Transcript M1 Chapter 2

Levels of Organization
Division of Labor &
The First Level
Within multi-cellular organisms there is division of labor. Division of
labor means that the work (labor) of keeping the organism alive
is divided (division) among the different parts of the body.
Each part has a job to do and as each part does its special job, it works
in harmony with all the other parts.
The arrangement of specialized parts within a
living thing is sometimes referred to as levels of
organization. Cells of course, are the first
level of organization.
Cells: LOTS of Different Kinds!
Here are two examples. Can you guess what kind?
Nerve Cells
Skin Cells
Second Level: Tissues
In any multi-cellular organism, cells rarely work alone. Cells
that are similar in structure and function are usually
joined together to form tissues. Tissues are the
second level of organization.
There are four basic/major types of tissues in the
human body: Muscle tissue, nerve tissue,
connective tissue, and epithelial tissue.
Let’s Look Again…
Here are the cells we saw before, but if you look
closely, you can see that they all look similar.
Nerve cells working together make nerve tissue,
and skin cells make up a special type of epithelial
Taken One At A Time….
Connective tissue
connects and supports
parts of the body. Blood,
fat, ligaments, cartilage,
bones, and tendons
are all connective
tissues.
Nerve tissue carries
messages back and forth
between the brain and
every other part of the
body. The brain, spinal cord,
and nerves are made up of
nerve tissue.
Muscle tissue can
Epithelial tissue covers and contract, or shorten.
lines the surfaces of your body Because of this, muscle
tissue makes parts of
and organs, inside and out.
They primarily serve as
your body move.
protective barriers. Skin is one
example.
Level Three: Organs
When a bunch of different types of tissues work together, they form
an organ. There are many organs in the body.
GET IT????
Level Four: Organ Systems
Each organ in your body
is part of an organ
system, a group of
organs that work
together to perform a
major function.
For example, your heart is part
of your circulatory system,
which carries oxygen and other
materials throughout your body.
Besides the heart, blood vessels
are organs that work in your
circulatory system.
The nervous system detects and
interprets information from the
environment outside the body and
from within the body; controls most
body functions.
The immune system fights
disease.
The excretory system
removes wastes.
The endocrine system
controls many body
processes by means of
chemicals, like hormones.
The muscular system
enables the body to move;
moves food through the
digestive system, and keeps
the heart beating.
The skeletal system
supports and protects the
body, and works with the
muscular system to allow
movement; makes and stores
blood cells and stores some
other materials.
The digestive system takes
food into the body, breaks the
food down into smaller
particles, and absorbs the
digested materials.
The respiratory system
takes oxygen into the body
and eliminates carbon
dioxide.
The reproductive system
produces sex cells that can
unite with other sex cells to
create offspring; controls
male and female
characteristics.
Let’s Review….
• 1st Level: Cells working together form
• 2nd Level: Tissues, which can form
• 3rd Level: Organs, which work together
to form
• 4th Level: Organ Systems, which work
together to form
• 5th Level:
Organisms!
Cell Structures, Functions and
Transport
• It wasn’t until the
1600s that scientists
were able to use
microscopes to
observe living things.
Cells
• In 1665, Robert
Hooke observed
cork cells under
the microscope.
He called them
cells.
• This is a drawing
he made of the
cork cells.
• Here is what cork cells look like in
a modern microscope with
special lighting.
tallest trees
adult human
chicken egg
frog embryo
most eukaryotic cells
mitochondrion
most bacteria
virus
proteins
diameter of DNA
double helix
atoms
Cell Theory
• It wasn’t long
before scientists
realized that all
living things were
made up of cells.
This discovery
brought about the
formulation of the
cell theory.
The Cell Theory States
1. All living things are
made of cells.
2. Cells are the basic
units of structure
and function in
living things.
3. New cells are
produced from
existing cells.
Types of Cells
• Cells are classified as
prokaryotic or
eukaryotic.
• Prokaryotic cells have
genetic material that
is not inside a
nucleus (no nucleus).
• Eukaryotic cells have
genetic materials in a
nucleus. (“true”
nucleus)
Prokaryotes
• The prokaryotes are bacteria.
• They have cell walls, a plasma
membrane, and a single
chromosome in the nucleoid
or nuclear region.
• Some may have flagella for
movement.
Eukaryotes
• Eukaryotes are more
complex organisms and
have many specialized
organelles.
• Eukaryotes include
organisms from Protista,
Fungi, Plantae, and
Animalia.
Figure 7-5 Plant and Animal Cells
Animal Cell
Section 7-2
Cytoplasm
Nucleolus
Nucleus
Go to
Section:
Cell Membrane
Eukaryotic Cell Organelles and Function
1. Nucleus
– Nickname: “The Control Center”
– Function: holds the DNA
– Parts:
1. Nucleolus: dark spot in the middle of the nucleus
that helps make ribosomes
The Nucleus
Nucleus- The nucleus is the control center of the
cell. It is the largest organelle in the cell and it
contains the DNA of the cell. The DNA of all cells is
made up of chromosomes.
DNA (Deoxyribonucleic Acid) contains all the
information for cells to live, perform their functions
and reproduce.
Inside the nucleus is another organelle called the
nucleolus. The nucleolus is responsible for making
ribosomes.
The circles on the surface of the nucleus are the
nuclear pores. These are where ribosomes, and
other materials move in and out of the cell.
Figure 7-5 Plant and Animal Cells
Animal Cell
Section 7-2
Cytoplasm
Nucleolus
Nucleus
Go to
Section:
Ribosomes
Cell Membrane
Eukaryotic Cell Organelles and Function
2. Ribosomes
– Function: makes proteins
– Found in all cells, prokaryotic and eukaryotic
Ribosomes
Ribosomes are protein assembly
organelles.
The ribosome connects the amino
acids.
Ribosomes can be “free” in the
cytoplasm or on the endoplasmic
reticulum.
Ribosome can be found in both
the Prokaryotes and Eukaryotes
Figure 7-5 Plant and Animal Cells
Animal Cell
Section 7-2
Cytoplasm
Nucleolus
Nucleus
Rough
Endoplasmic
Reticulum
Go to
Section:
Ribosomes
Cell Membrane
Smooth
Endoplasmic
Reticulum
Eukaryotic Cell Organelles and Function
3. Endoplasmic Reticulum (ER)
– Nickname: “Roads”
– Function: The internal delivery system of the
cell
Endoplasmic Reticulum
– 2 Types:
1.Rough ER:
– Rough appearance because it has ribosomes
– Function: helps make proteins, that’s why it has
ribosomes
2.Smooth ER:
– NO ribosomes
– Function: makes fats or lipids
Endoplasmic Reticulum (ER)
ER is a series of folded
membranes within a cell
smooth ER is site of most
membrane synthesis
rough ER looks spotted
due to ribosomes bound
on the surface
rough ER is location of
membrane, secreted or
otherwise targeted
protein synthesis
eukaryotes only
Endoplasmic Reticulum (ER)
ER is continuous with the
nuclear membrane
amount of ER varies by
cellular function
liver cells have lots of ERused to detoxify (clean) chemicals
cells optimized for protein
secretion have lots of rough ER
Figure 7-5 Plant and Animal Cells
Animal Cell
Section 7-2
Cytoplasm
Nucleolus
Nucleus
Rough Endoplasmic
Reticulum
Golgi Complex
Go to
Section:
Ribosomes
Cell Membrane
Smooth Endoplasmic
Reticulum
Eukaryotic Cell Organelles and Function
4. Golgi Complex
– Nickname: The shippers
– Function: packages, modifies, and transports
materials to different location inside/outside of
the cell
– Appearance: stack of pancakes
Golgi complex- It is organelle in the cell that
is responsible for sorting and correctly shipping
the proteins produced in the ER.
Just like our postal packages which should have
a correct shipping address, the proteins
produced in the ER, should be correctly sent to
their respective address.
In the cell, shipping and sorting done by the
Golgi complex. It is a very important step in
protein synthesis.
If the Golgi complex makes a mistake in
shipping the proteins to the right address,
certain functions in the cell may stop.
Figure 7-5 Plant and Animal Cells
Animal Cell
Section 7-2
Cytoplasm
Nucleolus
Nucleus
Rough Endoplasmic
Reticulum
Golgi Bodies
Go to
Section:
Ribosomes
Cell Membrane
Smooth Endoplasmic
Reticulum
Eukaryotic Cell Organelles and Function
5. Lysosomes: circular, but bigger than
ribosomes)
– Nickname: “Clean-up Crews”
– Function: to break down food into particles the
rest of the cell can use and to destroy old cells
Lysosome
• Digestive 'plant' for
proteins, fats, and
carbohydrates
• Transports undigested
material to cell membrane
for removal
• Cell breaks down if
lysosome explodes
Figure 7-5 Plant and Animal Cells
Animal Cell
Section 7-2
Cytoplasm
Nucleolus
Nucleus
Ribosomes
Cell Membrane
Mitochondria
Rough Endoplasmic
Reticulum
Golgi Bodies
Smooth Endoplasmic
Reticulum
Eukaryotic Cell Organelles and Function
6. 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
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
Mitochondria
•
•
Mitochondria are membraneenclosed organelles distributed
through the cytosol of most
eukaryotic cells. Their main function
is the conversion of the potential
energy of food molecules into ATP
Every type of cell has a different
amount of mitochondria.. There are
more mitochondria in cells that have
to perform lots of work, for exampleyour leg muscle cells, heart muscle
cells etc. Other cells need less energy
to do their work and have less
mitochondria.
Animal Cell
Cytoplasm
Nucleolus
Nucleus
Ribosomes
Cell Membrane
Mitochondria
Rough Endoplasmic
Reticulum
Golgi Bodies
Smooth Endoplasmic
Reticulum
• Now let’s talk about structures only found in
PLANT Cells!!
Figure 7-5 Plant and Animal Cells
Section 7-2
Plant Cell
Vacuole
Cell Membrane
Go to
Section:
Eukaryotic Cell Organelles and Function
7. Vacuoles
– Function: stores water
•
This is what makes lettuce crisp
– When there is no water, the plant wilts
Vacuoles
• Vacuoles are storage
organelles.
• They store water,
salts, proteins, etc.
• Plants have a large
Central Vacuole that
helps plants support
leaves and stems.
Figure 7-5 Plant and Animal Cells
Plant Cell
Section 7-2
Vacuole
Chloroplasts
Cell Membrane
Go to
Section:
Eukaryotic Cell Organelles and Function
8. 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
• Chloroplasts are
organelles that
capture sunlight
energy and
convert it into
chemical energy
in a process
known as
photosynthesis.
Figure 7-5 Plant and Animal Cells
Plant Cell
Section 7-2
Vacuole
Chloroplasts
Cell Membrane
Cell Wall
Go to
Section:
Eukaryotic Cell Organelles and Function
9. Cell Wall
– Function: provides support and protection to
the cell membrane
– Found outside the cell membrane in plant cells
Plant Cell
Cytoplasm
Vacuole
Smooth ER
Ribosomes
Chloroplasts
Cell Membrane
Cell Wall
Nucleolus
Golgi Bodies
Nucleus
Mitochondria
Rough ER
Plant & Animal Cells
• Similarities
– Both constructed from eukaryotic cells
– Both contain similar organelles
– Both surrounded by cell membrane
Plant & Animal Cells
•
Differences
– Plants have
• Cell wall – provides strength & rigidity
• Have chloroplasts, photosynthetic
– Animals have
• Other organelle not found in plants (lysosomes
formed from Golgi)
• Centrioles, important in cell division
Comparing Plant and Animal Cells
Plant
Animal