Biology 2382B Lecture Notes - Lecture 6: Phagocytosis, Fibroblast, Secretion

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yellowsheep958

20 Apr 2016

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An important version of the secretory pathway - brings things into the cell. Cell will need to internalize extracellular material. Cells engulf something very large in the extracellular space (vesicles are. Cells engulf liquid in the extracellular space (vesicles are very small) **cells want to be able to select what it is that they are bringing in, this is where. Selectively internalizing ligands from the extracellular space. Need a receptor for the ligand on the extracellular surface. Hundreds of things can be brought into the cell this way. Many others - follow a similar process to the one described for ldl. Lipids are transported in large well-defined water-soluble complexes/particles called lipoproteins. Has a single layer of phospholipids that make up an outer shell. Amphipathic shell = composed of a phospholipid monolayer called an apolipoprotein. Apolar core = hydrophobic, mostly cholesteryl esters. Has a hydrophilic surface (like water on the outside) and a hydrophobic interior - for the fats.

Related Questions

Cholesterol (in the form of LDL) is taken up into cells by receptor-mediated endocytosis. Patients suffering from severe hypercholesterolemia have a defect in cholesterol uptake, which results in high levels of cholesterol in the blood. Researchers studying cells from a patient with this disease found that they are homozygous for mutations in the LDL receptor gene. When they tested the cells from the patient, they found that LDL is not able to bind to the surface of the patientâs cells at all, so LDL is not internalized.

a. In a healthy person, which membrane compartments/organelles does LDL travel through, starting from the extracellular space?

b. In a healthy person, which membrane compartments/organelles does the LDL receptor travel through, starting from the extracellular space?

c. Which cytoskeletal elements serve as âtracksâ to move the LDL-containing vesicles to the correct organelles?

d. Which two components are required to work with that cytoskeletal element to move the LDL-containing vesicles within the cell?

e. Explain why the patientâs specific mutation causes such high levels of cholesterol to be in the blood?

rubytortoise720

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

I have this questions for my homework i need help with them look please it is important i need help so please give me the correct answers for each question and also please be clear to understand and aslo be correct it is very important becuase i need them so i really need the right answers. please help me and be correct and clear it is important ok

Question 5

At a constant temperature, if you increase the number of unsaturated fatty acid chains in the phospholipid, the membrane will become......

less fluid

more fluid

fluidity will be unchanged

Question 6

Bacteria in a hot spring at 80 degrees celsius would be expected to have ______________ in their cell membrane

high proportions of saturated phospholipids

high proportions of unsaturated phospholipids

an equal ratio of saturated to unsaturated phospholipid

Question 7

Membrane proteins have an important role in membrane fluidity

True

False

Question 8

The HIV virus can't attach to cells that have a mutation in the CCR5 gene and so such individuals are resistant to HIV. What population of people have a higher incidence of the mutant CCR5 gene and why?

europeans because their ancestors survived the bubonic plague

North Americans because their ancestors survived small pox

europeans because they have a longer evolutionary past with HIV

Africans because they have a longer evolutionary past with HIV

Question 9

Nematode trapping fungi have ______________ molecules called ______________ that recognize specific carbohydrates on the surface of the nematode worms. This is how a fungus can recognize that its prey, the nematode worm, has wriggled into the loop. Write two words on lowercase separated by a space with no other syntax

Question 10

Diffusion requires energy

True

False

Question 11

The net direction of molecule movement when molecules diffuse is

down their concentration gradient

random directions

Question 12

In osmosis, water molecules from a solution of higher solute concentration cross a semi-permeable membrane into a solution of lower solute concentration?

True

False

Question 13

Which best defines osmosis?

In osmosis, water from a solution of lower solute concentration move across a semi-permeable membrane into a solution of higher solute concentration?

In osmosis, water from a solution of higher solute concentration move across a semi-permeable membrane into a solution of lower solute concentration?

Question 14

Animal cells placed into a hypotonic solution would most likely?

lyse (burst)

shrink

remain unchanged in size

Question 15