Chapter 25: metabolism

Question 1

What is metabolism?

Answer 1

All chemical reactions in the body. Maintenance of homeostasis, balancing act between anabolic and catabolic reactions.

Question 2

Catabolism 

Answer 2

Larger molecules broken down into smaller building blocks.
Exergonic: release, more energy than consume.

Question 3

Anabolism 

Answer 3

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

Question 4

Oxidation and reduction reactions

Answer 4

Transfer of energy 

Question 5

Oxidation 

Answer 5

Loss of electrons or hydrogen ->loss of energy 

Carbs, fats, proteins, broken down, catabolic through oxidation - energy transferred - eventually used to make ATP 

Question 6

Reduction 

Answer 6

Gain of electrons are hydrogen gain of energy 

Question 7

ATP fast energy cash

Answer 7

Produce from energy transfer during catabolic, reactions of carbs, lipids, and proteins in this order
Made by phosphorylation of ADP to ATP 

Question 8

Carbohydrate, metabolism 

Answer 8

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 

Question 9

Glycolysis 

Answer 9

No oxygen required
Glucose equals two pyruvic acid/pyruvate
A little ATP made quickly
Occurs in all cells 

Question 10

Fates of pyruvate

Answer 10

Depends of O2 availability 

Question 11

Anaerobic respiration 

Answer 11

An absence of oxygen (anaerobic)
Pyruvic acid -> lactic acid 

Question 12

Aerobic respiration

Answer 12

In presence of O2 requires O2
Pyruvic acid oxidized
Lots of ATP made more slowly
Water and CO2 produced 

Question 13

Glycolysis
Location: cytoplasm
Many reactions

Answer 13

1. Energy investment stage two ATP used first.
   – Phosphor to G6P traps glucose, makes more reactive
2. Production of NADH.
   - NAD+ reduced to NADH
   - NADH is electron carrier - carries energy of electron to mitochondrion!
3. Energy harvesting stage: 4 ATP made
4. Pyruvate (3 carbon molecule) produced

Question 14

Glycolysis products
Now where is the energy from glucose we oxidized?

Answer 14

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

Question 15

Acetyl CoA production

Answer 15

Location: mitochondrial matrix
Pyruvate used to form Acetyl CoA
NAD+ —> NADH produced…we will follow them!
CO2 released and diffuses out of cell

Question 16

Absorptive
state

Answer 16

“fed state”, immediately after eat, nutrients absorbed
• Major energy fuel:
glucose
• Anabolism>
catabolism
– Glycogenesis
– Lipogenesis:
Triglyceride
storage!
– Protein
synthesis
makes protein

Question 17

Postabsorptive
state

Answer 17

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

Question 18

Glycolysis

Answer 18

Breakdown of glucose to pyruvate

Question 19

Glycogenesis

Answer 19

Glucose storage as glycogen (liver and skeletal muscles

Question 20

Glycogenolysis

Answer 20

Breakdown of glycogen for glucose

Question 21

Gluconeogenesis

Answer 21

Synthesis of glucose from non-carbs in liver
- triglycerides (glycerol), lactic acid, certain amino acids used