4.4 Flashcards
Define active transport. (3)
(1) movement of molecules…
(2) from an area of lowER conc. to an area of highER conc. …
(3) using energy from ATP + carrier proteins
Is active transport generic for all molecules or selective? (1)
selective
What are the 2 ways active transport uses ATP? (2)
(1) used directly by the carrier protein
(2) by using a conc. gradient that’s already been set up (CO-TRANSPORT)
Describe the process of direct active transport. (7)
(1) the molecule binds to the carrier protein to be transported
(2) inside, the ATP binds to the carrier protein
(3) the ATP breaks down into ADP and a phosphate molecule
(4) this causes the protein to change shape and open to the opposite side (inside)
(5) the molecule is released to the other side
(6) the phosphate molecule is released from the protein and recombines with the ADP to form ATP
(7) the protein goes back to its original shape.
Give 1 similarity and 2 differences between facilitated diffusion and active transport. (3)
(1) S = both use carrier proteins
(2) D = FD –> down the conc. gradient…. AT –> against conc. gradient
(3) D = FD –> doesn’t need ATP… AT –> needs ATP
How does ATP act as a source of energy? (5)
(1) ATP has 3 phosphates
(2) the bonds between the 3 phosphates = UNSTABLE
(3) so there’s a lower activation energy needed…
(4) to break these bonds.
(5) when they break, they release a considerable amount of energy.
What is the reaction called when ADP binds to a P molecule to form ATP? (1)
And when is ATP synthesised? (1)
(1) Condensation
(2) during reactions that release energy
What is the reaction called when ATP breaks down? (1)
And when is ATP hydrolysed? (1)
(1) Hydrolysis
(2) when reactions require energy, which is provided by this reaction
How is ATP synthesised? (3)
(1) it’s a reversible reaction
(2) energy is used to add an INORGANIC phosphate to ADP to reform ATP.
(3) this reaction is catalysed by the enzyme: ATP SYNTHASE
What is the equation of the hydrolysis of ATP? (1)
ATP + H2O —–> ADP + Pi + Energy
What exactly is ATP? (3)
(1) a nucleotide…
(2) that is an intermediate energy substance
(3) used to TRANSFER energy
Can ATP be stored? (1)
No
Give 5 processes in which ATP is used. Explain how ATP helps in these processes. (10)
(1) metabolic processes = (2) provides energy needed to build macromolecules
(3) movement = (4) provides energy for muscle contraction
(5) active transport = (6) provides energy to change the shape of the carrier proteins
(7) secretion = (8) ATP needed to form lysosomes for secretion
(9) activation of molecules = (10) ATP makes them more reactive to lower the AE in enzyme-catalysed reactions
Why do carrier proteins transport specific substances across the membrane? (1)
(1) because they have a SPECIFIC TERTIARY STRUCTURE
