West University College Biochemistry Lecture 1 PDF

West University College Faculty of Medicine Program Course: Biochemistry course Lecture 1 Prof. Mohamed Taha Yousif Elamien ❖ According to course content, the course consists of three major parts, these are: - Molecular biology - Conventional or Mendelian Genetics. - N...

West University College Faculty of Medicine Program Course: Biochemistry course Lecture 1 Prof. Mohamed Taha Yousif Elamien ❖ According to course content, the course consists of three major parts, these are: - Molecular biology - Conventional or Mendelian Genetics. - Non-Mendelian genetics and cytogenetics. Molecular biology applications: ❖ It is a branch of biology that seeks to understand the molecular basis of biological activity in and between cells, including bio-molecular synthesis, modification, mechanisms and interactions such as: ❖ structure and function of molecules and macromolecular systems associated with biological processes, especially the molecular basis of inheritance and protein synthesis. ❖ Compositions, interactions, structure, and functions of different biomolecules like amino acids, nucleic acids (DNA and RNA) proteins, carbohydrates, and lipids. ❖ Better understanding of genetic diversity, genetic evolution and emergency of new organisms. ❖ Response interactions such as gene therapy and manufacturing and discovery of vaccines and drugs. ❖ Some clinical research and medical therapies arising from molecular biology are covered under Gene therapy. ❖ The use of molecular biology or molecular cell biology in medicine is now referred to as Molecular medicine. ❖▪ It has tremendous value in application to a wide variety of problems affecting the overall human condition. ❖ Disease prevention, treatment and generation of new protein products. ❖ Molecular biology techniques are used to efficiently target new drugs. ❖ Diagnose disease in addition to discovery and identification of new emerging causal agents. ❖ It helps at better understanding of human cell physiology. ❖Manipulation of plants and animals for desired phenotypic traits. ❖In addition to all other applications that are routinely addressed by the application of molecular biology methods. The basic units of nucleic acids The basic units of nucleic acids Structure of nucleotide Difference between purines and pyremidines Nucleotides bonding between strands Nucleotides bonding with strand Bonding of nucleotides within strand  RNA/DNA strand is built from 5\ prime end to 3\ prime end  Structure of DNA A DNA molecule is composed of two long strands, each of which is made of building blocks called nucleotides bonded together. Every nucleotide is made of three components: a phosphate group, a deoxyribose sugar, and a nitrogen-containing base. Nucleotides are all identical except for their base. DNA has four different bases, known as adenine, thymine, cytosine, and guanine. Bases are often referred to by the letters A, T, C, and G. The two strands in DNA are held together by hydrogen bonding between the bases. DNA bases always pair in the same way: A with T and C with G. The double-stranded molecule is twisted into a double helix shape resembling a twisted ladder. Opposite strands run antiparallel to each other, meaning that they run in opposite directions. This ensures that the strands fit tightly together. Figure 1. The Structure of DNA  RNA structure ▪Ribonucleic acid (RNA): It is a molecule that is present in the majority of living organisms and viruses. It is made up of nucleotides, which are ribose sugars attached to nitrogenous bases and phosphate groups. The nitrogenous bases include adenine, guanine, uracil, and cytosine RNA structure  Differences between DNA and RNA DIFFERENCE DNA RNA STRANDS Double stranded Single stranded Sugar molecule Deoxy-ribose Ribose Nitrogen bases Adenine, Guanine, Adenine, Guanine, Cytosine and Thymine Cytosine and Uracil Length Varies in long to very Short strand long Propagation DNA is RNA is synthesized self-replicating. from DNA on an as-needed basis. Difference DNA RNA Reactivity The C-H bonds in DNA The O-H bond in the ribose make it fairly stable, of RNA makes the molecule plus the body destroys more reactive, compared enzymes that would with DNA. RNA is not stable attack DNA. The small under alkaline conditions, grooves in the helix plus the large grooves in also serve as the molecule make it protection, providing susceptible to enzyme minimal space for attack. RNA is constantly enzymes to attach. produced, used, degraded, and recycled. Ultraviolet Damage DNA is susceptible to Compared with DNA, RNA is UV damage. relatively resistant to UV damage.  Functions of DNA and RNA ▪DNA provides the code for the cell's activities, while RNA converts that code into proteins to carry out cellular functions. Functions of DNA, RNA and proteins  Definitions ▪Codon: A sequence of three consecutive nucleotides in a DNA or RNA molecule that codes for a specific amino acid. Certain codons signal the start or end of translation. These are called start or stop (or termination) codons. ▪ ranscription and translation: Are processes a cell uses to make all proteins the body needs to function from information stored in the sequence of bases in DNA. Chromatid: one of a pair of daughter strands of a replicated chromosome. Amino acids: Are the building blocks of proteins. They are the molecules that all living things need to make protein. Everybody need 20 of them to help your body and keep them functioning.  There are nine amino acids—histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine. They are not synthesized by mammals and are therefore dietarily essential or indispensable nutrients. These are commonly called the essential amino acids  General structure of the amino acids ❖ Gene: It is the basic physical and functional unit of heredity. Genes are made up of DNA and each chromosome contains many genes. ❖ Mutant is an organism or a new genetic character arising or resulting from an instance of mutation, which is generally an alteration of the DNA sequence. ❖Mutation process: is a change in the nucleotide sequence of a short region of a genome. ❖Many mutations are point mutations that replace one nucleotide with another; others involve insertion or deletion of one or a few nucleotides. DNA sequencing is a laboratory technique used to determine the exact sequence of bases (A, C, G, and T) in a DNA molecule. Sanger sequencing, also known as the “chain termination method”, is a method for determining the nucleotide sequence of DNA Best wishes