Which of the following microorganisms is used in the production of bread?
A. Aspergillus niger
B. Saccharomyces cerevisiae
C. Streptococcus
D. Lactobacillus
Answer: Option B
Solution (By JKExamLibrary)
Saccharomyces cerevisiae, commonly called baker's yeast, ferments sugars to produce CO₂ and ethanol. The CO₂ causes dough to rise, giving bread its porous texture. Lactobacillus is used in yogurt and cheese making, Aspergillus niger in citric acid production, Streptococcus in some dairy ferments. Yeast is a unicellular fungus. Fermentation is an anaerobic process. Alcohol evaporates during baking.
Explanation:
A food chain shows the flow of energy from producer to consumers. Grass (producer) → Grasshopper (primary consumer/herbivore) → Frog (secondary consumer/carnivore) → Snake (tertiary consumer). Arrows point in the direction of energy flow. Option A has incorrect order, C and D start with consumer. Typically, energy decreases at each trophic level. This illustrates the correct trophic sequence.
Explanation:
A codon is a triplet of nucleotides in mRNA that codes for a specific amino acid or signals termination of translation. There are 64 codons; 61 code for amino acids and 3 are stop codons. Anticodons are on tRNA, exons are coding regions of DNA, introns are non-coding.
Explanation:
Oxytocin, released from the posterior pituitary, increases the frequency and strength of uterine contractions during labor via positive feedback. Prolactin stimulates milk production, estrogen helps uterine growth, relaxin relaxes pelvic ligaments.
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