very briefly,…… virus prok –eubacteria gram plus and minus –archaebacteria euk –fungi...
TRANSCRIPT
Very briefly,……
• VIRUS• PROK
– Eubacteria• Gram plus and minus
– Archaebacteria
• EUK– Fungi– Yeasts, Molds
• ALGAE• PROTOZOA
VIRUSES
A medium-sized virion next to a flea
is roughly equivalent to
a human next to a mountain
twice the size of Mount Everest.
• A sub-microscopic particle (ranging in size from 20–300 nm) that can infect the cells of a biological organism.
• Can replicate themselves only by infecting a host cell.• Basically, consists of genetic material contained within a
protective protein coat called a capsid.• Can infect both eukaryotes (animals, plants, protists, and
fungi) and prokaryotes (bacteria and archaea).• A virus that infects bacteria is known as a bacteriophage,
often shortened to phage. • The study of viruses is known as virology.
The Lytic Cycle. (a) Before attachment. (b) Attachment. (c) Penetration and uncoating. (d) Replication. (e) Assembly. (f)
Release.
a) Before attachment. (b) Attachment, penetration and uncoating. (c) DNA circularization (d) DNA integration with host DNA and replication. Lysogeny if
cI proteins predominate. (e) Lysis if Cro proteins predominate. (f) Release.
ALGAE
• The study of marine and freshwater algae is called ??
• Found in damp places or bodies of water• Common in terrestrial as well as aquatic environments.• Lack vascular tissues to live on land. • Can, however, endure dryness, etc in symbiosis with a
fungus as lichen.• Phytoplankton:
– Provides food base for most marine food chains.– In very high densities (so-called algal blooms) these algae may
discolor the water and outcompete or poison other life forms.– Some used as human food or harvested for useful substances
such as agar or fertilizer.
Algae (singular alga)
• Groups of simple living aquatic organisms that capture light energy through photosynthesis, using it to convert inorganic substances into organic matter.
• Photosynthetic organisms• Single-celled to complex multicellular species.• The prokaryotic forms, referred to as blue-green algae
are only half-algae with a mixture of bacterial characteristics.
• All other forms belong as true eukaryota algae - they have a nucleus enclosed within a membrane.
Prokaryotic algae
• Cyanobacteria or cyanophytes or Blue-green algae
• Can be unicellular, colonial, or filamentous.• Have a prokaryotic cell structure typical of
bacteria• Conducts photosynthesis on specialized
cytoplasmic membranes called thylakoid membranes.
• Some filamentous blue-green algae have specialized cells, termed heterocysts, in which nitrogen fixation occurs.
Eukaryotic algae
• All other algae are eukaryotes and conduct photosynthesis within membrane-bound structures (organelles) called chloroplasts.
• Chloroplasts contain DNA and are similar in structure to cyanobacteria
Symbiotic relationships
• Algae supply photosynthates (organic substances) to the host organism providing protection to the algal cells.
• The host derives some or all of its energy requirements from the algae. Examples include:
• Lichens: – a fungus usually with a green alga or a cyanobacterium as its
symbiont.
• Corals: – Algae known as zooxanthellae (Symbiodinium) are symbionts
with corals.
• Sponges: – Green algae live close to the surface of Breadcrumb sponge
(Halichondria panicea).
A few applications…
• Fertilizer– Sea weeds
• Energy Source– Biodiesel– Hydrogen Production
• Pollution Control– Used in wastewater treatment facilities
• Stabilizing substances– used as "carrageenan". – Excellent stabiliser in milk products - it reacts
with the milk protein caesin, – Also, in petfoods, toothpaste, ice-creams and
lotions etc.
• Nutrition– Excellent sources of many vitamins including:
A, B1, B2, B6, niacin and C. – Rich in iodine, potassium, iron, magnesium
and calcium.– Commercially cultivated as the popular
SPIRULINA, a Cyanobacteria: Superfood– Other algal species cultivated:
• Chlorella (a green algae)• Dunaliella (High in beta-carotene)
• Production of Agar• The natural pigments produced by algae
can be used as an alternative to chemical dyes and coloring agents.– Non-recyclable paper products because of the
chemical inks that they use– Inks made from algae are much easier to
break down. – Colouring agents in food