BIOL 1001 Chapter : Chapter 5 Biology

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15 Mar 2019

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Fluid mosaic model: cell membranes= patchwork (mosaic) of different proteins, proteins within fluid of phospholipid bilayer, constantly shift and flow, membrane components remain constant, distribution of proteins and phospholipids changes over time. Fluidity of membrane: based on orientation and bonds of phospholipids, hydrophilic heads, orient towards watery environments, form hydrogen bonds with water molecules, hydrophobic tails, orient towards center of membrane, some with unsaturated fatty acids in tail. Degree of membrane fluidity: based on level of fatty acid saturation, amount of cholesterol, stabilizes bilayer, make membrane less permeable, varies between cells, allows cell to perform different functions, allows cells to function in different environments, ex. Soution: more unsaturated fatty acid and less cholesterol. Lysosomes: merge with membranes of other organelles (ex. Cell membranes: surround cell and organelles (eukaryotes, functions, phospholipid bilayer, isolates cell contents from environment, embedded proteins, transport essential molecules and ions. Between organelles and cytoplasm: regulate biochemical reactions, create attachments in and between cells, allow communication between cells.

Related Questions

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

Glucose and amino acids move into cells via carrier proteins, the same protein can move glucose or amino acids

True

False

Question 16

ATP powered pumps move substances into and out of cells by diffusion?

True

False

Question 17

For every 3 Na ions moved out, 2 K ions are moved into a cell by one cycle of the sodium-potassium pump.

True

False

Question 18

Bulk transport of fluid and any of the substances within that fluid is called

pinocytosis

phagocytosis

receptor-mediated endocytosis

exocytosis

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

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

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

Glucose and amino acids move into cells via carrier proteins, the same protein can move glucose or amino acids

True

False

Question 16

ATP powered pumps move substances into and out of cells by diffusion?

True

False

Question 17

For every 3 Na ions moved out, 2 K ions are moved into a cell by one cycle of the sodium-potassium pump.

True

False

Question 18

Bulk transport of fluid and any of the substances within that fluid is called

pinocytosis

phagocytosis

receptor-mediated endocytosis

exocytosis

Which of the following Scientist(s) described the contemporaryâfluid- mosiacâmodel of the plasma Membrane
Davson and Nicholson
Nicholson and Danielle
Singer and Davson
Nicholson and Singer
Answer:_________________________________________________________________

________________________________________________________________________

The âfluid-mosaicâ model of the PM differ from the first proposedmodel in that:
The first model did not have cholesterol
The first model was devoid of some lipids
The first model was devoid of some proteins
The first mode was devoid of some carbohydrates
Answer:_________________________________________________________________

________________________________________________________________________

Which is most likely to be a membrane receptor protein?
A glycosylated protein containing three hydrophobic regions
A glycosylated protein devoid of hydrophobic regions
A protein containing hydrophobic regions but devoid of sugars
A glycosylated protein devoid of hydrophilic regions
Answer:_________________________________________________________________

________________________________________________________________________

Which secondary structures of proteins are formed within thePM?
Alpha-pleated sheets
Beta-pleated sheets
Alpha-helicies
Beta-helicies
Answer:_________________________________________________________________

________________________________________________________________________

Intergal proteins project
entirely outside of the bilayer on the extracellular surface
entirely through the membrane having N- and C- terminusexposed.
entirely outside of the bilayer on the cytoplasmic surface
outside bilayer but covalently linked to lipids withinmembrane
Answer:_________________________________________________________________

________________________________________________________________________

Which is the driving force which maintains the lipid bilayer?
Van der waals forces
Hydrophobic interactions
Hydrophilic interactions
Ionic interactions
Answer:_________________________________________________________________

________________________________________________________________________

What affect do lipids with double bonds in their nonpolar tailshave on the integrity of the PM?
They increase the fluidity of the PM
They decrease the fluidity of the PM
They allow more lipids to pack tighter in the membrane
They cause the membrane to become less stable
Answer:_________________________________________________________________

________________________________________________________________________

As the fluidity of the PM increases, what happens to theentropy?
increases
decreases
stays the same
none of the above
Answer:_________________________________________________________________

________________________________________________________________________

The consistency of membranes at various temperatures can beunderstood using the Margarine and Butter analogy. Butter containslonger saturated chains of fat derived from animals while Margarinecontains short polyunsaturated fats derived from corn oil. Whentaken directly from the refrigerator, Margarine can be spread withease while the Butter does not. What conclusion should you drawregarding how the composition of membrane lipid regulate thefluidity of the PM?
Longer chains exhibit more double bonds and increases contact oflipids
Longer chain exhibit fewer double bonds and increases contact oflipids
Shorter chains exhibit more double bonds and increases contact oflipids
Shorter chains exhibit more double bonds and increases contact oflipids
Answer:_________________________________________________________________

_____________________________________________________________________
Which PM lipid covalently anchors proteins?
Phosphoglycerides
Sphingolipids
Cholesterol
Triglycerides
Answer:_________________________________________________________________

________________________________________________________________________

Which PM lipid is the least amphipathic?
Phosphoglycerides
Sphingolipids
Cholesterol
Triglycerides
Answer:_________________________________________________________________

________________________________________________________________________

Which of the following is not a function of the PM?
Signal Transduction
Energy Transduction
Regulates which molecules enters and exits cell
Site of Biochemical events such as production ofmacromolecules
Answer:_________________________________________________________________

________________________________________________________________________

Which two PM phospholipids have negative charges?
Phosphatidylcholine and Phosphatidylethanolamine
Phosphatidylethanolamine and Phosphatidylserine
Phosphatidylinositol and Phosphatidylserine
Phosphatidylserine and Phosphatidylcholine
Answer:_________________________________________________________________

________________________________________________________________________

Which PM lipid is the only true glycolipid?
Phosphatidylcholine
Phosphatidylethanolamine
Sphingolipid
d. Cholesterol
Answer:_________________________________________________________________

________________________________________________________________________

Which is NOT a function of the Plasma Membrane
It serves as a barrier allowing all molecules to enter cell
It serves as a site for energy and signal transductions
It is composed of lipids, proteins, and carbohydrates
It compartmentalizes the cells
Answer:_________________________________________________________________

________________________________________________________________________

Cholesterol, which is not present in bacteria, controls the PMfluidity of animal cells. Which is the CORRECT orientation of thehydroxyl group of the four-member ring of cholesterol in thePM.
The hydroxyl group is oriented inside the membrane
The hydroxyl group is oriented toward the cytoplasm
The hydroxyl group is oriented toward other cholesterolmolecules
The hydroxyl group is oriented toward the membrane surface
Answer:_________________________________________________________________

_____________________________________________________________________
PM carbohydrates are oriented:
Inside the membrane
Toward the cytoplasm
Toward other carbohydrate molecules
Away from the cytoplasm and inside organelles
Answer:_________________________________________________________________

________________________________________________________________________

Sugars constituents various on red blood cells depending on bloodtype, why would giving someone the wrong blood type be fatal?
Blood groups differ in the levels of hemoglobin they carry
The body would view the sugars as antigens and form antibodiesagainst them.
Because of the incompatible sugar arrangement, the blood would notflow to the heart properly.
The foreign sugar sequences will attack to the sugar sequences onnormal cells.
Answer:_________________________________________________________________

________________________________________________________________________

NaCl most likely get into cells by which of the followingmethods?
Diffusion
Facilitated Transport
Osmosis
Active Transport
Answer:_________________________________________________________________

________________________________________________________________________

Sufferers of type II diabetes (adult onset) have normal insulinlevels but no target cell response due to deficiency in receptorsfor insulin. Which type of transport is missing?
Diffusion
Facilitated Transport
Osmosis
Active Transport
Answer:_________________________________________________________________

________________________________________________________________________

The movement of molecules against a gradient refers to which typeof transport?
Diffusion
Facilitated Transport
Osmosis
Active Transport
Answer:_________________________________________________________________

________________________________________________________________________

Which is the correct exchange of sodium and potassium in the Na/Kpump of cells?
three sodium for three potassium
two sodium for three potassium
three sodium for two potassium
two sodium for one potassium
Answer:_________________________________________________________________

________________________________________________________________________

This type of transport is important to cells because they receivetheir oxygen and rid themselves of carbon dioxide by thismethod:
Diffusion
Facilitated Transport
Osmosis
Active Transport
Answer:_________________________________________________________________

________________________________________________________________________

Maintaining membrane fluidity is important to cells because?
Cells are able to maintain proper function at differenttemperatures
Cells can break down membranes lipids very quickly when energy isneeded
Larger molecules can pass through the membrane when fluidity isincreased
The membrane fluidity helps to maintain the positions ofglycoproteins and glycolipids
Answer:_________________________________________________________________

________________________________________________________________________

Scientists agreed that the plasma membrane was the site ofbiochemical events when peroxide was broken to produce bubblescontaining?
water
hydrogen
oxygen
carbon dioxide

Answer:_________________________________________________________________

________________________________________________________________________

BIOL 1001 Chapter : Chapter 5 Biology

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