Intro to Biochemistry The molecules of life!!

Organic Molecules Each diagram above shows a molecule found in living things (an organic molecule). Each circle in the diagrams is an atom. Atoms combine to make molecules like bricks combine to make a wall, because atoms are smaller than molecules.

Organic vs. Inorganic Molecules Organic molecules are molecules made by organisms All organic molecules are based on carbon atoms Inorganic molecules are made by non-living processes

Natural vs. Synthetic Molecules Natural molecules are found in nature, and they can be either organic (like a leaf) or inorganic (like a rock). Synthetic molecules have been invented by people working in laboratories – they are not found in nature (examples include all the different kinds of plastic and steel)

Why Organic Molecules are Important Organic molecules make up all the parts of cells – so they make up YOUR body! Organic molecules are the main components of all types of food, so you eat them every day! Modern medicine is largely based on enhancing or blocking the actions of organic molecules!

The Role of Carbon Atoms Organic molecules are always based on carbon atoms A carbon atom can bond with as many as 4 other atoms This allows the carbon atoms to form the backbone of many different molecules with many different shapes – and every shape has its own function Possible shapes of organic molecules include chains, rings, double-chains, spirals, and more

Carbon Atoms in Action A Carbon atom bonded to 4 Hydrogen atoms = CH4, which is methane Five Carbon atoms in a chain, with hydrogen sticking off of each side – this is a saturated fatty acid = C5H12 Six Carbon atoms bonded in a ring, along with Oxygen and Hydrogen atoms – this is similar to a sugar molecule = C6H6O4 Notice that C always has 4 bonds, O has 2 bonds, and H has 1 bond Also notice the double bonds in some cases!

Building and Breaking Molecules Monomers Dehydration Synthesis Hydrolysis Polymer

Vocabulary Monomer = a small molecule that is a building block of larger molecules Polymer = a large molecule made of many smaller molecules linked together Dehydration Synthesis = building polymers by removing water from monomers Hydrolysis = breaking down polymers by adding water to separate it into monomers

Four Classes of Organic Compounds Carbohydrates, such as sugars and starch Lipids, such as fats and steroids Proteins, such as insulin, hemoglobin, and enzymes Nucleic acids, such as DNA, RNA, and ATP

Monomers (building blocks) Carbohydrates Example Molecules & Their Functions Monomers (building blocks) Sugars Names always end in “–ose” Always have a ring shape (hexagon with 6 carbons or pentagon with 5 carbons) Sugars such as glucose (most basic sugar), fructose (fruit sugar), lactose (milk sugar), sucrose (table sugar) – their function is to provide quick energy. Starch – a long chain of sugars that stores energy in plants. Found in chips, rice, cereal, etc. Cellulose – a complex chain of sugars that makes up the cell walls of plants. We use it in wood, paper, and cotton.

Simplified Glucose molecule Draw this! Detailed Glucose Molecule C = Carbon H = Hydrogen O = Oxygen Starch Molecule

Monomers (building blocks) Lipids (aka, Fats) Example Molecules & Their Functions Monomers (building blocks) Fatty Acids and Glycerol (sometimes with phosphate) Sterol Rings Saturated Fats & Unsaturated Fats (properly called triglycerides) – their function is to store energy for long time periods. Found in animal fat (sat fat) and vegetable oils (unsat fat). Saturated fats are bad for your heart. Phospholipids – these make up the cell membranes that surround every one of your cells. Steroids such as cholesterol, testosterone, and estrogen – they act as hormones to send signals from one part of the body to another.

Simplified Triglyceride Glycerol 3 Fatty Acid Chains Phosphate “Head” Draw the simplified views! (shown with stars) Fatty Acid “Tails”

Monomers (building blocks) Proteins Example Molecules & Their Functions Monomers (building blocks) Hemoglobin – carries oxygen in our blood. Insulin – controls blood sugar levels. Antibodies – fight disease. Enzymes – control chemical reactions in cells. Actin & Myosin – slide past each other to make muscles contract (this is what you eat in meat!). Collagen – makes up tendons & ligaments & makes skin elastic. Chlorophyll – traps sunlight for photosynthesis in plants. And thousands more!!! Amino Acids – twenty different kinds!

Amino Acid Structure Draw this! C = Carbon H = Hydrogen O = Oxygen N = Nitrogen (R is a variable mix of atoms) Amino Group NH2 Carboxyl Group CO-OH Variable “R” Group 20 Different Kinds

Twenty kinds of amino acids Dozens or hundreds of amino acids join together into long protein chains Amino acids act like letters which can be combined to make many different proteins (like words) The shape of the protein gives its function Draw this! A short protein chain made of 8 amino acids linked together

Actual Proteins Collagen Antibody Insulin

Monomers (building blocks) Nucleic Acids Example Molecules & Their Functions Monomers (building blocks) DNA – carries the genetic code with instructions for building proteins. (double chain twisted into a double helix) RNA – builds the proteins following DNA’s instructions. (single chain – not a helix) ATP – moves energy around the cell. Nucleotides, which have 3 parts: Sugar Phosphate Nitrogen Base (five different kinds)

Nucleic Acids are made of Nucleotides A nucleotide has 3 parts: a sugar, a phosphate, and a nitrogen base Chains of nucleotides make nucleic acids, like DNA Phosphate N-Base Sugar Draw this!

A chain of nucleotides makes a nucleic acid P S NB A chain of nucleotides makes a nucleic acid P S NB Can you see that this is a chain of four nucleotides? Now imagine a mirror image of it on the right side, so it is a double chain, made of eight nucleotides – this would be a short strand of DNA! (Shown on the next slide) Now imagine that DNA strand made of 10,000 or more nucleotides! That’s what is in your cells! P S NB Draw this! P S NB

A double chain of nucleotides makes DNA P S NB P S NB A double chain of nucleotides makes DNA Yep, one side is upside down!

DNA RNA ATP