Transcript What is a cell?

Cell Structure
& Function
http://koning.ecsu.ctstateu.edu/cell/cell.html
Topic: Cell theory
• EQ: What are the parts of the cell theory?
What is a cell?
A cell is the smallest unit that is
capable of performing life
functions.
Who first discovered cells?
• Robert Hooke discovered the first cells. He
built the first microscope. He then viewed
cork from an oak tree. This is what he
saw.
He thought they looked like the little rooms,
so he called them “cells”
What part did microscopes
play?
• Microscopes allowed scientists to see cells
and other things that were too small to be
seen with just their eyes.
Time passed on….
• Better microscopes were built and other
scientists began to look for cells in other
places……….
• After many, many observations a theory
was made…..called The Cell Theory
Many scientists contributed to the cell
theory.
• The cell theory grew out of the work of
many scientists and improvements in the
microscope.
•
Cell Theory
The three principles of the cell theory:
• 1. All living things are made up of cells.
• 2. The cell is the smallest of all life
• 3. All cells come from preexisting cells
through cell division.
ISN 52
• Create a Cell Theory Bubble map
Topic: Prokaryotic vs Eukaryotic
Cells
• Prokaryotic
• Eukaryotic
2 Basic Types of Cells
• Prokaryotes (prokaryotic cells)
– Cells that DO NOT have a nucleus
– Examples: bacteria
• Eukaryotes (eukaryotic cells)
– Cells that DO have a nucleus and other
organelles
– Examples: plant cells and animal cells
Prokaryotic Cells
Prokaryotic
• DNA: free-floating, not
surrounded by a
membrane
• Organelles: Not many
organelles
• Level of organization:
One-celled (unicellular)
• Size: small
http://library.thinkquest.org/C004535/prokaryotic_cells.html
Eukaryotic
Plant
http://library.thinkquest.org/C004535/eukaryotic_cells.html
Animal
Eukaryotic Cells
• DNA: surrounded by a
membrane
• Organelles: Many
specialized parts
• Level of Organization:
Multicellular: plants, fungi,
animals, and protists
Size: larger
Examples of Cells
Amoeba Proteus
Plant Stem
Bacteria
Red Blood Cell
Nerve Cell
Homework
Types of Cells
Cell Types
Eukaryotic Cells
Plant Cells
Prokaryotic Cells
Animal Cells
http://www-class.unl.edu/bios201a/spring97/group6
“Typical” Plant Cell
http://waynesword.palomar.edu/images/plant3.gif
“Typical” Animal Cell
http://web.jjay.cuny.edu/~acarpi/NSC/images/cell.gif
Cell Parts
Organelles
Topic: Cell Organelles
(Shape and movement
EQ: Explain the function of
the 7 cell organelles.
Shape and movement
• Parts of a cell have unique functions. A
cell is made up of different structures that
keep it alive. They each have a different
job.
What is an organelle?
• An organelle is a part of the cell that has a
specific job. They are little organs or parts
inside of a cell.
What is the Nucleus?
• Directs cell activities (Boss of the cell)
• Contains genetic material – DNA
• Found in Plant and Animal Cells
What is the cell membrane?
• Flexible covering
• Protects and controls
movement in and out of
the cell
• Found in plant & animal
cells. It only allows certain
materials to pass
(selectively permeable)
http://library.thinkquest.org/12413/structures.html
What is a cell wall?
• Only in plants
• A stiff structure
outside the cell
membrane.
• Adds support & helps
the plant keep its
shape.
http://library.thinkquest.org/12413/structures.html
What is the cytoskeleton?
• A network of threadlike proteins that are
joined together and help give the cell its
shape and help it move.
Directions
• Cut out table on pg. 65
and glue in your ISN 56
Movement of materials in a cell
• EQ: Explain the function of the 7 cell
organelles.
How do materials move in and
out of the cell?
• Two processes:
• A. Diffusion
• B. Osmosis
What is Cytoplasm?
• A fluid inside a cell that contains salts and
other molecules.
• Surrounded by cell membrane
What is diffusion?
• The movement of molecules from an area
of higher concentration to an area of lower
concentration.
• Diffusion moves ALL KINDS of materials
in/out of cells
What does diffusion look like?
• http://highered.mcgrawhill.com/sites/0072495855/student_view0/
chapter2/animation__how_diffusion_works
.html
What is osmosis?
• The diffusion of water molecules through a
membrane
• This process refers to transferring only
WATER in/out of cells
What does osmosis look like?
• Osmosis
Why is osmosis and diffusion
important?
Both of these processes allows for things
the cell need (water, nutrients, etc.) to get
in and wastes have a way to leave out.
Double-Bubble
What is diffusion?
diffusion
What is osmosis?
osmosis
Where did you get this information?
Topic: Cells Energy and
Storage
• EQ: Explain the function of the 7 cell
organelles
Eukaryotic Cell Organelles and
Function
Mitochondria
– Nickname: “The Powerhouse”
– Function: Energy formation
•
Breaks down food to make ATP
– ATP: is the major fuel for all cell activities that
require energy
Animal Cell
Cytoplasm
Nucleolus
Nucleus
Ribosomes
Cell Membrane
Mitochondria
Rough Endoplasmic
Reticulum
Golgi Bodies
Smooth Endoplasmic
Reticulum
Eukaryotic Cell Organelles and
Function
Vacuoles
– Function: stores water
– Only in plant cells
•
This is what makes lettuce crisp
– When there is no water, the plant wilts
Figure 7-5 Plant and Animal Cells
Section 7-2
Plant Cell
Vacuole
Cell Membrane
Go to
Section:
Eukaryotic Cell Organelles and
Function
Chloroplasts
– Function: traps energy from the sun to
produce food for the plant cell
– Green in color because of chlorophyll, which
is a green pigment
– Found only in plant cells
Figure 7-5 Plant and Animal Cells
Plant Cell
Section 7-2
Vacuole
Chloroplasts
Cell Membrane
Go to
Section:
Nuclear Membrane
• Surrounds nucleus
• Made of two layers
• Openings allow
material to enter and
leave nucleus
http://library.thinkquest.org/12413/structures.html
Chromosomes
• In nucleus
• Made of DNA
• Contain instructions
for traits &
characteristics
http://library.thinkquest.org/12413/structures.html
Nucleolus
• Inside nucleus
• Contains RNA to build
proteins
http://library.thinkquest.org/12413/structures.html
Endoplasmic Reticulum
• Moves materials around
in cell
• Smooth type: lacks
ribosomes
• Rough type (pictured):
ribosomes embedded in
surface
http://library.thinkquest.org/12413/structures.html
Ribosomes
• Each cell contains
thousands
• Make proteins
• Found on ribosomes
& floating throughout
the cell
http://library.thinkquest.org/12413/structures.html
Mitochondria
• Produces energy through
chemical reactions –
breaking down fats &
carbohydrates
• Controls level of water and
other materials in cell
• Recycles and decomposes
proteins, fats, and
carbohydrates
http://library.thinkquest.org/12413/structures.html
Golgi Bodies
• Protein 'packaging
plant'
• Move materials within
the cell
• Move materials out of
the cell
http://library.thinkquest.org/12413/structures.html
Lysosome
• Digestive 'plant' for
proteins, fats, and
carbohydrates
• Transports undigested
material to cell
membrane for removal
• Cell breaks down if
lysosome explodes
http://library.thinkquest.org/12413/structures.html
Vacuoles
• Membrane-bound
sacs for storage,
digestion, and waste
removal
• Contains water
solution
• Help plants maintain
shape
http://library.thinkquest.org/12413/structures.html
Chloroplast
• Usually found in plant
cells
• Contains green
chlorophyll
• Where
photosynthesis takes
place
http://library.thinkquest.org/12413/structures.html