Carbon-Based Molecules Part 1

Biochemistry

Objectives

• SWBAT describe the bonding properties of carbon atoms.

• SWBAT compare carbohydrates, lipids, proteins, and nucleic acids.

Starter

• We have talked about carbon based molecules in other units. I want you to take a couple of minutes and make a list of the carbon based compounds we have touched on in this class or you have heard about in other places.– You may work in groups.

Vocabulary for Unit 2.3 (P. 44)• Monomer• Polymer• Carbohydrate• Monosaccharide• Polysaccharide• Starch• Cellulose• glycogen• Lipid• Fatty acid• Protein• Amino acid• Nucleic acid

Carbon: Building Blocks of Life

• Carbon atoms are the basis of most molecules making up living things. – They form the structure of living things.– Carry out most of the processes that keep

organisms alive. – Carbon atoms have special bonding properties,

due to its atomic structure, which are unique among elements.

Carbon: Building Blocks of Life

– Carbon atom has four unpaired electrons in its outer energy level – allowing it to form covalent bonds with up to four other atoms (including other carbon atoms).

Carbon: Building Blocks of Life

• Because Carbon can form four other covalent bonds, it can form large molecules (long chains and rings).

Hydrocarbons are classified based on how many carbons strung together

How Cleanly a hydrocarbon burns is based on the length of the carbon chain. Fewer carbons equals cleaner burning.

Quick Question

• Why is methane considered clean burning (when it burns, what does it produce)?

Carbon Chains and Rings

• Carbon-based molecules have 3 fundamental structures (creating a lot of flexibility):1. Straight chains (Pentene)

2. Branched chains (Iso-butane)

Carbon Chains and Rings

– Rings (Vanillin and Hexane ring)

• To reiterate, the bonding flexibility is due to the carbon’s ability to enter into up to 4 covalent bonds at the same time – forming large molecules

Links in a chain

• Large carbon molecules are made out of many smaller ones linked together.

Links are called monomers, the chains are polymers.

• Each link, a smaller molecule, is known as a monomer (mono means one).

• Monomers linked together form a polymer (a molecule that contains many monomers bonded together.

Links are called monomers, the chains are polymers.

Question to check understanding

• What is the difference between a monomer and a polymer?

Carbohydrates

• The word carbohydrate literally means “watered carbon.”

• Do you remember the chemical formula for glucose? How does that remind us of the formula for water?

• C6H12O6

Carbohydrate Definition

• Molecules composed of carbon, hydrogen, and oxygen – they are polymers of glucose. – They include sugars and starches.

• Carbohydrates can be broken down to provide a source of usable chemical energy for cells.

• They are a major part of plant cell structure (our producers).

Glucose – simple sugar

• The most basic carbohydrates are simple sugars. – Glucose is a simple sugar (it contains six carbons

and is called a monosaccharide).

Simple sugars can be bonded together

• Quick Test: When is glucose made?• Answer - photosynthesis

• Glucose molecules can be bonded to one another to make larger carbohydrates called polysaccharides. This is glucose

linked as polysaccharides.

Connecting a concept

• Glucose is a monosaccharide – this makes it a what?

• Answer – a monomer• A chain of glucose is a polysaccharide – so, a

chain of glucose monomers makes a . . .• Polymer – a polymer is known as a

macromolecule.

So . . .

• Multiple monosaccharides (monomers) linked together form polysaccharides (polymers).

• Examples:

This is a disaccharide known as table sugar

Starch (storage and source of energy in plants), glycogen (storage and energy source in animals, and cellulose (for plant structure), are polysaccharides

Cellulose, Starch, and Glycogen

• Cellulose is a rigid, straight polymer which makes up the cell walls of plants.– it is tough and fibrous (a good source of your fiber).

• Starch – made and stored by plants and can be broken down for energy by both plants and animals.

• Glycogen – made and stored in animals is highly branched but essentially does the same thing in animals that starch does in plants.

Interesting Fact

• Few animals have enzymes that allow them to hydrolyze cellulose.

• Primary consumers (cows, pigs, goats, deer, termites, etc.), however, are able to use cellulose for nutrients because of protists and bacteria living in their guts.

• Cellulose is the most abundant organic molecule on Earth.

Entrance Ticket for Next Time

• What elements make up a carbohydrate?

• Explain how the bonding properties of carbon atoms result in the large variety of carbon-based molecules in living things?