MUNDO CELULAR

LO GRANDE DENTRO DE LO INFINITAMENTE PEQUEÑO.

Martha Rocío Chacón VelascoDocente Biología CelularCiencias básicas UDES 2010

ARQUEOBACTERIA

A single ~200 micrometer (m) cell, the human egg, withsperm, which are also single cells. From the union of an eggand sperm will arise the 10 trillion cells of a human body.

Eubacteria;note dividing cells. These are Lactococcus lactis, which are usedto produce cheese such as Roquefort, Brie, and Camembert.

A mass of archaebacteria (Methanosarcina) that produce theirenergy by converting carbon dioxide and hydrogen gas tomethane. Some species that live in the rumen of cattle give riseto >150 liters of methane gas/day.

Blood cells, shown in falsecolor. The red blood cells are oxygen-bearing erythrocytes, thewhite blood cells (leukocytes) are part of the immune systemand fight infection, and the green cells are platelets that providesubstances to make blood clot at a wound.

A colonial single-celled green alga,Volvox aureus. The large spheres are made up of many individualcells, visible as blue or green dots. The yellow masses inside aredaughter colonies, each made up of many cells.

A singlePurkinje neuron of the cerebellum, which can form more than ahundred thousand connections with other cells through thebranched network of dendrites. The cell was made visible byintroduction of a fluorescent protein; the cell body is the bulb atthe bottom.

Prokaryotic cells have a simpler internal

organization than eukaryotic cells.

Electron micrograph of athin section of Escherichia coli, a common intestinal bacterium.The nucleoid, consisting of the bacterial DNA, is not enclosedwithin a membrane. E. coli and some other bacteria aresurrounded by two membranes separated by the periplasmicspace. The thin cell wall is adjacent to the inner membrane.

Electron micrograph of a plasma cell, a type of white bloodcell that secretes antibodies. Only a single membrane (the plasmamembrane) surrounds the cell, but the interior contains manymembrane-limited compartments, or organelles.

Scanning electron micrograph of mature oocystsand emerging sporozoites. Oocysts abut the external

surface of stomach wall cells and are encased within amembrane that protects them from the host immune

system. [

The yeast Saccharomyces cerevisiaereproduces sexually and asexually.

Viruses must infect a host cell to grow andreproduce.

The firstfew cell divisions of afertilized egg set the

stage for all subsequentdevelopment.

Proteins vary greatly in size, shape, andfunction

DNA consists of two complementary

strands wound around each other to form a double helix.

The coded information in DNA is convertedinto the amino acid sequences of proteins by a multistepprocess. Step

Chromosomes can be “painted” for easy identification.

The watery interior of cells is surroundedby the plasma membrane, a two-layered shell of phospholipids.

ATP is the most common molecule used by cells to capture

and transfer energy.

External signals commonly cause a changein the activity of preexisting proteins or in the amounts and types of proteins that cells produce.

During growth, eukaryotic cells continually progress through the four stages of the cell cycle,

generating new daughter cells.

Apoptotic cells break apart without spewing forth cell constituents that might harm neighboring Cells

During the later stages of mitosis, microtubules (red) pull the replicated chromosomes (black)toward the ends of a dividing cell.

ATP is the most common molecule usedby cells to capture and transfer energy. ATP is formed fromADP and inorganic phosphate (Pi) by photosynthesis in plantsand by the breakdown of sugars and fats in most cells. Theenergy released by the splitting (hydrolysis) of Pi from ATPdrives many cellular processes.

External signals commonly cause a change

in the activity of preexisting proteins or in the amounts

and types of proteins that cells produce.

During growth, eukaryotic cells continually progress through

the four stages of the cell cycle, generating new daughter

cells

Apoptotic cells break apart without

spewing forth cell constituents that might harm neighboring

cells.

During the later stages of mitosis,

microtubules (red) pull the replicated chromosomes (black)

toward the ends of a dividing cell.

genotype (alleles) phenotype is mutagen