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Explore Cells
At your assigned lab table, draw the slide that you observe under the microscope.
Write down any interesting details you would use to describe the slide.
Be prepared to share your findings with the group.
History of the cell
In 1665, Robert Hooke was the first to view cells from cork (dead plant material). He called them “cells” because they looked like tiny rooms.
Anton van Leeuwenhoek saw tiny living organisms in water in 1675.
In 1838, Matthias Schleiden determined that plants are made up of cells.
In 1839, Theodor Schwann determined that animals are made up of cells.
In 1855, Rudolf Virchow concluded that new cells are produced from the division of existing cells.
The Cell Theory
All living things are composed of cells.
Cells are the basic units of structure and function in living things.
New cells are produced from existing cells.
Types of Cells
Two kinds of cells depending on whether they have a nucleus
Prokaryote
Eukaryote
Genetic material
Prokaryotes
Usually small and simple
Genetic material (DNA) is not contained in a nucleus
The ONLY prokaryotes in the world are BACTERIA.
Eukaryotes
Usually larger and more complex than prokaryotes.
May be unicellular like an amoeba or multicellular like a plant
Contain dozens of specialized structures called organelles.
Includes protists, fungi, plants and animals.
Eukaryotic cell structure
Two major parts: Nucleus
Cytoplasm-portion of the cell outside the nucleus
Nucleus-The control center
Function:
Contains almost all of the cell’s DNA for coding proteins and other molecules.
DNA is found on chromosomes which contain genetic information.
Nucleus-The control center
Structure: Surrounded by a double
membrane called a nuclear envelope. It is dotted with many pores (holes) to allow materials (RNA, proteins, etc) in and out of the nucleus.
Small internal region called a nucleolus where ribosomes are made.
Ribosomes
Function: Site of protein
assembly.
Structure: Small pieces of RNA
and protein found throughout the cell.
Endoplasmic Reticulum
Function: Site where lipid parts of
cell membrane are made, along with proteins and other materials to export from the cell.
Structure: Rough ER- has
ribosomes on surface to assemble proteins
Smooth ER-NO ribosomes on surface
Golgi Apparatus
Function: Modify, sort, and
package proteins and other materials from the ER for storage in the cell or release from the cell. It puts the finishing touches on proteins.
Structure: Stack of closely
packed membranes
You have 3 minutes to compare your notes with a neighbor. Be sure to ask questions and fill in any blanks you may have in your notes at this time.
Lysosomes-The Clean Up Crew
Function: Breakdown of lipids,
carbohydrates and proteins into small molecules to be used by the rest of the cell
Breakdown used up organelles
Get rid of all “stuff” in the cell
Structure: Small, filled with
enzymes
Vacuoles - Storage
Function: Stores water, salts,
proteins and carbohydrates
Structure: Sac-like Plant cells have one
large central vacuole Animal cells have
many small vacuoles
Mitochondria - Energy
Function: Convert chemical
energy in food into materials easier for the cell to use.
Structure: Enclosed by two
membranes with the inner membrane folded up.
Contains it’s own DNA (unlike other organelles) that is identical to your mother’s!
Chloroplasts – Energy in Plants
Function: Captures energy from the
sun (solar energy) and changes it into food (chemical energy) for plants (photosynthesis)
Structure: Surrounded by two
membranes Contains own genetic
information like mitochondria
Contains green pigment called chlorophyll
Not found in animal cells!
With your neighbor, list similarities and differences between mitochondria and chloroplasts. Be prepared to share with the class.
Cytoskeleton- structure and support
Function: Helps maintain cell
shape Helps with
movement of the cell (i.e. flagella and cilia)
Structure: Two types:
microfilaments and microtubules
Cell Membrane
Function: Regulates what enters
and leaves the cell Provides protection
and support Structure:
Double membrane called a lipid bilayer
Flexible structure that forms a strong barrier between the cell and its surroundings
Cell Wall
Function: Provides support and
protection for the cell
Structure: Lies outside the cell
membrane Found in plants,
algae, fungi and many bacteria
NOT FOUND IN ANIMAL CELLS!
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