Lecture 11 Flashcards
Metabolism
All of the chemical reactions that occur in the cell to support life
Catabolism
Reactions that “break down” high-energy chemicals (“food”) into lower energy chemicals.
Catabolism produces energy
how a cell makes a living”
Glycolysis Aerobic Respiration Fermentation (Photosynthesis) etc.
Anabolism
Reactions that “build up” cellular macromolecules (proteins, nucleic acids, etc.) from biochemical monomers
Anabolism consumes energy
“how a cell makes more of itself”
Photosynthesis Synthesis of amino acids Synthesis of carbohydrates Synthesis of nucleotides Synthesis of lipids Replication of DNA Transcription of RNA Translation of proteins etc.
Where does the ATP used by the Na+/K+ pump come from?
Carbon cycle To generate ATP we release energy from chemical bonds in our food.Carbon cycle
Chemical bonds in our food
Lipids (repeated CH2 groups)
Proteins (repeated amino acids)
Carbohydrates (CH2O; C=carbo, H2O=hydrate)
Carbohydrates can be monosaccharides - glucose or fructose disaccharides - maltose or sucrose polysaccharides - glycogen, starch or cellulose 60-70% of our calories from carbs.
Polysaccharides
energy storage
how do we release energy from bonds in carbohydrate?
oxidation
Oxidation-reduction
Reactions involving the passage of electrons from one atom/molecule to another (a.k.a., redox reactions)
Loss of Electrons is Oxidation
Gain of Electrons is Reduction
Memorization tool: “LEO says GER”
Redox reactions always take place together because electrons have to come from & go somewhere
“Free” electrons are not just floating about in the environment
The transfer of electrons through these redox reactions also transfers energy
Reduction
capture electrons
Glycolysis
splitting of glucose into pyruvate
1st stage in cellular respiration
Takes place in the cytoplasm
Occurs in the presence or absence of oxygen
Involves 10 enzyme-catalyzed reactions
(these convert the 6-carbon glucose into two 3-carbon molecules of pyruvate)
Net generation of 2 ATP and 2 NADH
Fermentation
metabolism without oxygen
Pyruvate & catabolism
If anaerobe is capable of both aerobic respiration & fermentation, pyruvate goes one way (is O2 present?)
Krebs cycle
Krebs cycle (a.k.a., tricarboxylic acid cycle/ citric acid cycle) = metabolic furnace that oxidizes organic fuel from pyruvate 4 NADH, 1 FADH2, 1 ATP
How are the electrons released from the oxidation of our food converted into ATP?
Electrons from NADH & FADH2 get passed to the electron transport chain (ETC)
