Chapter 7 CELLS

DISCOVERY Robert Hooke 1665- examined a slice of cork and saw little boxes he called “cells”

DEFINITION CELL- the smallest unit of matter that can carry on all the processes of life (Plants, animals) Plant cells discovered by SCHLEIDEN in 1838 Animal cells discovered by SCHWANN in 1855

CELL THEORY- 3 parts 1. all living things are made of one or more cells 2. cells are the basic units of structure and function in an organism 3. cells come only from the reproduction of existing cells

CELL DIVERSITY SIZE- cells are limited in size by the ratio between their outer surface area and their volume Nutrients, oxygen, and other materials must pass through the surface of the cell

CELL DIVERSITY SHAPE- cells come in a variety of shapes to best fit their function Example Nerve Cell- long and slender with many branches White Blood Cell- can change shape, leave blood, and engulf bacteria

CELL DIVERSITY INTERNAL ORGANIZATION-cells contain a variety of structures called ORGANELLES ORGANELLES- “little organ”- performs specific functions for the cell

ORGANELLES CELL MEMBRANE- thin membrane that separates the cell from its environment

ORGANELLES NUCLEUS – large dense area near the center of the cell that controls all the cells functions and carries hereditary information EUKARYOTES ---“ true” “nucleus”- organisms whose cells have a membrane bound nucleus and other organelles Examples- PROKARYOTES- organisms that do not have a membrane bound nucleus

ORGANELLES CELL WALL- (CELLULOSE) –rigid structure on the outside of the cell membrane of plant cells. Provides structure and protection for the cell

ORGANELLES CYTOPLASM- liquid portion of the cell (up to 80% water) location of many chemical reactions

ORGANELLES MITOCHONDRIA- double membraned cell with CRISTAE (waves)-produces energy for the cell (ATP)

ORGANELLES ROUGH ENDOPLASMIC RETICULUM- sets of tubules located near the nucleus that are lined with ribosomes- synthesizes proteins

ORGANELLES SMOOTH ENDOPLASMIC RETICULUM- sets of tubules located near the rough ER that are without ribosomes- synthesizes fats, breaks down toxins

ORGANELLES RIBOSOME- tiny dots found on the Rough ER (or floating around) that synthesize protein

ORGANELLES GOLGI APPARATUS- (UPS of the cell) flattened stacks of membranes that receive, package, and transport materials throughout the cell

ORGANELLES LYSOSOME- (garbage disposal of the cell) vesicles filled with digestive enzymes. Breaks down dead cell parts, bacteria invaders, food.

ORGANELLES PEROXISOMES- vesicles filled with enzymes used to detoxify the cell

ORGANELLES CYTOSKELETON- network of long proteins that give the cell structure and move items around in the cell

ORGANELLES MICROTUBULES-long hollow tubes that provide support for the cell- helps in cell division

ORGANELLES MICROFILAMENTS- thin fibers of protein that help in movement of the cell and aide in contraction of muscle cells

ORGANELLES CENTRIOLES- specialized microtubules around the nucleus that helps with the division of the nucleus

ORGANELLES CHLOROPLASTS- double membraned organelle that collects light and makes glucose (PHOTOSYNTHESIS)

ORGANELLES CHLOROPHYLL- green pigment in chloroplasts that absorb visible light

ORGANELLES VACUOLES- large vesicle (in plants) and smaller in animals- that store fluids such as – enzymes, water, wastes, ions, food

ORGANELLES FLAGELLA- long whip like tail filled with microtubules that are used for motility.

ORGANELLES CILIA- small hairlike structure made of microtubules that aide in motility or collects food