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Cells
Bell Ringer
1. What did Robert Hooke observe with the use of a microscope? How did he describe what he saw?
2. What 3 components make up the cell theory?
3. Where is the DNA housed in a eukaryotic cell?
4. How do organelles in a cell compare to organs in the human body?
Learning Target
•“I can” analyze the difference between a prokaryotic cell and a eukaryotic cell.
•“I can” analyze the difference between a plant cell and an animal cell.
It’s a Rap
•http://www.youtube.com/watch?v=-zafJKbMPA8
Discovery of the Cells
•The discovery of the cell helped answer this question…▫How do living things differ from non-living
things?•Microscopes have made a huge impact on
the study of biology. ▫Microscope observations of organisms led
to the discovery of the basic characteristics common to all living things.
History
•1665, Robert Hooke observed a piece of cork under a microscope that only had the strength to magnify a specimen 30x. ▫Hooke observed many little boxes in the
cork. •They reminded Hooke of small rooms that
monks live in called “cells.” •Later, Hooke observed the same “little
boxes” in the stem and roots of plants.
History Cont.
•10 years later a Dutch man by the name of Anton Van Leeuwenhoek used a more powerful microscope that could magnify specimens 300x.▫He observed pond water and discovered
many living creatures in the water that he named animalcules, which means “tiny animals.”
•Thanks to Leeuwenhoek we now know these animalcules as single celled organisms (prokaryotes.)
History Cont.
•It took over 150 years for scientists to fully appreciate the studies of Hooke and Leeuwenhoek.
•Matthias Schleiden a German botanist, concluded that cells make up every part of a plant.
•1 year later Theodore Schwan a German zoologist, discovered that animals are also made up of cells.
History Cont.
•Rudolph Virchow, a German physician, proposed that cells only come from the division of other cells.
•All of the observations form Schleiden, Schwan, and Virchow helped form the Cell Theory.
Cell Theory
•The cell theory is composed of the following 3 things. ▫1. All living things are made up of one or
more cells. ▫2. Cells are the basic units of structure and
function in an organism. ▫3. All cells arise from existing cells.
Cell Shape
•Cells vary greatly in size and shape. •A cells shape reflects the cells function.
▫There are at least 200 types of cells.▫The human body is made up of about 100
trillion cells. •Larger cells often have shapes that
increase the surface area available for exchange.
Cell Size
•All substances that enter or leave a cell must pass through the surface of a cell.
•As a cell gets larger, it takes up more nutrients and releases more waste.
•Cell size is limited to by a cells surface area-to-volume ratio.
•Cells with a greater surface area-to-volume ratio can exchange substances more efficiently. ▫Ex: lungs
Cell Organelles • Cell Membrane- is the cells outer boundary.
▫It acts as a barrier between the outside environment and the inside of the cell.
• Cytoplasm- includes cytosol and almost all of the structures that are suspended in it. ▫Jelly like substance that is found in the inside of
the cell. • Ribosome- is a cellular structure on which
proteins are made. ▫Ribosomes are found all throughout the
cytoplasm.
Prokaryotic Cell • Prokaryote is a single celled organism.
▫ Ex: bacteria • Organization is very simple. DNA freely floats in the
middle of the cell instead of being trapped in the nucleus. ▫ Pro-No
• The prokaryotic cell wall surrounds the cell membrane. The cell wall provides strength and structure to the cell.
• Capsule- is a structure around the cell wall that enables prokaryotes to cling to surfaces, including, teeth, skin, and food.
• Prokaryotic cells are thought to be 3.5 billion years old.
Prokaryotic Cell
•Prokaryotic cells move around with the help of a flagella. ▫Flagella- Flagella are long projections
composed of protein. They rotate due to a protein motor secured in the plasma membrane.
•Prokaryotic cells also contain pili. ▫Pili- help bacteria stick to other cells. They
are short “hair like” projections.
Eukaryotic Cell
•Eukaryote is an organism made up of one or more cells. ▫Some live as single celled organisms. ▫Others are multicellular.
•Because of their complex organization, eukaryotic cells can carry out more specialized functions that prokaryotic cells can not.
•Eukaryotic cells first appeared 1.5 billion years ago
Eukaryotic •Eukaryotic cells contain an organelle called a
nucleus that houses the DNA for the cell. •Eukaryotes have membrane bounded
organelles. ▫Organelle- is a structure that carries out specific
activities inside the cell. Each organelle performs a distinct function.
•Eukaryotic cells contain, cytoplasm, ribosomes, cell membrane, mitochondrion, Golgi apparatus, endoplasmic reticulum, centrioles, Lysosomes, nucleolus, and a nucleus.
Bell Ringer
Prokaryotic vs. Eukaryotic •Compare and contrast a Eukaryotic and a
Prokaryotic cell.
Bell Ringer
•What 2 organelles prepare proteins for extracellular transport?
•What is a central vacuole and where can it be found?
•In the muscles there are tons of mitochondria, why is this?
Framework of the Cell
•The cytoplasm of a Eukaryotic cell is packed with structures particular to the cell.
•Cytoskeleton- helps the cell move, keep its shape, and organize its parts. ▫The cytoskeleton to the cell are like the
bones to the body.
3 types of Cytoskeleton • 1. Microfilaments- are long, thin fibers that
are made of the protein actin. ▫They contract to pull the membrane in some
places and expand to push it out in others.• 2. Microtubules- are, thick hollow fibers that
are made of the protein tubulin. ▫ Information molecules travel through these
tubes to various places in the cell. • 3. Intermediate Fibers- are moderately thick
and anchor organelles and enzymes to certain parts of the cell.
Directing Cellular Activity
•Cellular activity depends on the proteins that the cell makes.
•Instruction for making proteins is stored in the DNA.
•In a Eukaryotic cell, DNA is packed into the nucleus. ▫This protects the DNA from other activity
in the cell from getting lost or destroyed.
Directing Cellular Activity
•DNA Instructions are copied as RNA messages, which leave the nucleus in the cytoplasm ribosomes use the RNA messages to assemble proteins.
Nucleus •The nucleus is surrounded by a double
membrane called the nuclear envelope. •The nuclear envelope has many nuclear pores.
▫Nuclear pores- are small channels that allow certain molecules to move in and out of the nucleus.
•Nucleolus- located inside of the nucleus, this is where the ribosome parts are made. ▫Nucleolus nuclear pore cytoplasm Ribosome.
Ribosome •Ribosomes are made of RNA and many
proteins. •Free Ribosomes- Float freely in the
cytoplasm. ▫Their job is to make proteins that remain inside
the cell, such as proteins that build new organelles or enzymes to speed up reactions.
•Bound Ribosomes- are attached to the membrane of another organelle. ▫Their job is to make proteins that are exported
from the cell.
Protein Processing • The proteins produced by cells have many uses. • Proteins that are sent outside the cell must
remain separate from the cytoplasm. The cell does this with the help of a vesicle. ▫Vesicle- this is the site where proteins are
packaged. It is a small, often spherical shaped sac that is formed by a membrane.
• In a eukaryotic cell 2 organelles are responsible for modifying, packaging, and transporting proteins. ▫The Endoplasmic Reticulum and The Golgi
Apparatus.
Endoplasmic Reticulum
•Endoplasmic Reticulum (ER)- is a system of internal membranes that moves proteins and other substances through the cell. ▫The ER is connected to the outer
membrane of the nuclear envelope.
Two Types of ER• Rough ER- ribosomes are attached to the
surface of the ER. ▫Rough ER has a bumpy appearance. ▫1.As proteins are made they cross the ER
membrane, entering the ER. Then, the ER membrane pinches off to form vesicles around the protein.
• Smooth ER- the rest of the ER is called smooth ER, with no attached ribosomes. ▫Smooth ER has a smooth appearance. ▫Smooth ER performs various functions such as
making lipids and breaking down toxic substances.
Golgi Apparatus • Golgi Apparatus- is a set of flattened membrane-
bound sacs. ▫Cell products enter one side of the Golgi Apparatus,
which modifies, packs, and sorts them for distribution.
• 2. Repackaging-The vesicles membrane fuses with the Golgi membrane. Inside the Golgi apparatus, enzymes modify the protein as they move through the organelle.
• 3. As the vesicle membrane fused with the cell membrane, the completed proteins are released to the outside of the cell.
Storage and Maintenance
•Vesicles play many roles in the cell. ▫Vesicles- help maintain homeostasis by
storing and releasing various substances as cells need them.
•Lysosome- is a vesicle that contains specific enzymes that break down large molecules. ▫These enzymes can digest food particles to
provide nutrients for the cell. ▫They also help recycle materials in the cell
by digesting old, damaged, or unused organelles.
Lysosomes
•Lysosomes made by the Golgi Apparatus, prevent the enzyme from destroying the cell.
Central Vacuole
•Central Vacuole- large membrane bound compartment found in plant cells. ▫Stores water, ions, nutrients and wastes. ▫It can also store toxins and pigments.
•When the central vacuole fills up with water, it makes the cell rigid, allowing the plant to stand up right.
•When the central vacuole loses water it causes it to wilt and the cell shrinks.
Other Vacuoles
•Contractile Vacuole- Pumps excess water out of the cell. ▫This process controls the concentration of
salts and other molecules and helps the cell maintain homeostasis.
•Food Vacuole- forms when the cell membrane surrounds food particles outside the cell and pinches off to form a vesicle inside the cell.
Energy Production
•Cells need a constant source of energy. •The energy needed for cellular function is
produced by chemical reactions that occur in the mitochondria and chloroplasts. ▫Eukaryotic cells= mitochondria ▫Plant cells= chloroplasts
•In both reactions ATP is produced. ▫ATP is the form of energy that fuels almost
all cell processes.
Chloroplasts
•Chloroplast- is an organelle that uses light energy to make sugar from carbon dioxide and water. ▫In the inner membranes of the chloroplasts
is where the ATP producing chemical reactions take place.
Mitochondria
•Mitochondrion- an organelle that uses energy from organic compounds to make ATP. ▫Cells that have a high energy requirement,
such as muscle cells, will contain more mitochondria.
▫ATP producing enzymes are located on the inner membranes of the mitochondria.
Word Bank
•Cell Membrane •Cytoplasm •Ribosome•Nucleus •Nuclear envelope •Rough ER•Smooth ER •Golgi Apparatus •Chloroplasts
•Flagella •Pili •Capsule •Mitochondrion •Cell wall •Lysosome •Vacuole •DNA
Bell Ringer 1. I am like the assembly line for the cell
because I assemble items that the cell needs2. I am like the bricks for the cell because I
give it structure3. I am like the control center for the cell
because I hold on the instructions of life4. I am like the storage unit for the cell because
I stored materials until they are needed5. I am like a bakery for the cell because I only
make proteins
Bell Ringer
1.An army is like a __________ because it protects the U.S.A from its enemies.
2.A light bulb is like a ________because it gives us energy.
3.A coach is like a _________ because he makes all the decisions for the team.
4.A postman is like a ______ because he sorts and packages items for people.
PLANT VS. ANIMAL • If a scientist viewed a plant cell and an animal cell under
a microscope what could he or she expect to see? • On the poster that I pass out you need to list, define and
tell how that particular organelle helps the cell function.
Bell Ringer
•Get out your notebooks and study what we have covered so far in class.
•If you weren’t here Thursday you need to have your project out on your desk and your questions that you completed in your notebook out.
Word Bank
•Nucleus •Ribosomes•Endoplasmic
Reticulum •Cell Membrane •Cell Wall •Lysosome •Vesicle•Cytoplasm
•Golgi Apparatus •Nucleolus •DNA•Mitochondria •Chloroplasts •Nuclear Envelope •Vacuole
Diversity in Cells
•Prokaryotic cells are always unicellular and limited in size.
•Eukaryotes are often larger and can be either unicellular or multicellular.
•Prokaryotic cells lack a nucleus and membrane bound organelles. ▫The different organelles and features of
cells enable organisms to function in unique ways in different environments.
Diversity in Prokaryotes
• Prokaryotes can vary in shape, the way that they obtain and use energy, the makeup of their cell walls, and their ability to move.
•Prokaryotes contain ▫Flagella- long tail like structure that grows
out of the cell, allows the cell to move. ▫Pili- are short hair-like projections that
allow prokaryotes to attach to surfaces or to other cells.
Types of cells •The two types of Eukaryotic Cells are
▫Animal and Plant •Plant cells contain both cell walls and
chloroplasts which Animal cells do not.•Plant and animal cells have highly specialized
cells that form tissues and organs. ▫Tissue- a group of similar cells that perform
the same function Lung tissue Leaf tissue
Types of cells
•Organ- a collection of tissues that carry out a specialized function in the body.▫Leaf ▫Lung
•Organ System- a group of organs that work together to form body functions. ▫Circulatory System ▫ Root System
Body Types
•Multicellular Organisms- are composed of many individual, permanently associated cells that coordinate their activities.
•Colonial Organisms- a collection of genetically identical cells that are permanently associated but in which little or no integration of cell activities occur.
Multicellularity
•True multicellularity occurs in eukaryotes.
•Multicellular organisms begin as a single cells.▫For example a chicken develops from an
egg, new cells form by cell division.•Differentiation- is the process by which
cells develop specialized forms and functions.
BILL NYE
•http://www.youtube.com/watch?v=X6N82No4Nz8
LINCS chart words
1. Cell Membrane
2. Diffusion 3. Osmosis 4. Facilitated
Diffusion 5. Dynamic
Equilibrium 6. Hypotonic
7. Hypertonic 8. Isotonic 9. Active Transport 10.Pumps11.Exocytosis 12.Endocytosis
