Metabolism

Overview

How do our bodies break down food into energy and our building blocks (proteins)?

• Catabolic Reactions
  • Destroys the reactants reducing big complex substances into molecular rubble. Enzymes do the destruction
• Anabolic Reactions
  • Reassembles that rubble into new and bigger products

Metabolism refers to every single biochemical reaction that goes on in your body. It reconciles 2 processes that are always simultaneously active:

• Anabolism
  • Construct things and consume energy.
  • Take monomers in your food (monosaccharides, fatty acids, amino acids) and build them into polymers like carbs, fats, and proteins that are used in your cells
• Catabolic
  • Break down molecules and release energy
  • Polymers in your body get broken up, breaking bonds and releasing energy to provide your cells with fuel.

Nutrients

The molecules that your body is forever breaking up, and then rebuilding, only to have them break apart again

These nutrients come in 6 major groups

1. Water
2. Vitamins: Compounds that come in fat-soluble or water-soluble forms
   1. Vitamin C: Improves iron absorption
   2. Vitamin K: Crucial to blood clotting
   3. Vitamin B: important in the production of ATP from glucose
3. Minerals:
   1. Calcium, Magnesium, Phosphorous: Harden bones and teeth
   2. Iron: Crucial part of hemoglobin
   3. Potassium, Sodium, Chlorine: Maintain your body’s pH balance and are used in action potentials
4. Carbohydrates
5. Lipids (Fats)
6. Proteins

Carbohydrates

Most carbs originally came from plants

• Monosaccharides and Disaccharides: Fruits, honey, sugar beets, and sugar cane
• Polysaccharides: veggies and grains (starches)

Glucose (monosaccharide) is the be-all-end-all molecular fuel that your cells need to make ATP

ATP is the molecule that your cells use to drive anabolic reactions.
ATP is too unstable to store, so cells store energy in the form of glucose that they can catabolize and convert to ATP when needed

Cells can get energy from fats (lipids), but the most important cells (neurons and red blood cells) feed on glucose, so most of carbs your intestines absorb are converted to glucose.
Because even a short-lived dip in your blood sugar can severely depress brain function, your body is all up on constantly monitoring and regulating your glucose levels

If it’s not needed. that energy can also be stored as glycogen in your liver and muscles, or converted to glycerol and fatty acids to make triglyceride fats

Lipids (Fats)

The Adipose Tissue (body fat) store energy and fat-soluble vitamins as well as cushion your organs
Lipids also form the myelin that insulates the neurons in your brain and throughout your body. As well as the oil in your skin and they provide calorie content found in breast milk

There are other important lipids like:
Cholesterol: Precursor to things like testosterone and estrogen
Phospholipids: form the cell membrane in your cells

Plants have fats too (avocados, seeds, nuts) not just meats.

When you eat lipids your body breaks down triglycerides into glycerol and fatty acids, which may then be converted to ATP, or converted into other fatty acids

You liver can’t convert some fatty acids, like omega 6 and omega 3 fatty acids
These are called Essential Fatty Acids. Your body can not synthesize them, so they must be ingested.

Proteins

If carbs provide energy, and lipids store energy, proteins do everything else

Proteins form the bulk of your muscle and connective tissue. They are also what the ion channels and pumps are made of in your neurons and muscle cells. They also make up your enzymes, which are responsible for every chemical reaction in your body.

Proteins are made up of 20 Amino Acids.
So the thousands of unique proteins are based on the sequence of these amino acids

Of the 20 Amino Acids, there are 9 Essential Amino Acids you cannot synthesize in your body and must ingest.