Biology Assertion Reason Questions Part 3

  • Cell wall is permeable. Inter space allows free passage of ions in & out:
  • Lysosomes maintain pH = 5, hydrogen ions pumped in by special protein transport mechanism.
  • Tenoplast = fully permeable.
  • Lethal genes are transmitted as recessive & individuals carrying dominant lethal genes do not survive.
  • Larger the recombination frequency, less accurate is the measure of map distance as a cross over in one is likely to affect another.
  • Triplods are propagated vegetatively as they are sterile.
  • Deletions of pollen are not of much consequence in polyploidy as then are several sets of characteristics in pollen of polyploid plants.
  • B chromosomes are absent in well adopted agronomic stains due to selection.
  • Loops of lamp brush chromosomes are rich in RNA & protein as they synthesis the above:
  • Polytene chromosomes have dark band alternate to light bands due to aligned chromomeres.
  • In cell cycle, nuclear envelope break down in M phase as protein kinase phosphorylates the proteins.
  • Each chromosome must carry many factors. Number of characters of an origination vastly outnumbers the chromosomes.
  • For studying mutations, haploid are suitable than diploids as they have half of the genome.
  • DNA gyrase is essential for DNA replication in prokaryotes. It remove positive supercoils, which accumulate in front of replication fork.
  • A plasmid vector must be cleaved by the same enzyme, which cleaves the donor gene. A piece of DNA, cut by a restriction enzyme forms bonds with other DNA molecule which have been cut by the same restriction enzyme.
  • Euglena shows mixotrophic life style. Euglena is autotrophic in sunlight & heterotrophic in absent of light.
  • In life of most land plants, the sporophyte generation dominates as presence of vascular tissue is feature of sporophytic generation.
  • When starter cultures of streptococcus lactic are added to milk, lactic acid production stop within 30 minute. Bacteriophages destroy bacteria.
  • Distribution of receptor protein on host cell is crucial for tissue & host specificity of bacteriophage cap of virus to infect a cell depends on the ability to bind to cell wall.
  • Endospore is a resting stage in life cycle of bacteria. It is formed in only those, which are adequately supplied with food & energy.
  • Most fungi survive only under high condition of humidity. Water is essential for molecule resulting from extracellular digestion of food particle across fungal cell wall.
  • It is advisable to incorporate forest soil along with a forest tree when it is transplanted to a treeless area. Addiction of forest soil to tree less soil ensures mycorrhizal development with tree.
  • Walls of diatoms are indestructible made of cellulose + silica.