Lesson 5.4 Nucleic Acids PDF

Lesson 5.4 Nucleic Acids - A *house or any building* has a blueprint that defines or determines all of its construction specifications. - This ***blueprint*** is important because it includes layouts, materials, dimensions, and methods of construction. - Likewise, each cell in our b...

Lesson 5.4 Nucleic Acids - A *house or any building* has a blueprint that defines or determines all of its construction specifications. - This ***blueprint*** is important because it includes layouts, materials, dimensions, and methods of construction. - Likewise, each cell in our body also houses our own **\"blueprint.\"** This biomolecule, which is in the *[form of nucleic acid]*, **stores our genetic information** and **encodes all the information needed for protein synthesis.** **Overview of Nucleic Acids** **Nucleic Acids** 1. Found in nucleus or nucleoid 2. Store and transmit genetic information 3. [Two types]: Dna and rna **Structure of Nucleic Acids** **General Nucleotide Structure** - ***Nucleotides*** are the monomers of nucleic acids. - These are made up of a ***5-carbon*** sugar, a phosphate, and a base. **Basic nucleotide structure** **Components of Nucleotides** 1. Base 2. 5-Carbon Sugar 3. Phosphate Group **5-Carbon Sugar**  Pentoses or five-carbon sugars are present in DNA and RNA nucleotides. **Bases** - The ***nitrogenous bases in DNA and RNA*** can be *classified into* **[pyrimidines] with a single carbon-nitrogen ring**, while the [ **purines**] contain **two fused carbon-nitrogen rings.** **Bonds** - **Nucleotides and nucleosides** have *different types* of **[chemical bonds.]** - **Nucleosides** in cells are complexes of a ***5-C sugar*** and a ***nitrogenous base.***  ***Nucleosides*** **NUCLEOSIDES AND BONDS WITHIN NUCLEOTIDES** The ***bonds within a nucleotide*** include the **glycosidic bond and ester bond.** **Phosphodiester Linkages**  - **Nucleotides** in a *[polynucleotide]* are ***held together in phosphodiester linkages.*** Organization of Nucleotides in DNA - The **[sugar-phosphate backbone]** is a *structural feature of DNA* that is bound by repeating phosphodiester linkages. - This **backbone** gives the **DNA its negative charge.** Complementary Base Pairing - *DNA strands* are **linked by hydrogen bonds**. - A pairs with T, while - G pairs with C.  *The bases in DNA have specific pairings.* The Helical and Antiparallel Nature of DNA - The ***antiparallel nature of the DNA molecule*** is essential to the synthesis of new DNA molecules and complementary RNA molecules required for gene expression. **Differences Between DNA and RNA** ***[Organization of Nucleotides in RNA]*** - DNA and RNA ***differ in terms of*** the ***number of:*** 1. **S**trands, 2. **S**ugars, and 3. **B**ases.  *DNA and RNA structure* Summary of the differences between DNA and RNA  **Functions of Nucleotides and Nucleic Acids** ***[Roles of Nucleotides]*** 1. **I**nvolved in metabolic activities 2. **R**egulate enzymatic reactions 3. **S**tore large amounts of energy (ATP) **Roles of Nucleotides** - **Hydrolyzing the ester bond** in the *last phosphate group of adenosine triphosphate* - Releases a large amount of free energy that ***can be used to drive many cellular processes*** necessary for the maintenance and survival of organisms. **Roles of DNA Molecules** 1. **S**torage of Genetic Information 2. **E**xpression of Genetic Information 3. **A**bility to be replicated 4. **V**ariation through mutation **Roles of RNA Molecules** 1. **U**se protein-coding information of dna 2. **P**rotein synthesis 3. **R**na production 4. **M**rNA, tRNA, rRNA Metabolic Processes Involving Nucleic Acids ***[Nucleic Acid Degradation and Salvage Pathways ]***  - ***Nucleic acid catabolism*** (blue) and resynthesis of nucleotides by ***salvage pathways*** (red) always go together. - ***Nucleic Acid Degradation*** and ***Salvage Pathways*** **STEP 1** - Digestion in the small intestine ***through endonuclease enzymes*** **STEP 2** - Phospho-diesterases ***digest oligonucleotides.*** **STEP 3** - **Nucleotides** are *hydrolyzed through nucleotidases.* **STEP 4** - ***Nucleoside phosphorylase*** breaks down nucleosides. **A Summary Of The Steps Of The Degradation Of Nucleic Acids**  Nucleic Acid Degradation And Salvage Pathways **STEP 5** - **Reversible reaction** of the *nucleoside phosphorylase* **STEP 6** - *Nucleoside phosphorylation* through **[ATP ]** **STEP 7** - *Further degraded into uric acid* or beta-ureidopropionate Summary of the steps in the first step of salvage pathway of nucleic acid synthesis **Alternative Salvage Pathways**  - The **ribose-5-phosphate** will be ***activated into phosphoribosyl pyrophosphate***, - Which will be the **key intermediate in the biosynthesis of purines** and **pyrimidines.** Biosynthesis of Purine and Pyrimidine Nucleotides - ***De novo*** and ***salvage*** ***means*** are *available for purine and pyrimidine synthesis*. **COMPARISON OF PURINE AND PYRIMIDINE BIOSYNTHESIS** +-----------------------+-----------------------+-----------------------+ | **PARAMETERS** | **PURINE | **PYRIMIDINE | | | BIOSYNTHESIS** | BIOSYNTHESIS** | +-----------------------+-----------------------+-----------------------+ | ***Common precursors | Phosphoribosyl | Uridine monophosphate | | for the bases*** | pyrophosphate for | (from PRPP) for | | | both guanine and | uracil, cytosine, and | | | adenine | thymine | +-----------------------+-----------------------+-----------------------+ | ***Pattern*** | Starts as nucleotide | Starts as a base | | | before becoming | (orotate first before | | | individual bases | becoming nucleotides | +-----------------------+-----------------------+-----------------------+ | ***Nucleotide | Adenosine | Uridine triphosphate | | products*** | monophosphate | | | | | Cytidine triphosphate | | | Guanosine | | | | monophosphate | Thymidine | | | | triphosphate | +-----------------------+-----------------------+-----------------------+ | ***Corresponding base | Adenine, Guanine | Uracil, Cytosine, | | products*** | | Thymine | +-----------------------+-----------------------+-----------------------+ - ***Purine catabolism*** \-\-\-\-\-\-\-\-\--\> uric acid - ***Pyrimidine catabolism*** \-\-\-\-\-\-\-\-\-\-\--\> beta-alanine, ammonia, and carbon dioxide. ***Identify the term being described by the following statements.*** 1. This reaction links nucleotide monomers into long chains. 2. This special nucleotide is considered a high-energy molecule. 3. This type of bond holds together the nitrogenous bases of the two strands of DNA. **Write true if the statement is correct and false if it is otherwise.** 1. Nucleotides that consist of two nitrogen-carbon rings are called purines. 2. The three phosphate groups of nucleotides are directly attached to both the sugar and the base. 3. DNA molecules consist of two polynucleotide chains twisted together into a double helix. **SUMMARY** - ***Nucleic acids*** are polymers *made from monomers* called **[nucleotides.]** - ***Nucleotides*** are small organic molecules that may ***function as:*** 1. Energy carriers, 2. Enzyme helpers, 3. Chemical messengers, and 4. Information repositories. - **Nucleotides have three major components:** \(1) Five-Carbon Sugar, \(2) Phosphate Group, And \(3) Nitrogenous Base. - The **sugar and phosphate** are *linked together* *via an ester bond*, while the *base is linked to sugar* via glycosidic bond. - ***Two types of nucleic acids exist in cells***: the deoxyribonucleic acid **(DNA)** and ribonucleic acid **(RNA)**. - These ***two molecules differ in terms of their*** sugars, number of strands, and in one of their pyrimidines. - **DNA** has the pentose deoxyribose, whereas **RNA** has ribose. - **RNA** has the base uracil in place of the **thymine** present in DNA. - However, ***both of them have*** guanine, adenine, and cytosine. - Both of the **nucleic acids consist of nucleotides** that are ***linked together into chains*** via phosphodiester linkages. - **DNA**, being the genetic material, has a variety of functions in cells. -This molecule ***stores genetic information*** and ***allows this information to be transmitted across generations.*** -Also, this *molecule can undergo mutation* to allow *populations to evolve*. - **RNA**, which may exist in the **[form of]** a: 1. **M**essenger Rna, 2. **T**ransfer Rna, And 3. **R**ibosomal Rna -assist during the *expression of genetic information during protein synthesis.*  Graphical representation of the structures and functions of nucleotides and nucleic acids