CH 3 Molecules of Life Can you identify any of the molecules in the picture? By the end of this PowerPoint, you should be able to identify them.

Molecules and popbeads! How do you make a long strand of popbeads? How do you think this relates to creating macromolecules (large molecules)?

Anabolism Anabolism is the synthesis of complex molecules from simpler molecules. Monomer-a molecule that can bond to other molecules to form a polymer. A monomer is the repeating subunit of a polymer Polymer-a larger molecule made of many monomers

Analogy: The individual popbeads are the __________ The connected string of popbeads is the _____________ monomers polymer

Molecules and popbeads! How do you break down a long strand of popbeads? How do you think this relates to breaking down macromolecules?

Catabolism Catabolism is the breakdown of complex molecules into simpler molecules. In other words, breaking a polymer down into monomers.

Biosynthesis/Anabolism Catabolism Catabolism = the breakdown of larger molecules into smaller molecules (polymers into monomers) Anabolism = smaller molecules are used to build larger molecules Catabolism and Anabolism are both components of metabolism. Biosynthesis/Anabolism

Put the popbeads away!

Different ways to illustrate molecules When you draw molecules, you will use the model on the left. Solid lines are drawn between symbols for different elements to depict covalent bonds. A double line would depict a double covalent bond. Methane is composed of a carbon atom, which is bonded to four different hydrogen atoms with single covalent bonds. When we build molecules, they will look like the model in the middle. You will sometimes see the space-filling model used to portray molecules, which is similar to the ball and stick model. Some important rules to follow when drawing and building biological molecules: Carbon bonds four times (this is why it is bonded to four hydrogens in the methane molecule above). Hydrogen bonds once. Oxygen (not pictured above) bonds twice. Nitrogen (not pictured above) can bond two or three times. (note: these rules are based on the chemical properties of these elements. Review valence electrons and chemical bonding) structural formula for methane ball-and-stick model space-filling model

ball-and stick model for the linear structure of glucose The brown color balls represent carbon atoms. The red color balls represent oxygen atoms. The silver color balls represent hydrogen atoms. How many of each do you count? This is glucose in its linear form. You will learn how to build glucose in its ring form. ball-and stick model for the linear structure of glucose

six-carbon ring structure of glucose that usually forms inside cells Glucose in its ring form. six-carbon ring structure of glucose that usually forms inside cells

#Mustmemorize Practice drawing glucose using this picture as a model. When completing your drawing, go back and count the number of bonds between all atoms. All carbons should be bonded 4 times. All oxygen should be bonded twice. All hydrogens should be bonded only once.

Molecular Bonding Rules What are some patterns that you noticed in the previous molecule? Are there any rules we can follow?

General bonding guidelines Carbon forms 4 covalent bonds. This allows for a diversity of stable structures to exist. Oxygen forms 2 covalent bonds. Hydrogen forms 1 covalent bond.

Molecule Modeling Kits These kits allow us to model molecular structure. They are fun and helpful for learning. They are NOT TOYS, and they are VERY EXPENSIVE. Treat them with respect at all times. No throwing Your kit must be returned exactly as you found it, with the same number of everything in the same place

Failure to follow these guidelines will result in immediate loss of modeling kit privileges.

Look at your modeling kits! What color do you think represents a carbon atom? What color do you think represents a hydrogen atom? What color do you think represents an oxygen atom? How do you show a single bond? How do you show a double bond?

Let’s practice! I’ll show you a molecule, you build it!

Water

Ethanol This is the same molecule, but the drawing on the right gives us more information about the 3d structure

Valine How do we interpret this way of diagraming a molecule?

Glucose

Or…..glucose

Ethanol

Reaction Catalyzed by an Enzyme Most complex biological molecules are synthesized BY CELLS during anabolic metabolism (anabolism) by way of condensation reactions (i.e. dehydration synthesis) Reaction Catalyzed by an Enzyme This image is showing a anabolic (building up) reaction. When smaller molecules (monomers) are combined to make larger molecules, water is released as a byproduct. This is why it is called a condensation reaction (also called dehydration synthesis). The chemical evolution of hydroxyl groups was a huge step toward the evolution of life. Why?

Condensation Reactions Show me a condensation reaction with your ethanol molecules Could we connect more than two ethanol molecules this way?

Reaction Catalyzed by an Enzyme Most complex biological molecules are broken down BY CELLS during catabolic metabolism (catabolism) by way of hydrolysis reactions During the evolution of molecular complexity, before the evolution of the first protocells, the appearance of the hydroxyl functional group allowed small molecules (monomers) to combine into larger molecules (polymers).   Reaction Catalyzed by an Enzyme The image is showing the breakdown (catabolism) of a larger molecule into smaller molecules. Water (in blue) is added in order for this reaction to occur. This is why it is called a hydrolysis reaction. (hydro=water). The molecules are drawn in abbreviated form.

Hydrolysis Reactions Show me a hydrolysis reaction with your ethanol molecules

Create a monomer! Create a simple monomer that could undergo many condensation reactions. Build 3 copies of the monomer. Connect them all together with condensation reactions and show me your resulting polymer, along with all the water molecules created in the process.

Functional Groups: groups of atoms that give the molecules to which they are attached specific characteristics and functions. #Mustmemorize Functional groups are not molecules by themselves. They are parts of larger molecules. Functional groups have certain properties (acidic, polar, etc), which they impart to the molecules they are a part of.

Functional Groups: groups of atoms that give the molecules to which they are attached specific characteristics and functions. More functional groups. Notice that both the carboxyl group (on the previous slide) and the amine group can occur in ionized form, which often occurs when dissolved in water (such as in our cells).

Clean up!