Term
| what is the plasma membrane? |
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Definition
| is the membrane at the boundary of every cell that acts as a selective barrier, thereby regulating the cell’s chemical environment |
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Term
| what provides a 'fingerprint' for the cell type? |
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Definition
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Term
| why it is unlikely that you will contract HIV through casual contact? |
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Definition
| HIV binds to cell receptors that are present on cells inside the body, but not present on skin cells. Called CD receptors (cluster of differentiation). |
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Term
| what are the plasma membranes made of? |
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Definition
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Term
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Definition
| molecules which can form membranes naturally? |
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Term
| what does fluidity in membranes mean? |
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Definition
| there is lateral two-dimensional movement of the lipids and some proteins in the plane of the membrane |
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Term
| what does the 'mosaic' aspect of membranes mean? |
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Definition
| that there are proteins interspersed within the lipid bilayer |
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Term
| what are the three main funtions of membrane proteins? |
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Definition
1. transport proteins
2. receptors
3. cell-to-cell recognition |
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Term
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Definition
| proteins which have a corbohydrate attached to them and they are a recognition keys on the surface of cells |
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Term
| movement of molecules requires which two factors? |
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Definition
1. movement must be through a fluid (liquid or gas)
2. there must be a concentration gradient (defference in amount of molecules from one place to another) |
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Term
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Definition
| diffusion of a substance across a biological membrane |
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Term
| what is concentration gradient? |
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Definition
| it is a concentration change over a distance in a particular direction |
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Term
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Definition
| the net movement of a substance down a concentration gradient |
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Term
| movement is from _____ concentration to _______ concentration |
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Definition
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Term
| the ______ the concentration difference, the _____ the diffusion |
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Definition
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Term
| when does net movement stop? |
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Definition
| when the system reaches equilibium |
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Term
| what is selective permeability? |
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Definition
| the property of biological membranes which allows some substances to cross more easily than others |
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Term
| what are the 2 factors that influence permeability? |
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Definition
1. solubility characteristics of the substance crossing the membrane
2. facilitated diffusion by a carrier protein or a channel protein |
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Term
| is the phosphlipid layer nonpolar of polar? |
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Definition
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Term
| how is water able to enter a cell? |
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Definition
| through specialized protein channels called aquaporins |
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Term
| what are the interior of protein channels called aquaporins lined with? |
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Definition
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Term
| what is facilitated diffusion? |
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Definition
| diffusion across a membrane with the help of a protein |
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Term
| what are the 3 types of facilitated diffusion? |
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Definition
1. bind-and-release
2. selective channel (pore the size of the solute)
3. gated channel (selective channel only with a door) |
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Term
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Definition
| passive transport of water and/or the diffusion of water across a defferentially permeable membrane |
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Term
| in osmosis, water moves from a ___ concentration of a solute to a ___ concentration of a solute. |
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Definition
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Term
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Definition
a solution of equal concentration to another solution
(as in i so equal - gay i know, but it helps me remember... lol.) |
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Term
| what does hypertonic mean? |
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Definition
a solution with a greater concentration of a solute than another solution
(one solution is more hyper because of the HIGHER concentration of sugar than another... again, dont laugh... just helps me remember) |
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Term
| what does hypotonic mean? |
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Definition
a solution with a lower concentration of solute than another solution
(hypo = smaller, hippo = big!, opposites! again, jusr trying to remember... lol) |
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Term
| in a hypotonic enviorment what happens to the cell? |
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Definition
| water rushes into the cel, causing it to swell |
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Term
| in a hypertonic enviorment what happens to the cell? |
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Definition
| water leaves the cell, causing it to shrivel |
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Term
| in an isotonic enviorment what happens to the cell? |
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Definition
| it stays the same. no change. |
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Term
| The salt concentration of the fluid surrounding a cell is more concentrated than the fluid inside the cell. The cell will: |
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Definition
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Term
| The salt concentration of the fluid surrounding a cell is more concentrated than the fluid inside the cell. The cell will: |
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Definition
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Term
| The salt concentration of the fluid surrounding a cell is more concentrated than the fluid inside the cell. The cell will: |
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Definition
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Term
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Definition
| an energy-requiring process during which a transport protein pumps a molecule across a membrane against its concentration gradient (uses ATP) |
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Term
| In active transport, the energy source that moves a molecule against its concentration gradient is: |
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Definition
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Term
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Definition
| the cellular uptake of large molecules (a.k.a. macromolecules) and particulate substances (food) by the localized pinching off of a region of the plasma membrane to form a vesicle |
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Term
| three types of endocytosis are: |
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Definition
1. phagocytosis
2. pinocytosis
3. receptor-mediated endocytosis |
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Term
| what happens in phagocytosis? |
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Definition
(cell eating) - endocytosis of solid particules
(phattie!) |
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Term
| what happens in pinocytosis? |
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Definition
(cell drinking) - endocytosis of fluid droplests
('pin'a coladas!) |
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Term
| what happens in receptor-mediated endocytosis? |
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Definition
| importing of specific macromolecules into the cell by the inward buddinf of vesicles formed from coated pits, occurs in response to the binding of specific nutrients to receptors on the cell's surface |
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Term
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Definition
is the cellular secretion of large molecules (a.k.a. macromolecules) by the fusion of vesicles with the plasma membrane
(moves material out of the cell) |
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Term
| how are neurotransmitters such as serotonin releases from cells in the brain? |
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Definition
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Term
| cells are connected by _______ |
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Definition
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Term
| if the connection between cells needs to be watertight, then ____________ connect the cells |
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Definition
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Term
| communication between cells occurs via ____________ and ________ |
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Definition
| gao junctions; plasmodesmata |
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Term
| animal cells communicate through _________ where two channel proteins in adjacent cells line up |
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Definition
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Term
| how do gap junctions arise? |
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Definition
| by a stable alignment of channel proteins in adjacent cells so the pores are directly across from each other |
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Term
| what is the suspected reason cells continue to divide after meeting other cells? (becoming cancer) |
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Definition
| it is suspected cancer cells have fewer gap junctions and lose the communication ability of normal cells |
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Term
| In order for plants to move large amounts of macromolecules or water they need to use: |
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Definition
| wide interconnects known as plasmodesmata |
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Term
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Definition
| are large non-protein channels through both the cell membranes and the cell wall of neighboring plant cells |
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Term
| What type of cell junctions are needed for a tissue that must prevent fluids from leaking across its cell layer? |
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Definition
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Term
| Animal cells communicate with one another through: |
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Definition
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