Microbes in Human Welfare (Medical Entrance)
Biology Practice Test
Questions
Threonine operon of E.coli strains is exploited for threonine production. Which enzyme is coded by the thrB-gene of E.coli operon?
- Homoserine dehydrogenase
- Threonine synthase
- Aspartate semialdehyde dehydrogenase
- Homoserine kinase
Which organism is used for production of ethanol by fermentation of sulfite liquor?
- Aspergillus niger
- Candida utilis
- Kluveromyces fragilis
- Saccharomyces cerevisiae
Which product is obtained when Corynebacterium species is cultured with ammonia and carbohydrates from sugar beets, sugar cane, tapioca or molasses?
- Vitamin D
- Aspartame
- L- glutamate
- Threonine
During the biosynthesis of penicillin, which amino acid is added first to alpha aminoadipic acid to obtain a beta-lactam ring?
- L-valine
- L-cysteine
- L-methionine
- L-isoleucine
Umami is a savory taste. Which of the following organism produce amino acids that are responsible for umami constituents of soy sauce?
- Aspergillus acidus
- Aspergillus fumigatus
- Aspergillus sojae
- Aspergillus niger
In vitamin B12 production using Pseudomonas denitrificans, which of the following, if supplemented to the medium, would increase the yield of vitamin B12?
- Biotin
- Cobalt
- 5,6-dimethyl Benzimidazole
- Betaine
For which of the following purposes is alpha-amylase, sourced from Bacillus licheniformis, used?
- Ripening of fruits
- Preparation of detergents
- Banana juice preparation
- Making digestion pills
Xanthomonas campestris organism is used for xanthan gum production which is used in bubble gums. Which of the following is added to the fermentor to stop the reaction once xanthan gum is obtained?
- Isopropanol
- Glucose
- Lactic acid
- Penicillin
How does intermittent addition of lime help in the fermentation process of lactic acid?
- To separating out calcium lactate
- For sedimentation of lactalbumin
- Neutralise the acid produced
- Enhance the production of lactic acid
Zymomonas mobilis has several advantages over S. cerevisiae with respect to producing bioethanol. Which of the following is true with respect to its use for ethanol fermentation?
- Lower ethanol tolerance
- Can ferment xylulose and arabinose
- High sugar uptake and ethanol yield
- Can tolerate toxic inhibitors present in lignocellulosic hydrolysates
Benzene is used in downstream processing of ethanol production. It is used as a
- reaction terminator
- growth factor
- separating agent
- Precursor
In the synthesis of cortisone, which of the following microbes is used to introduce O2 at 11th position of steroid nucleus?
- Rhizopus arrhizus
- Rhizopus nigricans
- Rhizopus oryzae
- Rhizopus atrocarpi
In 2015, which of the following bacteria was proved to produce ascorbic acid from L-sorbosone?
- Acetobacter
- Ketogulonicigenium robustum
- Ketogulonicigenium vulgare
- Xanthomonas citri
Yakult, a probiotic drink founded in 1935, contains
- Lactobacillus acidophilus
- Lactobacillus casei
- Lactobacillus brevis
- Brevibacterium
In biotransformation used for production of riboflavin, glucose is converted into D-ribose in the first step of the procedure. Which of the following bacteria brings about this conversion?
- Ashbya gossypii
- Bacillus pumilus
- Eremothecium ashbyii
- Mycobacterium smegmatis