BIOLOGY 151 Chapter Notes - Chapter 8: Atp Hydrolysis, Ribose, Hydrolysis
ENERGY IN LIVING SYSTEMS
● REDOX REACTION: oxidation and reduction occurring together
ELECTRONS AND ENERGY
● The removal of an e- from a molecule oxidizing it=decrease in potential energy
ELECTRON CARRIERS
● NAD+ can accept e- form an organic molecule
● When e- ae removed from compound, it’s oxidized
● OXIDIZING AGENT: a compound that oxidized another
ATP IN LIVING SYSTEMS
● Excess free energy would result in an increase of heat in the cell
● ATP alters the structure of the integral protein that functions as the pump
● Overall, ATP is a source of energy that releases ~30 kj and energy from an ATP
molecule is released in small quantities to prevent damage to the cell. Energy released is
used for metabolism in the cell. It is dubbed as the universal unit of energy for living
organisms. Without it, various metabolic activities in the human body can't take place.
ATP STRUCTURE AND FUNCTION
● Composed of an adenine molecule bonded to a ribose molecule and to a single phosphate
group
● Ribose is a 5 carbon sugar found in RNA and AMP is one of the nucleotides in RNA
● Addition of a second phosphate group = ADP
● Addition of a third phosphate group = ATP
● Phosphate groups are negatively charged and thus repel one another when arranged in a
series
● DEPHOSPHORYLATION: release of one or two phosphate groups from ATP, releases
energy
ENERGY FROM ATP
● HYDROLYSIS” water’s split and the H+ atom and OH= are added to the larger molecule
○ Hydrolysis of ATP makes ADP with Pi and the release of free energy
● Energy comes from the metabolism of glucose
PHOSPHORYLATION
● During an endergonic chemical reaction, ATP forms an intermediate complex w/ the
substrate and enzyme in the reaction
● PHOSPHORYLATION: ATP to transfer its third phosphate group with its energy to the
substrate
○ Addition of the phosphate
○ When the intermediate complex breaks apart, the energy is used to modify the
substrate and convert it into a product of the reaction
SUBSTRATE PHOSPHORYLATION
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● A phosphate group is removed from an intermediate reactant in the pathway and the free
energy of the reaction is used to add the third phosphate to an available ADP molecule
making ATP
OXIDATIVE PHOSPHORYLATION
● CHEMIOSMOSIS: process of ATP production in cellular metabolism is used to generate
90% of the ATP made during glucose catabolism and used in the light reactions of
photosynthesis to harness the energy of sunlight
● OXIDATIVE PHOSPHORYLATION: production of ATP using the process of
chemiosmosis and involves oxygen
GLYCOLYSIS
● GLYCOLYSIS” first step in the breakdown of glucose to extract energy for cellular
metabolism
● ANAEROBIC: doesn’t use oxygen
● Takes place in the cytoplasm of prokaryotic and eukaryotic cells
● Enters heterotrophic in two ways:
○ Secondary active transport where the transport takes place against the glucose
concentration gradient
○ Uses a group of integral proteins called GLUT proteins
● 6 carbon ring shaped structure of a single glucose molecule and ends with two molecules
of a 3 carbon sugar aka PYRUVATE
● 2 distinct phases:
○ Traps the glucose molecule in the cell and uses energy to modify it
○ Extracts energy from the molecules and stores it in the form of ATP and NADH
FIRST HALF OF GLYCOLYSIS
● Catalyzed by hexokinase: an enzyme with broad specificity that catalyzes the
phosphorylation of 6 carbon sugars
○ Produces glucose-6-phosphate
● Prevents the phosphorylated glucose molecule from continuing to interact with the GLUT
proteins
● ISOMERASE: an enzyme that catalyzes the conversion of a molecule into one of its
isomers
● A second ATP molecule donates a high-energy phosphate to fructose-6-phosphate
● The newly added high energy phosphates further destabilize fructose-1
● Isomerase transforms the dihydroxyacetone-phosphate into its isomer
SECOND HALF OF GLYCOLYSIS
● Sugar is oxidized and is then phosphorylated by the addition of a second phosphate group
● If NAD+ isn’t available, the second half of glycolysis slows down or stops
● If there’s no oxygen, an alternate pathway (fermentation) can provide the oxidation of
NADH to NAD+
● A carbonyl group is oxidized to a carboxyl group
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Document Summary
Redox reaction: oxidation and reduction occurring together. The removal of an e- from a molecule oxidizing it=decrease in potential energy. Nad+ can accept e- form an organic molecule. When e- ae removed from compound, it"s oxidized. Oxidizing agent: a compound that oxidized another. Excess free energy would result in an increase of heat in the cell. Atp alters the structure of the integral protein that functions as the pump. Overall, atp is a source of energy that releases ~30 kj and energy from an atp molecule is released in small quantities to prevent damage to the cell. Energy released is used for metabolism in the cell. It is dubbed as the universal unit of energy for living organisms. Without it, various metabolic activities in the human body can"t take place. Composed of an adenine molecule bonded to a ribose molecule and to a single phosphate group.