Chapter 9 - Metabolism Flashcards
What is the definition of metabolism?
any chemical process that happens in your body
What are catabolic reactions?
reactions that breakdown and produce energy
What are anabolic reactions?
reactions that build up and use energy
What is ATP to the cell?
energy-currency
Can ATP be stored?
No, it must constantly be made
What does ATP stand for?
adenosine triphosphate
What process does ATP’s phosphates go through that releases energy?
phosphate uncoupling
What is adenine attached to?
ribose
By themselves, what are the phosphates that make up ATP?
inorganic
What happens when ATP is “drawn down”?
converts to ADP
What happens when ADP is “charged up”?
converts back to ATP
What is the function of enzymes?
speed up reactions
Enzymes are almost always what?
proteins
What are coenzymes?
they work with enzymes
What are some examples of coenzymes and what do they do?
NADH and FADH2
deliver electrons to the ETC
What vitamins act as coenzymes?
B vitamins
What are cofactors?
inorganic coenzymes
What controls REDOX reactions?
enzymes
When is something oxidized?
loses electrons
loses hydrogen
gains O2
When is something reduced?
gains electrons
gains hydrogen
loses O2
What is the oxidized form of Nicotinamide adenine dinucleotide?
NAD+
What is the reduced form of nicotinamide adenine dinucleotide?
NADH2
What is the oxidized form of flavin adenine dinucleotide?
FAD
What is the reduced form of flavin adenine dinucleotide?
FADH2
What is a component of nicotinamide adenine dinucleotide?
niacin
What is a component of flavin adenine dinucleotide?
riboflavin
What are the four steps of cellular respiration for carbohydrates?
glycolysis
transition reaction
citric acid cycle
ETC
What is the main goal of glycolysis?
break down 6C glucose to 2 molecules of 3C pyruvate
What are the byproducts of carbohydrate glycolysis?
2 molecules of pyruvate
NADH+H
2 net molecules of ATP
Where does glycolysis take place in the cell?
cytoplasm
What does NADH+H act as?
Electron deliverer for ETC
What must be present for pyruvate to enter the mitochondria?
oxygen
What happens after glycolysis if oxygen is present?
transition reaction in mitochondria
What happens after glycolysis if oxygen is not present?
lactic fermentation
What is lactic acid and when do you feel it?
toxic byproduct of anaerobic respiration
during exercise - THE BURN
What does anaerobic respiration/lactic fermentation allow for?
NADH to be converted to NAD+
allows glycolysis to restart
What is the energy output of anaerobic respiration/lactic fermentation?
2 ATP per glucose molecule
Where is lactic acid recycled?
liver
What is the process of lactic acid recycling called?
Cori cycle
What is the main goal of the transition reaction of carbohydrates?
convert pyruvate to acetyl-CoA
Where does the transition reaction occur in the cell?
mitochondria
What does the transition reaction require?
oxygen
Other than the conversion of pyruvate to acetyl-CoA, what else does the transition reaction produce?
NADH+H (for ETC)
Carbon dioxide
What is unique about the
carbohydrate conversion to acetyl-CoA?
irreversible reaction
What are acetyl-CoA’s options (carbs)?
- Make ATP by entering the citric acid cycle and finishing with ETC
- Be converted to fat storage
- Be converted to ketone bodies
What are the necessary conditions for acetyl-CoA to make ATP through the citric acid cycle and later ETC?
only happens if body has enough carbs in storage
What are the necessary conditions for acetyl-CoA to be converted to fat storage?
only happens if the body does not require additional ATP
What are the necessary conditions for acetyl-CoA to be converted to ketones?
only happens if the body does not have enough carbs available
What can be used to make energy?
ketone bodies
What is required for acetyl-CoA to enter the citric acid cycle?
can only enter if oxaloacetate is present
What does the binding of acetyl-CoA and oxaloacetate make?
citrate
What is oxaloacetate made from?
carbs
If carbs aren’t available, what doesn’t happen?
Krebs
What is the goal of the citric acid cycle?
produce coenzymes
NADH+H
FADH2
What else does the citric acid cycle produce?
potential ATP (guanine triphosphate) carbon dioxide
What does the citric acid cycle not require?
oxygen
What is another name for the electron transport chain?
oxidative phosphorylation
Where does the energy come from to form ATP in the ETC?
NADH+H and FADH2
During the ETC, what happens to NADH+H?
oxidized to form NAD+
During the ETC, what happens to FADH2?
oxidized to form FAD
What minerals does the ETC require?
iron and copper
Iron is the component of what?
cytochromes
During the ETC, how is oxygen used?
combined with H+ and electrons to form water
Where is the most ATP generated?
ETC
What does each component of a triglyceride turn into during cellular respiration?
glycerol turns into pyruvate
fatty acids turn into acetyl-CoA
What is another term for turning fat into ATP?
Beta-Oxidation
What happens to fatty acid chains during beta-oxidation?
the even-numbered chain is cut into 2-carbon pieces
What happens to the 2C pieces of a fatty acid chain during beta-oxidation?
each piece gets CoA to make an acetyl-CoA
Other than acetyl-CoA, what else is made during beta-oxidation?
NADH+H and FADH2
Why does fat yield more than 2x the energy than carbs and protein?
- more carbons to convert to acetyl-CoA
- have fewer oxygen molecules, which makes it easier to handle at a molecular level
If carbohydrates are too low to generate oxaloacetate during the cellular respiration of fat, what happens?
- citric acid cycle decreases
- Beta-oxidation continues, causing buildup of acetyl-CoA
- join together to form ketone bodies
How does the production of ketone bodies affect the kidneys?
it is an acidic process, so it is hard on the kidneys as they buffer
What other physical symptoms will someone experience during ketone body formation?
suppressed appetite
acetone leaves body (smells fruity)
What happens to triglycerides during fasting?
they are broken down
What does the breakdown of triglycerides trigger during fasting?
hormone-sensitive lipase
What increases and decreases hormone-sensitive lipase?
increase- glucagon, growth hormone, and epinephrine
decrease-insulin
During fasting, how are fatty acids transported to the mitochondria?
taken up by cells and shuttled into mitochondria via carnitine
Where does protein metabolism take place?
liver
sometimes muscle
Depending on the R-group, what can protein be turned into during cellular respiration?
glucose or acetyl-CoA
Amino acids being used for fuel must first undergo what?
deamination
What is required for deamination to take place?
vitamin B-6
What is the result of amino acid deamination during cellular respiration?
carbon skeleton that is either gluco-genic or keto-genic
What can glucogenic amino acids undergo?
gluconeogenesis
Where does glucogenic amino acid gluconeogenesis take place
kidney
liver
What does glucogenic amino acid gluconeogenesis require?
ATP Biotin Riboflavin Niacin B-6
What happens to ketogenic amino acids?
use carbons to form acetyl-CoA
What is the main pathway for alcohol metabolism?
alcohol dehydrogenase
What is the first step in alcohol metabolism?
alcohol is converted to acetaldehyde
For alcohol to be converted to acetyldehyde, what must be present?
ADH and NAD+
What is the byproduct of alcohol conversion to acetaldehyde?
NADH+H
What is the second step in alcohol metabolism?
acetaldehyde is converted to acetyl-CoA
For acetaldehyde to be converted to acetyl-CoA, what must be present?
coenzyme A
aldehyde dehydrogenase
What is the byproduct of acetaldehyde conversion to acetyl-CoA?
NADH+H
If alcohol consumption is too high, what takes over?
MEOS
If buildup of NADH is too much during alcohol metabolism, what happens?
acetyl-CoA can’t enter
acetyl-CoA is directed to fatty acid and triglyceride production
What happens to metabolism during feasting?
fat tissue increases insulin production increases more glucose burned for energy more glycogen more protein and fat synthesis
Where is excess consumed fat stored?
adipose tissue
Excess protein consumption results in what?
amino acids in pool
fatty acid formation
Carbohydrates consumed in excess will result in what?
-build glycogen stores
glucose for energy
fat synthesis
What happens during fasting?
- body uses glycogen and fatty acids for fuel
- fat is still broken down and can’t be used to fuel nervous system or RBCs
- glycogen stores depleted
- body tissue broken down to make glucose
During prolonged fasting, what happens?
- body protein depleted
- fatty acids can’t be used for gluconeogenesis
- sodium and potassium depleted and lost in urine with ketone bodies
- blood urea levels increase
What are the body’s adaptations to survive fasting?
- slows metabolic rate to reduce energy requirements and lean body tissue breakdown
- allows nervous system to use more ketone bodies
- organ failure
