Ingles celula animal
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Animal Cell Structure and Function
Names: Rodriguez Yaritza Level: XII H Gonzlez Jos Luis
Cell TheoryAll living things are made up of cells. Cells are the smallest working units of all living things. All cells come from preexisting cells through cell division.
Definition of CellA cell is the smallest unit that is capable of performing life functions.
Examples of CellsAmoeba ProteusRed Blood CellNerve CellBacteria
Human Muscle Cells
Two Types of Animal CellsProkaryoticEukaryotic
ProkaryoticDo not have structures surrounded by membranesFew internal structuresOne-celled organisms, Bacteria
Prokaryotic CellsProkaryotic cells include the bacteria and archaea.
Bacterial cells have these constant features:Outer Boundary: Cell wall Plasma membraneCytoplasm: Ribosomes Thylakoids (Cyanobacteria) Innumerable enzymesNucleoid: Chromosome (DNA only)3-*
3-*Bacterial cells may have plasmids, small accessory rings of DNA.Some bacteria have a capsule or a slime layer.Most bacteria have flagella.Some also have fimbriae that help cells attach to surfaces.Bacteria have a great metabolic diversity.
EukaryoticContain organelles surrounded by membranesMost living organisms
Evolution of the Eukaryotic CellAccording to the endosymbiotic hypothesis, eukaryotes arose from a symbiotic relationship between various prokaryotes.Heterotrophic bacteria became mitochondria.Cyanobacteria became chloroplasts.Host cell was a large eukaryotic cell.3-*
Animal cell anatomy3-*
Surrounding the Cell
Cell MembraneOuter membrane of cell that controls movement in and out of the cellDouble layer
Inside the Cell
Nucleus Repository for genetic materialDirects activities of the cellUsually single, some cells several, RBC noneNucleolus - region of intensive ribosomal RNA synthesisSurface of nucleus bound by two phospholipid bilayer membranesnuclear membraneNuclear pores protein gatekeepersUsually proteins going in and RNA going out
Nuclear MembraneSurrounds nucleusMade of two layersOpenings allow material to enter and leave nucleus
ChromosomesIn nucleusMade of DNAContain instructions for traits & characteristics DNA of eukaryotes is divided into linear chromosomes. exist as strands of chromatin, except during cell divisionassociated with packaging histones, packaging proteinsnucleosomes
NucleolusInside nucleusContains RNA to build proteins
CytoplasmGel-like mixtureSurrounded by cell membraneContains hereditary material
Endoplasmic ReticulumMoves materials around in cellSmooth type: lacks ribosomesRough type (pictured): ribosomes embedded in surface
Endoplasmic reticulumLargest internal membraneComposed of Lipid bilayerServes as system of channels from the nucleusFunctions in storage and secretionRough ER is rough because of associated ribosomes (sites of protein synthesisSmooth ER - lack associated ribosomes contained embedded enzymes, catalyze synthesis of carbohydrate and lipid molecules
RibosomesEach cell contains thousandsMake proteinsFound on ribosomes & floating throughout the cell
Golgi BodiesProtein 'packaging plant'Move materials within the cellMove materials out of the cell
MitochondriaProduces energy through chemical reactions breaking down fats & carbohydratesControls level of water and other materials in cellRecycles and decomposes proteins, fats, and carbohydrates
Mitochondria are needed for aerobic respiration which produces energy.The more active a cell, the more mitochondria are present.
LysosomeDigestive 'plant' for proteins, fats, and carbohydratesTransports undigested material to cell membrane for removalCell breaks down if lysosome explodes
VacuolesMembrane-bound sacs for storage, digestion, and waste removalContains water solutionHelp plants maintain shape
*Evidence for the endosymbiotic hypothesis is the following:Mitochondria and chloroplasts are similar to bacteria in both size and structure. Both organelles are bounded by a double membrane the outer membrane may represent the engulfing vesicle, and the inner membrane from the prokaryote. Mitochondria and chloroplasts each contain a limited amount of genetic material and divide by splitting. The DNA is a circular loop like that of prokaryotes. Most proteins of mitochondria and chloroplasts are now produced by the host cell, but these organelles do have their own ribosomes and do produce some proteins. Their ribosomes resemble those of prokaryotes.The RNA base sequence of the ribosomes in chloroplasts and mitochondria suggests a prokaryotic origin. **