Chloroplasts, Apoptosis, Endomembrane

Question 1

Photosynthesis

Answer 1

• Building carbohydrates (CH2O) using energy from sunlight and CO2

-Photosynthesis can be divided into two parts: light dependent and light independent reactions

Question 2

Light dependent reactions

Answer 2

• Occur in the thylakoid membrane
  -Chlorophyll in light harvesting complex
  -e- enters ETC (also in thylakoid membrane)
• H+ pumped into thylakoid membrane

Question 3

Light independent reactions

Answer 3

-Dark reactions/Calvin cycle
-Occur in stroma chloroplasts
-ATP and NADPH made in light reaction used to make CH2O

Question 4

Chlorophyll

Answer 4

Absorbs/reflects different wavelengths of light, which creates different colored plants

Question 5

Apoptosis

Answer 5

• Normal process that involves the death of cells in a coordinated sequence of events
• Part of an organisms growth or development

Question 6

Interdigital cell death

Answer 6

-Leads to regression of soft tissue between embryotic digits in many vertebrae

Question 7

Bone morphogenetic protein (BMP)

Answer 7

-A secreted protein that binds to Bmp receptors (BmpRs)

-Expression of non active BmpRs in duck embryonic hind limbs greatly reduced interdigital apoptosis and resulted in webbed feet

Question 8

Apoptotic cells

Answer 8

Characterized by:
- Shrinkage of cells
- Blebbing (bulge or protrusion) of the plasma membrane
-Fragmentation of DNA and nucleus
-Loss of attachment to other cells
-Engulfment by phagocytosis

Question 9

Intrinsic pathway of apoptosis

Answer 9

• Initiated by intracellular stimuli like genetic damage hypoxia virus
• “killer” proteins like Bax causes change in mitochondria membrane potential and to leak of Cytochrome C

-Release of apoptotic mitochondrial proteins commits the cell to apoptosis

• Release of Cytochrome c and nuclear fragmentation during apoptosis

Question 10

Apoptosis and disease

Answer 10

-Various diseases can be associated with Apoptosis:

• To little apoptosis can lead to cancer
• To much apoptosis can cause Alzheimer or Parkinson’s (degenerative diseases)

Question 11

Cytoplasmic endomembrane system

Answer 11

• Early EM focusing on the cytoplasm revealed membrane bound organelles and vesicles as well as extensive network of membranous canals and stacks of “sacs” (cisternae)

Question 12

Cytoplasmic endomembrane system contains

Answer 12

• Endoplasmic reticulum (ER)
  -Endosomal transport vesicles
  -Golgi complex
  -Lysosomes
  -Vacuole

Question 13

Polarized structure of a secretory cell

Answer 13

-Secreted protein (e.g mucin, a glycoprotein component of mucus)

-Synthesized in the rough ER
-Processed in the rough ER
-Further processed in Golgi
-Concentrated in Golgi
-Delivered to plasma membrane for secretion

Question 14

Using GFP to track cell components

Answer 14

• The green fluorescent protein from jellyfish can be fused with other cellular protein
• GFP fused protein can be visualized under a microscope

-Observation of the fusion protein provides information about the endogenous protein (e.g where it is localized in a cell or organism)

Question 15

Key elements of vesicle trafficking compartments

Answer 15

1. Movement of vesicle - uses cytoskeleton and motor proteins (can be anterograde or retrograde)
2. Tethering vesicle to target compartment -via proteins from the Rab family of protein and other more specialized proteins
3. Docking vesicles to target compartments (uses proteins called snares)
4. Fusion of vesicle and membrane