Book 1 Ch 3 Ctnd

Question 1

What happens in nucleolus?

Answer 1

Assembly of ribosomes- proteins and RNA molecules.
Genes needed for production of components on several of chromosomes.
Chromosomes loop in and out of nucleolus and ribosomal RNA translated from DNA - these are packaged with ribosomal proteins from cytosol

Question 2

What happens in smooth rer?

Answer 2

Synthesis of lipids

Question 3

What happens in rough RER?

Answer 3

Synthesis of lysosomal proteins (mainly digestive)
Cell membrane proteins
Secreted proteins

Question 4

Cotranslocational localisation

Answer 4

Ribosomes that make lysosomal proteins, or those to be secreted, or those making cell membrane
This is the process that directs them to rough Rer.

Question 5

Function of Golgi

Answer 5

Sort proteins and lipids from ER
Complete glycosylation 
Package proteins and lipids into vesicles according to their destination
A) lysosomes
B) cell membrane
C) secretion from cell

Question 6

Constitutive secretion vs regulated

Answer 6

Substances constantly delivered to cell membranes eg secretion of mucus from epithelial cells

Molecules released in response to a signal eg gastrointestinal and digestive enzymes

Question 7

What are lysosomes

Answer 7

Spherical
Contain digestive enzymes
Fuse with membrane bound endosomes containing ingested nutrients and digest large nutrient molecules

Question 8

Autophagy

Answer 8

Cells degrade and recycle components of own organelles and structures when old or damaged or if no nutrients (starving)

Membrane around cell component
Fuses with lysosomes

Question 9

What are peroxisomes

Answer 9

Contain enzymes that break down fatty acids and amino acids
Result in hydrogen peroxide (toxic)
Also contain enzyme - catalyse - that break down hydrogen peroxide into water and oxygen (harmless)
Plentiful in liver cells and adipocytes