Cells : The Units of Life. The Cell Theory Some Random Cell Facts The average human being is...
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Transcript of Cells : The Units of Life. The Cell Theory Some Random Cell Facts The average human being is...
Cells: The Units of Life
The Cell Theory
Some Random Cell Facts
The average human being is composed of around 100 Trillion individual cells!!!
It would take as many as 50 cells to cover the area of a dot on the letter “i”
Discovery of Cells
1665- English Scientist, Robert Hooke, discovered cells while looking at a thin slice of cork.
He described the cells as tiny boxes or a honeycomb
He thought that cells only existed in plants and fungi
Anton van Leuwenhoek
1673- Used a handmade microscope to observe pond scum & discovered single-celled organisms
He called them “animalcules”
He also observed blood cells from fish, birds, frogs, dogs, and humans
Therefore, it was known that cells are found in animals as well as plants
150-200 Year Gap???
Between the Hooke/Leuwenhoek discoveries and the mid 19th century, very little cell advancements were made.
This is probably due to the widely accepted, traditional belief in Spontaneous Generation.
Examples:
-Mice from dirty clothes/corn husks
-Maggots from rotting meat
19th Century Advancement
Much doubt existed around Spontaneous Generation Conclusively disproved by Louis Pasteur
Pasteur: Ummm, I don’t think so!!!
+
=?
Development of Cell Theory
1838- German Botanist, Matthias Schleiden, concluded that all plant parts are made of cells
1839- German physiologist, Theodor Schwann, who was a close friend of Schleiden, stated that all animal tissues are composed of cells.
Development of Cell Theory
1858- Rudolf Virchow, German physician, after extensive study of cellular pathology, concluded that cells must arise from preexisting cells.
The Cell Theory Complete
The 3 Basic Components of the Cell Theory were now complete:
1. All organisms are composed of one or more cells. (Schleiden & Schwann)(1838-39)
2. The cell is the basic unit of life in all living things. (Schleiden & Schwann)(1838-39)
3. All cells are produced by the division of preexisting cells. (Virchow)(1858)
Modern Cell Theory
Modern Cell Theory contains 4 statements, in addition to the original Cell Theory:
The cell contains hereditary information(DNA) which is passed on from cell to cell during cell division.
All cells are basically the same in chemical composition and metabolic activities.
All basic chemical & physiological functions are carried out inside the cells.(movement, digestion,etc)
Cell activity depends on the activities of sub-cellular structures within the cell(organelles, nucleus, plasma membrane)
How Has The Cell Theory Been Used?
The basic discovered truths about cells, listed in the Cell Theory, are the basis for things such as:– Disease/Health/Medical Research and Cures(AIDS,
Cancer, Vaccines, Cloning, Stem Cell Research, etc.)
Parts of the Cell: Organelles
COMMON CELL TRAITS
A cell is the smallest unit that is capable of performing life functions.
2 Types of Cells
COMPARING CELLS
The size & shape of a cell relates to its function. (job it does)
Prokaryotic Cells(proh KAYR ee yah tihk)
cells without membrane-bound structures
EX: bacteria
pond scum
Eukaryotic Cells(yew KAYR ee yah tihk)
cells with membrane-bound structures
EX: animals, plants, fungi and protists
protects the cell gives shape is made of cellulose A cell wall is found in plants, algae, fungi, & most
bacteria.
CELL WALL
CELL MEMBRANE
Outer covering, protective layer around ALL cells
For cells with cell walls,the cell membrane is inside the cell wall
Allows food, oxygen, & water into the cell & waste products out of the cell.
CYTOPLASM
gelatin-like inside cell membrane constantly flows aka protoplasm
CYTOSKELETON
scaffolding-like structure in cytoplasm
helps the cell maintain or change its shape
made of protein
NUCLEUS
Directs all cell activities Contains instructions
for everything the cell does
These instructions are found on a hereditary material called DNA
Usually the largest organelle
NUCLEAR MEMBRANE
separates nucleus from cytoplasm
controls movement of materials in & out of nucleus
NUCLEOLUS
Aka “little nucleus” Found in the nucleus
CHROMATIN
contains genetic code that controls cell made of DNA & proteins
CHLOROPLASTS
Green organelles that make food
found only in plant cells
CHLOROPHYLL
A green pigment that gives leaves & stems their color
Captures sunlight energy that is used to produce food called glucose
Glucose is a type of sugar
MITOCHONDRIA
Organelles that release energy from food
This energy is released by breaking down food into carbon dioxide
AKA the powerhouse b/c they release energy from food
Some muscle cells have 20,000 mitochondria
RIBOSOMES
Make proteins Float freely or attached to
the endoplasmic reticulum (ER)
Ribosomes are made in the nucleolus
ENDOPLASMIC RETICULUM
A series of folded membranes that move materials (proteins) around in a cell
like a conveyor belt Smooth ER – ribosomes not
attached to ER Rough ER – ribosomes
attached to ER
GOLGI BODIES (GAWL jee)
Stacked flattened membranes
Sort and package proteins
VACUOLES
Temporary storage spaces
Store food, water, waste
LYSOSOMES (LI suh sohmz)
The word "lysosome" is Latin for "kill body." The purpose of the lysosome is to digest things.
They might be used to digest food or break down the cell when it dies.
Break down food molecules, cell wastes & worn out cell parts
FROM CELL TO ORGANISMCell
The basic unit of life
TissueGroup of cells working together
OrganGroup of tissues working together
OrganismAny living thing made of 1 or more cells
Organ SystemGroup of organs working together
NAME THE ORGANELLE
d. Mitochondriab. Chloroplast
c. Golgi body a. Nucleus
1- Nucleus
2- Chromosomes
3- Mitochondria
4- Ribosomes
5- Chloroplasts
6- Vacuoles
7- ER
8- Cell Membrane