ELAINE N. MARIEB EIGHTH EDITION 3 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings PowerPoint ® Lecture Slide Presentation by Jerry L. Cook, Sam Houston University ESSENTIALS OF HUMAN ANATOMY & PHYSIOLOGY PART B Cells and Tissues Cell Division/Protein Synthesis

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Cell Life Cycle  Cells have two major periods  Interphase  Cell grows  Cell carries on metabolic processes  Cell division- Mitosis  Cell replicates itself  Function is to produce more cells for growth and repair processes

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings DNA Replication  Genetic material duplicated and readies a cell for division into two cells, 1 st step  Occurs toward the end of interphase  DNA uncoils and each side serves as a template: Adenine-Thymine (A-T) (T-A) Cytosine-Guanine (C-G) (G-C) Figure 3.14

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Events of Cell Division  Mitosis  Division of the nucleus  Results in the formation of two daughter nuclei  Cytokinesis  Division of the cytoplasm  Begins when mitosis is near completion  Results in the formation of two daughter cells

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Stages of Cell Cycle  Interphase (I)- (separate from mitosis)  No cell division occurs  The cell carries out normal metabolic activity and growth  DNA is replicated

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Stages of Mitosis  Mitosis has four phases:  Prophase (Pick)  First part of cell division  Centrioles separate and move toward opposite sides of the cell.  Metaphase (‘Maters)  Spindle from centrioles are attached to chromosomes that are aligned in the center of the cell  Chromosomes “meet in the middle”

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Stages of Mitosis  Anaphase (And)  Centromeres split and Daughter chromatids are pulled apart, toward the poles  The cell begins to elongate  Telophase (‘Taters)  Daughter nuclei begin forming  A cleavage furrow (for cell division) begins to form

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Stages of Mitosis Figure 3.15 Sketch Interphase, early prophase, metaphase, anaphase, & telophase.

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Stages of Mitosis Figure 3.15(cont) Sketch Interphase, early prophase, metaphase, anaphase, & telophase.

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Protein Synthesis  Gene – DNA segment that carries a information for building one protein or polypeptide chain, found in nucleus  RNA is essential for protein synthesis, found outside the nucleus  RNA bases are same as DNA except Uracil replaces Thymine. (U & A)

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings 3 steps in Protein Synthesis 1.DNA uncoils, the DNA segment or gene that specifies one polypeptide chain or protein uncoils. 2.Transcription (DNA directed synthesis of mRNA)- one strand of DNA acts as a template for the synthesis of the complimentary mRNA molecule, and there is a transfer of information from the DNA’s base sequence (code) into the complementary base sequence of mRNA (codon)

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings 3 steps in Protein Synthesis Translation (RNA- directed synthesis of a polypeptide or protein)involves 5 steps: 1. mRNA leaves the nucleus and attaches to the ribosomes. 2.tRNA (anticodon) transports an amino acid to the mRNA strand and recognizes a mRNA molecule (codon). 3.The codon and the anticodon bind. 4.The ribosome moves the mRNA strand along as each codon is read sequentially (in order). 5.Each amino acid is bound to the next in a chain, the chain is released when a termination (stop) codon is read.

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Protein Synthesis DNA to RNA to Protein  DNADNA  AT  C G  DNAmRNA  AU  TA  CG  mRNAtRNA  AU  CG (DNA) Triplets (mRNA) Codons (tRNA) Anticodons

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Triplets, Codons, & Anticodons  Triplets- a three base sequence of DNA, carries information coding for a particular amino acid. ex.DNA CAT-CGT triplets GTA-GCA (complementary sequence of DNA) Codons- a corresponding three base sequence of mRNA ex. mRNA UUA-GCA-AGC—codons tRNA AAU-CGU-UCG- anticodons  Anticodons- three base sequence on tRNA which carries the Amino Acid to the ribosome for placement with codon (mRNA )

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Role of RNA  Messenger RNA (mRNA)  Carries the instructions for building a protein from the nucleus to the ribosome.  Transfer RNA (tRNA)  Transfers appropriate amino acids to the ribosome for incorporation into a protein.  READ ONLY DO NOT COPY:  Ribosomal RNA (rRNA)  Helps form the ribosomes where proteins are built.

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Transcription and Translation  TranscriptionDNAmRNA  Transfer of information from DNA’s base sequence to the complimentary base sequence of mRNA completed in the nucleus. Each new sequence begins with AUG. Universal start codon  TranslationmRNAtRNA  Base sequence of nucleic acid is translated to an amino acid sequence completed on a ribosome in the cytoplasm, occurs outside the nucleus.  Amino acids are the building blocks of proteins

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Practice Transcription/Translation  DNA= A-T-G-C-C-A-T-T-G-C-A-A  DNA=  mRNA= Amino Acids

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Amino Acids / RNA Sequences Read from inside out. Ex. If mRNA is UAC. Go to big U in middle, then work outward to the A, then the C. Amino Acid is: Tyrosine

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings DNA mRNA Amino Acid Molecules tRNA Molecule C T G mRNA G A C G A A C U U A U A Anticodons C U U G A A C T T G A A T A T G A C G A A C U U A U A