Ribosomes

Question 1

Ribosomes are

Answer 1

small organelles that are either free in the cytoplasm (of all cells) or are attached to the rough endoplasmic reticulum (only in eukaryotic cells)

Question 2

Ribosomes are the site of protein synthesis (where………..)

They ‘read’ RNA to make ………… in a process called

Answer 2

(where proteins are made)

polypeptides (proteins) in a process known as translation

Question 3

Ribosomes are themselves formed from

Answer 3

RNA and proteins

Question 4

The RNA that forms part of the structure of ribosomes is a specific type of RNA known as

Answer 4

known as ribosomal RNA (rRNA)

Question 5

The rRNA in ribosomes has

Answer 5

enzymatic properties that catalyse the formation of peptide bonds between amino acids

Each ribosome is a mixture of ribosomal RNA and proteins

Question 6

Ribosomes in eukaryotic cells are larger than those in prokaryotic cells. In both cell types, ribosomes are composed of a small subunit and a large subunit

where are they found and what sub units in eukaryotic cells

What size ribosomes and where are they found

Answer 6

80S ribosomes (composed of 60S and 40S subunits) are found in eukaryotic cells

70S ribosomes (composed of 50S and 30S subunits) are found in prokaryotic cells, as well as in the mitochondria and chloroplasts of eukaryotic cells

Question 7

The large subunit is the site of translation
The rRNA and proteins of the large subunit hold …..

Answer 7

tRNA molecules (with their attached amino acids) in place
Condensation enzymes linked to rRNA can then catalyse the formation of peptide bonds between amino acids

Question 8

Condensation enzymes linked to rRNA can then catalyse the formation of peptide bonds between ………

Answer 8

amino acids

Question 9

mRNA sits between the

Answer 9

two subunits and the ribosome moves along it as it translates it into a polypeptide

Unlike some organelles, ribosomes are not surrounded by a membrane