BIOLOGY 1.5 Marks Questions

Lactic Acid Bacteria (LAB) or Lactics constitute a diverse group of microorganisms associated with plants, meat, and dairy. They are used in the manufacture of dairy products such as acidophilus milk, yogurt, buttermilk, and cheeses.
Role of LAB in human stomach:
lactic acid bacteria have a number of well-established benefits. They can improve lactose digestion, play a role in preventing and treating diarrhea and act on the immune system, helping the body to resist and fight infection. It play a very beneficial role in checking disease-causing microbes

The major steps of fermentation are as follows:
i. Sterilisation of the fermentors/bioreactor and nutrient medium in steam, under pressure.
ii. Inoculation of a selected strain of the yeast.
iii. Recovery of the product.

A. Trophoblast - Gets attached to the endometrium and draws nutritive material secreted by uterine endometrium gland.
B. Inner cell mass - Differentiates as Embryo.

i. A Thalamus, B - Seed, C - Endocarp.
ii. In apple, along with the ovary the thalamus also contributes to fruit formation. So, apple is called false fruit.

Process 'a' is Transcription and process 'b' is Translation.

Foreign gene is usually ligated to a plasmid vector and introduced in the host. As plasmid replicates and makes multiple copies of itself, so does the foreign gene gets replicated and its copies are made. When the most organism divides, its progeny also receive the plasmid DNA containing the foreign gene.