Download The Cell Theory - Science with Mrs. Stevenson

Objectives
●List scientists who contributed to the cell theory
●List the components of the cell theory
●Compare prokaryote and eukaryote cells
●Label a plant and an animal cell
●Know the functions of cell organelles
The Cell Theory
1. Every living organism is
made of one or more cells.
2. The cell is the basic unit of
structure and function.
3. All cells arise from preexisting cells.
*Why is the Cell Theory
called a Theory and not
a Fact?
Early Contributions
● Robert Hooke - First person to see cells, he was
looking at cork and noted that he saw "a great many
boxes. (1665)
● Anton van Leeuwenhoek - Observed living cells in
pond water, which he called "animalcules" (1673)
Leeuwenhoek saw these things in pond water.
What did he call them?
●Theodore Schwann - zoologist who observed tissues of
animals had cells (1839)
●Mattias Schleiden - botanist, observed tissues of plants
contained cells ( 1845)
●Rudolf Virchow - also reported that every living thing is
made of up vital units, known as cells. He predicted that
cells come from other cells. (1850 )
Checkpoint
What was their contribution?
Hooke
Leeuwenhoek
Schwann
Schleiden
Virchow
The Cell Theory
1. All living things are made of _____
2. Cells are the basic unit of _______ and ______
3. Cells come from _______________ cells.
Cell Features
ALL cell have these parts
●Ribosomes – make protein for use by the
organism
●Cytoplasm – fluid material within cell
●DNA – genetic material
●Cytoskeleton – internal framework of cell
●Cell Membrane – outer boundary, some things
can cross the cell membrane
Comprehension Checkpoint
Answer true or false
1.Robert Hooke was the first person to see cells.
2.Bacteria cells have a cell membrane.
3.The Cell Theory was developed by a single scientist.
4.Plant cells have cytoplasm.
5.Cells taken from fungi do not have DNA.
6.Cells can only come from pre-existing cells.
7.It only took five years to develop the Cell Theory.
Prokaryote Cells
● The first cells to inhabit the earth
● Simple cells
● Bacteria
● These cells do NOT have a nucleus, their DNA is
circular and floats in the cytoplasm
Some bacteria have a taillike structure called a
flagella, that helps it to
move.
A capsule surrounds
some bacteria and helps
them avoid the body’s
immune system
Bacteria Images
Bacteria that causes Anthrax
CHECKPOINT
LABEL THE
BACTERIA
Bacteria belong to a
group of cells that do
not have a
____________
Eukaryotic Cells
Cells found in plants, animals, protists, and
fungi
The cell is composed of 4 main parts:
1.Cell membrane
2.Cytoplasm
3.Nucleus – “control center” of cell, DNA
4.Organelles – small structures that carry
out specific functions (“little organs”)
Nucleus
● Usually found at center of cell
● Has a nuclear membrane & nuclear pores
● Contains cell’s DNA in one of 2 forms
o chromatin - DNA and proteins, becomes...
o chromosomes - during cell division
Nucleolus - which makes the cell’s ribosomes
True of False
1. All cells have a nucleus.
2. All cells have a cell membrane.
3. Eukaryote cells are the only cells to have a
flagellum.
4. The nucleus contains the cell’s DNA.
5. Chromatin will become chromosomes.
6. The nucleolus makes the cell’s DNA.
Cell Organelles
Mitochondria – cell’s energy center; turns food
into a chemical energy called ATP
The mitochondria is sometimes called the
“powerhouse” of the cell
Cell Organelles
Golgi Apparatus – processes, packages
and secretes proteins. It is comparable to
a factory or a post office.
*A vesicle forms with
Golgi to transport
substances outside
cell.
Cell Organelles
Lysosome – Contains digestive enzymes,
breaks things down, "suicide sac”
Endoplasmic Reticulum –
Transport, "intracellular
highway".
-Rough ER contains many
ribosomes & is involved in
protein synthesis
-Smooth ER no ribosomes
Vacuole – storage area for water and other
substaces, plant cells usually have a large
central vacuole
Protein Production
The cell is like a factory. Its product is protein which
goes to body to serve different functions.
1.DNA has instructions to build protein
2. Instructions are sent to ribosomes
3.The ribosomes build protein and sends it
through ER
4.The proteins go to golgi where they are packaged
for export
THE ANIMAL CELL
Cheek Cells Seen Through
Microscope
NAME THE PARTS
Plant Cells
●CELL WALL – provides additional support
●CHLOROPLASTS – contain green pigment,
photosynthesis
●CENTRAL VACUOLE – large water container
PLANT CELL
Can you identify
the parts?
Anacharis Cells Viewed With a
Microscope
Animal Cell vs Plant Cell
CELL MEMBRANE
● Selectively permeable ; it regulates what comes into
the cell and what leaves the cell
● It is composed of a double layer of phospholipids
with proteins embedded throughout