Chloroplasts and Endosymbiosis

Via what process do eukaryotic algae originate?

endosymbiosis

Explain the transfer and alteration of genes during endosymbiosis

• gene transfer from cyanobacterium to host

• cyanobacterium genome is reduced

Which layers are lost and which are retained during endosymbiosis?

Lost: peptidylglycan layer and phagosomal membrane

Retained: outer and inner membranes of cyanobacterium

What are proplastids?

Small organelles with few thylakoids (usually 3-4 strands)

Which phytoplankton divisions have a double membraned chloroplast?

Rhodophyta and Chlorophyta

Which phytoplankton divisions have an endoplasmic reticulum with one membrane?

Euglenophyta and Dinophyta

Which phytoplankton divisions have an endoplasmic reticulum with two membranes?

Cryptophyta, Prymnesiophyta, and Heterokontophyta

True or false: cyanobacteria lack chloroplasts

True

Describe the location and function of stroma.

Stroma is the matrix inside the chloroplast envelope and is the site for CO2 fixation.

Where are pyrenoids and what enzyme do they contain

Located inside the chloroplasts and contain rubisco

Where are lipid droplets located and what function do the serve?

Located inside or just outside of chloroplasts and act as photoreceptors.

Explain the structure of thylakoids

• membranous vesicles or disks

• contain chlorophyll

• may form bands or be free (depending on phylum)

Which phytoplankton division(s) have free thylakoids with phycobilisomes on surface?

• Cyanobacteria

• Rhodophyta

Which phytoplankton division(s) have two bands of thylakoids?

• Cryptophyta

Which phytoplankton division(s) have three bands of thylakoids with a girdle?

• Euglenophyta

• Heterokontophyta

Which phytoplankton division(s) have three bands of thylakoids without a girdle?

• Dinophyta

• Prymnesiophyta

• Eustigmatophyceae

Which phytoplankton division(s) have 2-6 bands of thylakoids?

Chlorophyta

What are the two main lineages of primary endosymbiosis?

• red plastids (Rhodophytes)

• green plastids (Chlorophytes)

Explain the structure of chloroplasts in Rhodophyta

• chloroplast envelope with two membranes

• single thylakoids

• phycobilisomes on thylakoid bands

  • capture light and transfer to reaction centers

Explain the structure of chloroplasts in Chlorophyta

• chloroplast envelope with two membranes

• 2-6 bands of thylakoids

Explain the structure of chloroplasts in Cryptophyta

• chloroplast envelope with three membranes

• two bands of thylakoids

• two membranes of chloroplast endoplasmic reticulum

Explain the structure of chloroplasts in Heterokontophyta

• chloroplast envelope with three membranes

• three bands of thylakoids

• two membranes of chloroplast endoplasmic reticulum

Explain the structure of chloroplasts in Dinophyta and Euglenophyta

• chloroplast envelope with three membranes

• three bands of thylakoids

• one membrane of chloroplast endoplasmic reticulum