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Title: AP Biology Chapter 7 Membrane Structure and Function Notes
Description: This note package contains all the key vocabulary for Chapter 7: Membrane Structure and Function of AP Biology as well as key concepts that you will need to understand before the test. The notes are divided up into 5 sections: 7.1 - Cellular membranes are fluid mosaics of Lipids and Proteins, 7.2 - Membrane Structure Results in Selective Permeability, 7.3 - Passive Transport: Diffusion Across a Membrane w/ no Energy Investment, 7.4 - Active Transport uses Energy to Move Solutes Against their Gradients, and 7.5 - Bulk transport across the Plasma Membrane: Exocytosis & Endocytosis.
Description: This note package contains all the key vocabulary for Chapter 7: Membrane Structure and Function of AP Biology as well as key concepts that you will need to understand before the test. The notes are divided up into 5 sections: 7.1 - Cellular membranes are fluid mosaics of Lipids and Proteins, 7.2 - Membrane Structure Results in Selective Permeability, 7.3 - Passive Transport: Diffusion Across a Membrane w/ no Energy Investment, 7.4 - Active Transport uses Energy to Move Solutes Against their Gradients, and 7.5 - Bulk transport across the Plasma Membrane: Exocytosis & Endocytosis.
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Chapter 7 Membrane Structure and Function - Reading Questions
7
...
Selective permeability
: allows some substances to cross it more easily than others
...
Membranes
are mostly composed of
lipids and proteins
, with the most abundant lipids
being phospholipids
...
Phospholipids amphipathic
are
molecules, meaning it has both a hydrophilic region
and a hydrophobic region
...
4
...
5
...
The temperature in which a membrane solidifies depends on
the types of lipids it is made of
...
6
...
However, as cholesterol also hinders the close
packing of phospholipids, it lowers the temperature required for the membrane to
solidify; thus, cholesterol can be thought of as a “fluidity buffer” for the membrane,
resisting changes in membrane fluidity that can be caused by temperature changes
...
Membranes must be fluid to properly function; when a membrane solidifies, its
permeability changes, and enzymatic proteins in the membrane may become inactive if
their activity requires them to be able to move within the membrane
...
Fishes
that live in extreme cold temperatures have a high proportion of unsaturated
hydrocarbon tails, enabling their membranes to remain fluid
...
9
...
10
...
Peripheral proteins
not embedded in the lipid bilayer; they are appendages loosely
bound to the surface of the membrane
...
(a)
Transport
shuttle a substance from one side to the other by changing shape
...
(c)
Signal Transduction
receptor whose specific shape that fits the chemical
messenger
(d)
Cellcell recognition
identification tags that are recognized by other cells
(e)
Intercellular Joining
membrane proteins of adjacent cells may hook up
(f)
Attachment to the Cytoskeleton and Extracellular Matrix (ECM)
microfilaments or
other elements of the cytoskeleton may be covalently bound to membrane proteins, a
function that helps maintain cell shape and stabilizes the location of certain membrane
proteins
...
Carbohydrates serve as markers that distinguish one cell from another
...
13
...
7
...
Selectively permeable means that substances do not cross the barrier indiscriminately,
as the cell is able to take up some small molecules and ions and exclude others
...
15
...
Polar
molecules such as glucose and other sugars pass only slowly through a lipid bilayer
...
Transport proteins
help transport substances so they do not come in contact with the
lipid bilayer
...
Channel proteins
function by having a hydrophilic channel that certain molecules or
atomic ions use as a tunnel through the membrane
...
Carrier proteins
hold onto
their substances and change shape in a way that shuttles them across the membrane
...
3 - Passive Transport: Diffusion Across a Membrane w/ no Energy Investment
18
...
Concentration Gradient: the region along which the density of a chemical substance
increases or decreases
...
Diffusion is spontaneous because there is no requirement of energy
...
20
...
Aquaporins allow water to diffuse very rapidly
...
Carbon dioxide diffuses from the blood circulating around the lungs into the alveolar air
space
...
Osmosis
is the diffusion of free water across a selectively permeable membrane, and is
crucial to organisms
...
Tonicity
: the ability of a surrounding solution to cause a cell to gain or lose water
Hypertonic
: refers to nonpenetrating solutes
...
Hypotonic
: water will enter the cell faster than it leaves, and the cell will swell and lyse
...
24
...
Animal cells function best in an isotonic solution
...
Osmoregulation
, the control of solute concentrations and water balance, is important or
cells who lack rigid cell walls in order to maintain their water concentration
...
Turgid
: very firm (high water concentration = healthy)
Flaccid
: limp (surroundings are isotonic)
Plasmolysis
: wilt (the plasma membrane pulls away from the wall)
27
...
28
...
Certain kidney cells have a high number of aquaporins, allowing them to
reclaim water from urine before it is excreted
...
29
...
7
...
Active transport
requires a cell to expend energy, which means moving solutes against
their concentration gradients, usually through the supply of ATP
...
31
...
32
...
33
...
34
...
The main
electrogenic pump in plants, fungi, and bacteria is a
proton pump
, which actively
transports protons out of the cell
...
Cotransport eans that a single ATPpowered pump that transports a specific solute
m
can indirectly drive the active transport of several other solutes
...
7
...
Exocytosis
: a cell secretes certain biological molecules by the fusion of vesicles with
the plasma membrane
...
Neurons use exocytosis to release
neurotransmitters that signal other neurons or muscle cells
...
A small area of the plasma membrane sinks in
to form a pocket, and as the pocket deepens, it pinches in, forming a vesicle containing
material that had been outside the cell
...
nom
...
Phagocytosis
: a cell engulfs a particle by wrapping pseudopodia around it and
packaging it within a membranous sac called a food vacuole
...
nonspecific
to substances it transports
...
38
...
Title: AP Biology Chapter 7 Membrane Structure and Function Notes
Description: This note package contains all the key vocabulary for Chapter 7: Membrane Structure and Function of AP Biology as well as key concepts that you will need to understand before the test. The notes are divided up into 5 sections: 7.1 - Cellular membranes are fluid mosaics of Lipids and Proteins, 7.2 - Membrane Structure Results in Selective Permeability, 7.3 - Passive Transport: Diffusion Across a Membrane w/ no Energy Investment, 7.4 - Active Transport uses Energy to Move Solutes Against their Gradients, and 7.5 - Bulk transport across the Plasma Membrane: Exocytosis & Endocytosis.
Description: This note package contains all the key vocabulary for Chapter 7: Membrane Structure and Function of AP Biology as well as key concepts that you will need to understand before the test. The notes are divided up into 5 sections: 7.1 - Cellular membranes are fluid mosaics of Lipids and Proteins, 7.2 - Membrane Structure Results in Selective Permeability, 7.3 - Passive Transport: Diffusion Across a Membrane w/ no Energy Investment, 7.4 - Active Transport uses Energy to Move Solutes Against their Gradients, and 7.5 - Bulk transport across the Plasma Membrane: Exocytosis & Endocytosis.