Answer: The correct answer is-
an agent that causes a mutation in DNA.
Mutagen is an agent or a substance that causes permanent change in the genetic material of living organisms ( DNA, deoxyribonucleic acid). This process is called mutation.
A mutagen can be a chemical, physical or biological agent that causes mutation in the DNA.
Example- Physical agents such as -
- Ionizing radiations like alpha particles, gamma rays, X-rays that brings break in the DNA and cause other damages.
- Ultraviolet radiations that creates pyrimidine dimers ( T=T) and causes replication errors if damage is not repaired.
There may be a shortage of clean drinking water in the future
I have searched everywhere, but I have not found the proposals of the question, but I will explain to you what is the endoplasmic reticulum so that you can answer it.
The endoplasmic reticulum is a eukaryotic organelle located in the cytoplasm.
The endoplasmic reticulum is a network of membrane tubules (often interconnected) scattered throughout the cytoplasm of eukaryotic cells. Its membrane, which alone represents more than half of the cellular membrane system, is in contact with the nuclear envelope.
The endoplasmic reticulum can be:
Granular (or rough) (RER) that is to say associated with ribosomes.
Smooth (SER).
The granular endoplasmic reticulum is the place of synthesis (in the associated ribosomes) of the proteins secreted outside the cell and of the proteins and lipids constituting the membranes of the cellular organelles. Golgi, lysosomes, mitochondria, nucleus, ribosomes, vesicles ...). It participates in the correct folding of the proteins that have just been synthesized.
The smooth endoplasmic reticulum participates in cellular metabolism, synthesizing lipids and storing calcium.
Answer: C
Explanation:
For example, in trp-operon, an abundance of tryptophan. coli inhibits the expression trp-operon genes.
Trp operon is a negative repressible feedback mechanism
trpR gene is expressed continually at a low level
Answer:
True . It contains hundreds to thousands genes.
