1. DISCUSS HOW CLASSIFICATION SYSTEM HAVE UNDERGONE SEVERAL CHANGES OF A PERIOD OF TIME?
ANSWER:
From early period Many attempts had done to classify living organism. ARISTOTLE was the first who classified plants on the simple morphological character i.e. herb, shrubs, and tree . and animals as red blood and no blood.
After Aristotle , CAROLUS LINNAEUS classified living inti two categoriesi.e. Plantae and Animalia. this classification continued till very recent time, but the classification did not distinguish between prokaryotes( false nucleus) and eukaryotes(true nucleus), unicellular and multicellular, autotrophic and heterotrophic.
Hence it was found inadequate system, and a new system was needed.
THE RECENT AND MOST ACCEPTED CLASSIFICATION SYSTEM IS FIVE KINGDOM CLASSIFICATION SYSTEM BY R.H.WHITTAKER.
2. STATE TWO ECONOMICALLY IMPORTANT USES OF
(A) HETETOTROPHIC BACTERIA.
(B) ARCHAEBACTERIA
ANSWER: heterobacteria-
Lacto bacillus is used in converting milk into curd.
- bacteria are used to produce antibiotic.
archaebacteria- Methanogens are used ase methane gas producer.
-
extraction are being explored, including the use of acidophiles, in a process known as bioleaching.
3.WHAT IS THE NATURE OF CELL WALL IN DIATOMS?
ANSWER: the cell wall of diatoms are made up of two thin overlapping shell,which fixes as soap box. silica are embedded in its cell wall, hence its wall is indestructible.
4.FIND OUT WHAT DO THE TERMS 'ALGAL BLOOM' OR 'RED-TIDES' SIGNIFY.
ANSWER: algal bloom or red tides is the result of rapid multiplication of the dinoflagellates -
Gonyaulax. this dinoflagellates is red in colour and spread over
the sea, which appears red coloured sea, and the tides also appears red.
5.HOW ARE VIROIDS DIFFERENT FROM VIRUSES?
ANSWER: viroids are smaller than virus.
it has only free RNA and no DNA.
it lacks protein coat.
the RNA of viroids are of low weight
6.DESCRIBE BRIEFLY THE FOUR MAJOR GROUP OF PROTOZOA.
ANSWER:1.
Amoeboid protozoans- they live in fresh water, marine water, moist soil
they have pseudopodia e.g.- amoeba they have silica shell on surfacee.g.- entamoeba2.Flagellated protozoans-they are either free living or parasitic. they have flagella e.g. - Trypanosoma3.Ciliated protozoans-they are aquatic and actively moving organism. they have thousand of cilia. e.g.- paramoecium4.Sporozoans- this includes diverse organism. Plasmodium is it example which is cause very dangerous disease nemed Malaria.7.PLANTS ARE AUTOTROPHIC. CAN YOU THINK OF SOME PLANTS THAT ARE PARTIALLY HETEROTROPHIC?
ANSWER:yes some plants like
Cuscuta is parasite, Bladderwort and Venus fly trap are insectivorous. they are not autotrophes.
8.WHAT DO THE TERM PHYCOBIONT AND MYCOBIONT SIGNIFY?
ANSWER: phycobiont and mycobiont are respectively algal and fungal component of Lichen.
phycobiont make food for mycobiont and mycobiont absorbe minerals and water for phycobiont.
9. GIVE A COMPARATIVE ACCOUNT OF THE CLASSES OF KINGDOM FUNGI UNDER THE FOLLOWING:
A. MODE OF NUTRITION
B. MODE OF REPRODUCTION.
ANSWER:
mode of nutrition mode of reproduction
phycomycetes mostly parasite asexual-zoospores aplanospores
sexual-zygospores
ascomycetes saprophtyic asexual-conidia
parasite sexual-ascospore coprophilous
basidiomycetes parasite vegetative-fragmentation no sexual reproduction
but fusion of somatic cell
deuteromycetes saprophyte asexual-conidia parasite
10. WHAT ARE THE CHARACTERISTIC FEATURES OF EUGLENOIDS?
ANSWER: *majority lives in fresh and stagnant water.
*they have protein rich layer called Pellicle, so its body is flexible.* they don't have cell wall.*they are autotroph in presence of sun light and heterotroph in absence of sun light.*pigments of euglenoids are same as in higher plants.*example ; Euglena
11.GIVE A BRIEF ACCOUNT OF VIRUSES WITH RESPECT TO THEIR STRUCTURE AND NATURE OF GENETIC MATERIAL?
ANSWER: VIRUS- viruses are non-cellular organism. they have inert crystalline structure outside the living body. -when they invert living cell they take over the machinery of the host cell to replicate themselves and kill the host cell. -D.J.IVANOWSKY(1892) named virus means poisonous fluid. -M.W.BEIJERINEK(1898) discovered TMV(tobacco mosaic virus) -W.M.STANLEY (1935) showed that virus could be crystallised and crystals consist largely of proteins. -viruses are obligate parasites. -it contain genetic material DNA or RNA. -Bacteriophages or bacterial viruses are usually have double strand DNA. -the protein coat of virus of capsid, made up of small subunits called capsomeres protect the nucleic acid. -these capsomere are arranged in helical or polyhedral geometric form.
