Bio 20 - Macromolecules Notes PDF

Bio 20: Macromolecules You are made of atoms, atoms form molecules, molecules form bigger molecules which form organelles, etc. Biochemistry is the chemistry of life – the study of molecules that build and run living organisms. Living organisms need many different types of molecules...

Bio 20: Macromolecules You are made of atoms, atoms form molecules, molecules form bigger molecules which form organelles, etc. Biochemistry is the chemistry of life – the study of molecules that build and run living organisms. Living organisms need many different types of molecules to build and run properly. These include: o Proteins, carbohydrates, lipids, nucleic acids, vitamins, minerals and hormones. Our focus will be on the macromolecules of carbohydrates, lipids and proteins. They that are mostly made of six main elements: CHONPS – carbon, hydrogen, oxygen, nitrogen, phosphorous and sulfur. Macromolecules Are made of smaller molecules (called monomers) They can be assembled into larger macromolecules (called polymers) by a process called dehydration synthesis. During dehydration synthesis, a new covalent bond forms between the two smaller molecules while an OH (hydroxyl group) and a H (hydrogen) are released from the chemical reaction. The OH and the H form a water (H2O) molecule that is removed from the new molecule. When large macromolecules (or polymers) are disassembled into smaller subunits, it’s called hydrolysis. During hydrolysis, bonds are broken by inserting a split water molecule putting an OH (hydroxyl group) onto one subunit and a H (hydrogen) onto the other subunit.  Carbohydrates Carbohydrates provide short- and long-term energy for living things. It is the body’s most USEABLE source of energy. We can not make carbohydrates but must get them from the food we eat. Carbohydrates are made of carbon, hydrogen and oxygen in a 1 carbon :2 hydrogen :1 oxygen ratio There are two main types of carbohydrate: monosaccharides/disaccharides (simple sugars) and polysaccharides (complex carbohydrates). They are based on the number of sugar units (monomers) they contain. Simple sugars o Monosaccharides – one monomer (C6H12O6). They can be found in a ring form or a chain form and can alternate between them. o Disaccharide – two monomers (C12H22O11). Bonds between the monomer are called glycosidic bonds (formed by dehydration synthesis). Complex carbohydrates o Polysaccharides – three or more monomers ***They all have the same chemical elements in the same amount, but the different arrangements of the elements gives it different properties. Lipids Lipids are large molecules that are all insoluble in water and perform many different functions in living things: o Store energy – they are the BEST source of energy but not the most useable form o Make up cell membranes (phospholipids) o Function as hormones (estrogen and testosterone). o Carriers for many vitamins (A, D, E, and K) in the body o Insulation and cushioning for the body and its organs Triglycerides Made up of glycerol and three fatty acid chains (whose length varies giving it varying properties) Saturated fats are triglycerides that do not contain any double bonds between the carbons in their fatty acid “tails”. o tend to stay solid at room temperature and are referred to as animal fats. o they are harder to breakdown and they accumulate in the blood vessels. Unsaturated fats are triglycerides that do contain some double bonds between the carbons in their fatty acid tails. o Tend to stay liquid at room temperature and are referred to as plant oils. o The double bonds provide a more ”reactive’ spot to breakdown the lipid and therefore they do not stay as is and accumulate in the blood vessels. Phospholipids The “head” and the “tail” of a phospholipid have very different properties. The glycerol phosphate head is hydrophilic which means that it loves water. The fatty acid tails are hydrophobic which means that they hate water. Make up cell membranes (phospholipid bilayer) Steroids lipids with a unique ring structure that serve as both a membrane component (cholesterol) and a chemical signal (hormones). Proteins both structural components (cell organelles, hair, muscles) that make up living organisms and functional molecules (enzymes, antibodies) that run living organisms. Can be used as an energy source, but is neither the primary source nor the best source of energy Amino acids are the subunit monomers of proteins. They have a common structure with a N – C – C “backbone. They differ by the “R group” or by the chemical group that is attached to the middle carbon. There are 20 different R groups/amino acids. 11 can be made by humans, but 9 must be obtained from the food we eat. Can contain sulfur in addition to carbon, nitrogen, hydrogen and oxygen Proteins are formed by linking the different types of amino acid subunits in endless combinations. The links between the amino acid subunits is called a peptide bond. The order of the amino acids is determined by the DNA.  These long chains of thousands of amino acids fold into complex 3D shapes based on the properties of the amino acids. The shapes determine their function. Denaturation – a temporary change in the protein shape when exposed to heat, radiation, pH, etc Coagulation – a permanent change in the shape of a protein Nucleic acids use a chemical code to direct the growth and development of all living things. There are two types of nucleic acids: RNA (ribonucleic acid) and DNA (deoxyribonucleic acid). The only macronutrient that can NOT be used as an energy source Contain phosphorus in addition to carbon, nitrogen (in rings), oxygen and hydrogen. DNA, found in the nucleus, contains genes which hold the information needed to build proteins. When needed, a gene is copied into RNA then transported to the cytoplasm where the proteins are made in the endoplasmic reticulum. The monomers for DNA and RNA are called nucleotides. The monomers for DNA are form bonded base pairs that “stack up” along a sugar phosphate backbone to form a double-stranded helix (twisted ladder). The monomers for RNA form a single-stranded molecule.