Download The Cell Notes

The Cell
Cell Theory and Structure
Scientists Contributing to The Cell
Theory
Anton van Leeuwenhoek– one of the first people
to study nature with a microscope– he made
detailed drawings of little creatures he found in
pond water
Robert Hooke- Coined the term “cell”. He
looked at cork through the microscope and said
the compartments looked like the rooms that
monks lived in “cells”
Rudolph Virchow, Schleiden and Schwann said
that cells come from other cells and all plants
and animals are made of cells
The Cell Theory
All the scientists previously mentioned
contributed to the Cell Theory which
states:
– All living things are composed of cells
– Cells are the basic unit of structure and
function in living organisms
– New cells are produced from pre-existing cells
Prokaryotes and Eukaryotes
Prokaryotes- simple cells with no nucleus
or membrane-bound organelles.
Examples are bacteria
Eukaryotes- complicated cells with a
control center (nucleus) and other
organelles (means little organ) Animals
and plants have Eukaryotic cells
Cell Structures-
Animal Cell
Plant Cell
The Outer Cell
Cell membrane- a thin, flexible barrier
around the cell. Cell membranes are
semi-permeable, meaning that they allow
certain materials in and out of the cell
Cell Wall- Thick, outer covering of plant
cells, bacteria cells, fungi cells and algae
cells. Cell walls provide support and
protection for the cell. Made of cellulose
(plants) and chitin (fungi)
Picture It!
Cell Membrane
Cell Wall
The Nucleus
Scottish botanist Robert Brown first identified the
nucleus in 1831
The nucleus controls much of the cell’s activity
and contains the cell’s hereditary information in
the form of DNA (Deoxyribonucleic Acid)
Almost all eukaryotic cells including plant and
animal cells contain a nucleus
Prokaryotic cells like bacteria have no nucleus
The Nucleus, Cont.
An Actual
Nucleus
Model of a Nucleus
“Matrix”
Nucleus
Inside the Nucleus
Chromatin- the granular material inside the
nucleus. It is made of DNA bound to protein, and
carries the hereditary information in the cell
Chromosomes- chromatin condenses to form
chromosomes during cell division
Nucleolus- Small dense region inside the
nucleus that is responsible for the assembly of
ribosomes, which make proteins
Nuclear membrane- outer covering of the
nucleus, allows a steady stream of RNA in and
out.
Nucleolus
Chromatin
Chromosomes
Cytoskeleton
Network of protein filaments
that helps the cell maintain
its shape
Also involved in many forms
of cellular movement (cilia
and flagella
Microtubules are hollow
protein tubes that maintain
cellular shape and serve as
“tracks” on which organelles
can travel
Microfilaments- protein
filaments that provide
structure for the cell
Cilia and Flagella
Organelles in the Cytoplasm
The cytoplasm is the liquid
“goo” like material inside
the cell. It is made of water
and salts, and contains all
the cell organelles (little
organs)
Ribosomes are made of
RNA and protein. They
assemble proteins following
the coded information
stored in the nucleus.
Electron Microscope
image of Ribosomes
Endoplasmic Reticulum
Internal membrane
system in which cell
membrane
components are
made and proteins
are modified
Smooth ER- does not
contain ribosomes
Rough ER- “studded”
with ribosomes
Smooth ER
Rough ER
More Cytoplasmic Organelles
Golgi Apparatus- packages and ships
materials, attaches necessary
carbohydrates and lipids to proteins. This
organelle is a stack of sac-like membranes
Lysosomes- breaks down carbohydrates
and lipids, also “eats” dead organellescleans up the cell
Vacuoles- store food and water for cells to
use, plant cells have huge vacuoles
Can you find the vacuole?
Energy! Energy! Energy!
Mitochondria- Found in
both animal and plant
cells. Breaks down
glucose (food) to release
energy (ATP)
Chloroplasts- Found in
plant, algae and some
bacteria cells.
Autotrophic, the organelle
that converts sunlight into
glucose
Putting it All Together
An Amazing Journey
Tiny little cells are so very complex! Imagine taking a magic
journey inside one of your cells… what would you see????