Module 16- Metabolism Flashcards
what is metabolism?
how we extract and store energy from absorbed nutrients
what is ATP?
adenosine triphosphate
it powers the cells in your body
ex. na/k pump, releasing actin from myosin, etc
What are proteins digested as?
Amino acids
What are carbohydrates digested as?
monosaccharides
we mainly consider glucose
What are fats digested as?
fatty acids and gylcerol
monoglycerides and cholesterol too
What are the four fuels our body uses for energy?
amino acids, glucose, fatty acids, glycerol
anabolism
taking smaller units (ex. absorbable nutrients like glucose) and building them into larger molecules for STORAGE
How is excess glucose stored?
as GLYCOGEN
a limited amount is stored in muscle/liver tissue, or other cells (except brain)
once ^ fill with glycogen, the rest becomes TRIGLYCERIDES to be stored in adipose tissue
How is excess amino acids stored?
instead of stored as protein in muscle, its stored as TRIGLYCERIDES in the adipose tissue (as fat)
How is excess fat stored?
stored as TRIGLYCERIDES (fat) in adipose tissue
What percent of cell energy is generated in the cell from glucose?
1% total body energy
stored as glycogen in limited amounts
What percent of cell energy generated in the cell from fatty acids?
77% total body energy
fatty acids taken from adipose storage
what percent of cell energy generated in the cell from amino acids?
22% total body energy (IF NEED BE)
last resort if all other resources have been used up
will have to sacrifice muscles in order to generate energy, only happens due to malnourishment
what are the 3 reactions that the cell carries out to produce ATP from nutrients?
1) Glycoysis–> 2 ATP
2) Citric Acid Cycle–> 2 ATP
3) Oxidative Phosphorylation–> 34 ATP
what is glycolysis
- 2 ATP from 1 glucose
- occurs in CELL CYTOPLASM
- no oxygen required
what is Citric Acid Cycle (CAC)
- 2 ATP from 1 glucose
- mitochondria
- requires oxygen
what are the by-products of creating ATP?
CO2 and water
what stage of energy cycle does glucose enter?
beginning of glycolysis
what stage of energy cycle does amino acids enter?
-convert to acetyl CoA–> CAC
OR
-convert to pyruvate–> glycolysis
what stage of energy cycle does triglycerides enter?
- 1st broken down into FATTY ACIDS and GLYCEROL
- glycerol enters at glycolysis
- fatty acid–> converted to acetyl CoA–> CAC
can the brain store glycogen?
no it cannot
which energy source can the brain ONLY use?
glucose
after eating, our blood has lots of glucose circulating. explain how cells change glucose into G6P
- cells turn glucose into GLUCOSE 6 PHOSPHATE
- G6P has 2 options:
1) enter glycolysis for atp
2) be stored as glycogen
glycogen. …
2a) it can be converted back to G6P to make atp later
2b) G6P goes thru a rxn to make atp and PYRUVATE
3) PYRUVATE has 2 options :
3a) WITH oxygen–> CAC
3b) NO oxygen–> LACTIC ACID
what is the purpose of lactic acid?
- when exercising, blood cant be pumped fast enough to bring enough o2 to muscle cells for making atp with CAC
- glycolysis is anaerobic (no o2 needed to rxn) but produces a lot of PYRUVATE
- too much pyruvate is BAD–> solution= create lactic acid
what effect does lactic acid have on the body once produced?
- burning sensation in muscles
- causes fatigue–> interferes w contractile proteins in muscle cells
- causes blood vessels to dialate and _ pH to get more o2 from hemoglobin
how is lactic acid a reversible reaction once o2 is replenished?
- lactic acid can convert for 2 purposes:
1) TO USE IMMEDIATELY: lactic acid–> pyruvate–> CAC–> 2 ATP
2) TO STORE ENERGY: lactic acid–> pyruvate–> g6p–> glycogen for storage
is g6p to glucose a reversible reaction?
no. it can only happen in the liver, nowhere else
after g6p goes thru glycolysis for 2atp, it becomes (1)_____. IF OXYGEN IS PRESENT, it will be transformed into (2)_____ to enter the (3)_____ reaction, then finally the (4)______ reaction for more atp.
IF NO OXYGEN IS PRESENT, it becomes (5)_____ to generate more atp (anaerobic rxn).
1) pyruvate
2) acetyl CoA
3) CAC
4) Oxidative phosphorylation
5) lactic acid
what is acetyl CoA?
- acetyl coenzyme A
- the pyruvate from Glycolysis–> converted to acetyl coa
- acetyl coa enters CAC and oxidative phosphorylation–> total of 36 atp
- makes H20 and CO2 as byproducts
what are the two options for aa’s being turned into atp?
1) turned into pyruvate–> glycolysis
2) turned into acetyl CoA–> enter CAC
how is fat turned into atp?
- fat generates a fatty acid + glycerol
- fatty acids can convert into acetyl CoA–> CAC
- glycerol can directly enter glycolysis–> becomes pyruvate
what is the fed state?
after a meal when you have lots of glucose circulating that doesnt need to be used immediately. AKA STORE IT!
how is excess glucose stored in the body?
- INSULIN!
- a hormone from pancreas (BETA cells) secretes when theres too much glucose (ex. after a meal)
- triggers storage and inhibits release of storage
what is diabetes mellitus?
- body does not produce insulin
- things cannot be stored very well without insulin to trigger
what is the fasting state?
when you are in between meals, your body gets energy from storage in the body
what hormone is released in the fasting state to trigger release from storage?
Glucagon
- triggered by low glucose in the blood
- released from Pancreas (ALPHA cells) opp to insulin
- allows the catabolism of energy (break down of)
- breaks glycogen–> g6p… (GLYCOGENOLYSIS) –> to go into glycolysis
what is glycogenolysis?
the breakdown of glycogen into G6P
what is lipolysis?
breakdown of triglycerides into fatty acids and glycerol
what is Gluconeogenesis?
the ability of the liver to create new glucose from non-glucose products
-takes pyruvate, glycerol, and aa’s to make glucose
what is the purpose of thyroid hormone
regulating metabolic demands.
-too much thyroid hormone= not enough storage initiated (insulin) and too much catabolized (too much glucagon triggered)
how does cortisol affect metabolism?
stress causes body to go into overdrive–> takes OUT of storage
how does epinephrine affect metabolism?
when you need a boost of energy, adrenaline stims removing energy from storage
