Biology 1202B Lecture Notes - Lecture 3: Pinocytosis, Integral Membrane Protein, Phospholipid

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erinfox426

16 Jan 2017

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Document Summary

Small and uncharged molecules can move across a membrane freely. Larger and charged molecules need some sort of transport (usually a protein) Some molecules too large to move through a protein; need exocytosis and endocytosis. Exocytosis involves things that need to be removed (i. e. hormone, or signalling molecules) Used to remove waste from the cell & as a potential method of communication with other cells. Occurs when there is a pinching off of the plasma membrane, which brings materials into the cell. The vesicle can move off the membrane into the cell, fuse w/ the lysosome: pinocytosis. Brings in molecules in a non-specific fashion. Cell is usually in an aqueous environment: receptor mediated endocytosis. Brings in molecules in a specific fashion because receptors are involved. Receptors indicate that the process is specific. Proteins recognize the target molecule, which results in a signal (binding of multiple molecules) This process requires energy and results in a high concentration of the solute.

Related Questions

Fill in the blank assignment

Biological membranes are primarily formed from two types oforganic molecules, (16)______, composed of amino acids and(17)_____, composed of phosphates, glycerol and fatty acids.Membranes are (18)___ ____ to molecules allowing some to freelypass through and restricting or preventing the passage of others.Molecules may cross membranes on their own moving from areas ofhigher to lower concentration, with no expenditure of externalenergy, in a process called (19)____. Protein molecules that spanthe membrane may assist or carry other molecules across themembrane, (20)_____ _____, also from areas of higher to lowerconcentration. (21)____ _____ moves molecules across membranes fromareas of lower to higher concentration with the use of energy inthe form of ATP. As opposed to the process of passive transport,illustrated by answers (19) and (20), molecules move against their(22) ______ _______.

If you compare two situations on either side of a cellularmembrane, they are said to be (23)_____ if their soluteconcentrations are equal. Solutions that have higher soluteconcentrations are (24)_____ when compared to solutions with lowersolute concentrations, (25)______. If molecules or substances aretoo large to pass through membranes on their own or with the use ofprotein carriers, vesicles may help to move these materials in orout of the cell as vesicles fuse with or pinch off membranes. This(26)____ ____ of materials is called (27)____ if materials aremoved into cells. The transport of lage solids or "cell-eating" is(28)_____. Entry of liquids is termed (29)____ or "cell drinking."Movement of materials out of the cell is (30)_____.

bronzemosquito2

coffeesquirrel210

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 on Questions 6 and 9 please help me with it hope you can help me with the correct answers please

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