how are ribosomes formed and transferred to other places in prokaryotic cells ?

[sunc...@gmail.com]

hello ,everyone .as i know ,prokaryotic cell has no cytoskeleton and
its cytosol can not move .so can its ribosomes move ? what is the
mechanism ? whether they are formed here ,but transferred to other
places and function there , or they just function where they are formed
? can you give me a persuasive answer ? i need your help .

[cognix2006]

THE FIRST PART OF MY ANSWER :

 

TWO CELL TYPES DOMINATE LIFE ON EARTH : PROKARYOTIC CELLS

AND EUKARYOTIC CELLS

 

PROKARYOTIC CELLS, BY DEFINITION, ARE CELLS WITHOUT NUCLEI.

TWO MAJOR LINES OF PROKARYOTES SPLIT SOMETIMES BEFORE

THREE BILLION YEARS AGO, THE ARCHAEA AND THE BACTERIA.

ARCHEANS ARE FOUNDS IN HABITATS THAT SEEMS MOST UNFRIENDLY

TO LIFE SUCH AS; DEEP IN EARTH'S CRUST BREAKING WHERE THEY USE

INORGANIC COMPOUNDS AS AN ENERGY SOURCE; IN HOT SPRINGS AND

UNDERSEA HOT VENTS WHERE TEMPERATURES EXCEED 100 DEGREES

CELSIUS; IN ANIMAL INTESTINES CONVERTING WASTE IN METHANE GAS

AND IN BRINE POOLS THAT WOULD SHRIVEL OTHER CELLS.

EUKARIOTIC CELLS, CELLS WITHOUT NUCLEI, MAKE UP THE BODIES OF

PLANTS, ANIMALS AND FUNGI.

THE SWARMS OF UNICELLULAR PROTISTS ARE, IN THEMSELVES, EUKARYOTIC CELLS. BUT EXACTLY HOW DID THE CELL NUCLEUS ORIGINATE?

ONE THEORY IS THAT A NUCLEUS EVOLVED IN ASSOCIATION WITH THE

LOSS OF CELL WALL, A LOSS THAT ALLOWED THE WALL-LESS MUTANTS

TO ENGULF OTHER MICRORGANISMS.THIS INTERNALIZED THE DIGESTIVE

PROCESS, SUBJECTING THE PREDATORY CELL'S UNPROTECTED DNA

TO A WHOLE NEW SET OF HAZARDS. THIS SITUATION SET THE STAGE

FOR THE SELECTION OF SOME FORM OF MEMBRANE PROTECTED DNA.

THE SECOND PART OF MY ANSWER:

 

A RIBOSOMES IS A CELL STRUCTURE THAT USES GENETIC INSTRUCTIONS

TRANSPORTED IN RIBONUCLEIC ACID (RNA) TO LINK A SPECIFIC SEQUENCE

OF AMINO ACIDS INTO CHAIN TO FORMS PROTEINS. THESE ORGANELLES

ARE PRETTY SMALL, MADE UP OF FIFTY PROTEINS AND SEVERAL LONGS

RNA STRANDS BOUND TOGETHER.

RIBOSOMES ARE FOUND DISPERSED IN THE CYTOPLASM OF ALL PROKARYOTIC CELLS: BACTERIA.

THEY ARE ALSO FOUND IN THE CYTOPLASM OF EUKARYOTIC CELLS :

PROTISTS, FUNGI, PLANTS, AND ANIMALS, WHERE THEY ARE EITHER

FREE TO FLOAT IN THE CYTOPLASM OR ARE BOUND TO NETWORKS OF

ENDOPLASMIC RETICULUM WHICH ARE MEMBRANE-ENCLOUSED TUBULES

IN THE CYTOPLASM. ALSO, IN EUKARYOTIC CELLS, TWO TYPES OF CELL

STRUCTURE CALLED MITOCHONDRIA AND CHLOROPLASTS CONTAIN RIBOSOMES.

RIBOSOMES ARE THE SITES OF PROTEINS SYNTHESIS, WHERE RNA IS

TRANSLATE INTO PROTEIN.

WHEN CELLS NEED LARGE NUMBERS OF PROTEINS, THEY MUST FIRST BUILD  NUMEROUS RIBOSOMES. BECAUSE PROTEIN SYNTHESIS

IS SO IMPORTANT TO CELLS, THEY ARE LARGE NUMBERS OF RIBOSOMES

FOUND THROUGHOUT CELLS OFTEN  NUMBERING IN THE HUNDREDS OR

THOUSANDS.

IN EUKARYOTIC CELLS, THREE OF THE FOUR RIBOSOMAL RNA STRANDS

ARE SYNTHESIZED OUTSIDE OF  THE NUCLEOLUS, A STRUCTURE IN THE

NUCLEUS.

THE FOURTH RIBOSOMALRNA STRANDS ARE SYNTHETIZED OUTSIDE OF THE

NUCLEOLUS AND THEN TRANSPORTED IN THE NUCLEOLUS FOR RIBOSOMA

ASSEMBLY. RIBOSOMAL PROTEINS ENTER THE NUCLEOLUS AND COMBINE

WITH THE FOUR RIBOSOMAL RNA STRANDS TO CREATE THE LARGE AND

SMALLS UNITS WHICH ARE TWO RIBOSOMAL STRUCTURES. THE TWO

SUBUNITS UNITE OUTSIDE THE NUCLEUS JUST BEFORE THE RIBOSOME

BEGINS TO MANUFACTURE PROTEINS.

PROKARYOTIC  CELLS LACK A NUCLEUS OR NUCLEOLUS AND THEREFOR

RIBOSOMAL SYNTHESIS TAKE PLACE IN THE CYTOPLASMS.

WITHOUT THE RIBOSOMES THE MESSAGE WOULD NOT TO READ AND

PROTEINS COULD NOT BE PRODUCED.

 

THE THIRD PART OF MY ANSWER :

 

ALL LIVING CELLS CONTAIN RIBOSOMES, TINY ORGANELLES COMPOSED OF

APPROXIMATELY 60 PERCENT RIBOSOMAL RNA (rRNA), AND 40 PERCENT

PROTEIN. HOWEVER, THOUGH THERE ARE GENERALLY DESCRIBED

AS ORGANELLES, IT IS IMPORTANT TO NOTE THAT RIBOSOMES ARE NOT

BOUND BY A MEMBRANE AND ARE MUCH SMALLER THAN OTHER ORGANELLES. SOME CELL TYPES MAY HOLD A FEW MILLIONS RIBOSOMES,

BUT SEVERAL THOUSAND IS MORE TYPICAL.

 

PLEASE, TOMORROW THE REST OF MY ANSWER...

REGARDS.

DR. MAURICIO CORTE, Ph.D., GENETIC ENGINEERING,

ARIZONA STATE UNIVERSITY.

 

 

"sunc...@gmail.com" <sunc...@gmail.com> wrote:

---

Check out the New Yahoo! Mail - Fire up a more powerful email and get things done faster.