Cell Biology A Review Molecular Genetics Mendelian Genetics Reading Ch 2 HS The Cell Basic unit of all life Smallest unit capable of reproduction Two types of cells Prokaryotic Cells Eukaryotic Cells Organelles Cytoplasm Mitochondria Power plant Major site for energy production Nucleus Headquarters of the cell directs cell activity contains DNA Endoplasmic reticulum communication network Rough endoplasmic reticulum ribosomes protein synthesis Smooth endoplasmic reticulum fat synthesis Organelles Golgi Complex Packaging site for protein Lysosomes Cell s digestive system Suicide sacs Peroxisomes Detoxify harmful chemicals Alcohol metabolism Centrioles Essential for symmetric cell replication Two Types of Eukaryotic Cells Chromosomes Sex Cells Somatic Cells DNA sequences are bound together by proteins histones in long strands called chromosomes that are found within the nucleus of each cell Tightly wound packets of Found in the nucleus DNA 1 To Each His Own Chromosomes Chromosomes occur in pairs These pairs are homologous or carry the same traits A karyotype is the chromosome profile of an individual Two types of chromosomes Autosomes Sex chromosomes Cell Replication Mitosis Cell Replication Meiosis Meiosis is sex cell division Daughter cells may not be identical to parent cell Sex cells are haploid So how many chromosomes does a human sex cell contain How many homologous pairs Mitosis is somatic cell division Somatic cells are diploid So how many homologous pairs do humans have in their somatic cells Other apes Functions of DNA Transmit genetic information from one generation to the next Transmit genetic information to the somatic cells governing cell function Instruct cells to manufacture proteins Direct cell replication 2 DNA Replication Process by which DNA makes copies of itself all the DNA is duplicated raw material is nucleotides end product is DNA Each cell in your body except for sex cells and red blood cells contains your entire genome As cells are replicated for growth and maintenance of organs and structures each needs a full set of instructions or a full complement of DNA DNA is composed of two chains of nucleotides made up of three components Sugar molecules deoxyribose Phosphate Nitrogenous base Complementary The nitrogenous bases make up the genetic code DNA Replication How Enzymes break the hydrogen bonds exposes the bases each side works as a template The exposed bases attract unattached nucleotides The result is two double stranded DNA molecules that are exactly like the original DNA Structure The structure of DNA was discovered in 1953 Nobel for medicine and physiology in 1962 Rosalind Franklin James Watson Francis Crick DNA structure had to account for the three properties of DNA Source of infinite variability Self replicating Method for protein synthesis DNA Structure Now You Try GCA TTC ACG TGG CGT AAG TGC ACC Molecular Genetics DNA The Genetic Code Review The DNA molecule provides the codes for biological structures and the means to translate this code DNA provides information for building operating and repairing biological organisms DNA consists of two strands arranged in a helix joined together by chemical bases 3 Videos Mitosis http www youtube com watch v VlN7K1 9QB0 NR 1 Meiosis http www youtube com watch v D1 mQS FZ0 eurl http 3A 2F 2Fwww 2Efacebook 2Ec om 2Fhome 2Ephp feature player embedded Replication http www youtube com watch v 4jtmOZaIvS0 feature related Proteins All living things are composed of proteins Proteins are large complex molecules made up of long chains of amino acids Proteins have four main functions Tissues Hormones Enzymes Transportation Genetic Code Table Proteins cont DNA directs the construction of proteins out of amino acids The number of amino acids and their sequence determines the protein Where do we get amino acids What holds the chain together The sequence of DNA bases determines the amino acid These bases are read in sets of three called triplets You Can t Get There From Here Where did we leave those instructions Where do we plan to build DNA vs RNA DNA RNA Double stranded Single stranded Deoxyribose Ribose Strand Number Sugar Bases Thymine Uracil Passage Remains in nucleus Leaves nucleus 4 RNA nucleus DNA must be copied into RNA so that it can leave the There are 2 different kinds of RNA involved in protein synthesis mRNA messenger RNA tRNA transfer RNA Transcription Transcription formation of a messenger RNA mRNA molecule from a DNA template This copying of the genetic code does not alter the code itself Occurs in the nucleus Short segment of DNA separate Bases attract their complementary nucleotides with uracil replacing thymine RNA strand peels away from DNA and leaves the nucleus 5 to 3 5 to 3 http www youtube com watch v p835L4HWH68 Protein Synthesis Translation Translation The process of assembling amino acids on a messenger RNA template to build a protein or part of a protein Occurs in the cytoplasm at the ribosome The mRNA is read in sequences of three called This takes place at the ribosome codons 5 Translation Translation The first tRNA attaches to the mRNA at the start codon Ribosome moves along the mRNA strand and next tRNA joins The amino acid attached to tRNA 1 binds to the amino acid from tRNA 2 tRNA 1 then leaves the ribosome anticodons tRNA is read in groups called Let s Review The Genetic Code The ribosome moves along the mRNA strand until the stop codon simultaneously Many ribosomes work on the same mRNA The genetic code is a sequence of bases read three at a time that specifies the amino acids The genetic code is Universal Triplet Continuous Redundant 4 3 64 possible combinations but only 20 amino acids Why would this be beneficial 6 Practice DNA mRNA tRNA Amino acids GCA TTC ACG TGG triplets Genetic Code Table mRNA Answers DNA GCA TTC ACG TGG triplets mRNA You could just replace the Ts with Us to get from CGU AAG UGC ACC codons triplets to anticodons tRNA GCA UUC ACG UGG anticodons Amino acids argenine lysine cysteine threonine Try Again anticodons UAC AGC UUU GUA triplets codons amino acids Genetic Code Table mRNA 7 Answers Videos tRNA UAC AGC UUU GUA anticodons DNA TAC AGC TTT GTA triplets mRNA AUG UCG AAA CAU anticodons Amino acids methionine serine lysine histidine Remember it occurs in this order Protein Synthesis http www youtube com watch v NJxobgkPEAo e url http 3A 2F 2Fwww 2Efacebook 2Ecom 2Fh ome 2Ephp feature player embedded Real Time http www youtube com watch v 41 Ne5mS2ls N R 1