A microscope is to see smaller things that you can’t see and it is a really good tool.
Answer:
The second statement is correct: "The "host range" for a virus is determined by the presence or absence of particular components on the surface of a host cell that are required for the virus to attach."
Explanation:
The virus attaching itself to the host cell is the first step for it to successfully infect the host. Viruses are smaller in size than bacteria, so the first statement is incorrect. The third statement is incorrect because viruses do not have the necessary machinery to carry out protein synthesis or to generate ATP, this precisely why they seek out a host to begin with. The fourth statement is false because the virus will either have DNA or RNA, but both at the same time.
Hope that answers the question, have a great day!
Answer:
A, a prokaryotic cell
Explanation:
Prokaryotes are organisms whose cells lack a nucleus and other organelles. Prokaryotes are divided into two distinct groups: the bacteria and the archaea, which scientists believe have unique evolutionary lineages.
Explanation:
The use of CRISPR/Cas9 avoids the need for protein engineering to develop a site-specific nuclease against a specific DNA target sequence, requiring only the synthesis of a new piece of RNA. This dramatically simplifies and greatly reduces the time needed for gene editing design and implementation.
Answer: Positive feedback loop
Explanation:
Even before the food reaches the stomach (before ingesting it), the glands of the stomach mucosa begin to release its gastric secretion. The main characteristic of this secretion is acidity, as measured by pH (one of the physiological variables).
This acidity is a result of the presence of hydrochloric acid, which is part of the secretion composition. In addition to it, water, pepsinogen (which will give rise to the enzyme pepsin) and the intrinsic factor. The acid has a function of the protection of the entire system by eliminating microorganisms. It is also responsible for the activation of pepsin (which only occurs with acid pH), the enzyme that digests proteins containing the amino acids leucine or phenylalanine or tryptophan or tyrosine.
The concept of Positive feedback loop states that the body tries to increase the value of a variable (acidity, in the case of pepsinogen) when it is below its optimal value (called a point adjustment) and decreases this value when it is above optimal.
