Lecture I Intro to Genetics & DNA Replication with a review in DNA, RNA, & Protein Synthesis

Standards Covered 4a~ students know the general pathway by which ribosomes synthesize proteins, using tRNA’s to translate genetic information in mRNA 4a~ students know the general pathway by which ribosomes synthesize proteins, using tRNA’s to translate genetic information in mRNA 4b~ students know how to apply the genetic coding rules to predict the sequence of amino acids from a sequence of codons in RNA 4b~ students know how to apply the genetic coding rules to predict the sequence of amino acids from a sequence of codons in RNA 4e~ students know proteins can differ from one another in the number and sequence of amino acids 4e~ students know proteins can differ from one another in the number and sequence of amino acids

Standards Covered 5a~ students know the general structures and functions of DNA, RNA, and proteins 5a~ students know the general structures and functions of DNA, RNA, and proteins 5b~ students know how to apply base-pairing rules to explain precise copying of DNA during semi- conservative replication and the transcription of information from DNA into RNA 5b~ students know how to apply base-pairing rules to explain precise copying of DNA during semi- conservative replication and the transcription of information from DNA into RNA

Important Vocabulary Heredity – the passing on of characteristics from parents to offspring Heredity – the passing on of characteristics from parents to offspring Traits – characteristics that are inherited (for example your eye color) Traits – characteristics that are inherited (for example your eye color) Genes – a piece of DNA that provides a code or instructions to make a certain protein Genes – a piece of DNA that provides a code or instructions to make a certain protein A gene’s specific location within your DNA code is called its locus A gene’s specific location within your DNA code is called its locus This is like a “home address” This is like a “home address”

Important Vocabulary Genotype – the genetic makeup of an individual or referring to a specific gene or trait Genotype – the genetic makeup of an individual or referring to a specific gene or trait Phenotype – the physical expression of a gene or trait as “coded for” by the Genotype Phenotype – the physical expression of a gene or trait as “coded for” by the Genotype Allele – any alternative form of a gene that can be possible for a specific gene at a specific locus Allele – any alternative form of a gene that can be possible for a specific gene at a specific locus Dominant – the allele that is expressed when two different alleles are present Dominant – the allele that is expressed when two different alleles are present Recessive – the allele that is expressed only when two copies of that allele are present Recessive – the allele that is expressed only when two copies of that allele are present

Genotype vs. Phenotype Your DNA is the genetic blueprint for all of your physical characteristics we call “traits” Your DNA is the genetic blueprint for all of your physical characteristics we call “traits” The DNA code for a trait is called the genotype and the trait that is expressed is the phenotype The DNA code for a trait is called the genotype and the trait that is expressed is the phenotype

DNA Polymerase – a special enzyme responsible for a process called DNA Replication DNA Polymerase – a special enzyme responsible for a process called DNA Replication Semi-conservative replication – the process of making a copy of a DNA strand by using each complimentary half as a “template” for two new strands Semi-conservative replication – the process of making a copy of a DNA strand by using each complimentary half as a “template” for two new strands Important Vocabulary

The Cell Cycle Cells go through the cell cycle during their lifetime Cells go through the cell cycle during their lifetime MOST of the life of a cell is in Interphase MOST of the life of a cell is in Interphase DNA is packed into chromosomes during late G1 DNA is packed into chromosomes during late G1

DNA Arranged in a Chromosome

A cell makes copies of its DNA during the S-Phase of the cell cycle where the chromosomes “duplicate” and the cell prepares for cell division A cell makes copies of its DNA during the S-Phase of the cell cycle where the chromosomes “duplicate” and the cell prepares for cell division S Phase & DNA Replication

The Structure of DNA DNA is a long molecule made up of nucleotides Each nucleotide is made up of three parts: 5-carbon sugar called deoxyribose 5-carbon sugar called deoxyribose Phosphate group Phosphate group Nitrogen Base Nitrogen Base

AdenineGuanine Phosphate group CytosineThymine (Deoxyribose) 5-Carbon Sugar The Nucleotides Nitrogen Bases A- adenine G- guanine C- cytosine T- thymine

Chargaff’s Rules According to Erwin Chargaff: Adenine always pairs with Thymine Cytosine always pairs with Guanine

Central Dogma Review The term central dogma is used in science to describe the “making of proteins” from instructions coded in the DNA The term central dogma is used in science to describe the “making of proteins” from instructions coded in the DNA An equation to remember for Central Dogma would be: An equation to remember for Central Dogma would be: DNA mRNA Amino Acid Chain DNA mRNA Amino Acid Chain TranscriptionTranslation

Transcription inside the Nucleus Adenine (DNA and RNA) Cystosine (DNA and RNA) Guanine(DNA and RNA) Thymine (DNA only) Uracil (RNA only) RNA DNA RNA polymerase

Central Dogma Proteins are assembled into polypeptides Proteins are assembled into polypeptides These are long chains of amino acids These are long chains of amino acids There are 20 different types of amino acids There are 20 different types of amino acids The properties of proteins are determined by which order these amino acids are joined The properties of proteins are determined by which order these amino acids are joined

Transcription & Translation Each of these amino acids that mRNA “codes” for recognizes the three base pair sequence Each of these amino acids that mRNA “codes” for recognizes the three base pair sequence A codon consists of “three nucleotides in a row” that code for a single amino acid A codon consists of “three nucleotides in a row” that code for a single amino acid AUG codes for the amino acid Methionine AUG codes for the amino acid Methionine

The (20) Amino Acids Methionine is the universal “start codon” for all proteins