Intro to Bioenergetics Flashcards
(33 cards)
What is bioenergetics?
the study of the transformation of energy in living organisms.
Why is bioenergetics important? (3)
- understand how bioenergetics affects normal living.
- use our knowledge to optimise nutrition to push athletes to their best performances.
- to understand the changes in metabolism which leads to harmful adaptations.
what is metabolism?
the sum of all chemical reactions in the body.
what are the two main types of metabolic reactions?
catabolic and anabolic
what are catabolic reactions?
the break down / degradation of molecules e.g. while we age our body starts to break down due to catabolic reactions taking place.
what are anabolic reactions?
the synthesis / growth of new molecules. the energy released from anabolic reactions can be used to build new molecules. e.g. skeletal muscles synthesise new molecules causing them to grow and get stronger , cancer growth is an anabolic reaction.
what re the four main catabolic pathways?
proteolysis, lipolysis, glycolysis and glycogenolysis.
what re the four main anabolic pathways?
protein synthesis, lipogenesis, gluconeogenesis and glycogenesis.
what are the three ways metabolic pathways are regulated?
substrate supply, hormonal control and allosteric control.
what is substrate supply?
food and other compounds.
what is hormonal control?
switch on or turn off pathways & alter enzyme activity.
what is allosteric control?
speed or slow enzyme activity.
can pathways occur simultaneously?
No. molecules cannot be broken down and synthesised at the same time, it will either be catabolic or anabolic.
what is our body fuelled by?
ATP (adenosine triphosphate) - the energy currency of the cell. the food we consume is digested and used to generate ATP so we can use that ATP to produce these metabolic reactions to keep us alive.
How is energy released by ATP?
the energy rich bonds between two of the three phosphate groups is broken releasing energy. this creates ADP (adenosine diphosphate). the bond between the remaining two phosphate groups is also broken to release energy leaving AMP (adenosine monophosphate).
what are enzymes and what do they do?
enzymes are proteins which speed up reactions, without them we would die. enzymes lower the activation energy, the initial energy required for the reaction to take place. they basically move molecules into the correct positions and roll them over the edges.
why can’t enzymes catalyse all metabolic reactions?
enzymes are specific to specific substrates due to their active binding sites. this means they can only catalyse one metabolic reaction.
do enzymes carry out catabolic or anabolic reactions?
both.
what are the two ways to explain interaction and specificity of enzymes and substrates?
lock and key, induced fit.
what is lock and key?
the binding site of the enzyme has a complementary shape to its substrate(s).
what is induced fit?
contact between part of the binding site and the substrate induces a change in shape of the active site to bind tot eh substrate.
wha6 is allosteric control?
when a molecule other than the molecules and substrate itself can bind to the enzyme and changes the shape of the enzyme. this can mean that the substrate can no longer fit or it could change the shape so that the substrate can now fit.
how does energy status affect allosteric binding?
if the energy status is low (AMP or ADP) it will cause allosteric activation meaning enzyme shape is changed to allows substrates to fit whereas if the energy status is high (ATP) it will cause allosteric inhibition meaning the enzyme shape is changed to inhibit the metabolic pathway.
what is enzyme activity affected by?
the local environment, including:
substrate concentration.
pH,
enzyme concentration,
temperature.
