1. photosynthesis, respiration and ATP Flashcards
why do plants need energy
photosynthesis, active transport e.g. taking minerals into their roots, DNA replication, cell division and protein synthesis
why do animals need energy
muscle contraction, maintaining body temperature, active transport, DNA replication, cell division, protein synthesis
photosynthesis is the process where
energy from light is used to make glucose from H2O and CO2 (light energy is converted to chemical energy in the form of glucose)
overall equation for photosynthesis
6CO2 + 6H2O + energy -> C6H12O6 (glucose) + 6O2
energy is stored in the glucose till the plants
release it by repiration
how do animals obtain glucose
eating plants (or other animals) then respire the glucos to release energy
plant and animal cells release energy from glucose. this process is called
respiration
two types of respiration
aerobic repiration (using O2) anaeorbic respiration (without O2)
Aerobic respiration produces
CO2, water and releases energy
overall equation for aerobic respiration
C6H12O6 (glucose) + 6O2 -> 6CO2 + 6H2O + energy
Anaerobic respiration in plants and yeast produces
ethanol, carbon dioxide and releases energy
Anaerobic respiration in humans produces
lactate and releases energy
a cell cant get its energy directly from glucose so in respiration energy is released from glucose to make
ATP (which carries energy around the cell to where it is needed)
ATP is synthesised via a
condensation reaction between ADP and inorganic Phosphate (using energy from an energy-releasing reaction)
how does ATP get to the part of the cell that needs energy?
it diffuses
when ATP reaches the part of the cell it is
hydrolysed back into ADP and an inorganic phosphate. chemical energy is released from the phosphate bond and used by the cell
what enzyme catalyses the break down of ATP
ATP hydrolase
ADP and inorganic phosphate are
recycled and process starts again qw
why ATP is a good energy source
stores/releases only a small manageable amount of energy so
no energy is wasted as heat
why ATP is a good energy source
small soluble molecules so it can be
easily transported around the cell
why ATP is a good energy source
its easily broken down so
energy can be easily released instantaneously
why ATP is a good energy source
it can be quickly
re-made
why ATP is a good energy source
it can make other molecules more reactive by
transferring one of its phosphate groups to them (phosphorylation)
why ATP is a good energy source
ATP cant pass out of the cell so
the cell always has an immediate supply of energy
terms
metabolic pathway
a series of small reactions controlled by enzymes e.g. respiration and photosynthesis
terms
phosphorylation
adding phosphate to a molecule e.g. ADP is phosphorylated to ATP
terms
Photophosphorylation
adding phosphate to a molecule using light
terms
photolysis
splitting of a molecule using light energy
terms
photoionisation
when light energy ‘excites’ electrons in an atom or a molecule, giving them more energy and causing them to be released
the release of electrons causes the atom or molecule to become a positivley charged ion
terms
hydrolysis
splitting of a molecule using water
terms
decarboxylation
removal of CO2 from a molecule
terms
dehydrogenation
removal of hydrogen from a molecule
terms
redox reaction
reactions that involve oxidation and reduction
if something is reduced it has
gained electrons e-
may have gained Hydrogen or lost oxygen
if something is oxidised it has
lost electrons e-
may have lost hydrogen or gained oxygen
oxidation of one molecule always involves
reduction of another molecule
what is a coenzyme
a molecule that aids the function of an enzyme
how do coenzymes work
by transferring a chemical group from one molecule to another
a coenzyme used in photosynthesis is
NADP
examples of coenzymes used in respiration
NAD
Coenzyme A
FAD
NAD and FAD transfer
H from one molecule to another can reduce (give H to) or oxidise (take H from) a molecule
NADP transfers
Hydrogen from one molecule to another. this means it can reduce (give H to) or oxidise (take H from) a molecule
Coenzyme A transfers
acetate between molecules
