There are four types of biological macromolecules Carbohydrates Lipids Proteins Nucleic acids

lipids are mainly made up of what elements?

Most lipids are hydrophobic.. What does that mean? Easy demo

What Are Lipids? All lipids contain large chains of nonpolar hydrocarbons (chains of carbon and hydrogen) Most lipids are therefore hydrophobic and water insoluble

What Are Lipids? Diverse in structure Do not form polymers

Types of Lipids Triglycerides Waxes Phospholipids Sterols

Triglycerides Fats and oils used for long-term energy storage – 38 KJ of energy per gram (2X carbs) Slower to build up and break down than carbs

Triglycerides Formed by condensation reactions 3 fatty acids + glycerol  triglyceride

A fatty acid is a long chain of mostly carbon and hydrogen atoms with a COOH group (“carboxyl”) at one end.

Saturated Fatty Acid Have mostly single C-C bonds in the fatty acid chains Are typically solid at room Temperature Are often from animal sources Draw saturated example

Unsaturated Fatty Acids Have one or more C=C double bond in the fatty acid chain Are typically liquid at room temperature, because kinks in the tails prevent tight Packing Are often from plant sources

The American Heart Association recommends eating fish (particularly fatty fish) at least two times (two servings) a week. Each serving is 3.5 ounce cooked, or about ¾ cup of flaked fish. Fatty fish like salmon, mackerel, herring, lake trout, sardines and albacore tuna are high in omega-3 fatty acids.

Saturated or unsaturated?

Saturated

Saturated or unsaturated?

unsaturated

On your personal white boards Draw the molecule. Indicate if it is saturated, unsaturated or polyunsaturated… circle the area that justifies your answer

Question: saturated, unsaturated or polyunsaturated?

Saturated- As many hydrogens as possible

Question: saturated, unsaturated or polyunsaturated?

Unsaturated- double bond prevents hydrogen from taking the spot

Question: saturated, unsaturated or polyunsaturated?

Polyunsaturated- two double bonds

Question: Unsaturated fatty acid is CIS or TRANS?

Unsaturated fatty acid (cis double bond)

Question: Unsaturated fatty acid is CIS or TRANS?

Unsaturated fatty acid (trans double bond)

Phospholipids Formed by attachment of two fatty acids plus a phosphate group to a glycerol. Are the main structural components of membranes.

Phospholipids Hydrophobic AND hydrophilic Fatty acid tails= hydrophobic “water-fearing” PO4 head = hydrophilic “water- loving Interaction with water is complex & very important

Phospholipids in water can self-assemble into: – bubbles = “micelle” – can form a bilayer – early evolutionary stage of cells?

Why is this important? Phospholipids create a barrier in water -define outside vs. inside -they make cell membranes!

Review Slides

Lipids: are made from a condensation reaction between a glycerol and three fatty acids.

A lipid with only single bonds in the carbon chain is “saturated” A lipid with a double bond in the carbon chain is “unsaturated” A lipid with only single bonds in the carbon chain is “saturated”

Polyunsaturated lipids have many double bonds.

Lipids are formed during a condensation reaction between one glycerol and one, two or three fatty acids. Lipids are broken down by hydrolysis

Functions of Lipids: 1. Energy storage (lipids have twice the energy as the same mass of proteins or carbohydrates)

2. Thermal insulation (subcutaneous fat keeps animals warm)

3. Lipids are the main component of cell membranes (phospholipid bilayer)

As food is broken down, it is converted into simple sugars for immediate use. In Animals Some is stored as glycogen in the liver (this energy is used between one meal and another). All other energy is stored as lipids because it is more efficient (carries more energy in less weight)

In plants Store most energy as carbohydrates(ie carrots, potatoes) because plants don’t move. The only plant lipids are stored in seeds (sunflower oil) where weight is an issue.