chapter 25 Flashcards
(31 cards)
metabolism
sum total of all the chemical reactions occurring within the cells of an organism
atp
is the primary energy carrying molecule of the cell
stage one of the nutrient processing
digestion occurs in the GIT and absorbed nutrients enter the blood to reach tissue cells. break down of the food Starts here it gets broken down into smaller pieces so the blood can absorb its nutrients which are them distributed in the body
stage 2 of the nutrient process
occurs in the cytoplasm of tissue cells
absorbed nutrients are: 1) used to build complex molecules (lipids, proteins, glycogen) by anabolic pathways
OR 2) broken down by catabolic pathways to harvest their bond energy to form pyretic acid and acetyl CoA
anabolic pathways
simple building blocks to create a larger structure. it happened because cells need different lipids or proteins for different things.
stage 3 of nutrient processing
occurs in the mitochondria and is almost entirely catabolic (break down). it requires oxygen and completes the breakdown of food to CO2 and H2O generating large amounts of ATP through oxidative phosphorylation. does it in a way where molecules are stripped off of electrons and are handed over to electron transport chain which is a serous membrane.
phosphorylation
adding a phosphate group to something
carbohydrates metabolism
carbohydrates are broken down into monosaccharides
liver cells convert fructose and galactose to glucose
can transfer energy from glucose to ATP
other nutrients like fats or amino acids, can generate ATP and are linked to glucose breakdown pathways
liver cells
hepatocytes
glucose
is the major fuel its what gets broken down
glucose catabolism
breaking things down from larger structures to smaller structure. glucose catabolism is central to ATP production
cellular respiration
is the process that releases energy from glucose and makes it available of cellular use
it involves oxidation reaction -ALWAYS HAPPEN TOGETHER
Oxidized
when a electron is lost (LEO) exergonic. the energy is existing
reduced
gaining an electron (GER) endergonic. going an electron/hydrogen atom. endergonic is energy making a new bond so energy is trapped between the bond
what are the two co enzymes?
nicotinamide adenine dinucleotide (NAD+) and Flavin adenine dinucleoride (FAD)
nicotinamide adenine dinucleotide
FAD (oxidized) –> (+2H) FADH2 (reduced)
flavin adenine dinucleotide
FAD (oxidized) –> (-2H) FADH2 (reduced)
what are the four sets of reactions with cellular respirations
- glycolysis
- formation of acetyl CoA
- Krebs cycle (citric acid cycle)
- electron transport chain reactions (ETC)
summarized cellular respiration
C6H2O6 (glucose) + 6O2 –> 6CO2 + 6H2O + 32 ATP + heat
glycolysis
occurs in the cytoplasm.
is an anaerobic process (does not need O2)
series of 10 reactions which convert 1 glucose (6C) into 2 molecules of pyretic acid (3C). (Takes glucose molecules and splits it in half so they have 3 carbons). glucose has lost 4 hydrogen atoms which are now bond to 2 molecules of NAD+. produces 2 NADH + 2H+.
also results in a net gain of 2 ATP.
the fate of pyretic acid depends on oxygen availability. if oxygen is unavailable (anaerobic conditions), the pyretic acid will be reduced.
formation of acetyl CoA
if oxygen is available (aerobic conditions), the pyretic acid is converted to acetyl coenzyme A (CoA).
pyretic acid (3 carbon) loses a C atom as CO2, and a pair of H atoms as it enters the mitochondria
the 2C molecule formed (acetic acid) is attached to coenzyme A to produce acetyl CoA (form to every molecule of glucose)
H’s are transferred to NAD+ to produce NADH+
acetyl CoA enters the Krebs cycle
Krebs cycle (Citrix acid cycle)
occurs in the matrix of mitochondria. an aerobic process
series of 8 cyclical reactions
begins with 1 acetyl CoA and results in:
- formation of 2 CO2
- H’s are picked up by FAD to form 1 FADH2
- H’s are picked up by NAD+ to form 3 NADH
- formation of 1 atp
much of the energy original persent in the bonds of glucose is now present in the reduced coenzymes. most of the energy is now found in the NADH and FADH now
high energy electrons are handed off to the electron transport chain (last step) which couples this energy to ATP synthesis
electron transport chain
occurs on the crustal of the inner mitochondrial membrane
electrons from NADH and FADH2 are transferred to a series of membrane proteins that act as acceptors
electrons are passed from acceptor to acceptor along the chain and run downhill
**hydrogen atoms are split apart as they transfer from coenzymes to the ETC.
energy from NADH+ H+ passes along the ETC and is used to pump H+ from the metric to the inter membrane space (proton pump)
this creates an area of high H+ concentration in the inter membrane space.
H+ then diffuse back down the concentration gradient into the matrix through ATP synthase complexes to form ATP from ADP.
each pair of electron is donated to ETX by NADH provided enough energy to pump enough protons to produce about 2.5 molecules of ATP (1.5 ATP for each FADH2)
oxygen acts as the final electron acceptor at the end of the ETC
- electrons are recombined with protons to form hydrogen which is combined with oxygen to form water 6H2O
ATP produced in glycolysis
2 atp
