topic: cells aim: how do we describe cells?. how do we know that cells exist? the discovery of the...
TRANSCRIPT
TOPIC: CELLSAIM: How do we describe cells?
How do we know that cells
exist?
The discovery of the microscope
RobertHooke
•Observed slices of cork with a comp. microscope (1600’s)
Anton van Leeuwenhoek
1600’sUsed a simple microscope
First to look at living cells
Observed one- celled organisms like bacteria
Rain pond water, the mouth, intestines
MatthiasSchleidan
Observed plant cells
All plants are made of cells
TheodorSchwann
Observed animal cells
All animals are made of cells
RobertVirchow
All cells are made from pre-existing cells.
(Cells divide more cells)
CellTheory
1. Cells are the basic unit of structure in all living things.
(Living things are made of cells)
2. Cells are the basic unit of function of all living things
(They carry out life processes)
3. All cells come from pre-existing cells.
Exceptionsto the CellTheory
1. Viruses are NOT cells, and are NOT made of cells.
Virus do not reproduce by division because they are not
cells.
2. Mitochondria & Chloroplasts
cell parts that have their own DNA and reproduce on their own.
(Don’t need the nucleus to reproduce)
3. The first cell could not have come from a pre-existing cell.
Cells •Microscopic•Found in living
things•There are
different types•Smallest living
thing on earth
EXAMPLES OF CELLS
Skin cells
Bone cells
MORE CELLS
Brain cells
Blood cells
If there are so
many cells how do we
classify them? 2.Based on the type of
organism it belongs to• Plant cell• Animal cell
1.Based on location or function of the cell
• blood cell• muscle cell
Organism • Any living thing
• Examples:–Shark -Tree-Bacteria–Human -Bird
Nucleus or No Nucleus or No Nucleus??Nucleus??
Some cells have a nucleus, they are called
EUKARYOTES(Hey, you!! Do you have a nucleus?)
• Animal and Plant cells are eukaryotes.
Some cells don’t have a nucleus, they are called PROKARYOTES
• Bacteria are prokaryotic cells.
Cells work (perform life activities) because
they contain organelles
Organelles• Structures
that are found in the cell that perform all cell activities
• a.k.a cell parts
Examples of
organellesNucleus
• Located in the center of the cell
• Appears as a circle• Sometimes solid in
color
The function is to be the control center for the cell and contains chromosomes. Contains a Nucleolus – helps in protein production.
Chromosomes - contain hereditary genetic information
Cell Membrane
• Located around the entire cell
• Appears as a thin line• Similar to the walls
of the classroom
• The function is to be a barrier (wall) between the outside of the cell and the inside. AND……
• Allows materials to transport in and out of the cell
Cytoplasm • Located inside the cell membrane and outside the nucleus
• Appears as the “liquid” between all the organelles
• The function is to support all the organelles AND…
• Transport materials around the cell
• Similar to the ______in our bodies
Vacuole• Location is
scattered around the cytoplasm
• Appears as an empty circle
• The function is to be the storage site for wastes and other cellular materials
• Similar to the garbage pails in each room
Endoplasmic Reticulum
• Located around the nucleus
• Appears as canals • A.k.a. – ER
• The function of the ER is to transport materials within the cell
AND….Sometimes contains
ribosomes
Ribosomes • Located on the ER and scattered around the cytoplasm
• Appears as dots
• The function is protein formation (synthesis)
• RIBosomes---Baby-back ribs give you protein
What do cells need to do all this work?
Mitochondria
• Located within the cytoplasm
• Appear as bean shaped structures
• The function is the production of energy
• A.k.a – the powerhouse
More OrganellesGolgi Bodies • Located in the
cytoplasm• Appear as a
structure with many folds
• The function is to package all the wastes for removal
Lysosome • Located in the cytoplasm
• Appear as small circular structures with particles inside
• The function is to digest (break down) cellular materials
Centriole• Located in the
cytoplasm• Often near the nucleus• Appears in a set of two• ONLY IN ANIMAL CELLS
• The function is to help the cell with cellular division of the chromosomes
Chloroplasts• Located around the edge
of the cell• Appear as oval structures
with lines • ONLY IN PLANT CELLS• Contain Chlorophyll
• The function is to perform photosynthesis
Photosynthesisprocess in which plants produce their own food
Cell wall• Located outside
the cell membrane• ONLY IN PLANT
CELLS
• The function is to provide support and structure for the cell
Organelle Challenge