Bacteria produce yogurt from milk by (a) conjugation (b) aerobic respiration (c) fermentation (d) fixing nitrogen
I'm missing school for a week so I need help with a few Biology problems.
aerobic respiration?
To determine the answer to this question, we need to understand how yogurt is produced from milk by bacteria.
The correct answer is (c) fermentation.
Explanation:
Fermentation is a metabolic process that occurs in the absence of oxygen. In the case of yogurt production, bacteria ferment the lactose, the natural sugar found in milk, and convert it into lactic acid. This process is carried out by specific bacteria known as lactic acid bacteria, such as Lactobacillus bulgaricus and Streptococcus thermophilus.
Here's how the process of yogurt production by bacteria occurs:
1. Inoculation: The milk is first heated to kill any harmful bacteria present and to denature the milk proteins. Then, a small amount of starter culture containing live bacteria, usually bought from a reliable source, is added to the milk. The starter culture contains a mix of lactic acid bacteria strains that initiate the fermentation process.
2. Fermentation: The lactic acid bacteria begin to consume the lactose in the milk and convert it into lactic acid. This acidification process gives yogurt its tangy taste and causes the milk to thicken.
3. Incubation: The milk is kept at a warm temperature (around 40-45°C or 104-113°F) for several hours to allow the lactic acid bacteria to grow and multiply. During this time, the bacteria produce more lactic acid, further thickening the milk and enhancing the yogurt's flavor.
4. Cooling and maturation: After the desired fermentation time, the yogurt is cooled rapidly to stop the bacterial activity. It is then refrigerated to slow down any further fermentation and allow the yogurt to set and develop its characteristic texture and taste.
In summary, bacteria produce yogurt from milk by fermenting the lactose present in the milk, resulting in the production of lactic acid and the transformation of milk into a thick and tangy product.
Note: Conjugation is a genetic process of bacterial reproduction, aerobic respiration is a type of energy production using oxygen, fixing nitrogen is a process by which some bacteria convert atmospheric nitrogen into a form that plants can use. These processes are not directly involved in the production of yogurt from milk.