Multiple Choice QuestionsEarthworms have no skeleton but during burrowing, the anterior end becomes turgid and acts as a hydraulic skeleton. It is due to
Coelomic fluid
blood
gut peristalsis
gut peristalsis
Cornea transplant in humans is almost never rejected. This is because
its cells are least penetrable by bacteria
It has no blood supply
It is composed of enucleated cells
It is composed of enucleated cells
The energy -releasing process in which the substrate is oxidised without an external electron acceptor called
fermentation
photorespiration
aerobic respiration
aerobic respiration
Select one of the following pairs of important features distinguishing Gnetum from Cycas and Pinus and showing affinities with angiosperms
the absence of resin duct and leaf venation
the presence of vessel elements and absence of archegonia
perianth and two integuments
perianth and two integuments
Thorn of Bougainvillea and tendril of Cucurbita are examples of
analogous organs
homologous organs
vestigial organs
vestigial organs
In the light of recent classification of living organisms into three domains of life (bacteria, archaea and eukarya), which one of the following statement is true about archaea?
Archaea resemble eukarya in all respects
Archaea have some novel features that are absent in other prokaryotes and eukaryotes
Archaea completely differ from both prokaryotes and eukaryotes
Archaea completely differ from both prokaryotes and eukaryotes
Thermococcus, Methanococcus and Methanobacterium emplify
archaebacteria that contain protein homologous to eukaryotic core histones
archaebacteria that lack any histones resembling those found in eukaryotes but DNA is negatively supercoiled
bacteria whose DNA is relaxed or positively supercoiled but which have cytoskeleton as well as mitochondria
bacteria whose DNA is relaxed or positively supercoiled but which have cytoskeleton as well as mitochondria
A competitive inhibitor of succinic dehydrogenase is
malonate
oxaloacetate
alpha-ketoglutarate
alpha-ketoglutarate
A.
malonate
Succinic dehydrogenase oxidised the succinate to fumarate. In eukaryotes, succinate dehydrogenase is tightly bound to the inner mitochondrial membrane, in prokaryotes to the plasma membrane. Electrons pass from succinate through the FAD and iron-sulphur centres before entering the chain of electron carriers in the mitochondrial inner membrane malonate, an analogue of succinate is a strong competitive inhibitor of succinate dehydrogenase and therefore, blocks the activity of citric and cycle.
In Krebs cycle, the reversible hydration of fumarate to malate is catalysed by fumarase enzyme.
In the last reaction of Krebs cycle NAD- linked L-malate dehydrogenase catalyses the oxidation of L-malate to oxaloacetate.
The isocitrate dehydrogenase in Krebs cycle catalyses oxidative decarboxylation of isocitrate to form alpha-ketoglutarate, which in next step through oxidative decarboxylation converted to succinyl Co-A
Vacuole in a plant cell
is membrane-bound and contains storage
is membrane-bound and contains water and excretory substances
lacks membrane and contains air
lacks membrane and contains air
Which one of the following items gives its correct total number?
Floating ribs in humans - 4
Amino acids found in proteins - 16
Types of diabetes - 3
Types of diabetes - 3
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