CELL TRANSPORT MECHANISMS Flashcards
What substances are excreted from the cell surface membranes? (2)
-ammonia
-urea (animals)
what substances are secreted from the cell surface membrane? (3)
-neurotransmitter substances
-hormones
-enzymes
what are the types of protein molecules involved in facilitated diffusion? (2)
-carrier proteins
-protein channels
what is the lipid bilayer permeable to? (2)
-non - polar substances (including steroids and glycerol)
-oxygen and carbon dioxide in solution
what substances are always moving across the cell membrane? (4)
-water
-respiratory gases (O2 and CO2)
-nutrients (glucose and essential ions)
-excretory products
how is ATP converted back down to ADP? (2)
when ATP reacts with water (a hydrolysis reaction) and is converted back to ADP and Pi (e.g muscle contraction).
what nutrients pass across the cell surface membrane? (4)
-sugars
-amino acids
-fatty acids
-vitamins
what is diffusion? (1)
the free passage of molecules (atoms and ions) from a region of their high concentration to a region of low concentration until they are evenly distributed.
what concentration of ATP is usually present within cell? (1)
0.5 - 2.5 mgcm(-3)
what are the important features of ATP? (3)
-move easily within cells, by facilitated diffusion
-take part in many steps in cellular respiration and in very many reactions of the metabolism
-transfer energy in relatively small amounts, sufficient to drive individual reactions.
what is ATP formed from? (1)
formed from ADP and a phosphate ion by transfer of energy from other reactions.
what does ADP stand for? (1)
adenosine diphosphate
what substances pass through the cell surface membrane in respiration? (2)
in: oxygen
out: carbon dioxide
what free energy is available in ATP? (1)
30 - 34 KJ mol(-1)
what does ATP stand for? (1)
adenosine triphosphate
what are peripheral proteins? (1)
proteins present in the cell surface membrane that are superficially attached to the lipid bilayer.
what molecules is ATP? (2)
ATP is a soluble organic molecule. it carries three phosphate groups linked together in a linear sequence.
what is energy transferred to within the cytoplasm of a cell? (1)
ATP
who proposed the fluid mosaic model? (2)
S. J Singer and G. L Nicolson
what are integral proteins? (1)
proteins present in the cell surface membrane that are partially or totally buried within the lipid bilayer.
what molecules does facilitated diffusion transport? (2)
-carbohydrates
-amino acids
what molecules does exocytosis transport? (2)
-enzymes
-hormones
what molecules does simple diffusion transport? (3)
-oxygen
-carbon dioxide
-hydrophobic molecules
what molecules does active transport, transport? (1)
ions e.g sodium
what does the lipid bilayer contain? (7)
-glycoproteins
-glycolipids
-channel proteins
-integral proteins
-peripheral proteins
-phospholipids
-cholesterol
how do molecules travel across the membrane in osmosis? (1)
between phospholipids (aquaporins)
how do molecules travel across the membrane in simple diffusion? (1)
between the phospholipid bilayer
how do molecules travel across the membrane in phagocytosis? (1)
through vesicles
which cell transport mechanisms require energy? (4)
-active transport
-phagocytosis
-pinocytosis
-exocytosis
how do molecules travel across the cell membrane in active transport? (1)
through carrier proteins