V. Origin of the eukaryotic condition
1. －origin of the earth－4600mya
－origin of the life－3800mya
－the oldest prokaryotic fossils－3500mya
－oxygen-evolving photosynthetic forms－3000mya
－the oldest rukaryotic fossils－1500mya
11.Value (Algae and humans)
(1) Base of food chain
Phytoplankton－most unicellular algae
Production of carbohydrates,
Solar energy→chemical enery.
(2) fixation of nitrogion－blue-green algae
(3) food－Kelp, red algae.
(4) fodder－seaweeds
(5) fertilizer－Kelp
(6) reef building
－coralline algae (red algae)
Cell wall contains limestone石灰質CaCo3
(7) agar－wall of red algae, polysaccharide culture, ice cream.
(8) Algin酸性物質，可做安定劑 ( alginic acid)－wall of brown algae gel,
stabilizer.
(9) pharmaceutical－eg. Red algae, industrial Kelp-petroleum.
(10) 50%O2in air－photosynthesis of algae
(11) bioindicator－water pollution→eutrophication優養化→(red tide
[雙鞭藻、渦鞭藻], bloom藻華)
Π. Algae in which the chlorophyll is wholly or predominantly chlorophyll a
－Prokatyotic forms: Cyanophyta 藍綠藻門
(Cyanobacteria, blue-green algae)
－Eukaryotic forms: Glaucophyta [不知名，無人翻譯]
Rhodophyta 紅藻門
Class Cyanophyceae 藍綠藻綱
Gr. kyanos＝blue
Gr. Phyta＝plant
A. Comparison of blue-green algae and bacteria.
Similarity:
1. cell organization: ptokaryotic
2. cell wall: non-cellulose, with peptidoglycan (＝murein)
Dissimilarity:
1. the most of blue-green algae－photosythesis
most of bacteria－no photosynthesis, no release of 02
2. pogmentation－chlorophyll a
B. General characteristic
1. Habitats
－aerial
terrestrial
aquatic (marine and fresh water)→85℃
symbiotic in lichen, root,…
2.Pigmentation:
chlorophyll a
carotenoid
phycobillins 藻膽色素
allophycocyanin 異藻藍素
phycobillins phycocyanin 藻藍素
phycoerythnin 藻紅素
phycobillins + protein→phycobikisome 藻膽色素體
PSΙ: chlorophyll a
PSΠ: cyanobacteria－phycobilins[輔助色素] (plants－chlorophyll b)
3.Food reserve (phtosynthate)
cyanophycean starch
(＝a-granule, like glycogen)
20% primary production of sea
4.Reproduction[無有性生殖]
cell division－unicellular
fragmentation斷裂－colonial and filamentous
exospores 外孢子
heterocyst異型細胞[缺N2] and akinetes厚壁細胞－regenerate
5. Cell organization
(1) outermost－sheath (slime gelatinous material)
(2) well－3 layered outer
middle
??????
(3) protoplast
(a) prokatyotic
(b) thylakoids－flattened,
chlorophyll containing sacs
no membrane
outer surface with phycobilisomes
(c) no central vascuole
(d) with peripheral (gas vacuole)小管狀，像一把洋傘，有遮光作用，
陽光越強張的越開，若則反之。
(e) no protoplasmic movement
6.no motile stage, no flagella
7.no cellulose
8.plant body－
unicellular
colonial
filamentous unbranched
branched
falsely branched.偽分支
9.heterocyst and N2－fixation (N2→NO3-)
(1) heterocyst sp.
(eg. Nostoc, Anabaena, Calothrix美髮藻)
heterocyst－site of N2－fixation
(2) non-heterocyst sp.
(eg. Gloeocapsa, Plectonema)
also with nitrogenase activity.
(3) vegetative cell
－anaerobic condition→nitrogenase
anrobic condition→no nitrogenase
(O2 inhabits N2－fixation)
(4) heterocyst in NO3- medium培養基
－formation of heterocyst↓
N2－fixation↓
heterocyst→germination→vegetative cell
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