Chapter 25: metabolism Flashcards
(21 cards)
What is metabolism?
All chemical reactions in the body. Maintenance of homeostasis, balancing act between anabolic and catabolic reactions.
Catabolism 
Larger molecules broken down into smaller building blocks.
Exergonic: release, more energy than consume.
Anabolism 
Smaller joined together to make larger molecules with new bonds
Endergonic: uses more ATP than release
The benefit energy transferred to ATP some heat release too
Oxidation and reduction reactions
Transfer of energy 
Oxidation 
Loss of electrons or hydrogen ->loss of energy 
Carbs, fats, proteins, broken down, catabolic through oxidation - energy transferred - eventually used to make ATP 
Reduction 
Gain of electrons are hydrogen gain of energy 
ATP fast energy cash
Produce from energy transfer during catabolic, reactions of carbs, lipids, and proteins in this order
Made by phosphorylation of ADP to ATP 
Carbohydrate, metabolism 
Polysaccharides, carbs, broken down to monosaccharides
Glucose monosaccharide preferred cellular fuel
Glucose broken down, catabolism , used to make ATP energy 
Once cell ATP energy demands met - excess glucose stored away as glycogen for later glycogenesis – skelter muscles, liver 
Glycolysis 
No oxygen required
Glucose equals two pyruvic acid/pyruvate
A little ATP made quickly
Occurs in all cells 
Fates of pyruvate
Depends of O2 availability 
Anaerobic respiration 
An absence of oxygen (anaerobic)
Pyruvic acid -> lactic acid 
Aerobic respiration
In presence of O2 requires O2
Pyruvic acid oxidized
Lots of ATP made more slowly
Water and CO2 produced 
Glycolysis
Location: cytoplasm
Many reactions
- Energy investment stage two ATP used first.
– Phosphor to G6P traps glucose, makes more reactive - Production of NADH.
- NAD+ reduced to NADH
- NADH is electron carrier - carries energy of electron to mitochondrion! - Energy harvesting stage: 4 ATP made
- Pyruvate (3 carbon molecule) produced
Glycolysis products
Now where is the energy from glucose we oxidized?
2 ATP (net gain: used 2 made 4)
NADH….we will follow them - has electron (with energy) on it!
Pyruvate (not done yet)
Some energy released as heat
Acetyl CoA production
Location: mitochondrial matrix
Pyruvate used to form Acetyl CoA
NAD+ —> NADH produced…we will follow them!
CO2 released and diffuses out of cell
Absorptive
state
“fed state”, immediately after eat, nutrients absorbed
• Major energy fuel:
glucose
• Anabolism>
catabolism
– Glycogenesis
– Lipogenesis:
Triglyceride
storage!
– Protein
synthesis
makes protein
Postabsorptive
state
fasting state”; hours
after eat, no
nutrients absorbed
• Goal: maintain blood
glucose!
• Catabolism >
anabolism
– Glycogenolysis:
break down glycogen stores
– Lipolysis: break
down trig storage
– Gluconeogenesis: make glucose from non-carbs
Glycolysis
Breakdown of glucose to pyruvate
Glycogenesis
Glucose storage as glycogen (liver and skeletal muscles
Glycogenolysis
Breakdown of glycogen for glucose
Gluconeogenesis
Synthesis of glucose from non-carbs in liver
- triglycerides (glycerol), lactic acid, certain amino acids used
