Unit 6 Notes: Cell Basics Monday 2-1-2010 Unit 6 Notes: Cell Basics

(1) Big Ideas: All cells need to divide and make more cells. Cells come from pre-existing cells. Non-Sex Cells divide using Mitosis. Sex-Cells divide using Meiosis. If a cell is copied incorrectly it is either terminated, or can lead to cancer.

(2) Cell Review Cell: Basic Unit of Life. Eukaryotic  With A Nucleus Prokaryotic  No Nucleus Must Complete “Life Processes”: Homeostasis Reproduce Digest & Excrete Respond & Adapt

(3) The Nucleus & DNA Nucleus: Organelle in eukaryotic cells, which stores nucleic acid (DNA). Nucleic Acid = Genetic Information DNA contains instructions for making cell parts DNA: Deoxyribonucleic Acid A type of nucleic acid which stores cellular genetic information. Condenses during Cell Division… DNA  Chromatin  Chromosomes

(4) Genes & Alleles A gene is a specific sequence of DNA. Each gene comes in different “flavors”: Allele: Variation of a gene. Dominant or Recessive

(5) Multicellular Organisms Multicellular: Organisms which are made of more than one cell. Multicellular  More Complex: Cells are specialized (each has unique function) Cells form Tissues  Organs  Organ Systems Examples: Plants Animals

(6) Why Divide? Repair + Replace Reproduce Grow

(7) Mitosis vs. Meiosis Non Sex Cells (Somatic Cells) Start w/1 Cell, End w/2 Identical 2n  2n Sex Cells (Gametes, Sperm/Egg) Start w/1 cell, End w/4 unique 2n  n