Download an introduction to cells

AN INTRODUCTION
TO CELLS
Science 8 – Mr. Klasz
CELL THEORY
• There are two main postulates (parts) to the cell theory:
• All living things are composed of cells.
• All cells come from pre-existing cells.
CELLS OVERVIEW
• There are two main groupings of cells: Animal cells and plant cells
• Within each cell, there are a number of organelles.
• These organelles perform specific functions within the cell, very similar to
the organs in your body.
• We will learn about the following organelles this year:
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The Cell Membrane
The Nucleus
The Cytoplasm
The Vacuoles
The Golgi Apparatus
The Lysosomes (not in my plant cells)
The Endoplasmic Reticulum
The Mitochondria
The Ribosomes
The Cell Wall (only found in plant cells)
The Chloroplasts (only found in plant cells)
THE ANIMAL CELL
THE PLANT CELL
THE NUCLEUS
• The nucleus is the brain of the cell.
• It controls and directs all of the cell’s activities
• The chromosomes are found within the nucleus
• The genetic material (DNA) is contained within the
chromosomes.
THE CELL MEMBRANE
• The cell membrane is the gatekeeper of the cell.
• It determines what can enter/exit the cell and what
cannot.
• The cell membrane is porous, such that it allows nutrients
and waste enter and exit the cell.
• It hold the cell together. It is like our skin.
THE CYTOPLASM
• The cytoplasm is a gel like fluid that fills the cell.
• The cytoplasm provides stability to the organelles,
allowing them to remain in relatively the same position
in the cell (rather then bouncing around).
• The cytoplasm contains “highways” that allow essential
materials to be quickly transported into/out of/across
the cell.
• Waste produced by the cell is also stored here until it
can be disposed of.
THE VACUOLE
• The vacuole is the stomach of the cell.
• Each vacuole is filled with fluid, and stores all water and
nutrients required by the cell.
• Animal cells contain multiple smaller vacuoles
• Plant cells contain one large central vacuole.
THE MITOCHONDRIA
• The mitochondria is the “powerhouse” of the cell.
• It provides energy, through a process called cellular
respiration.
THE ENDOPLASMIC
RETICULUM
• The endoplasmic reticulum (ER) surrounds the nucleus.
• It is a series of folded membranes.
• It creates proteins & fats.
• It transports materials through the cytoplasm.
• There are two types of ER:
• Smooth No ribosomes attached
• Rough Ribosomes attached
RIBOSOMES
• Ribosomes are attached to the rough ER.
• They produce proteins, which are essentially building
blocks for the cell.
• The look like little dots on the ER.
THE GOLGI APPARATUS
• After proteins are produced by the ribosomes, they are
held in the Golgi Apparatus.
• This is like the “packing station” of the cell.
• The proteins are put into packages called vesicles.
• Once proteins are in vesicles, they are transported
around the cell, or outside of the cell, depending on
their function.
THE LYSOSOMES
• Lysosomes are NOT found in most plant cells.
• Lysosomes float through the cytoplasm and clean up.
• They contain digestive enzymes,
• Lysosomes can be compared to our stomach acid.
• Lysosomes break down:
• Large food molecules into small molecules that the cell
can use.
• Cellular waste so that it can be discharged from the cell.
THE CELL WALL
• ONLY plant cells contain cell walls.
• The cell wall extra support and protection for the plant
cell.
• It is porous and contains small holes that food, water,
and waste can pass through.
• The cell membrane is located under the cell wall in
plant cells.
THE CHLOROPLAST
• ONLY plant cells contain chloroplasts.
• Chloroplasts contain chlorophyll, which allows plant
cells to make their own food, using light from the sun.
• Chlorophyll is what makes plants green.
ANIMAL VS. PLANT CELLS
Animal Cell
Plant Cell
Does not contain a cell wall
Contains a cell wall
Does not contain chloroplasts
Contains chloroplasts
Contains lysosomes
Most do not have lysosomes
Contains many small vacuoles
Contains one large central vacuole