last Friday we talked about:
♣ the cell membrane: is the part of the cell that separates the cell of the outside, it controls the movement of the material that goes in or goes out. the cell membrane is a two-layered structure made up by lipids, proteins and carbohydrates. extra: also have the quality to be "selectively permeable", this means that it select what passes through it freely or just a slight or nothing at all.
♠the structure and functions of the organelles of the cell and how they work together, this is called the endoplasmatic system, the endomembrane system has a chemical structure (made up of phospholipids) different to the mitochondria. the main labor in here is to produce proteins.
organelles
the nucleus is the organelle that store inside of it the DNA.the DNA is like the blueprints of the cell, it tells to the cell what things it need to have, produce and all the information that it need to function. DNA can´t get out of the nucleus, so a copy of it, called RNA, is made. the RNA goes to the "rough endoplasmatic reticulum"
nucleus
in this picture it can be see a double membrane nuclear envelope (we didn´t saw it in class, i don´t thing it is important)
the endoplasmatic reticulum is together with the nucleus, this organelle is divided into two, the rough endoplasmatic reticulum (R.E.R) and the smooth endoplasmatic reticulum (S.E.R). in the R.E.R are located the ribosomes that translate the RNA that lays in there.
endoplasmatic reticulum
in this picture you can saw how close it is to the nucleus, also the R.E.R and the S.E.R, the little dots in the R.E.R are called ribosomes, the ribosomes are sites of protein synthesis in the cell. then it passes through S.E.R to get details and glucose.
the Golgi apparatus storage and packs the proteins together so they can be send to the part of the cell that requires them and in different amounts.
Golgi apparatus
the cilia and the flagella are made up of proteins their function is the cell´s movement, they usually are a few flagella on a cell but they are a lot of cilia that work in group opposite to flagella.
cilia and flagella structure
if you cut a cilia or a flagella, you can observe that their structure have 9 pairs of tubs, each tube push the next to him, with this movements between them, is the way the cell moves around, also they have to simple tubs in the center. this microtubules are composed of a protein named tubulin.
a question to ponder (reflexionar):
"why do have to eat proteins if we are capable to produce them?"
because we can produce some amino acids but not all of them
in total there are 20 aminoacids; in them are 8 aminoacids called "essential aminoacids", this ones we can´t produce them,
a way to get them easily is eating egg, because the yolk contains the 20 aminoacids
"the fabric analogy":
if you didn´t understand you can consider this analogy:
first, imagine a fabric from the outside, the only thing you can see is the wall, this wall is the cell membrane in our analogy, this fabric is divided in departments, every different department have a mission to accomplish, each department is an organelle, the director of the fabric, who directs everything from his office is the nucleus, this president of our fabric know everything, of course is his fabric, have all the ideas, the budged, the blueprints in his laptop (all the information: DNA) so, to let know his employees what they need to do, he send some memos(RNA) from his office, this is how every organelle knows what to do. in the production room (R.E.R) made ribosomes as the memo said, from here the ribosomes are send to put some details (S.E.R) later all that was produced pass to the quality inspection(Golgi apparatus), the boss whats to know if everything have a high quality standard. so in the Golgi apparatus the deficient product (lysosomes) can be sent back to the S.E.R or R.E.R even to the nucleus, because is a cycle system, the good product is packed and storage and when it is needed go out of fabric vesicles.
important concepts:
>cell: The basic structural and functional unit in people and all living things.
http://www.medterms.com/
>tissue:part of an organism consisting of an aggregate of cells having a similar structure and function
wordnetweb.princeton.edu/perl/
>system: a group of organs that work together to perform a specific function. Biology The study of life Prentice Hall Schraer and Stoltze Page. 101
>chemical structure: A chemical structure includes molecular geometry, electronic structure, and crystal structure of a chemical compound
http://en.wikipedia.org/wiki/
>organelles:is a specialized subunit within a cell that has a specific function, and is usually separately enclosed within its own lipid membrane.
en.wikipedia.org/wiki/
- nucleus: a part of the cell containing DNA and RNA and responsible for growth and reproductionwordnetweb.princeton.edu/perl/
webwn - RER: The "rough" appearance of the rough endoplasmic reticulum (RER) results from the presence of ribosomes that are bound to the cytosolic side of the endoplasmic reticulum membrane. The presence of ribosomes on the RER indicates that it is involved in protein synthesis.http://academic.
brooklyn.cuny.edu/biology/ bio4fv/page/rougher.htm - SER: The smooth endoplasmic reticulum (SER) has no such bound ribosomes and is not involved in protein synthesis. However, the SER is involved in cholesterol metabolism, membrane synthesis, detoxification, Ca++ storage along with other cellular processes.http://academic.
brooklyn.cuny.edu/biology/ bio4fv/page/rougher.htm - vesicle: Small membrane-bound spaces in most plant and animal cells that transport macromolecules into and out of the cell and carry materials between organelles in the cell. www.emc.maricopa.edu/faculty/
farabee/BIOBK/BioBookglossV. html - golgi bodies: serve as processing, packing and storage center for the products released form the cell. Biology The study of life Prentice Hall Schraer and Stoltze Page. 86
- mitochondria: round or slipper-shaped organelles that release the energy in food molecules for us by the cell. it is surronded by a double membrane. Biology The study of life Prentice Hall Schraer and Stoltze Page. 86
>endoplasmatic system: Membrane system within the cytoplasm of a eukaryotic cell, important in the synthesis of proteins and lipids. The ER usually makes up more than half the membrane of the cell and is continuous with the outer membrane of the nuclear envelope. There are two distinct regions of ER: the rough ER, or RER (so called because of the protein-synthesizing ribosomes attached to it), and the smooth ER (SER), which is not associated with ribosomes and is involved in the synthesis of lipids and the detoxification of some toxic chemicals.
http://encyclopedia2.
>cilia: which is a hair-like structure that moves in a waving motion. Cilia are used for motility in some one-celled organisms and for moving particles or fluids in certain cells of more advanced organisms.http://score.dnr.sc.
>flagella: long whip-like tail protruding from the surface of a cell that propels the cell, acting as a locomotive device.www.dnr.state.md.us/
>lysosome: An organelle found in all types of animal cells which contains a large range of digestive enzymes capable of splitting most biological macromolecules en.wiktionary.org/wiki/
>protein: A molecule composed of amino acids linked together in a particular order specified by a gene's DNA sequence. Proteins perform a wide variety of functions in the cell; these include serving as enzymes, structural components, or signaling molecules.
www.hhmi.org/genetictrail/
Juana Montoya
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