Cells

By:

Jon Jefferis

Kevin Busch

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What is a cell?

• Cells are the building blocks of all life.• Cell comes from the latin word cellular, which

means a small room.

Cell Theory

• The cell theory was first developed in 1839 by Schleiden and Schwann

• The cell theory states that all organism are made of one or more cells

• It also states that all cells come from preexsisting cells, all vital functions of an organisms happen within cells, and they also store the hereditary information needed to pass on to the next generation of cells

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Types of cells

Prokaryotic

Eukaryotic

Animal cells vs. Plant cells

Different shapes of cells

Liver cells

Each cell has a different shape for its location

Blood cells Kidney cells

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Golgi Apparatus

• Also called Golgi body or Golgi complex

• It is typically made up of a group of five to eight cup-shaped, membrane-covered sacs called cisternae that look like a stack of deflated balloons

• It is used for the distribution and shipping department of the cell's chemical products

• It is similar to the human heart

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Discovery of the Golgi Apparatus

• It was one of the first organelles of the cell to every be discovered because of its large size

• It was discovered in 1897 by a italian physician named Camillo Golgi.

• He was able to see the golgi apparatus due to a method that is now called Golgi Staining

The purpose of the Golgi Apparatus

• It modifies proteins and fats (lipids) that have been made in the endoplasmic reticulum and makes them ready to be shipped out to other parts inside and outside of the cell

• Vesicles from the endoplasmic reticulum float around in the cytoplasm until they reach the Golgi Apparatus

• The vesicles form with the Golgi Apparatus emptying their contents into the Golgi Apparatus

• Once inside the molecules are changed and shipped out to their destination

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What is a Chloroplast

• Chloroplasts are small organelles that are found only in plant cells and eukaryotic algae

• They are an essential part of photosynthesis

• It is derived from the Greek words chloros which means green and plast which means cell or organelle

• The chloroplast is similar to the human intestines

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Function of the Chloroplast

• Chloroplasts absorb sunlight and combine it with water and carbon dioxide to make food for the plant

• Chloroplasts capture light energy from the sun to produce the free energy stored in the cell through a process called photosynthesis

Structure of the Chloroplast

• Chloroplasts are typically flat disks 1-2 micrometers thick by 2-10 micrometers in diameter

• The chloroplast has two membranes between them is the intermembrane space

• The liquid in the chloroplast is called stroma

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Vacuole

• They are compartments that are covered by a membrane used for storage and disposing of waste

• They are in plant cells and some eukaryotic cells

• Used as food storage in protists

• The vacuole is similar to the human stomach

Function of the Vacuole

• May be used as a defensive mechanism in some plants

• It also stores plant food called cell sap

• Helps to maintain turgor pressure

• Vacuoles help plant cells to grow

Other Functions of the Vacuole

• removing unwanted structural debris

• isolating materials that might be harmful to the cell

• containment of waste products

• maintaining internal hydrostatic pressure or turgor within the cell

• maintaining an acidic internal pH

• containing small molecules

• exporting unwanted substances from the cell.

• enabling the cell to change shape.

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Cytoskeleton

• Act as skeleton within the cell

• Also known as microfilaments

• Found in all eukaryotic

• Studies have shown that a cytoskeleton is present in some prokaryotic cells

• It is located just beneath the plasma membrane

Purpose of the Cytoskeleton

• It is an important part of cell movement and cell division

• They retain the cells shape

• They help with muscle contractions and other bodily functions

• They help in cell-cell and cell-matrix bonds

• They help transport organelles such as mitochondria and vesicles

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Nucleus

• The nucleus is similar to the human brain• It is not always in the center of the cell• Not all cells have nuclei• Holds the DNA of the cell

Function of the Nucleus

• Controls almost every part of the cell

• It mainly controls eating, movement, and reproduction

• It contains instructions for the production of proteins and the reproduction of the cell

The Structure of the Nucleus

• Made up of the main parts, the nucleolus, the nuclear

envelope, and the chromatin.• The nucleolus contains ribosomes, RNA, DNA, and

proteins

• The chromatin contains DNA and proteins that have been formed into packets called chromosomes.

• The nuclear envelope helps the nucleus control the cell.

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The Plasma (Cell) Membrane

• The plasma membrane is the outer layer of the cell, that is composed of protein covered phospholipids

• It is similar to our skin

• It is very flexible because of the way the proteins and phospholipids are arranged

• Controls the input and output of the cell

Function of the Plasma Membrane

• The plasma membranes lets in nutrients to the cell such as glucose, amino acids, and lipids.

• It forms a boundary between the cell and the outside.

• Allows some molecule to defuse in and out of the cell

The Structure

• Made of a phospholipid bilayer

• Contains specific proteins and lipids parts that enable It attaches parts of the cytoskeleton to the cell membrane in order to provide shape.

• It attaches cells to an extra-cellular matrix in grouping cells together to form tissues.

• It transports molecules into and out of cells by such methods as ion pumps, channel proteins and carrier proteins.

• It acts as receptor for the various chemical messages that pass between cells such as nerve impulses and hormone activity.

• It takes part in enzyme activity which can be important in the metabolism or as part of the body's defense mechanism.

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• Found only in eukaryotic cells

• It is formed from a network of tubules, vesicles, and cisternae

• Similar to the plasma membrane

• Part of the endomembrane system

• There are two types, Rough ER and Smooth ER

• Located near the nucleus

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Smooth ER

• Stores key enzymes and their products

• In muscle cells it stores calcium which it then releases in the contraction process

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Rough ER

• It combines and exports proteins and glycoproteins

• A series of vesicles and flattened sacs

• Ribosome’s surround the outside and make proteins which are then transported into the inside of the ER

• The rough ER works with Golgi Apparatus to do its job

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The Mitochondria

• It is a membrane enclosed organelle and is found in most eukaryotic cells

• They are like power plants inside the cell

• There are usually around 2000 mitochondria in a cell

• It is similar to the human stomach

Structure of the Mitochondria

• The mitochondria contains inner and outer membranes

• The membranes have different properties

• There are 5 compartments inside the mitochondria, the outer membrane, the intermembrane space, the inner membrane, cristae space, and the matrix

The Function of the Mitochondria

• Turns inorganic material into cellular energy

• Plays a big part in our metabolism

• It produces ATP (a form of cell energy)

• each mitochondria is different depending on where it is located, for example mitochondria in the liver contain enzymes.

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Lysosomes

• Contain digestive enzymes

• They digest excess or worn out organelles, food particles, and engulfed viruses or bacteria.

• It can fuse with vacuoles to let their enzymes out in the vacuole

• It is similar to the human mouth

Functions of the Lysosome

• The lysosomes are used for the digestion of macromolecules

• It helps in the cells recycling process

• It digests any unwanted molecules or objects

• Hey also serve as being a membrane patch

Structure of the Lysosome

• There are only enzymes in a lysosome, they are:

• Lipase, which digests lipids,

• Carbohydrases, which digest carbohydrates (e.g., sugars),

• Proteases, which digest proteins,

• Nucleases, which digest nucleic acids.

• Phosphatases, which digest phosphoric acid

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Ribosomes

• It is similar to the human liver because both make proteins

• Not much is known about the Ribosome and it is a very active field of study

Function of the Ribosome

• Translates mRNA to protien

• Pairs RNA with amino acids to form DNA

Structure of the Ribosome

• Made of two parts that fit together perfectly

• Binds to endoplasmic reticulum

• There are “Free Ribosomes” that float around in the cell

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Centrioles

• It is a barrel shaped microtubule (protein structures found within cells) structure found in most animal cells and algae

• It is not found in plants very often• It is similar to the human testicles because it plays

a major role in cell reproduction

                              

Purpose of the Centriole

• They organize material that then later helps the cell divide.

• Very important to cell division

• They duplicate themselves each time the cell divides so each new cell has a centriole.

Structure of the Centriole

• The walls are made up of 9 triplets of microtubules.

• Every other triplet of microtubules form a right angle to each other

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Cell Wall

• a fairly rigid layer surrounding a cell located outside of the plasma membrane

• Helps in the support and protection of the cell.

• Only found in plant cells

Purpose of the Cell Wall

• provide rigidity to the cell for structural and mechanical support

• maintaining cell shape

• the direction of cell growth

• And the design and shape of the plant

• The cell wall's main purpose is to protect the interior from any physical movement that may damage the cell

• It does not select what molecules can enter the cell

Structure of the Cell Wall

• Made up of cellulose (It forms the primary structural component of green plants), hemicellulose (a random structure with little strength) and pectin (sugar that is not in the sugar group)

• Contains proteins

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Eukaryotic cells

• 10 times the size of prokaryotic cells and can be as much as 1000 times greater in volume

• Have a cell nucleus

• There are 2 types of eukaryotic cells, animal and plant cells

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Prokaryotic cells

• Do not have a nuclear cell membrane• Do not have most of the intercellular organelles of

eukaryotic cells• Mitochondria chloroplasts and golgi apparatus are replaced

by the plasma membrane • Have appendages called flagella and pili• Have a cell envelope, which is made of a capsule, a cell

wall , and a plasma membrane• A cytoplasmic region contains DNA and ribosomes• Chromosomes are usually circular molecules

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The Quiz

• What is a cell?

A. The building block of life

B. A round thing that has no point

The Quiz

• When was the cell theory created?

A. 1838

B. 1883

The Quiz

• How many types of cells are there?

A. 2

B. 46

The Quiz

• Last Question Who are the coolest people in the world

A. Mr. Theil, Kevin, and Jon

B. Everyone else

Bibliography

• Sullivan, Jim. "Cells Alive." [http://www.cellsalive.com/toc.htm]. May 2006.

• "Wikipedia." [http://en.wikipedia.org/wiki/Main_Page]. December 2006.

• Andrew Rader Studios. "Cells." [http://www.biology4kids.com/files/cell_main.html]. 2006.