Lecture 18: Chloroplasts, Apoptosis, Endomembranes

Question 1

Photosynthesis happens in the…?

Answer 1

Chloroplast

Question 2

What are the two different reactions that photosynthesis can be divided into?

Answer 2

Light-dependent reactions
Light-independent reactions

Question 3

Chloroplast have…

Answer 3

Double membrane

Question 4

Stroma of the chloroplast is the

Answer 4

inter membrane space

Question 5

Thylakoid membrane inside the thylakoids has..

Answer 5

All of the necessary things to allow photosynthesis to take place

Question 6

Light dependent reactions occur..

Answer 6

In the thylakoid membrane

Question 7

Function of the light-dependent reactions is to

Answer 7

Excite electrons that are used to generate a proton gradient

Question 8

Light-dependent reactions steps

Answer 8

Electron enters ETC, and H+ is pumped into the thylakoid membrane

Question 9

Co-enzyme in light-dependent reactions is

Answer 9

NADP+ and NADPH

Question 10

Light-independent reactions occur in

Answer 10

Stroma of the chloroplast

Question 11

Light-independent reactions are also known as..

Answer 11

Dark reactions/calvin cycle

Question 12

What happens in the light-independent reactions?

Answer 12

CO2 is reduced to carbohydrates by ATP and NADPH

Question 13

Programmed cell death (Apoptosis) is…

Answer 13

A normal process that involves the death of cells in a coordinated sequence of events, it is part of an organisms growth and development

Question 14

Programmed cell death genes…

Answer 14

Are sequenced in every single cell, however they are just not activated if a cell isn’t undergoing apoptosis

Question 15

How does apoptosis happen?

Answer 15

Bone morphogenetic protein (bmp) is a secreted protein that binds to bmp receptors which activates apoptosis

Question 16

Apoptosis is characterized by

Answer 16

• shrinkage of the cell
• fragmentation of DNA and nucleus
• blebbing (bulge or protrusion) of the plasma membrane
• loss of attachment to other cells
• engulfment by phagocytosis

Question 17

What stimuli can cause apoptosis?

Answer 17

• genetic damage, hypoxia, virus infection
• proteins such as Bax cause change in mitochondria membrane potential and to the leak of cytochrome c
• release of apoptosis mitochondria proteins commits cell to apoptosis

Question 18

Bax proteins function like…

Answer 18

• bind to mitochondria
• forms pores in membrane and cytochrome c spills out into cytosol
• apoptosome is formed by cytochrome c and Bax
• this forms other structures which trigger apoptosis

Question 19

What are the functions of Caspases?

Answer 19

• disrupts cell adhesion
• destroys laminate
• breaks down cytoskeleton
• activates DNase

Question 20

Too little apoptosis…

Answer 20

Leads to cancer

Question 21

Too much apoptosis leads to…

Answer 21

Alzheimer’s

Question 22

Function of the cytosol

Answer 22

Protein synthesis, many metabolic pathways

Question 23

Endoplasmic reticulum function

Answer 23

Synthesis of lipids, synthesis of proteins

Question 24

Golgi apparatus function

Answer 24

Protein modification, packaging of proteins and lipids

Question 25

Lysosomes function

Answer 25

Degradation of cellular material

Question 26

Endosomes function

Answer 26

Sorting, recycling

Question 27

What is the endo membrane system?

Answer 27

Extensive network inside the cell that consists of: ER, Endosomal transport vesicles, golgi complex, lysosomes, vacuoles

Question 28

GFP is?

Answer 28

Fluorescent protein that can be fused with cellular proteins, and can be expressed in cells to track proteins

Question 29

Vesicular transport destinations

Answer 29

Organelle to PM and vice versa Organelle to Organelle and vice versa

Question 30

During vesicular transport…

Answer 30

The vesicle buds off donor compartment and makes its way to recipient compartment via motor protein

Question 31

What is being transported during vesicular transport?

Answer 31

Certain proteins must stay in donar compartment and certain proteins will be transported to recipient compartment. These proteins are sensed by receptors present in the cytosol of the compartment

Question 32

Key elements of vesicular trafficking:

Answer 32

1. Movement of vesicle - uses cytoskeleton and motor proteins, can be anterograde or retrograde 2. Tethering vesicle to target compartment - via proteins from Rab family 3. Docking of vesicle to target compartment - uses proteins called SNAREs 4. Fusion of vesicle and target membrane

Question 33

Anterograde vs retrograde

Answer 33

Anterograde - forward (from ER to Golgi) Retrograde - backward (Golgi to ER)