Genetic Engineering Lecture 1 2024-2025 PDF

College of applied science Department of biotechnology Genetic engineering 4th stage Dr. noor Thaer Adnan Lecture -1 2024-2025...

College of applied science Department of biotechnology Genetic engineering 4th stage Dr. noor Thaer Adnan Lecture -1 2024-2025 Genetic Engineering - Dr.Noor Thaer 1 Genetic Engineering ▪ Genetic engineering :The intentional manipulation of genetic material (primarily DNA) to alter, repair, or enhance form or function or introduce a new trait. ▪ Traditionally, humans have manipulated genome indirectly by controlling and selecting offspring with desired traits. ▪ Most often in genetic engineering a gene from a different species is selected and introduced into the host to transfer the desired phenotype Genetic Engineering - Dr.Noor Thaer 2  DNA Structure  DNA consists of two molecules that are arranged into a ladder-like structure called a Double Helix.  A molecule of DNA is made up of millions of tiny subunits called Nucleotides.  Each nucleotide consists of: 1. Phosphate group 2. Pentose sugar 3. Nitrogenous base The nitrogen containing bases are the only difference in the four nucleotides.  Nucleotides always pair in the same way. The base-pairing rules show how nucleotides always pair up in DNA. – A pairs with T – C pairs with G Because a pyrimidine (single G ring) pairs with a purine (double C A T ring), the helix has a uniform width. DNA Structure/ bonds Hydrogen bond: Between complementary nitrogenous bases on opposite strands. Phosphodiester bonds covalent linkage between the phosphate of one nucleotide and the hydroxyl (OH) group attached to the 3′ carbon of the deoxyribose sugar in an adjacent nucleotide, forming what is known as the “sugar-phosphate backbone” of DNA Glycoside bonds: exists between the pentose sugar covalent bond molecule and nitrogenous base hydrogen bond Genetic Engineering - Dr.Noor Thaer 6 Watson and Crick determined the three-dimensional structure of DNA by building models. They realized that DNA is a double helix that is made up of a sugar-phosphate backbone on the outside with bases on the inside. They were awarded with the Nobel Prize in Physiology or Medicine in 1962 Watson and Crick’s discovery built on the work of Rosalind Franklin and Erwin Chargaff. – Franklin’s x-ray images suggested that DNA was a double helix of even width. – Chargaff’s rules stated that A=T and C=G.  Most DNA double helices are right-handed; that is, if you were to hold your right hand out, with your thumb pointed up and your fingers curled around your thumb, your thumb would represent the axis of the helix and your fingers would represent the sugar-phosphate backbone. Only one type of DNA, called Z-DNA, is left-handed. The DNA double helix is anti-parallel, which means that the 5' end of one strand is paired with the 3' end of its complementary strand (and vice versa). Genetic Engineering - Dr.Noor Thaer 9 The importance of an antiparallel DNA double helix structure is because of its hydrogen bonding between the complementary nitrogenous base pairs. Additionally, the phosphodiester bonds in one strand go from a 3' cardon of one nucleotide to a 5, carbon of adjacent nucleotide, whereas those in complementary strand go vice versa to maximize the efficiency of base-pair packing There are three different DNA configurations: 1.A-DNA A-DNA is right-handed DNA. It has a double helix structure. The A form of this DNA type is mainly formed because it can protect the DNA while there are any occurrences of extreme conditions, namely desiccation. Mostly this type is obtained by dehydrated DNA. The protein binding around it helps remove the solvent from is considered the most common form of DNA conformation. It consists of a right-handed helix structure. B-type DNA Moreover, under normal psychological conditions, it is very common to see that much DNA possesses a B-type conformation. 3.Z-DNA This DNA type is left-handed DNA. Here, a double helix is present, with the wind in a zigzag pattern to the left. Genetic Engineering - Dr.Noor Thaer 10  Genetic Engineering - Dr.Noor Thaer 11 GENES Geneis the basic unit of heredity. Passed from parents to offspring and contain the information needed to specify physical and biological traits. Most genes code for specific proteins, or segments of proteins, which have differing functions within the body. Humans have approximately 20,000 protein-coding gene Types of genes : Structural genes : encode to amino acids. Regulatory genes : found in promoter (upstream) , a gene that regulates the expression of one or more structural genes by controlling the production of a protein (as a genetic repressor) which regulates their rate of transcription. Housekeeping genes : genes that are consistently expressed across tissues, essential, carrying out cellular maintenance, Pseudogenes : Pseudogenes are nonfunctional segments of DNA that resemble functional genes have start and stop codons Genetic Engineering - Dr.Noor Thaer 12  Gene is sequence of DNA which must be begin with start codon (ATG) and ended with stop codon (TAG, TGA or TAA) from 5' to 3' direction. '5 … ATG ATG CCC AAA TTT CCA TAA … '3 '3… TAC TAC GGG TTT AAA GGT ATT … ‘5 Gene size is measured in base pair (bp) :- is unit of measure molecular size of DNA that is employed in molecular biology.each base pair bind together by hydrogen bond and joined together to form double helix DNA (Adenine bind to Thymine by double hydrogen bonds and Cytosine bind to Guanine by triple hydrogen bonds) If there are two start (or stop) codons at specific gene, the first start (or stop) should be chosen and another one is normal codon. Start codon (ATG) encoded for Methionine. Genetic Engineering - Dr.Noor Thaer 13 upstream regulatory region the region of a gene where RNA ORF Polymerase and other nucleotide sequence known as accessory transcription modulator Proteins bind and an open reading frame (ORF) interact to control RNA is located between the start synthesis codon and the stop codon. Genetic Engineering - Dr.Noor Thaer 14  CENTRAL DOGMA OF BIOLOGY Genetic Engineering - Dr.Noor Thaer 15 An intron is a region that resides within a gene but does not remain in the final mature mRNA molecule following transcription of that gene and does not code for amino acids that make up the protein encoded by that gene. Homework/due next week What is the origin of introns? Genetic Engineering - Dr.Noor Thaer 16  Mwt of DNA and RNA is measured by Daltons. 1 base pair (bp) = 650 Dalton In prokaryote, molecular size of DNA (bp) = molecular size of RNA (bases). Ex : How many base pair of gene encoded to protein with 650,000 D and how many bases of RNA template? bp of gene = 650,000 / 650 = 1000 bp bases of RNA = 1000 bases All codons encoded to amino acids except stop codon (terminator). → No. of amino acids = No. of gene's codons – 1 → No. of peptide bonds = No. of amino acids – 1 → Molecular size of DNA is measured by base pairs and molecular size of RNA is measured by bases. Genetic Engineering - Dr.Noor Thaer 17 Q:Suppose Mwt of protein (x) = 390 KD. Estimate : 1) Molecular size of gene / DNA (x) : 390 * 1000 = 390,000 D 390,000 ÷ 650 = 600 bp. 2) Molecular size of mRNA (x) : 600 bases Genetic Engineering - Dr.Noor Thaer 18 Q:Suppose Molecular size of mRNA= 900 bases Estimate : 1) Molecular size of gene / DNA (x) : 2) Molecular weight of protein resulted: Genetic Engineering - Dr.Noor Thaer 19 Q:Suppose Molecular size of mRNA= 900 bases Estimate : 1) Molecular size of gene / DNA (x) : DNA= 900 bp 2) Molecular weight of protein resulted: 1 base pair (bp) = 650 Dalton 900*650=585.000 Daltons = 585 KD Genetic Engineering - Dr.Noor Thaer 20  Don’t forget next week You have a Quiz And your Homework Genetic Engineering - Dr.Noor Thaer 21