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?
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?
Related textbook solutions
Related questions
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. |
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 |
