mitochondrion is more like a eukaryotic cell plasma membrane.

b. The outer membrane of the mitochondrion is more like a prokaryotic outer membrane.

c. Mitochondria have ribosomes that are a different size from those in the rest of the cell.

d. Mitochondria have their own DNA that encodes very few proteins.

e. Mitochondria store Calcium ions

3.The unique length-tension relationship of muscle is due to:

a. the limit on the amount of ATP the muscle can produce.

b. the fact that tension is proportional to the amount of overlap between actin fibers and myosin heads

. c. the ability of kinesin to move along filaments.

d. the limit imposed on cross-sectional area of muscle in organisms.

e. the shortening of actin filaments.

4.The enzyme âFlippaseâ causes the flip-flop of dolichol phosphate from one side of a membrane to the other as part of the process leading to:

a. binding of a receptor by a ligand

b. glycosylation of newly synthesized proteins

c. transfer of proteins to the golgi apparatus.

d. membrane fusion during secretion

e. formation of coated vesicles

5. What do the photosystems of a chloroplast capture from the splitting of water during the light reactions?

a. ATP

b. Protons

c. electrons

d. neutrons

e. oxygen

Biology 2382B Lecture Notes - Lecture 21: Rigor Mortis, Atp Hydrolysis, Immunoglobulin Light Chain

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