Basic Structure
What two relative size terms describe the main parts of a ribosome?
The large and small subunits.
What are ribosomes called when they float freely in the cytoplasm?
Free ribosomes.
Which single-stranded RNA carries genetic code from DNA to the ribosome?
mRNA (messenger RNA).
What site letter represents the entry point for incoming tRNA?
The A site (Aminoacyl).
What common nickname is given to ribosomes based on their job?
Protein factories.
What protective double-layer boundary do ribosomes lack?
A membrane.
What organelle gets its "rough" texture from bound ribosomes?
The rough endoplasmic reticulum (Rough ER).
Which RNA molecule delivers specific amino acids to the ribosome?
tRNA (transfer RNA).
What middle site holds the tRNA attached to the growing protein chain?
The P site (Peptidyl).
What medical drugs clear bacterial infections by targeting 70S ribosomes?
Antibiotics.
What specific nucleic acid works with proteins to build a ribosome?
rRNA (ribosomal RNA).
Where do proteins made by free ribosomes usually stay?
In the cytosol (or cytoplasm).
What is a three-base sequence on mRNA called?
A Condon
What final site lets empty tRNA leave the ribosome?
The E site (Exit).
What is an RNA molecule called when it acts as an enzyme?
A ribozyme.
What region inside the nucleus makes ribosomal subunits?
The nucleolus.
What organelle modifies and ships proteins sent from the Rough ER?
The Golgi apparatus.
What three-base sequence on tRNA matches up with mRNA?
An Anticondon
What type of chemical bond links amino acids together inside the ribosome?
A peptide bond.
What is a cluster of ribosomes reading the same mRNA strand called?
A polyribosome (or polysome).
What Svedberg rating distinguishes smaller prokaryotic ribosomes from 80S eukaryotic ones?
70s
Which two eukaryotic organelles have their own internal, bacteria-like ribosomes?
Mitochondria and chloroplasts.
What three-letter codon (AUG) signals the ribosome to start translation?
The start codon.
What protein enters the A site to end translation when a stop codon appears?
A release factor.
Who was the scientist behind the "S" unit used to measure ribosome density?
Theodor Svedberg.