Anatomical Terminology and Orientation Review Always refer to anatomical position with directions!!
Planes • Removes the top of the head? • Divides the toes from the body?
Body landmarks Brachial Pateller
DNA Inherited genetic material inside each cell Composed of nucleotides 3 parts to a nucleotide: 1. Nitrogenous base -A – T -G -- C 2. Pentose sugar 3. Phosphate group - “backbone”
DNA in the Cell Located within the cell’s nucleus Remains loosely coiled in nondividing cells but forms into chromosome before dividing
Passing on DNA • Cells divide to pass on genetic material • Somatic (body) cells undergo mitosis and cytokinesis • Replaces dead or injured cells • Adds new cells during growth • Germ cells (sperm or oocytes) undergo meiosis • Produces gametes
The Cell Cycle Mitosis: Cell duplicates its contents and divides in two 3 Main Stages Interphase Mitosis Cytokinesis
Interphase • DNA replicated • Cell does most of its growing • 3 Phases: G1 - replication of most organelles and cytosolic components S – DNA replication G2– enzymes and other proteins are synthesized in prep for division
Mitotic Phase • Prophase • DNA shortens into chromosomes • Each centrosome moves to an opposite pole of cell • Nucleolus disappears, nuclear envelope dissolves • Spindle fibers and asters become visible
Mitotic Phase • Metaphase • Centromeres of chromatid pairs are aligned at exact center • Anaphase • Centromeres split, indentical sets of chromosomes moved to opposite poles
Mitotic Phase • Telophase • Chromosomes uncoil and revert to chromatin form • Nuclear envelope forms around each mass
Cytokinesis • Division of the cytoplasm • NOT A PART OF MITOSIS!! • Mitosis is a nuclear event, cytokinesis is cytoplasmic
Genotype Phenotype • AA, Ab • aa
Heterozygous female with freckles x heterozygous male with freckles 1 : 2 : 1
Incomplete Dominance Neither trait is dominant Heterozygotes show a blending of the traits
X – linked traits • Traits passed on by the sex chromosomes
Epistasis Action or expression of a gene influences that of another
Next Week • Quiz first 15-20 minutes of class. Do not be late!!! • Covers material from Labs 1 & 2 and definitions from Lab 3.
What is due today? • Integrate: Heredity: Principles of Inheritance • Objectives on page 31 • Skip questions on “sex-influenced” and “holandric” (questions # 10 & 14) • Read and answer Activity Questions on pages 33- 40, 42, and 45-46 (only do section V) • General questions # 1 - 3