Absence of oxygen means anaerobic respiration ; which has 2 different pathways.
First Pathway ; Alcoholic fermentation which takes place in yeast.
Pyruvate is decarboxylated into ethanal releasing co2 as waste product.
Ethanal is toxic , so its reduced by help of NADH to ethanol in presence of alcohol dehydrogenase enzyme , and Free NAD is released to continue glycolysis.
2) The second pathway is Lactic fermentation which takes place in mammalian muscles.
Pyruvate accepts hydrogen and is converted to lactate by the help of enzyme lactate dehydrogenase , again free NAD is released to continue glycolysis.
Hope I made it clear enough :)
The theory of natural selection was first expounded by Charles Darwin and today it is believed to be the main process that brings about evolution.
This process is defined as the process whereby organisms who better adapt to their environment tend to survive and produce more offspring.
Hence, according to this statement, option C is correct.
More organisms are born than can survive.
The lac operon, which stands for Lactose operon is known as an inducible system. It is the an operon required for the transport and metabolism of lactose some enteric bacteria (Echerichia coli for example). The Lac operon is only activated in the presence of a key molecule. The key molecule is lactose.
From the given options the following best describes the Lac operon:
D. The repressor is freed from the operator when lactose is present.
Answer:
true
Explanation:
Plants appear green because they contain a pigment called chlorophyll. Chlorophyll absorbs lights; however, the green light is not absorbed but reflected, making the plant appear green.
