MCQ
Vitamin $B_{12}$ is produced directly during the course of fermentation by
- AAshbya gossypii
- BRhizopus stolonifer
- CSaccharomyces cerevisiae
- ✓Propioni bacteria
(d)It has been demonstrated that Propionibacteria species has the highest potential to accumulate vitamin $B _{12}$ intracellularly. Propionibacterium shermanii and Propionibacterium freudenreichiiare most widely used. Propionibacteriaproduce vitamin $B _{12}$ intracellularly and excrete mainly propionic acid and acetic acid extracellularly.
All Propionibacterium strains employed for vitamin $B _{12}$ production are microaerophilic and produce vitamin $B _{12}$ in high yields only under very low oxygen concentrations.
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$I.$ Flippers of whale and wings of bat exhibit analogy.
$II.$ Wings of butterfly and wings of bird exhibit homology.
$III.$ Organs with dissimilar structure are called analogous organs.
$IV.$ Organs with similar structure and origin are called homologous organs.
$(a)$ It results in the formation of haploid gametes
$(b)$ Differentiation of gamete occurs after the completion of meiosis
$(c)$ Meiosis occurs continuously in a mitotically dividing stem cell population
$(d)$ It is controlled by the Luteinising hormone (LH) and FollicleStimulating Hormone (FSH) secreted by the anterior pituitary
$(e)$ It is initiated at puberty
Choose the most appropriate answer from the options given below: