10 02 2013 10 2 Cells and DNA replication Protein synthesis Transcription o Occurs inside the nucleus o DNA molecule unravels o Two polynucleotides stands chains separate One acts as a template Transcribe the pre messenger RNA premRNA One is a coding strand Not used in transcription by the law of complementarity of bases The base sequence in the pre MRNA is similar to the base sequence in the coding strand except if the premRNA has uracil it is replaced by thymine in the coding strand Example Two DNA polynucleotide strands CCC template Coding strand will have GGG coding strand You will use the template to make the premRNA CCC GGG After transcription the premRNA will contain introns and exons RNA processes s plicing editing premRNA minus introns exons form the mRNA exons code for amino acids introns do not code for amino acids Translation o 3 base sequence of mRNA CODON o 3 base sequence of DNA TRIPLET o mRNA moves through the nuclear pore premRNA cannot go through the nuclear pore because of size exclusion if you do not get editing and splicing you do not get transcription o premRNA processes are imperative of translation o Occurs inside the cytoplasm o All 3 types of RNA are involved o The mRNA codons when a codon is covered by a functional ribosome subunits consists of rRNA o tRNA with complementary bases to the covered codon attaches o Ribosome covers the codon mRNA GGG o Antiocodon with complementary bases CCC will bind o At the tail of the tRNA is a specific amino acid o The primary structure of the protein is synthesized by the formation of peptide bonds between adjacent amino acids Amino acid 1 amino acid 2 amino acid 3 o Thymine is replaced by Uracil in the anticodon of a triplet o Translation brings the message back into it s original form Membranous Epithelial Tissues Simple Epithelial o Simple Squamous o Simple Cuboidal lining the tubules in the kidney where reabsorption absorbing substances filtered back into blood and secretion occur in the formation of urine Function secretion absorption Germinal Epithelium outer covering of the ovary composed of simple cuboidal epithelial tissue Composition tissue type Location o Simple Columnar single layer of tall cells Ciliated Simple Columnar Epithelial Tissue contain goblet cells that secrete mucus Cilia beat to create a unidirectional current that propels mucus lines the fallopian uterine tube Cilia beat to create a unidirectional current that moves ova eggs or zygotes if the ova are fertilized by sperm Location loose parts of the respiratory system such as the bronchi tube like structures that branch from the trachea into the lungs Function secretion of mucus by the goblet cells propulsion of mucus by ciliary action Non ciliated Simple Columnar Epithelial Tissue cilia are absent microvilli may be present Location lines much of the GI tract the lining of the small intestine expresses microvilli which increase the surface area of the small intestine for Function absorption secretion of digestive absorption enzymes o Pseudosteatified Columnar a single layer of tall cells of different heights hence their nuclei also appear at different heights giving the false impression pseudo of stratification two forms Stratified Epithelial Tissues Columnar cells in the Ciliated Pseudostratified columnar Epithelial tissue are endowed with goblet cells Ciliated pseudostratified columnar epithelial tissue with cells endowed with goblet cells referred to as RESPIRATORY EPITHELIUM composition and location Location lines most of the structures in the respiratory system Nonciliated Pseudostratified Epithelial Tissue lines ducts in the male reproductive system where this tissue confers some level of protection Sperm carrying ducts in the male epididymis vas deferens ejaculatory duct urethra o Stratified Squamous several layers of cells apical cells are flattened squamous Keratinized Stratified Squamous apical cells are impregnated with a tough fibrous protein called Keratin hence this tissue is abrasive resistant Location only one location in the human body in the epidermis of the skin Function protection against trauma and Nonkeratinized confers protection to structures it infection lines Location lines structures in the tracts of the body a tract is a body system with an opening to the exterior GI tract has 2 openings urinary tract 1 opening reproductive tract 1 opening respiratory tract 1 opening The entry point of these tracts are lined by the non keratinized stratified squamous epithelium o Stratified Cuboidal o Stratified Columnar Function o Transitional Epidermis Tissue 6 layers dome shaped cuboidal cells when urine containing structures are empty 3 layers with flattened apical cells when urine containing structures are full of urine 10 02 2013 10 2 13 Epithelial Tissue basal lamina reticular lamina o Those two are the basement membrane a selective membrane that regulates substances diffusing from the underlying connective tissue Connective tissue areolar connective tissue or dense irregular connective tissue Epithelial Tissue o They are highly vascularized types of connective tissues Membranous sheet like epithelial tissue o Simple a single layer of cells Simple Squamous epithelial tissue a single layer of cells that appear flattened with flattened nuclei on the surface of cells Location forms part of the filtration membrane in the kidneys involved in filtration forms part of the respiratory membrane in the lungs involved in the diffusion of gasses lines structures in the circulatory system where the simple squamous epithelial tissue is specifically referred to as the endothelial simple squamous epithelial tissue forms part of the serious membrane where the simple squamous epithelial tissue is specifically referred to as the mesothelium Endothelium composition and location Mesothelium composition and location Provide a frictionless surface for the movement of substances o Circulatory System Cariovascular system blood circulates Lymphatic system lymph circulate Function Stratified at least two layers of cells Granular involved in secretion 10 7 see Powerpoint Tissues CT2 starting at slide 18 50 ductless glands endocrine are not equipped with ducts endocrine glands release hormones directly into extracellular fluid made up of the interstitial fluid and blood plasma exocrine glands unicellular exocrine glands not equipped with ducts example only type in the human body of unicellular exocrine glands are GLOBLET cells which are dispersed in
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