Energy and ATP Flashcards
What is energy?
The ability to do work
Give examples of different forms of energy
light, heat, sound, kinetic, magnetic, electrical, mechanical, chemical, atomic
Why do organisms need energy?
metabolism movement active transport maintenance, repair and division production of substances - secretion maintenance of body temperature
What are the three stages of the flow of energy through living systems?
light energy from sun - converted by plants into chemical energy in photosynthesis
chemical energy - converted into ATP during respiration of cells
ATP - used by cells to perform useful work
How does ATP store energy?
bonds between the phosphate groups are unstable and have a low activation energy
when the bonds are broken energy is released
Give the equation for the hydrolysis of ATP
ATP + H2O –> ADP + Pi + ENERGY
Give the equation for the condensation of ADP
ADP + Pi + ENERGY –> ATP + H2O
What does the synthesis of ATP from ADP need?
the addition of a phosphate molecule
What are the three ways in which a phosphate molecule can be added to ADP?
photo phosphorylation
oxidative phosphorylation
substrate-level phosphorylation
Where does photo phosphorylation occur?
takes place in the chlorophyll-containing plant cells during photosynthesis
Where does oxidative phosphorylation occur?
takes place in the mitochondria of plant and animal cells during the process of electron transport
Where does substrate-level phosphorylation occur?
takes place in plant and animal cells when phosphate groups are transferred from donor molecules to ADP to make ATP
Why do cells only store a little bit of ATP? Why is this not an issue?
immediate energy source so cells only have a few seconds’ supply
ATP is rapidly re-formed from ADP AND Pi
Why is ATP a better immediate energy source than glucose?
ATP releases less energy than glucose so energy for reactions is released in smaller, more manageable quantities
the hydrolysis of ATP to ADP is a single reaction that releases immediate energy - breakdown of glucose is a lengthy process
What is ATP the source of energy for?
metabolic processes - build up macromolecules from their basic units
movement - provides energy for muscle contractions
active transport - provides energy to change the shape of carrier proteins in plasma membranes
secretion - forms lysosomes
activation of molecules - allows enzyme-catalysed reactions to occur more readily
