endomembrane system & bulk transport processes (lecture 4)

Question 1

name the types of bulk transport across plasma membrane

Answer 1

exocytosis:
constitutive
regulated
endocytosis:
phagocytosis (eat)
pinocytosis (drink)
receptor-mediated endocytosis (specifies)

Question 2

name the components of the endomembrane system

Answer 2

nuclear envelope, ER (smooth & rough), Golgi apparatus, vesicles, lysosomes, vacuoles, plasma membrane, interconnected membrane system

Question 3

name three overarching processes proteins endure to exit a cell

Answer 3

• synthesise (ER)
• tag and package (Golgi)
• deliver (vesicles)

Question 4

outline the functions of the smooth endoplasmic reticulum (sER)

Answer 4

• metabolism of carbohydrates
• lipid synthesis for membranes
• detoxification of drugs and poisons
• storage of calcium ions
  these processes require extensive sER and an be in/decreased to meet demand

Question 5

outline the functions of the rough endoplasmic reticulum (rER)

Answer 5

• involved in protein synthesis
• the lumen creates an entryway for secreted and membrane bound proteins
• processes and releases these proteins from the cell or from the membrane

Question 6

outline the functions of the Golgi complex

Answer 6

• receives, modifies, sorts and send off proteins arriving from the rER
• due to its polarity vesicles arrive at the cis face and processed vesicles leave at the trans face
• glycosylation - addition, or modification of carbs to proteins
• produces many polysaccharides
• sorting proteins to direct them in the right place
• directs vesicle trafficking, ‘tags’ vesicles to allow for proper binding at the correct location

Question 7

name types of vesicles

Answer 7

transport vesicles (move within), secretory vesicles (transport out/fused with lysosomes), vacuoles, artificial vesicles (liposomes are used for drug/vax delivery)

Question 8

outline the role of lysosomes

Answer 8

they are membrane bound active organelles, containing hydrolytic enzymes in order to degrade proteins, lipids, carbohydrates and nucleic acids to release breakdown products into the cell.
they also digest/recycle unwanted cellular materials (autophagy) and cell death

Question 9

outline the roles of vacuoles

Answer 9

Larger vesicles derived from the rER and Golgi to ensure phagocytosis on a larger scale. The large central vacuole absorbs water allowing plant cells to grow.