cell.structure.bio 2

7/30/2019 Cell.structure.bio 2

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CELL STRUCTURECytology is the study of cells.


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Discovery of Cells

1665- English Scientist, Robert Hooke, discovered cells

while looking at a thin slice of cork.

He described the cells as tiny boxes or a honeycomb

He thought that cells only existed in plants and fungi


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Anton van Leuwenhoek

1673- Used a handmade microscope to observe pond scum

& discovered single-celled organisms

He called them animalcules

He also observed blood cells from fish, birds, frogs, dogs,

and humans Therefore, it was known that cells are found in animals as

well as plants


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THE CELL THEORY

All organisms are made of one or more cells and

the products of those cells.

The cell is the basic unit of function of all livingthings. All life activities are carried on by cells.

New cells arise only from other living cells by a

process of cell division.


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Cell Organelles

Some Relationships


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Mitochondria and Chloroplasts

Participate in energy transformations involving ATP

Have DNA, making them capable of reproducing themselves

Have ribosomes

Believed to have once been independent cells according to the

Endosymbiotic Hypothesis


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ENDOSYMBIOTIC HYPOTHESIS
http://www.sumanasinc.com/webcontent/anisamples/nonmajorsbiology/organelles.html


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Centrioles, Cilia, Flagella, Basal Bodies

All involved in motion of some kind

All are made of microtubules

Centrioles aid in movement of chromosomes.

Basal bodies create cilia and flagella.

Cilia and flagella propel certain types of cells.

Cilia can also be used to clean respiratory tracts.


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Centrioles, Basal Bodies, Mitochondria,

Chloroplasts

All have their own DNA


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Nucleus, ER, Golgi, Lysosomes, Endosomes

The nucleus contains DNA. DNA directssynthesis of RNA, which travels to the

ribosomes to aid in the manufacture of

proteins. Some of these proteins are enzymeswhich are packaged by Golgi into lysosomes.

lysosomes hook up to endosomes (food

vacuoles, which are formed after phagocytosisof food particles. The food is digested within

the food vacuole by enzymes from the lysosome.


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Other Cellular Transport Mechanisms

Facilitated DiffusionUses a channel protein to aid in thetransport of substance along/with the concentration gradient. It isa form of passive transport like diffusion an osmosis since it doesnot require energy.

Active TransportUses energy and a pump protein to transport

substances against their concentration gradient.

Endocytosisprocesses which take substances into cell

Phagocytosis ( cell eating )the engulfing of solidparticles

Pinocytosis ( cell drinking )the engulfing of water anddissolved substances

Exocytosisprocess which takes substances out of the cell


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Diffusionthe movement of a substance from a region where it ismore concentrated to a region where is less concentrated.

Osmosisthe diffusion of water through a selectively permeablemembrane from a region where it is more concentrated to aregion where it is less concentrated.

Aselectively permeable membraneis one which allows certainsubstances to pass and not others (also called differentiallypermeable or semipermeable).


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CELLULAR TRANSPORT ANIMATIONS
http://www.northland.cc.mn.us/biology/Biology1111/animations/transport2.html

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