Organization of Life Chapter 2

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

Cellular Organization 1-Cell- basic unit of structure and function in living things. 2-Tissue- group of cells that function together to carry out an activity.

3-Organ- group of two or more tissues that perform an activity together. 4-Organ system- group of organs that work together to perform a major life function

. 5-Organism- an entire living thing that carries out all the basic life functions.

Organism Organ system Organ Tissue Cells

The Discovery of the Cell

Robert Hooke discovered and named cells in 1665 when he examined thin slices of cork with a compound microscope he designed.

“Cells” got their name because they reminded Hooke of the small, boxy living quarters of monks.

Perhaps inspired by Hooke, Anton van Leeuwenhoek took up microscopy and built more than 500 microscopes, grinding the lenses himself.

This enabled him to discover and describe red blood cells and bacteria taken from scrapings off his teeth.

Schleiden and Schwann Schleiden used microscopes to observe plant cells. Schwann observed animal cells under microscopes. Schleiden and Schwann summarized their observations and conclusions into the cell theory.

Virchow Approximately 20 years later Virchow saw that cells could not develop from anything except other cells.

Cells The Basic Units of Life

Objectives

1. Identify major cell organelles given a diagram. 2. Distinguish between plant and animal cells given a diagram of a plant. 3. Identify the cell organelle in which photosynthesis occurs.

Cell Wall Supports and protects plant cells. Made of non-living cellulose. Makes plants stiff.

Cell Membrane Gate of the cell Is found on the outside of the cell. Allows materials to pass into and out of the cell. Protects the cell and supports it. Gate of the cell

Nucleus Control center The large oval structure. Directs the activities of the cell like a “brain” Contains the nucleolus and chromosomes. Control center

Nuclear Membrane Surrounds the nucleus and allows materials to pass into or out of the nucleus.

Chromosomes/Chromatin Thick, rodlike objects that direct the activities of the cell and passes on its traits to new cells.

Nucleolus Ribosome factory The round nucleolus is located inside the nucleus. It produces ribosomes and is responsible for making new and repairing cells. Ribosome factory

Cytoplasm Clear, thick, jelly-like substance in the cell between the nucleus and the cell membrane.

Endoplasmic Reticulum Clear, tubular passageways that carry proteins from one part of the cell to another. It is the transportation system for the cell. Roadways

Ribosomes Where amino acids are assembled into proteins. Protein factory

Mitochondria Power plants Rod shaped structures that break down food and release energy. This energy will be used in the cell’s reactions. Power plants

Vacuoles Plant cells have very large vacuoles Stores water and other materials

Vacuoles/Animal Cells Round water-filled sacs that store food and water for the cell. Storage units

Lysosomes Small, round structures that digest food and break down old cells. Cleanup Crew

Golgi Apparatus Post Office flattened membrane sacs that package cell material and ship them to other organelles or out of the cell. Post Office

VESICLES Storage centers for the cell

Chloroplasts Green, irregularly shaped structures that capture the energy of sunlight and produces food through the process of photosynthesis. Energy producers