Ribosomes

Question 1

Definition

Answer 1

Non membranous organelle formed of rrna and proteins

Question 2

Origin

Answer 2

Protein is formed in cytoplasm and enter nucleus through pores in nuclear envelope and rrna is formed in nucleolus and they join to form small and large subunits then leave again in pores to cytoplasm to join during protein synthesis

Question 3

Lm

Answer 3

Cause basophilia of cytoplasm due to acidity of the phosphate group
Can be focal, diffused or localized

Question 4

Em

Answer 4

Small electron dense granules formed of large and small subunits held together by mrna
Large subunit has groove for for accommodation of polypeptide chain
Free form is presented scattered in cytoplasm or in polysomes as rosette or spiral in shape
Attached form is attached to reroutes surfaces by ribophorins receptors

Question 5

Function

Answer 5

Free ribosomes are used to synthesize proteins used inside cells as glycolytic enzymes
Attached ribosomes synthesize extracellular proteins as hormones and enzymes