Ribosomes Flashcards
its not really a…becasue …
not really a organelle because it is not surrounded by a membrane
focal point for what important cellular activity?
protein synthesis
found in all cells…
- where do they differ?
- each cell type has a unique..?
- ribosomes differ in bacteria, archaea, and eukaryotes
- each cell has a unique type of ribosomal RNA
a way of expressing the size of such a small particle is to…?
refer to its sedimentation coefficient
what is the sedimentation coefficient?
a measure of how rapidly the particle sediments in a ultracentrifuge, expressed in Svedberg units (S)
what is the sedimentation coefficient in eukaryotes? in bacteria?
- in euk. = 80S
- in bacteria = 70S
what does a ribosome consist of?
-two subunits differing in size, shape, and composition
In euk, what are the sedimentation coefficients of the large and small subunit?
in bacteria?
- 60S and 40S in euk.
- 50S and 30S in bacteria
why does the S values of the large and small subunits not add up to the value for the whole ribosome?
b/c the S value depends on both size and shape and are therefore not linearly related to molecular weight
Ribosomes are far more numerous than most other cellular structures…
- how many in prokaryotes?
- in eukaryotes?
- prok. cells contain thousands
- euk. cells contain millions
ribosomes are also found in…
where they function in…
- mitochondria and chloroplast
- where they function in organelle specific protein synthesis
ribosomes in the same cell/different organelle
ribosomes of the euk. organelles ( mitochondria and chloroplast) differ in size and composition from the ribosomes in the cytoplasm of the same cell
