Biomolecules & Central Dogma of Life PDF

## Biomolecules and the Central Dogma of Life ### Bromolecules & the Central Dogma of Life * Fatty acids make up lipids. * Biomolecules are molecules that occur naturally in living organisms. They also include small molecules that take part in maintenance & metabolic processes. These are usually...

## Biomolecules and the Central Dogma of Life ### Bromolecules & the Central Dogma of Life * Fatty acids make up lipids. * Biomolecules are molecules that occur naturally in living organisms. They also include small molecules that take part in maintenance & metabolic processes. These are usually obtained from food. ### All Biomolecules Contain Carbon * Carbon is the most versatile & prominent element in functions of life. Other elements include: Hydrogen, Oxygen, Nitrogen, Sulfur, Sodium, Calcium & Magnesium. ### Levels of organization * **Atoms** - **Molecules** - **Macromolecules** * Macromolecules are large molecules composed of thousands of covalently connected atoms. ### Functions of Biomolecules * **Carbohydrates:** are the body's main source of energy. This allows us to survive when carbohydrates are not being supplied to the body. * **Lipids:** Provide stored energy reserves * **Protein:** Helps us to stay strong by forming new bones, muscles & helping us fight diseases * **Nucleic Acids:** are responsible for making each person functional & unique. They are the blueprint for genetic structure. ### Making or Breaking of Macromolecules * Macromolecules are polymers built from monomers. * A polymer is a long molecule consisting of many similar building blocks known as monomers. ### The 4 Classes of Life's Organic Molecules * **Carbohydrates** * **Lipids** * **Proteins** * **Nucleic Acids** **Dehydration reaction occurs when 2 monomers join together, The loss of a water molecule condenses them.** **Conversely, polymers are disassembled to monomers by hydrolysis, a reaction that's essentially the reverse of dehydration rxn.** ### Making of Macromolecules/Polymers * A Glucose molecule (monomers) can bond to form a dimer (2 monomers) such as maltose. ### Breaking of Macromolecules: Hydrolysis * This is where a dimer such as maltose or any polymer can be broken apart into its constituent monomer. ### Polymers * Macromolecules are made of polymers, which are made of smaller, repeating parts called monomers. * **Carbohydrates (polymer)** * **Monosaccharides** are the monomers for carbohydrates. They are joined by **glycosidic** bonds. * **Proteins (polymer)** * **Amino Acids** are the monomers for proteins (polypeptides) joined by **peptide** bonds. * **Nucleic Acids (polymer)** * **Nucleotides** are the monomers for nucleic acids joined by **phosphodiester** bonds. * **Lipids** are not considered polymers. They have no monomers. ### Carbohydrates * Carbohydrates (polysaccharides) are long chains of sugar. * **General formula:** (CH₂O)n * **Monosaccharides:** are simple sugars that are composed of 3-7 carbon atoms. They have a free aldehyde (aldases) or ketone (Ketoses) group which acts as reducing agents. This refers to them as reducing sugars. * Building blocks composed of Carbon, Hydrogen & Oxygen in a 1:2:1 ratio. * Monosaccharides are the monomers e.g. glucose, galactose & fructose. ### Functions: * **Main source of energy for living things.** (monosaccharides) * **Energy storage:** (polysaccharides) - glycogen in animals, starch in plants. * **Structural:** to build cell wall (cellulose - plants), chitin - fungi). ### Oligosaccharides * They are formed by condensation of 2-9 monosaccharide units. These units are joined with the help of specialized glycosidic bonds. * Examples of oligosaccharides: * **Disaccharides**: e.g. Lactose, maltose & sucrose * **Trisaccharides**: e.g. Raffinose * **Tetra saccharides**: e.g. Stachyose, sesamin ### B. Lipids * They are hydrophobic (water fearing & don't dissolve in water). * **Saturated bonds:** the carbons are single bonded. * **Solid at room temperature:** mainly fats. * **Clog arteries (bad)**: e.g. of saturated lipids: stearic acid, palmitic acid, butyric acid. * **Unsaturated:** They have at least one double bond between carbons present. * **Liquid at room temperature:** mainly plant based fats. * **Lower blood pressure (good)** * **Eg of Unsaturated Lipids:** Linolenic acid, oleic acid, arachidonic acid, linoleic acid. ### Building Block of Lipids * They are mostly made from carbon & hydrogen atoms. * Some Oxygen. ### Components: * A fat molecule consists of 3 fatty acids joined to a molecule of glycerol. * Phospholipids in cell membranes are made of a phosphate group & 2 fatty acid chains ### Function & examples: * **Long term energy storage molecules (fat)** * **Cell membrane of organisms:** (phospholipids) * **Steroid hormones as chemical signals.** (testosterone/estrogen) ### Phospholipids * Major lipid related molecule. * Major component of cell structure, membrane * One fatty acid is replaced by a polar phosphate group, which creates: * **hydrophilic head region** * **hydrophobic tail region** ### Proteins * **Peptide bonds:** formed between amino acids. * **Polypeptide:** many peptide bonds = protein. * Proteins are very large molecules made of carbon, hydrogen, oxygen, nitrogen & sometimes sulfur. * **Protein molecules are made up of smaller molecules called Amino Acids**. ### Protein Structure (Note: The diagram: to identify structure): * **Primary:** The linear sequence of amino acids linked together by peptide bonds. * **Secondary:** Polypeptide folding into an alpha helix or beta sheet arrangement. * **Tertiary:** 3D folding of a single polypeptide. * **Quaternary:** Association of two or more folded polypeptides to form a multi-meric protein. ### Nucleic Acids * Are molecules that store info for cellular growth & reproduction. * **Elements:** C, H, N, O, P. * **Two types of nucleic acid:** deoxyribonucleic acid (DNA) & ribonucleic acid (RNA) * These are polymers consisting of long chains of monomers called nucleotides. * A nucleotide consists of a nitrogenous base, a pentose sugar & a phosphate group. ### Pentose Sugar * There are two related pentose sugars: * **RNA** contains *ribose* * **DNA** contains *deoxyribose* * The sugars have four carbon atoms, numbered with primes to distinguish them from the nitrogenous base. ### Structure of RNA/DNA * Three components: Phosphate group, Pentose group & nitrogenous base. **Note:** What differentiates RNA from DNA is what's attached to carbon 2. If it's OH it's RNA. If it's H it's DNA. * **Nitrogenous Base:** A, G, C & Thymine (in DNA), Uracil (in RNA) * **Purines:** e.g. Adenine & Guanine * **Pyrimidines:** e.g. Cytosine, Thymine (in DNA), Uracil (in RNA) * **Mnemonic:** Agree to Purify a CUTE Pyramid.?? ### Structure of DNA * **Watson & Crick (1953)** determined the 3-D structure. * They realized that DNA is a double helix that's made up of a sugar phosphate backbone on the outside, with bases on the inside. * They built it on the work of Rosalind Franklin's X-ray images. * **Erwin Chargogg:** Suggested that DNA was.a double helix of even width. * Chargogg's rules stated that A=T & G=C. * Adenine - Thymine * Guanine - Cytosine. * **Chargogg's rule for relative estimation of the 4 dyme nucleotides** * The rule states the amount of adenine in the DNA of a cell going to be equal to the amount of thymine in the same cell. It also states the amount of cytosine in the DNA of a cell going to be equal to the amount of guanine in the same cell. * (A+T = G+C) ### Structures By DNA - * Nucleotides always pair in the same way. * The base pairing rules show how nucleotides always pair up in DNA, * A pairs with T. * G pairs with C. * Because a purine (Single ring) pairs with a purine (double ring). The helix has a uniform width. **Note:** Covalent bonds between atoms that form the backbone. In DNA, A pours with T because DNA doesn't have T. The backbone is connected by covalent bonds & hydrogen bases. **Formation of phosphodiester bonds**. * The carbon 5' of pentose sugar is prime to differentiate from the phosphate structures. * When a nucleotide wants to join to B - the 5' of the incoming nucleotide pours up under no. 3' of B. * This is known as The phosphodiester bonds . ### RNA vs. DNA * RNA is a messenger that allows the instructions from DNA to be delivered to the rest of the cell. * DNA -> RNA -> Protein. * RNA is different from DNA in that: * **The sugar:** in RNA is ribose, the sugar in DNA is deoxyribose. * **RNA is a single strand of nucleotides & DNA is a double strand**. * **RNA is found inside & outside of the nucleus whereas DNA is only found inside the nucleus.** * **Nitrogenous base in RNA:** GC, AU. * **Nitrogenous base in DNA:** GA, CT. ### A general diagram of life, NEXT. ### Central Dogma * The Central Dogma words that genetic information is expressed in a scientific order from DNA to protein synthesis. ### DNA Replication * **is The process of making copies of DNA**. * A single strand of DNA serves as a template for a new strand. * The rules of base pairing direct replication. * DNA is replicated during the 'S' (synthesis) stage of the cell cycle. * Each body cell gets a complete set of identical DNA. ### Models of DNA Replication * There are 3: * **Semiconservative:** Each daughter has one parental & one new strand. * **Conservative:** 2 parent strands stay together. * **Dispersive:** DNA is fragmented, both new & old DNA coexist in the same strand. ### Semiconservative replication * The process of DNA replication is called semiconservative replication. This means that in each new daughter helix of DNA, one strand was from the parent. * **Mesel**