Introduction to Biochemistry

Biochemistry Chemistry of living organisms. The study of biology at the molecular level.

Elements Make up all matter. 92 occur in nature. Identified by names or chemical symbols (abbreviations of modern or Latin names). Identified by number (based on structure of subunits or atoms). Described and organized in periodic table.

Periodic Table

Atoms Subunits of elements. Smallest complete units of matter. Cannot be broken down or changed by ordinary chemical and physical means. facstaff.gpc.edu

Atomic Structure Nucleus – Positively charged protons. – Neutrally charged neutrons. – Surrounded by negatively charged electrons.

Molecules and Compounds Molecules Formed when two or more atoms unite on the basis of their electron structures Can be made of like atoms or atoms of different elements Compounds Composed of two or more elements

Biomolecules Carbohydrates Lipids Proteins Nucleic acid

Carbohydrates Composed of carbon, hydrogen, and oxygen. Sugars Monosaccharides – Ex. Glucose Disaccharides – Ex. Sucrose Polysaccharides – Ex. Glycogen, Peptidoglycan

Carbohydrate - Glucose

Carbohydrate - Sucrose

Carbohydrate - Peptidoglycan

Carbohydrate - Glycogen

Lipids Fatty Acids – The building blocks of lipids. biology.clc.uc.edu courses.cm.utexas.edu

Lipids Examples are: – Waxes – Fats and oils – Phospholipids – Steroids Phospholipid Cell Membrane.

Proteins Made up of polymers of amino acids. “beads on a string.” 20 primary amino acids exist. A polymer of 3 or more amino acids forms a polypeptide.

Proteins Primary Structure – Linear sequence of amino acids. Secondary Structure – Form helices or sheets due to their structure. Tertiary Structure – A folded protein. Quaternary Structure – 2 or more polypeptide chains bonded together.

Protein Structure

Enzymes Are proteins. Are considered biological catalysts. – Speed up a chemical reaction without being altered. Names often end in “- ase.” – Ex. Lipase, carbohydrase. Act on a substrate. Proteins, including enzymes, can be denatured.

Nucleic Acids DNA and RNA. – (DNA - deoxyribonucleic acid, RNA - ribonucleic acid). Is the “hereditary molecule.” Contains genes that code for a certain product. DNA is translated into RNA which is used to produce a protein or other product.

Nucleic Acid Structure DNA nucleotides – Building blocks of DNA. RNA nucleotides – Building blocks of RNA.

Nucleic Acid Structure DNA – Nitrogenous base – Deoxyribose – Phosphate group RNA – Nitrogenous base – Ribose – Phosphate group

Nitrogenous Bases Adenine (A) Guanine (G) Cytosine (C) Thymine (T) – only DNA Uracil (U) – only RNA DNA and RNA

Nitrogenous Bases A and G – Purines (double- ring structures) C, T, and U – Pyrimidines (single-ring structures) hyperphysics.phy-astr.gsu.edu

DNA Structure Nucleotides bond between sugar and phosphate groups to form long polymers. Double-stranded DNA - The two nucleotide polymers bind at the nitrogenous bases. – Bonding forces cause the double-stranded polymer to form a double helix.

DNA Structure James Watson (left) and Francis Crick (right) discovered the double-helix structure of DNA and its process of replication in the 1950s.

DNA Replication Occurs during cell division. Both strands of the double-helix unwind and replicate a complimentary strand. The parent strand and new daughter strand form a new double-helix. DNA polymerase is one enzyme used in replication process.

DNA Replication – Semiconservative Replication courses.cm.utexas.edu

Gene Expression A gene contains the instructions for making a gene product. The genetic code is based on the sequence of the nitrogenous bases (A, T, C, and G). The gene product is usually a protein but may be different types of RNA.

The Central Dogma Proposed by Francis Crick in Explains the flow of genetic information within a cell. DNA RNAProtein

The Central Dogma 1. Genetic information contained in one gene of DNA molecule is used to make one molecule of mRNA by a process called transcription. – mRNA (messenger RNA) is one of 3 types of RNA used in protein synthesis. 2. The genetic information in the mRNA molecule is used to make a protein in a process called translation.

Transcription The genetic code from the DNA molecule is transcribed to produce an mRNA molecule. trc.ucdavis.edu

Translation The process of translating the mRNA sequence, which directs the proper sequence of amino acids to produce a particular protein or product.

The End