Ribosome Flashcards
What is the composition of eukaryotic ribosomes?
Eukaryotic ribosomes are composed of almost an equal amount of RNA and protein, making them ribonucleoprotein.
They are characterized as 80S ribosomes.
Where are ribosomes formed in a cell?
Ribosomes are formed in the nucleolus.
They are then transported to the cytoplasm through the nuclear pore.
In what locations can ribosomes be found in eukaryotic cells?
- Attached to the rough endoplasmic reticulum (RER)
- Freely dispersed in the cytoplasm
- In the matrix of mitochondria
- In the stroma of chloroplasts
The ribosomes in mitochondria and chloroplasts are prokaryotic (70S) in nature.
What are the sizes of the two subunits that compose eukaryotic ribosomes?
- Large subunit: 60S
- Small subunit: 40S
The two subunits combine to form 80S particles.
What is the significance of magnesium ions in ribosome function?
Magnesium ions control the attachment of ribosomal subunits and form salt bonds between the phosphate group of RNA and the amino group of amino acids.
This is crucial for the function of ribosomes during protein synthesis.
What is a polysome?
A polysome is a chain of many ribosomes attached to one mRNA molecule.
This allows for the production of several copies of the same polypeptide in a short amount of time.
What type of microscope was used to first observe ribosomes?
Ribosomes were first observed using an electron microscope.
They appear as dense granules.
True or False: Eukaryotic ribosomes are larger than prokaryotic ribosomes.
True
Eukaryotic ribosomes are characterized as 80S, while prokaryotic ribosomes are characterized as 70S.
Fill in the blank: Ribosomes are roughly __________, granular, non-membranous bodies found in both eukaryotic and prokaryotic cells.
spherical
Eukaryotic ribosomes are larger than prokaryotic ones.
