BIOL 112 Lecture Notes - Lecture 11: Organelle, Phagosome, Endosome

1. The histones that form the core of the nucleosome get into the nucleus by which of the following?

a) Passive diffusion through nuclear pores

b) Selective and facilitated active transport through nuclear pores

c) Ribosomes located in the nucleus synthetize histones in the nucleus

d) Histones are made at the ER membrane and then diffuse to the nucleus

2. Membrane proteins that belong to the golgi, lysosome, or plasma membrane first pass through which organelle before reaching their final subcellular destination?

a) The golgi apparatus

b) The smooth ER

c) The nucleus

d) The ER membrane

e) The ER lumen

3. Where in the cell would a ribosomal protein be located if it has had its nuclear export signal inactivated (non-functional or non-existent).

a) The protein would be found in the ER lumen

b) The protein would remain in the nucleus

c) The protein would be secreted

d) The protein would remain in the cytoplasm

e) The protein would be in the ER membrane

4. Where would be the final destination of a protein if it contained a NLS anywhere in the protein sequence (and which is exposed to the cytoplasm after protein folding) but also contained an ER signal sequence at the carboxy terminus?

a) The ER lumen

b) The nucleus

c) The cytoplasm

d) The inner nuclear membrane

e) The ER membrane

5. The sequence K-D-E-L serves as a retention/retrieval signal for ER proteins.

a) True

b) False

6. The following are true for both cell membrane proteins and secretory proteins EXCEPT?

a) Precursors of the mature proteins contain signal sequence.

b) Both types of proteins contain stop-transfer sequences

c) Both types of proteins enter the ER while being synthetized

d) Both types of proteins pas through the golgi apparatus

e) Both are carried by clatherin-coated vesicles

7. If you isolate a regulated secreted protein from a secretory/storage vesicle and inject it into the cytosol, is will?

a) Be secreted through channels in the plasma membrane

b) Be taken up into secretory vesicle and secreted

c) Remain in the cytosol until it is degraded

d) Be taken up into the rough ER and follow the secretory pathway

Some cells in plant and animals are specialized for the production and release of a particular chemical, often a protein or some other regulatory molecule. These cells generally produce and release their product only when the proper signal is present. Describe the series of events in this cell that would lead from the perception of this signal to the release of the desired product. Begin by providing specific information on: 1) the transduction of the signal across the membrane by the G protein system with subsequent release of the appropriate second messenger(s); 2) the process by which the signal is amplified by the MAP kinase pathway; 3) how the product(s) produced by the MAP kinase cascade reach the nucleus to initiate the transcription of the relevant gene(s).

Assume now that transcription has already occurred, that a mature mRNA has been produced in the nucleus and has migrated to the cytosol, and that this mRNA has been recruited by a ribosome to initiate translation. Since the protein product is secretory, synthesis of the protein will be associated with the rough endoplasmic reticulum. Continue by providing information on 4) how the free ribosome becomes associated with the endoplasmic reticulum to allow for the release of the synthesized protein into the rough ER; 5) the modification or processing of the protein that occurs in the endoplasmic reticulum; 6) the packaging and/or modification of the protein for transport from the ER to the Golgi apparatus; 7) the modification, processing, and packaging of the protein in the Golgi apparatus; and 8) the steps leading to the eventual release of the target protein from the cell via exocytosis.

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

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QUESTION 11

During skeletal muscle contraction, the roles of ATP include:

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QUESTION 12

One of the functions of smooth endoplasmic reticulum is

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QUESTION 13

The function of COP-II coated vesicles is mainly:

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QUESTION 14

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

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QUESTION 15

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

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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

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QUESTION 17

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

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QUESTION 18

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

True

False

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QUESTION 19

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

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QUESTION 20

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