PowerPoint Lecture Slide Presentation by Patty Bostwick-Taylor, Florence-Darlington Technical College Cells and Tissues 3PART C
Protein Synthesis Gene DNA segment that carries a blueprint for building one protein Proteins have many functions Building materials for cells Act as enzymes (biological catalysts) RNA is essential for protein synthesis
Role of RNA Transfer RNA (trna) Transfers appropriate amino acids to the ribosome for building the protein Ribosomal RNA (rrna) Helps form the ribosomes where proteins are built Messenger RNA (mrna) Carries the instructions for building a protein from the nucleus to the ribosome
Transcription and Translation Transcription Transfer of information from DNA s base sequence to the complimentary base sequence of mrna Three-base sequences on mrna are called codons
Transcription and Translation Translation Base sequence of nucleic acid is translated to an amino acid sequence Amino acids are the building blocks of proteins
Protein Synthesis Nucleus (site of transcription) DNA Cytoplasm (site of translation) mrna specifying one polypeptide is made on DNA template Amino acids mrna Nuclear pore Nuclear membrane mrna leaves nucleus and attaches to ribosome, and translation begins Growing polypeptide chain Correct amino acid attached to each species of trna by an enzyme Synthetase enzyme Released trna reenters the cytoplasmic pool, ready to be recharged with a new amino acid As the ribosome Met moves along the mrna, a new amino Gly acid is added to the growing protein Ser chain Phe Ala Peptide bond C G G Incoming trna recognizes a complementary mrna codon calling for its amino acid by binding via its anticodon to the codon trna head bearing anticodon Large ribosomal subunit A U U U C G C C A U A G U C C Portion of mrna already Codon Direction of ribosome translated Small ribosomal advance; ribosome moves subunit the mrna strand along sequentially as each codon is read Figure 3.16
Protein Synthesis Nucleus (site of transcription) DNA Cytoplasm (site of translation) mrna specifying one polypeptide is made on DNA template mrna Nuclear pore Nuclear membrane Figure 3.16, step 1
Protein Synthesis Nucleus (site of transcription) DNA Cytoplasm (site of translation) mrna specifying one polypeptide is made on DNA template mrna Nuclear pore Nuclear membrane mrna leaves nucleus and attaches to ribosome, and translation begins U A G U C C Large ribosomal subunit Small ribosomal subunit Codon Figure 3.16, step 2
Protein Synthesis Nucleus (site of transcription) DNA Cytoplasm (site of translation) mrna specifying one polypeptide is made on DNA template Amino acids mrna Nuclear pore Nuclear membrane mrna leaves nucleus and attaches to ribosome, and translation begins Correct amino acid attached to each species of trna by an enzyme Synthetase enzyme Large ribosomal subunit U A G U C C Small ribosomal subunit Codon Figure 3.16, step 3
Protein Synthesis Nucleus (site of transcription) DNA Cytoplasm (site of translation) mrna specifying one polypeptide is made on DNA template Amino acids mrna Nuclear pore Nuclear membrane mrna leaves nucleus and attaches to ribosome, and translation begins Correct amino acid attached to each species of trna by an enzyme Synthetase enzyme Incoming trna recognizes a complementary mrna codon calling for its amino acid by binding via its anticodon to the codon U A G U C C trna head bearing anticodon Large ribosomal subunit Small ribosomal subunit Codon Figure 3.16, step 4
Protein Synthesis Nucleus (site of transcription) DNA Cytoplasm (site of translation) mrna specifying one polypeptide is made on DNA template Amino acids mrna Nuclear pore Nuclear membrane mrna leaves nucleus and attaches to ribosome, and translation begins Growing polypeptide chain Correct amino acid attached to each species of trna by an enzyme Synthetase enzyme As the ribosome Met moves along the mrna, a new amino Gly acid is added to the growing protein Ser chain Phe Ala Peptide bond Incoming trna recognizes a complementary mrna codon calling for its amino acid by binding via its anticodon to the codon C G G trna head bearing anticodon Large ribosomal subunit G C C A U A G U C C Small ribosomal subunit Codon Direction of ribosome advance; ribosome moves the mrna strand along sequentially as each codon is read Figure 3.16, step 5
Protein Synthesis Nucleus (site of transcription) DNA Cytoplasm (site of translation) mrna specifying one polypeptide is made on DNA template Amino acids mrna Nuclear pore Nuclear membrane mrna leaves nucleus and attaches to ribosome, and translation begins Growing polypeptide chain Correct amino acid attached to each species of trna by an enzyme Synthetase enzyme Released trna reenters the cytoplasmic pool, ready to be recharged with a new amino acid As the ribosome Met moves along the mrna, a new amino Gly acid is added to the growing protein Ser chain Phe Ala Peptide bond C G G Incoming trna recognizes a complementary mrna codon calling for its amino acid by binding via its anticodon to the codon trna head bearing anticodon Large ribosomal subunit A U U U C G C C A U A G U C C Portion of mrna already Codon Direction of ribosome translated Small ribosomal advance; ribosome moves subunit the mrna strand along sequentially as each codon is read Figure 3.16, step 6
Body Tissues Tissues Groups of cells with similar structure and function Four primary types Epithelial tissue (epithelium) Connective tissue Muscle tissue Nervous tissue
Epithelial Tissues Locations Body coverings Body linings Glandular tissue Functions Protection Absorption Filtration Secretion
Epithelium Characteristics Cells fit closely together and often form sheets The apical surface is the free surface of the tissue The lower surface of the epithelium rests on a basement membrane Avascular (no blood supply) Regenerate easily if well nourished
Epithelium Characteristics Figure 3.17a
Classification of Epithelia Number of cell layers Simple one layer Stratified more than one layer Figure 3.17a
Classification of Epithelia Shape of cells Squamous flattened Cuboidal cube-shaped Columnar column-like Figure 3.17b
Simple Epithelia Simple squamous Single layer of flat cells Usually forms membranes Lines body cavities Lines lungs and capillaries
Simple Epithelia Figure 3.18a
Simple Epithelia Simple cuboidal Single layer of cube-like cells Common in glands and their ducts Forms walls of kidney tubules Covers the ovaries
Simple Epithelia Figure 3.18b
Simple Epithelia Simple columnar Single layer of tall cells Often includes mucus-producing goblet cells Lines digestive tract
Simple Epithelia Figure 3.18c
Simple Epithelia Pseudostratified columnar Single layer, but some cells are shorter than others Often looks like a double layer of cells Sometimes ciliated, such as in the respiratory tract May function in absorption or secretion
Simple Epithelia Figure 3.18d
Stratified Epithelia Stratified squamous Cells at the apical surface are flattened Found as a protective covering where friction is common Locations Skin Mouth Esophagus
Stratified Epithelia Figure 3.18e
Stratified Epithelia Stratified cuboidal two layers of cuboidal cells Stratified columnar surface cells are columnar, cells underneath vary in size and shape Stratified cuboidal and columnar Rare in human body Found mainly in ducts of large glands
Stratified Epithelia Transitional epithelium Shape of cells depends upon the amount of stretching Lines organs of the urinary system
Stratified Epithelia Figure 3.18f
Glandular Epithelium Gland One or more cells responsible for secreting a particular product
Glandular Epithelium Two major gland types Endocrine gland Ductless since secretions diffuse into blood vessels All secretions are hormones Exocrine gland Secretions empty through ducts to the epithelial surface Include sweat and oil glands