cells…they are kind of a big deal (figuratively)

Cells…they are kind of a big deal (figuratively)(because they are soooo tiny)

Cell theory in a nut shell• BIG IDEA- cells are the basic units of living things!• This guy Robert Hooke was looking at tiny slices of a wine

cork…• Basics:• All living things or organisms are made of cells and their products.• New cells are created by pre-existing cells dividing into two.• Cells are the basic building units of life.

Two types

Prokaryotes

• Prokaryotes lack a nucleus (though they do have circular DNA) and other membrane-bound organelles (though they do contain ribosomes). • Bacteria and Archaea are

two examples of prokaryotes.

Eukaryotes• Eukaryotes: Eukaryotes, on

the other hand, have distinct nuclei bound by a nuclear membrane and membrane-bound organelles (mitochondria, chloroplasts, lysosomes, rough and smooth endoplasmic reticulum, vacuoles). In addition, they possess organized chromosomes which store genetic material.

The overall picture

Nucleus• The most obvious of the organelles to point out. Usually large

and oval.• The Nucleus holds the DNA of the cell, which controls all the

other functions. It is like the coding to run a video game… the DNA gives instructions to what the cell should be doing.

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Cell Membrane • outer layer• *selectively permeable• *support• *protection• *controls movement of materials in/out of cell• *barrier between cell and its environment• *maintains homeostasis

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Golgi Apparatus• One of the places to which vesicles travel is the Golgi

apparatus or Golgi bodies. These look like stacks of water-balloon-pancakes. They are sort of like the shipping and receiving department of the cell. Materials are received as vesicles unite with the Golgi apparatus, and sent elsewhere as other vesicles pinch off. Materials are temporarily stored in the Golgi bodies, and some further chemical reactions do take place there.

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Mitochondria • Mitochondria are found in nearly all eukaryotic cells, usually

several or many per cell. They burn sugar for fuel in the process of cellular respiration: they’re the “engine” of the cell. Mitochondria consist of a smooth outer membrane and a convoluted inner membrane separated by an intermembrane space. The convolutions of the inner membrane are called cristae and the space inside the inner membrane is the mitochondrial matrix. As sugar is burned for fuel, a mitochondrion shunts various chemicals back and forth across the inner membrane (matrix to/from intermembrane space).

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Chloroplast• Plant cells normally contain another type of organelle that is

not found in animals: chloroplasts. Chloroplasts convert light energy (from the sun) to chemical energy via the process of photosynthesis. The main pigment (green color) located in chloroplasts and involved in photosynthesis is chlorophyll. Chloroplasts are surrounded by an outer membrane and inner membrane separated by an intermembrane space. The fluid within the center of the chloroplast is called stroma. Within this fluid is an interconnected system of stacks of disks, kind of like more water-balloon-pancakes. Each sack is called a thylakoid. and has chlorophyll and other useful pigments built into its membranes. A stack of thylakoids is called a granum.

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Cytoskeleton • The cytoskeleton is made of various types of special proteins.

Microtubules are hollow tubes made of globular proteins. Most notably, they are found in cilia, flagella, and centrioles. The arrangement of microtubules in cilia and flagella consists of nine doublets around the edge and two single microtubules in the center, all running the length of the structure. This is referred to as the “nine-plus-two formula.”

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endoplasmicreticulum (E.R.)• *network of tubes or membranes• *carries materials through cell• There are two kinds of ER: smooth ER and rough ER. Typically

ER closer to the nucleus is rough and that farther away is smooth.

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