Lecture 19

Question 1

Describe cyanobacterial cells

Answer 1

• cell wall - no lignin
• plasma membrane - similar to eukaryotes
• nucleoid - location of a single circular dna molecule
• thylakoids - extensive inner membrane on which photosynthetic pigments are found
• food reserve - glycogen (Starch carbohydrate)

Question 2

Explain the relationship between cyanobacteria and chloroplasts, and describe
the differences and similarities between the two

Answer 2

• same size
• chloroplast has
  – multiple copies of DNA
  – no cell wall
  – envelope made up of two membranes
  – thylakoids stacked into granae
  – starch granules for temp food storage

Question 3

Name the cyanobacterial pigments and discuss their roles in photosynthesis.

Answer 3

• chlorophyll a
  – reflects green light
  – transfers electron to other molecules
• carotenoids
  – transfer absorbed energy from photon to chlorphyll
• phycobilins
  – phycocyanin absorbs red reflects blue-green
  – phycoerythrin absorbs green reflects red
  – found in cytoplasm

Question 4

Describe the process of reproduction in cyanobacteria

Answer 4

• reproduce by binary fission
• also can reproduce by budding of filaments

Question 5

Describe the structure and functions of gas vesicles, heterocysts, and akinetes

Answer 5

Gas vesicles
- bright protein bound nanocompartments
- allow cyanobacteria to regulate position with8in water column
- optimize light quality and quantity
Akinetes
- heat and drought resistant spores
- enlarged cell surrounded by thickened envelope
Heterocysts
- fix N2 to NH4
- lack PS2
- surrounded by thick cell wall to prevent 02 from entering

Question 6

Name some environments in which cyanobacteria can be found

Answer 6

• freshwater
• soil dwelling
• antarctic meltwater
• hotsprings
• polar bear fur

Question 7

Recognize Prochlorococcus as a genus of cyanobacteria, and describe its
ecological role in the ocean

Answer 7

• most numerous
• 5% of photosyntgeus globally becayse of it