Chapter 7: metabolism Flashcards
Metabolism
The sum of all the chemical reactions that go on in living cells
Energy
The capacity of doing work, stored in food
stored as chemical bonds
How does the body obtain energy from food
food provides fuel through a series of reactions that release energies from chemical bonds
bonds break, release energy water and waste
The liver
metabolizes, packages, stores, or ships them out for use by other organs and detoxifies other organs
The liver and Carbs
-Converts things to glucose
-makes and stores glycogen
-breaks down glycogen and releases glucose
-makes glucose from some amino acids and glycerol when needed
-converts excess glucose to fatty acids
The liver and Proteins
-manufactures nonessential amino acids that are in short supplu
-takes certain extra amino acids out of circulation and turns them into glucose or fatty acids
- removes amonia from the blood for excretion
-Makes nitrogen containing compounds
-makes transport and blood proteins
The liver and lipids
-builds and breaks down triglycerides, phospholipids and cholesterol as needed
-breaks down. fatty acids for energy when needed
-packages extra lipids in lipoproteins for transport to other body organs
-manufactures bile to send to the galbladder for use of fat digestion
- makes ketone bodies when necessary
Liver’s other functions
detoxifies alcohol, other drugs, and poisons, prepares waste products for excretion
-helps dismantle old red blood cells and captures iron for recycling
-stores most vitamins and many minerals
-converts vitamin D into a =n intermediate, metabolic form
Anabolism
Building reactions like making glycogen. they require energy
Catabolism
The breakdown reactions
making glucose from glycogen reactions release energy to the body
Chemical reactions in the bodyThe transfer of energy in reactions
ATP
Chemical reactions in the body
powers all the activities of living cells
ATP
High energy storage compound that captures some of the energy from catabolism conains 3 phosphate groups whos negative charges make them vulnerable to hydrolysis. When the phosphate bonds are broken they release energy that was captured from catabolism
Coupled reactions
the body uses ATP to transfer the energy from catabolic reactions to power anabolic reactions
The transfer of energy in reactions
-energy is captures in the high-energy storage compound, ATP
-Negative charges of phosphate groups are vulnerable to hydrolysis
- cleaving P groups releases energy
Enzymes
Almost always required
-facilitate reactions
-remain unchanges
Coenzyme
-complex, organic molecules
-not proteins
-associate with enzymes
-required for enzymes to function
(some vitamin B
Digestion (macronutrients are broken down)
Carbohydrates
-Glucose
Fats
-Glycerol and fatty acids
Proteins
-Amino acids
Catabolism is the further breakdown into atoms
Metabolic pathways
Glucose, glycerol, fatty acids and amino acids all take different metabolic pathways
Pyruvate
3 carbon structure
Can be used to make glucose
Acetyl CoA
2 carbons and coenzyme CoA
cannot be used to make glucose
Fatty acids
Converted to acetyl CoA and therefore cannot make glucose
Amino acids and glycerol
Can be converted to pyruvate and therefore can provide glucose for the body
TCA cycle
-Tricarboxylic acid cycle, also called the citric acid cycle or the krebs cycle
-all energy-yielding nutrients can enter this pathway
-acetyl coa reacts with 4-c molecules
- each turn of TCA cycle releases 8 electrons
Electron Transport Chain
-The final pathway in energy metabolism that transports electrons from hydrogen to oxygen
- captures about half the energy released by breaking C-C bonds and storing it in the high energy bonds of ATP
Glycolysis
Takes one 6 C molecule to another 6 C molecules and it splits into two 3 C molecules
-the 3 C molecules are then converted to other 3-C molecules until they are eventually converted to two pyruvate muscles
-2 ATP used and 4 produced (net yield of 2)
Pyruvate to acetyl CoA
Aerobic
enters mitochondria
3-C pyruvate becomes 2-Carbin compound
becomes CO2
released into bloodstream and breathed out
Pyruvate to lactate
Anaerobic
accepts H from glycolysis
pyruvate becomes lactate
coenzymes freed and return to glycolysis
cori cycle
Glycerol and Fatty acids
Triglycerides are broken down into glycerol and fatty acids
-glycerol enters the pathway that converts glucose then makes acetyl CoA
-fatty acids are broken down via fatty acid oxidation, this forms abundant acetyl CoA, fatty acids cannot make glucose
Amino Acids
Amino acids are deaminated before entering energy pathways
-several entry points for amino acids
- because they are converted to pyruvate they can be turned into glucose
-if they enter the TCA cycle directly they can also be made into glucose
Glucogenic amino acids
Amino acids can be converted into glucose
Ketogenic
Amino acids that are converted to acetyl CoA and can’t be made into glucose
Electron transport chain
a series of proteins that accept electrons and pass them to the next carrier on the inner mitochondrial membrane
-as the coenzymes deliver theur electrons from the TCA cycle, glycolysis and fatty acid oxidation to the ETC, each carrier receives the electrons and passes them on to the next carrier.
-o2 accepts the electrons and combines with hydrogen atoms to produce water
-As the electrons are passed from carrier to carrier, H atoms are pumped across the membrane to the outer portion which are then later pumbed back into the inner portion (powers ATP synthesis)
- once formed ATP can travel into the cytosol where it can be used to drive cell function
