Group 7

Question 1

RER and protein translation

Answer 1

-ribosomes are targeted to the ER membrane by a specific signal sequence
-the signal sequence is locates in the amino-terminus (N-terminus)
-contains several consecutive hydrophobic amino acids
-directs synthesis to the ER compartments

Question 2

Functions of the smooth ER

Answer 2

1) lipid synthesis
2) production steroid hormones
-endocrine cells
3) detoxification
-liver cells
4) sequestration - Ca2+
- muscle cells

Question 3

Endocytosis

Answer 3

• the capture of substances from outside the cell by engulfing them in a vesicle derived from the cell membrane
  -from plasma membrane to organelle
  -uses transport vesicles and has directed movement as it uses cytoskeleton and motor proteins

Question 4

Exocytosis

Answer 4

• the release of substances from the cell to the outside by fusing vesicles with the plasma membrane
• from organelle to plasma membrane

Question 5

transport of transmembrane proteins

Answer 5

• orientation of a transmembrane protein with respect to the cytoplasm and the interior of the membrane - bound compartments is maintained during its travel through the endomembrane system

Question 6

Vesicular transport/trafficking

Answer 6

transport of material between compartments:
-organelle — PM
- organelle — organelle
1) Utilizes transport vesicles
-small, spherical, membrane-enclosed organelles that bud off clonar compartments and fuse with acceptor or recipient compartments
2) Targeted movement (directed):
- uses cytoskeleton and motor proteins
- sorting signals recognized by receptors

Question 7

Apoptosis

Answer 7

the death of cells which occurs as a normal and controlled part of an organism’s growth or development.
- in some cases, the problem is due to too little apoptosis
ex: cancer, too little apoptosis occurs in resulting in tumors
-in other cases, too much apoptosis occurs resulting in diseases like Alzheimer’s disease

Question 8

The intrinsic pathway of apoptosis

Answer 8

• initiated by intracellular stimuli like genetic damage, hypoxia or virus infection
• “killer” proteins like Bax causes changes in mitochondrial membrane potential and leads to the leak of cytochrome C
• release of apoptotic mitochondrial proteins commits the cell to apoptosis

Question 9

Apoptosis is characterized by:

Answer 9

• shrinkage of cells
  -fragmentation of DNA and nucleus
• blebbing of the plasma membrane
  -loss of attachment to other cells
  -engulfment by phagocytosis

Question 10

bmp

Answer 10

• is a secreted protein that binds to bmp receptors (bmpRs)

Question 11

Light - independent reactions

Answer 11

• dark reactions / calvin cycle
• occurs in the stroma of cholorplasts
  ATP & NADPH made in light reaction used to make CH2O

Question 12

Light - dependent reactions

Answer 12

• occurs in the thylakoid membrane
• 2 light harvesting complexes
  - complex 1 and complex
  photosystem 1and 2
• electrons enters the ETC
  H+ pumped into the thylakoid lumen
  -ATP and NADPH made in light reaction are used to make CH2O in light - dependent reactions

Question 13

Chloroplasts: structure and function

Answer 13

Function: photosynthesis
Structure:
- thylakoid - disk looking things
- granum - stack of disks
- outer membrane
- inner membrane
- stroma - space holding everything

Question 14

Coenzymes acting as electron carries can exist as either:

Answer 14

1) Oxidized - can accept electrons

2) Reduced- can donate electrons when returning to their oxidized state

Ex: oxidized - NAD+
reduced: NADH

oxidized: FAD
reduced: NADH