Cell Organelles

Question 1

What organelle makes up the largest percentage of total cell membrane volume in a liver hepatocyte and in a pancreatic exocrine cell

Answer 1

Liver hepatocyte- Mitochondria

Pancreatic exocrine cell- Rough ER

Question 2

Functions of smooth ER, and what type of cell would have a large amount of smooth ER

Answer 2

Glycogen metabolism
Lipid/phospholipid synthesis
Detoxification
Steroidgenesis
Calcium regulation
-Abundant in cells that make steroids or lipids

Question 3

Cis vs Trans colgi

Answer 3

Cis is usually the entrance point of proteins coming from rough ER. Trans is usually the exit point

Question 4

Golgi functions

Answer 4

Modifications of carbs attached to glycoproteins
Poly/oligosaccharide synthesis
Synthesis of sphingomyelin
Sorting secretory products, packaging into vesicles

Question 5

Clathrin coated vesicles are used for

Answer 5

Transporting products from Golgi to lysosomes or from exterior of cell to lysosomes

Question 6

COPI coated vesicles are used for

Answer 6

Transporting products b/w stacks of the Golgi apparatus

Question 7

COPII coated vesicles are used from

Answer 7

Transporting products from ER to the golgi

Question 8

What is Dynamins function

Answer 8

Surrounds neck of the invaginated clathrin coated pit, causing neck of the vesicle to pinch off from plasma membrane

Question 9

What is Adaptins function

Answer 9

Mediates clathrin binding to the vesicle membrane

Question 10

How are lysosomal enzymes sorted

Answer 10

In the Golgi, they get a Mannose-6-phosphate attached to them, which attaches to the M6P receptor in the trans Golgi where it buds off as a clathrin coated vesicle and eventually loses the clathrin and becomes a lysosome

Question 11

Difference b/w primary and secondary lysosomes

Answer 11

Primary lysosomes are storage site for hydrases, no enzymatic activity. Secondary lysosomes are engaged in catalytic processes and have active enzymes

Question 12

Characteristics/cause of familial hypercholesterolemia

Answer 12

Characterized by elevated levels of LDL (the primary transport protein for cholesterol)
Primary defect is mutation in the gene encoding the LDL receptor
-leads to atherosclerotic plaques

Question 13

Peroxisome functions

Answer 13

Synthesis/degradation of hydrogen peroxide
B-oxidation of LCFA
Bile acid/cholesterol synthesis
Detoxify alcohol

Question 14

Zellwinger syndrome

Answer 14

Absence of or reduced numbers of peroxisomes

Caused by defects in the assembly of the peroxisome

Question 15

What is a major cause of mitochondrial DNA diseases

Answer 15

Mutations in mt tRNA genes