Biology: The Study of Life! Living Organisms

Living Vs. Non-Living  Can you classify something that is living versus something that is non-living?

The Characteristics of all Living Organisms  What makes something “alive”?  All living things have  Cellular organization  Contain similar chemicals  Use energy  Respond to their surroundings  Grow, develop, and reproduce

Cellular Organization  Cell- the basic unit of structure and function in an organism  Organisms can be:  Unicellular- single celled  Multicellular- composed of many cells

The Chemicals of Life  Water  Carbohydrates (main energy source)  Proteins and lipids (the building blocks of cells)  Nucleic acids (genetic material)

Energy use, Growth and Development  Living organisms need energy to do everything!!  Growth- to become larger  Development- the process of change that occurs to produce a more complex organism  Reproduction- to produce offspring

Responding to Surroundings  Stimuli- changes in temperature, light, sound, and other factors  Response- an action or change in behavior

The Needs of Living Things  What do you need to live?  Water  Food  Living Space  Stable internal conditions  Homeostasis- the maintenance of stable internal conditions

Cell Structure & Function

Two Types of Cells Prokaryotic Eukaryotic

Prokaryotic  Do not have structures surrounded by membranes  Few internal structures  One-celled organisms, Bacteria

Eukaryotic  Contain organelles surrounded by membranes  Most living organisms PlantAnimal

“ Typical ” Animal Cell /~ acarpi/NSC/images/cell.gif

Cell Parts Organelles

Surrounding the Cell

Cell Membrane  Outer membrane of cell that controls movement in and out of the cell  Double layer

Cell Wall  Most commonly found in plant cells & bacteria  Supports & protects cells

Inside the Cell

Nucleus  Directs cell activities  Separated from cytoplasm by nuclear membrane  Contains genetic material - DNA

Nuclear Membrane  Surrounds nucleus  Made of two layers  Openings allow material to enter and leave nucleus

Chromosomes  In nucleus  Made of DNA  Contain instructions for traits & characteristics

Nucleolus  Inside nucleus  Contains RNA to build proteins

Cytoplasm  Gel-like mixture  Surrounded by cell membrane  Contains hereditary material

Endoplasmic Reticulum  Moves materials around in cell  Smooth type: lacks ribosomes  Rough type (pictured): ribosomes embedded in surface

Ribosomes  Each cell contains thousands  Make proteins  Found on ribosomes & floating throughout the cell

Mitochondria  Produces energy through chemical reactions – breaking down fats & carbohydrates  Controls level of water and other materials in cell  Recycles and decomposes proteins, fats, and carbohydrates

Golgi Bodies  Protein 'packaging plant'  Move materials within the cell  Move materials out of the cell

Lysosome  Digestive 'plant' for proteins, fats, and carbohydrates  Transports undigested material to cell membrane for removal  Cell breaks down if lysosome explodes

Vacuoles  Membrane-bound sacs for storage, digestion, and waste removal  Contains water solution  Help plants maintain shape

“ Typical ” Plant Cell

Chloroplast  Usually found in plant cells  Contains green chlorophyll  Where photosynthesis takes place

Cell Division

MITOSIS

Mitosis The process of cell division which results in the production of two daughter cells from a single parent cell. The daughter cells are identical to one another and to the original parent cell.

Mitosis can be divided into stages Interphase Prophase Metaphase Anaphase Telophase & Cytokinesis

Interphase The cell prepares for division  Animal Cell  DNA replicated  Organelles replicated  Cell increases in size

Interphase Photographs from:

Prophase The cell prepares for nuclear division  Animal Cell  Packages DNA into chromosomes

Prophase Photographs from:

Metaphase The cell prepares chromosomes for division  Animal Cell  Chromosomes line up at the center of the cell  Spindle fibers attach from daughter cells to chromosomes at the centromere

Metaphase Photographs from:

Anaphase The chromosomes divide  Animal Cell  Spindle fibers pull chromosomes apart  ½ of each chromosome (called chromotid) moves to each daughter cell

Anaphase Photographs from:

Telophase The cytoplasm divides  Animal Cell  DNA spreads out  2 nuclei form  Cell wall pinches in to form the 2 new daughter cells

Telophase Animal Cell Plant Cell Photographs from:

Mitosis Animation

Animal Mitosis Review Interphase Prophase Metaphase Anaphase Telophase Interphase