General Biology

General Biology – Semester 1 – Quarter 1 STEM 11 SCIENTISTS
Robert Hooke
CELL THEORY  observed cells in cork
Modern Cell Theory  coined the term “cells”
Modern Cell Theory contains 4 statements, in addition  described cells as “tiny holes” or
to the original Cell Theory: “honeycomb”
 The cell contains hereditary information  thought cells existed only in plants and fungi
(DNA) which is passed on from cell to cell
during cell division Anton van Leuwenhoek
 All cells are basically the same gin chemical  used a handmade microscope to observe pond
composition and metabolic activities scum & discovered single-cell organisms
 All basic chemical & physiological functions  called them “animalcules”
are carried out inside the cells (movement,  observed blood cells from fish, birds, frogs,
digestion, etc.) dogs, and humans
 Cell activity depends on the activities of sub-  it was known then that cells are found in
cellular structures within the cell ( organelles, animals as well as plants
nucleus, plasma, membrane) Robert Brown
 noticed pollen grains in water jiggled
The 3 Basic Components of the Cell Theory were  called “Brownian Motion”
now complete:  discovered Nucleus
 All organisms are composed of one or more
 discovered nuclei within the cells, pave the
cells (Schleiden & Schwann) way to discover other nuclear components,
 The cell is the basic unit of life in all living chromosomes & DNA
things (Schleiden & Schwann)
 All cells are produced by the division of pre- Felix Dujardin
existing cells (Virchow 1858)  described a formless substance, sarcode –
protoplasm
How Has The Cell Theory Been Used?
The basic discovered truths about cells, listed in the Matthias Schleiden
Cell Theory, are the basics for things such as:
 botanist
Disease/Health/Medical Research and Curses (AIDS,
 concluded that “all plants are made of cells”
Cancer, Vaccines, Cloning, Stem Cell Research, etc.)
Theodor Schwann
 zoologist
 concluded that “all animals are made of cells”

Rudolph Virchow
 physician
 did research on cancer cells
 concluded “Omnis cellula e cellula” / “All
cells are from other pre-existing cells”
 cells must arise from pre-existing cells

, CELL STRUCTURE & FUNCTIONS
Example of Cells: Mitochondria
 Amoeba Proteus  produces energy through chemical reactions -
 Bacteria breaking down fats & carbohydrates
 Nerve Cell  control levels of water & other material in cell
 Plant Stem  recycles and decomposes proteins, fats, and
 Red Blood Cell carbohydrates

Cell Membrane Golgi Bodies
 outer membrane  protein ‘packaging plant’
 controls movement in and out  move materials within the cell
 double layer  move materials out of the cell

Cell Wall Lysosome
 commonly found in plant cells & bacteria  Digestive ‘plant’ for proteins, fats, and
 supports & protects cells carbohydrates
 Transports undigested material to cell
Nucleus membrane for removal
 directs cell activities  Cell breaks down if lysosome explodes
 separated from cytoplasm by nuclear
membrane Vacuoles
 contains genetic material - DNA  membrane-bound sacs for storage, digestion,
 control center and waste removal
 contains water solution - meaning it’s watery
Nuclear Membrane  help plants maintain shape
 surrounds nucleus
 made of two layers Chloroplast
 openings allow material to enter and leave  usually found in plant cells
nucleus  contains green chlorophyll
 where photosynthesis takes place
Chromosomes
 in nucleus
 made of DNA
 contains instructions for traits &
characteristics

Nucleolus
 inside nucleus
 contains RNA
 build proteins

Cytoplasm
 gel-like mixture
 surrounded by cell membranes
 contains hereditary material - DNA

Endoplasmic Reticulum
 moves materials around in cell
 Smooth Type - lacks ribosomes
 Rough Type - ribosomes embedded in surface

Ribosomes
 each cell contains thousands
 make proteins
 found floating throughout the cytoplasm