Biology: Macronutrients, Enzyme Kinetics, and Lipoproteins Overview

Proteins

Made of amino acids (nitrogen-containing). Basic structure: An amino group, a carboxyl group, and a unique R-group side chain.

Carbohydrates

Monomers are monosaccharides (like glucose). Basic structure: Carbon, Hydrogen, and Oxygen in a 1:2:1 ratio.

Lipids

Often made of fatty acids and glycerol. Basic structure: Long hydrocarbon chains (non-polar/hydrophobic).

High GI

Simple carbs (white bread, sugar) digest fast, causing a quick glucose spike.

Low GI

Complex carbs with fiber or fats (whole grains, beans) digest slowly.

Factors affecting GI

Fiber content, fat/protein presence (slows emptying), and food processing (more processed = faster digestion).

Maximum Velocity

The point where every enzyme molecule is 'busy' (saturated) with substrate. Adding more substrate won't speed it up.

Michaelis Constant

The substrate concentration at which the reaction is at half of maximum velocity.

Lower Michaelis Constant

Indicates enzyme has high affinity for substrate (works well even at low amounts).

Competitive inhibitors

Increase Michaelis Constant (you need more substrate to reach half speed).

Non-competitive inhibitors

Decrease maximum velocity.

Proteinuria

Protein in the urine; usually indicates kidney damage (the 'filter' is leaking).

Iodine Indicator

Specifically tests for starch.

Positive Iodine Test

Blue/Black color.

Reaction finished (Iodine Test)

When the blue color disappears/stops forming, it means the enzyme (amylase) has successfully broken all starch down into maltose/glucose.

Lipoproteins

The 'Cholesterol' Carriers.

Order of Lipoproteins by Density

VLDL < IDL < LDL < HDL.

LDL

Low-Density: 'Bad.' Carries cholesterol to the tissues. High levels lead to plaque.

HDL

High-Density: 'Good.' Carries cholesterol away from tissues to the liver for disposal.

Liquid Conversions

There are 1,000,000 microliters in 1 liter.

Nitrogen Calculation Formula

Most proteins are approximately 16% nitrogen. If you know the nitrogen weight, multiplying by 6.25 gives you the total protein weight.

Standard Curve

Uses known concentrations to find a 'factor' or an equation.

Concentration Formula Logic

Finding the ratio of how 'dark' your sample is compared to a known standard and multiplying by that standard's value.