Sac revision Flashcards
Simple diffusion
a type of diffusion in which the molecule can pass directly through the lipid bilayer
Facilitated diffusion
a type of diffusion in which a carrier or channel protein is needed because the molecule cannot pass the lipid bilayer directly
Osmosis
movement of water which occurs from a low concentration of solution to a high concentration of solution
Active transport
movement of molecules across a cell membrane from a region of lower concentration to a region of higher concentration—against the concentration gradient. Requires energy
Bulk Transport
Bulk transport is the movement of large molecules, those that are too large for facilitated diffusion.
Factors which affect diffusion across a membrane
size tonicity temperature hydrophobic/hydrophilic polarity
Hypertonic
Higher solute, Lower water
decreased weight because water moves out of the cell
Hypotonic
Lower solute, Higher water
increase in the weight of cell because water has moved in
Isotonic
when the concentration of two solutions is the same
hydrophilic
Water loving
passive transport
the movement of substances across a cell membrane without the use of energy by the cell
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extracellular
outside the cell
intracellular
within the cell
solute
A substance that is dissolved in a solution.
solution
mixture of two or more substances in which the molecules of the substances are evenly distributed
Function of the plasma membrane- Transport
A plasma membrane is permeable to specific molecules that a cell needs. Transport proteins in the cell membrane allow for selective passage of specific molecules from the external environment. Each transport protein is specific to a certain molecule
Function of the plasma membrane- Communication
Your cell membrane plays an integral role in cellular communication because it holds the proteins, carbohydrates, and other molecules that are essential to cellular communication. These communications may come from signalling molecules sent by other cells, from cell-to-cell interactions, or from within the cell itself.
Function of the plasma membrane- Retain contents
The cell membrane, therefore, has two functions: first, to be a barrier keeping the constituents of the cell in and unwanted substances out and, second, to be a gate allowing transport into the cell of essential nutrients and movement from the cell of waste products.
Function of the plasma membrane- Surround organelles
provides protection for a cell, transport nutrients into the cell and also to transport toxic substances out of the cell.
Phospholipids
Phospholipids are a class of lipids whose molecule has a hydrophilic “head” containing a phosphate group and two hydrophobic “tails” derived from fatty acids, joined by an alcohol residue. 0==
Lipid bilayer
The lipid bilayer (or phospholipid bilayer) is a thin polar membrane made of two layers of lipid molecules. These membranes are flat sheets that form a continuous barrier around all cells. (plasma membrane)
Carrier and channel proteins
Channel proteins are proteins that have the ability to form hydrophilic pores in cells’ membranes, transporting molecules down the concentration gradient. Carrier proteins are integral proteins that can transport substances across the membrane, both down and against the concentration gradient.
Cholesterol
mainly functions to prevent the phospholipids from packing in too tightly and becoming stiff. Cholesterol is not present in plant cell membranes.
transmembrane proteins
Transmembrane proteins span the entire plasma membrane
carbohydrates
and often act as labels or identifying signals for other cells/molecules. These cellular markers are needed for communication with other cells, such as those from the nervous and immune systems.
Aim
Overview of what is to be achieved or tested
Hypothesis
If/Then/Because
if (independent variable) then (dependent variable) because (justification using knowledge)
Independent variable
The manipulated variable
Dependent variable
The variable measured
Controlled variable
the variable that is not changed
Graphing results
Tables
conclusion
Support or disprove the hypothesis
Concentration gradient
From a high concentration to a low concentration
equilibrium
when the concentration is equal on both sides. molecules still move but the overall concentration on either side stays the same.
diffusion
movement of molecules along a concentration gradient
diffusion continues until equilibrium is reached
hydrophobic
water hating
Molecules That Can Pass Through the Lipid Bilayer by Simple Diffusion
gasses, water, alcohol, lipids, steroid hormone and anything very small and hydrophobic
Molecules That Can Pass Through the Lipid Bilayer by Facilitated Diffusion
glucose, anything larger and hydrophilic
SA:V
surface area to volume ratio
Exocytosis
the export of large molecules using vesicles (and atp)
Endocytosis
the import of large molecules using vesicles (phagocytosis and pinocytosis)
Phagocytosis
the import of large solid molecules using vesicles (type of endocytosis)
Pinocytosis
is the import of liquids that are too large for diffusion (type of endocytosis)
