Biochemistry: Carbohydrates

• Term 2 focuses on biology topics, including:
• Biochemistry, microbiology, and cell biology
• An online quiz at the end of term 2 is required

Biochemistry

• Biochemistry focuses on carbohydrates, lipids/fats, amino acids/proteins, and nucleic acids (DNA/RNA)
• The lesson will address the types and usage of carbohydrates
• It will also address polysaccharide formation from monosaccharides via dehydration and Glycosidic bonds

Carbohydrates

• Carbohydrates serve as energy sources and structural components of cell walls in plants and prokaryotes
• Examples: glucose, fructose, sucrose, cellulose, and starch
• The general molecular formula for carbs is (CH₂O)n, where n ≥ 3
• Some contain nitrogen, phosphorus, or sulfur
• Monosaccharides (monomers) are the simplest carbs, with glucose being the most common and containing six carbons
• Glucose is found in fruits, vegetables, corn syrup, and honey
• Disaccharides are made up of two monosaccharides
• Sucrose (table sugar): glucose and fructose
• Maltose (malt sugar): two glucose monomers
• Lactose (milk sugar): galactose and glucose
• Polysaccharides are made of hundreds/thousands of monosaccharides linked by dehydration reactions via glycosidic bonds
• Starch and cellulose are the most abundant, made by plants
• Starch serves as a storage polysaccharide in plants
• When a plant needs energy/carbon, it can hydrolyze (add water) some of its stored starch to release glucose as fuel

Lipids

• Biochemistry Part 2 will identify the three lipid types, describe their functions, discuss fat formation via dehydration, and describe saturated vs. unsaturated fatty acids
• Lipids include biological compounds not soluble in water but soluble in organic solvents like methanol/ethanol
• Examples: fats, oils, some vitamins, and hormones
• Lipids, like carbohydrates, mainly consist of carbon, hydrogen, and oxygen atoms linked by covalent bonds
• Lipids release large amounts of energy upon breakdown
• Three types:
• Fats and oils (principal stored forms of energy)
• Phospholipids
• Sterols
• Fats contain three fatty acid molecules attached to the three hydroxyl groups of a glycerol molecule
• Glycerol and fatty acids undergo dehydration to form fats
• Animal fats contain more saturated fatty acids and are waxy/solid at room temperature
• Vegetable oils contain more unsaturated fatty acids and are liquids at room temperature
• Healthy fats include omega, polyunsaturated, and monounsaturated fats (help lower total cholesterol)
• Unhealthy fats include trans and saturated fats
• Trans fats raise LDL ("bad") cholesterol, lower HDL ("good") cholesterol, and increase the risk of heart disease

Proteins

• Biochemistry, part 3 will describe the overall structure of an amino acid and examine the 20 structures of the 5 different R groups
• The lesson will also address how peptide bonds (amide linkage) link amino acid residues in a polypeptide chain
• It will distinguish between primary, secondary, tertiary, and quaternary protein structures
• Proteins are abundant biological macromolecules in cells and perform many enzymatic functions, structural functions, and other roles
• They are polymers of amino acids
• There are 20 amino acids, differentiated by their R group
• Glycine is the simplest amino acid
• All common amino acids (except proline) have a hydrogen, amino group, and carboxyl group bonded to the central carbon atom
• Amino acids are classified into five main classes:
• Non-polar and aliphatic R groups
• Aromatic R groups
• Polar but uncharged R groups
• Negatively charged R groups
• Positively charged R groups
• Peptide bonds are formed through a dehydration reaction
• Polypeptide chains are polymers of amino acids linked by peptide bonds (amide linkage)
• The linear amino acid sequence in a polypeptide chain linked by covalent peptide bonds (including disulfide bonds)
• Secondary protein structure arises from regular folding patterns of adjacent amino acid residues stabilized by hydrogen bonds
• Tertiary protein structure refers to the 3-D shape formed by interactions between R groups
• Quaternary structure involves the arrangement of two or more polypeptide chains into a multi-subunit molecule (e.g., hemoglobin)

Nucleic Acids

• Biochemistry part 4 focuses on identifying the two different types of nucleic acid and their differences
• The lesson will also describe the overall structure of nucleotides
• the nitrogenous bases present in DNA and RNA
• It will identify complementary pairing in DNA and how the double helix structure in DNA is stabilized
• DNA and RNA are the two types of nucleic acids and are crucial molecules in cell biology for storing/reading genetic information
• They differ in structure and function
• DNA stores genetic information: a blueprint
• RNA converts DNA's genetic information to build proteins and moves it to ribosomal protein factories
• Nucleic acids are linear polymers
• DNA is deoxyribonucleic acid
• RNA is ribonucleic acid
• Nucleotides link into nucleic acids
• A nucleotide consists of:
• A pentose sugar (5-carbon sugar)
• a phosphate group
• a nitrogenous base (purine or pyrimidine)
• Four possible nitrogenous bases in DNA and RNA
• DNA: adenine (A), guanine (G), thymine (T), cytosine (C)
• RNA: adenine (A), guanine (G), uracil (U), cytosine (C)
• Purines consist of a two cyclic structure
• Adenine and Guanine
• Pyrimidines consist of one cyclic structure: Cytosine, Thymine, and Uracil
• There are 3 RNA types:
• Messenger RNA (mRNA): copies genetic code (transcription) and transports these copies to ribosomes
• Ribosomal RNA (rRNA): a component of the ribosome factory needed for protein production
• Transfer RNA (tRNA): brings amino acids to the protein factories in response to mRNA instructions
• A double helix shape of DNA whereas RNA is a single polynucleotide chain
• A double helix structure of DNA is stabilized by hydrogen bonding
• A segment is an area of DNA segment that contains information to synthesis the function biological products
• A gene contains hundreds/thousands of nucleotides in a specific sequence
• Genes control the sequence of amino acids, controlling protein synthesis
• A codon is a sequence of three DNA or RNA nucleotides that corresponds with a specific amino acid for start and stop signals during protein synthesis
• The genetic code has "words" known as codons
• It is a sequence of three DNA or RNA nucleotides
• 61 of 64 codons code for amino acids used to make proteins
• A DNA can translate into a protein syntheses
• E.g, sequence ATGACGGAG codes for the amino acids methionine (Met), threonine (Thr) and glutamic acid (Glu)

This resource explores the world of carbohydrates. It's designed to help explain their role as energy sources and structural components in plants and prokaryotes, specifically focusing on monosaccharides, disaccharides, and polysaccharides.