Multiple Choice Questions

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A polygenic inheritance in human beings is

  • Skin colour

  • Sickle cell anaemia

  • Colour blindness

  • Phenylketonuria


A.

Skin colour

Genes that when acting individually have a small effect but that collectively produce a significant phenotypic expression are called polygenes, e.gr inheritance of kernel colour in wheat and skin colour in human.


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In gymnosperms, the pollen chamber represents

  • A cell in the pollen grain in which the sperms are formed

  • A cavity in the ovule in which pollen grains are stored after pollination

  • An opening in the megagametophyte through which the pollen tube approaches the egg

  • The microsporangium in which pollen grains develop


Nucleic acid segment tagged with a radiactive molecule is called

  • Clone

  • Probe

  • Plasmid

  • Vector


One gene-one enzyme relationship was established for the first time in

  • Neurospora crassa

  • Salmonella typhimurium

  • Escherichia coli

  • Diplococcus pneumoniae


The Montreal Protocol refers to

  • Persistent organic pollutants

  • Global warming and climate change

  • Substances that deplete the ozone layer

  • Biosafety of genetically modified organisms


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Powdery mildew of wheat is caused by a species of

  • Puccinia

  • Erysphe

  • Ustilago

  • Albugo


Biological Oxygen Demand (BOD) is a measure of

  • Industrial wastes poured into water bodies

  • The extent to which water is polluted with an organic compound

  • Amount of carbon monoxide inseparably combined with haemoglobin

  • Amount of oxygen needed by green plants during the night 


Ten percent law of energy transfer in a food chain is given by

  • Schimper

  • Elton

  • Haeckel

  • Lindemann


Double fertilization occurs in

  • Riccia

  • Pteridium

  • Cycas

  • Capsella


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The Okazaki fragments in DNA chain growth

  • Results in transcription

  • Polymerise in the 3' to 5' direction and forms replication fork

  • Prove semi-conservative nature of DNA replication

  • Polymerise in the 5' to 3' direction and explain 3' to 5 DNA replication