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Membrane Structure and Function ch5

STUDY
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phospholipids
The plasma membrane is composed primarily of _____
nonpolar, hydrophobic, and directed inwards in the bilayer
The tails of the phospholipids are _____
fluid-mosaic
Electron micrographs support the _____ model of the plasma membrane
The phospholipids form a bilayer around the cell
The amount of phospholipid extracted from red blood cells led researchers to propose that ____
proteins
According to the fluid-mosaic model, _____ are partially or wholly embedded in a fluid phospholipid bilayer.
true
All membranes do not appear the same in electron micrographs (true or false)
true
The plasma membrane is permeable to some nonlipid substances. (true or false)
true
According to the fluid-mosaic model the hydrophilic heads of the phospholipids face the intra and extracellular fluids.(true or false)
Cholesterol
What is another type of lipid besides phospholipids that are in the plasma membrane.
cholesterol
The permeability of most membranes is reduced by the presence of _____ in the membrane.
glycoplipid
A sugar attached to a lipid is called a _____.
glycolipids and gylcoproteins
The plasma membrane is "sugar-coated" by _____.
true
The proper functioning of some of the membrane proteins depends on the fluidity of the membrane. (true or false)
phospholipids, cholesterol, and glycolipids
Which lipids may be found in the plasma membrane?
membrane
The two halves of the plasma ________are not identical.
false
The plasma membrane is a stiff and rigid structure. (True or false)
species to species, individual to individual, and cell to cell
Glycolipids and glycoproteins vary from __________.
channel proteins
Particular molecules or ions freely cross the plasma membrane with assistance from _____.
glycoproteins and glycolipids
Transplant rejections are the result of the immune system's response to foreign__________________
glycoproteins
A person's blood type is determined by the presence of particular _____ in the red blood cells' membranes
molecule
Receptor proteins in the plasma membrane do not bind to any kind of _________
peripheral
What kind of protein is found on the inside surface of the plasma membrane ?
true
Lipid-soluble molecules move freely across the plasma membrane. (true or false)
sodium
What does NOT move freely (without energy or a carrier protein) across the plasma membrane?
active transport
What kind of transport requires energy?
false
During diffusion molecules move from areas of low concentration to areas of high concentration. (true or false)
true
The hydrophobic tails of the phospholipids in the plasma membrane are what prevent ions and charged molecules from freely crossing the membrane.(true or false)
solute
The sugar you stir into your coffee is an example of a _____.
water
Osmosis is specifically about the movement of _____ in and out of cells.
1% NaCl
If the inside of a cell is 1% NaCl, which solution is isotonic to the cell?
>1% NaCl
If the inside of a cell is 1% NaCl, which solution is hypertonic to the cell?
hypotonic
A_______solution has fewer solutes than the cell.
pinocytosis
Fluids and dissolved substances are transported into the cell by __________.
isotonic
Solutions that cause cells to neither gain nor lose water are known as ______ solutions.
The central vacuole gains water.
When a plant cell is placed in a hypotonic solution what will occur?
red blood cells that burst after being placed in a hypotonic solution
The term hemolysis refers to ______.
facilitated and active transport
Carrier proteins are required for _____.
Osmotic Pressure
What affects water retention by the kidneys, water uptake from tissue fluids by the capillaries, and water absorption from the large intestine?
Molecules move from high concentration to low concentration.
What correctly describes facilitated transport?
carrier proteins are needed, it requires the expenditure of energy. molecules move from areas of low concentration to areas of high concentration. and all of the above.
Which of the following correctly describes active transport?
exocytosis
Insulin leaves insulin-secreting cells by _____.
phagocytosis
Macrophages, immune system cells, engulf bacteria by _____.
receptor mediated endocytosis
Specific molecules enter cells by _____.
binding a receptor protein in the plasma membranes
The peptide hormone, follicle stimulating hormone, would activate its specific target cells by _____.
True
Bacteria, fungi and plants all have an extracellular component called a cell wall. (true or false)
a secondary cell wall
Woody plants are characterized by _____.
True
The extracellular matrix of animal cells supports them and fills the spaces between the cells.(true or false)
plasmodesmata
Plant cells are able to exchange materials through _____.
collagen
People may get injections of _____, a component of the extracellular matrix of animal cells, to get rid of their wrinkles.
adhesion junctions
Organs with tissues that get stretched a lot like the heart and bladder are characterized by _____.
True
Tight junctions between cells make tissues leakproof. (true or false)
gap junctions
Heart cells are able to contract in unison because of the flow of ions through _____.
plasma membrane
All cells have a _____.
false
The plasma membrane allows anything to move freely in or out of the cell. (true or false)