10/2:Cells and DNA replication:Protein synthesis:TranscriptionOccurs inside the nucleusDNA molecule unravelsTwo polynucleotides stands/chains separateOne acts as a templateTranscribe the pre messenger RNA (premRNA)One is a coding strandNot used in transcription by the law of complementarity of basesThe 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 strandExample:Two DNA polynucleotide strandsCCC templateCoding strand will have GGG coding strandYou will use the template to make the premRNACCC GGGAfter transcription the premRNA will contain introns and exons:RNA processes: s-plicing editingpremRNA minus intronsexons form the mRNAexons code for amino acidsintrons: do not code for amino acids3 base sequence of mRNA CODON3 base sequence of DNA TRIPLETmRNA 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 transcriptionpremRNA processes are imperative of translationTranslationOccurs inside the cytoplasmAll 3 types of RNA are involvedThe mRNA codons, when a codon is covered by a functional ribosome (subunits consists of rRNA)tRNA with complementary bases to the covered codon attachesRibosome covers the codon (mRNA) GGGAntiocodon with complementary bases CCC will bindAt the tail of the tRNA is a specific amino acidThe primary structure of the protein is synthesized by the formation of peptide bonds between adjacent amino acidsAmino acid 1 amino acid 2 amino acid 3….Thymine is replaced by Uracil in the anticodon of a tripletTranslation brings the message back into it’s original formMembranous Epithelial Tissues:Simple EpithelialSimple SquamousSimple Cuboidal: lining the tubules in the kidney where reabsorption (absorbing substances filtered back into blood) and secretion occur in the formation of urineFunction: secretion, absorptionGerminal Epithelium: outer covering of the ovary composed of simple cuboidal epithelial tissueComposition (tissue type)LocationSimple Columnar: single layer of tall cellsCiliated 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 actionNon ciliated Simple Columnar Epithelial Tissue: cilia are absent, microvilli may be presentLocation: lines much of the GI tract, the lining of the small intestine expresses microvilli which increase the surface area of the small intestine for absorptionFunction: absorption, secretion (of digestive enzymes)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 formsColumnar cells in the Ciliated Pseudostratified columnar Epithelial tissue are endowed with goblet cellsCiliated 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 systemNonciliated 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, urethraStratified Epithelial Tissues: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-resistantLocation: only one location in the human body, in the epidermis of the skinFunction: protection against trauma and infectionNonkeratinized: confers protection to structures it 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 epitheliumStratified Cuboidal:Stratified Columnar:^^ Function:Transitional Epidermis Tissue6 layers, dome shaped (cuboidal cells)when urine containing structures are empty3 layers, with flattened apical cellswhen urine containing structures are full of urine10/2/13Epithelial Tissue:basal laminareticular laminaThose two are the basement membrane: a selective membrane that regulates substances diffusing from the underlying connective tissueConnective tissue: areolar connective tissue, or dense irregular connective tissueThey are highly vascularized types of connective tissuesEpithelial Tissue:Membranous (sheet like epithelial tissue)Simple: a single layer of cellsSimple Squamous epithelial tissue: a single layer of cells that appear flattened with flattened nuclei on the surface of cellsLocation: 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 mesotheliumEndothelium: composition and locationMesothelium: composition and locationProvide a frictionless surface for the movement of substancesCirculatory System:Cariovascular system: blood circulatesLymphatic system: lymph circulateFunction:Stratified: at least two layers of cellsGranular (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
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