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 )
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. It is the smallest unit that can perform life functions.
4. All cells arise from pre-existing cells.
*Why is the Cell Theory called a Theory and not a Fact?
ALL cells 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
Answer true or false
Robert Hooke was the first person to see cells.
Bacteria cells have a cell membrane.
The Cell Theory was developed by a single scientist.
Plant cells have cytoplasm.
Cells taken from fungi do not have DNA.
Cells can only come from pre-existing cells.
The first cells to inhabit the earth
These cells do NOT have a nucleus, their DNA is circular and floats in the cytoplasm
Some bacteria have a tail-like structure called a flagella, that helps it to move. A capsule surrounds some bacteria and helps them avoid the body’s immune system
Bacteria-prokaryotic Bacteria that causes Anthrax
Cells found in plants, animals, protists, and fungi
The cell is composed of 4 main parts:
Nucleus – “control center” of cell, houses DNA
Organelles – small structures that carry out specific functions (“little organs”)
Usually found at center of cell
Has a nuclear membrane & nuclear pores
Contains cell’s DNA in one of 2 forms
chromatin - DNA bound to protein (non-dividing cell)
chromosomes - condensed structures seen in a dividing cell (look like Xs)
Also contains an organelle called nucleolus - which makes the cell’s ribosomes
Cell Organelles Mitochondria – this is the cell’s energy center. It 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 is used with the Golgi to transport substances outside cell, like a messenger delivering a package.
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 ribosomes not found on surface
Cell Organelles Cytoskeleton – Helps cell maintain support & shape; movement a. microtubules -hollow structures; also help build cilia flagella b. microfilaments -threadlike c. centrioles -only in animal cells; used during cell division (paired) Vacuole – storage area for water and other substaces, plant cells usually have a large central vacuole
The cell is like a factory. Its product is protein which goes to body to serve different functions.
DNA has instructions to build protein
These instructions are sent to ribosomes
The ribosomes build protein and send it through ER
The proteins are delivered to golgi where they are completed and “tagged” for export outside cell
THE ANIMAL CELL
Cheek Cells Seen Through Microscope
Have additional structures
CELL WALL – surrounds membrane & provides additional support
CHLOROPLASTS – contain green pigment, function in photosynthesis
CENTRAL VACUOLE – large water container in center of cell
PLANT CELL Can you identify the parts?
Anacharis Cells Viewed With a Microscope
Organelles With DNA
Mitochondria and chloroplasts have their own DNA (separate from the nucleus)
This supports the ENDOSYMBIOSIS THEORY which states that eukaryotic cells evolved when prokaryote cells engulfed or absorbed other cells.
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