8.1 how organisms obtain energy 2014
DESCRIPTION
Metabolism OverviewTRANSCRIPT
8.1 How Do Organisms Obtain Energy?
Many chemical reactions and processes are going on in your body even when you are not aware of it!–These cellular activities require
ENERGY!
Energy
Energy = the ability to do work
Thermodynamics1st Law = energy can be converted
from one form to another, but it cannot be created nor destroyed.
Thermodynamics
2nd Law = energy cannot be converted without the loss of useable energy
–Usually lost as heat
–Disorder (entropy) increases
Entropy
All organisms need energy to live Autotrophs =
organisms that make their own food
– Example: Plants
Heterotroph = organisms that ingest food to obtain energy- Example: You!
How do cells release energy? Energy stored in food molecules is
released in a series of enzyme-catalyzed chemical reactions.
When cells break down molecules, some of the energy released is in the form of heat.
The rest of the energy is stored as ATP.
ATP“Energy Currency” –
It is like money
that can be
spent throughout
the cell!
How is ATP constructed?
Adenosine triphosphate: is made of• Adenine• Ribose sugar• 3 phosphates
Adenosine diphosphate:• remove 1 phosphate,
you have ADP
ATP ADP + P
When one phosphate breaks off the energy is RELEASED
When one phosphate is added the energy is STORED in the phosphate-phosphate bond
Cellular Respiration Series of reactions that break down
organic molecules into carbon dioxide, water and creates ATP
Photosynthesis Series of reactions that change light
energy from the sun into chemical energy to be used by the cell
Metabolism: all of the chemical reactions in a cell
Two Metabolic Pathways:
Catabolic: the breakdown of nutrient molecules into useable forms - “count them down”
example = Cellular Respiration
Anabolic: build new molecules from the products of catabolic pathways
“add them up” example = Photosynthesis