Probiotics Exam 1 Questions with Complete Solutions (Latest 2025) List the characteristics of lactic acid bacteria that makes them suitable as cell factories - Correct Answers ✅(1) Their food grade status and beneficial effects in the gastrointestinal tract (2) The availability of genetics tools for strain improvement and their small genome sizes (3) A relatively simple and fast metabolism (4) The possibility of using cheap substrates for growth (5) The capability of directly applying their metabolites in food products Define nutraceutics - Correct Answers ✅a food or part of a food that provides medical or health benefits, including the prevention or cure of a disease Enumerate and characterize the nutraceutics that can be produced by lactic acid bacteria - Correct Answers ✅(1) low calorie sugars- used as natural sweeteners from fruits and vegetables
(Ex: mannitol + erythritol)
(2) short chain fatty acids- produced through pyruvate fermentation
(Ex: butyrate + propionate + acetate) 1 / 3
Probiotics Exam 1 Questions with Complete Solutions (Latest 2025) (3) conjugated linoleic acid (CLA)- beneficial in inflammation, metabolic disorders, and cardiovascular diseases
(Ex: Lactobacillus + Streptococcus + Bifidobacterium +
Propionibacterium) (4) bioactive peptides- hormone like effect; in vivo or in vitro; antimicrobial, opioid, antioxidant
(Ex: milk proteins + Lactobacillus helveticus + L. delbruekii +
Lactococcus lactis) (5) gamma aminobutyric acid (GABA)- non protein amino acid that is a major inhibitory neurotransmitter in the sympathetic nervous system; hypotensive, tranquilizer, diuretic
(Ex: Lactobacillus brevis, L. lactis, L. helveticus, L. platarum)
(6) vitamins- essential micronutrients for metabolism but cannot be secreted into the media
(Ex: B12/Lactobacillus reuteri + B11/Lactococcus
lactis/Streptococcus thermophilus/L. amylovorus + B2/lactobacillus) List the commodity chemicals produced by lactic acid bacteria - Correct Answers ✅(1) lactic acid (2) 2,3 butanediol (3) 1,3 propanediol 2 / 3
Probiotics Exam 1 Questions with Complete Solutions (Latest 2025) (4) ethanol (5) butanol List the general characteristics of bacteriophages - Correct Answers ✅(1) virus (2) consists of molecule of DNA or RNA enclosed in a coat of protein (3) cannot reproduce independent of living cells nor carry out cell division (4) usually very small (5) contain a nucleocapsid (6) may have an envelope Compare and contrast the characteristics of the two cycles of bacteriophages - Correct Answers ✅Lytic cycle (1) host cell is destroyed Lysogenic cycle (1) viral DNA integrates into the host genome becoming a latent prophage Name the most common families of bacteriophages found in lactic acid bacteria - Correct Answers ✅(1) lactococcus lactis (2) streptococcus thermophilus
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