1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
12345 [234]
2 years ago
8

1. What was some early evidence of the existence of viruses? Why were they difficult to study?

Biology
1 answer:
kogti [31]2 years ago
5 0

Answer:

Answer No 1:

The earliest evidence for the occurrence of viruses was the discovery of an infectious agent in the sap of a tobacco plant. Experiments were set with different filters from which bacteria could pass but viruses being even smaller than bacteria could not pass.

Viruses were difficult to study because they are very small and couldn't be seen even under a microscope.

Answer No 2:

Wendell Stanley made his studies on the tobacco mosaic virus (TMV). Wendell Stanley developed techniques and crystallized this virus. At that time, it was known that even a very simple cell does not undergo crytallization. Hence, Wendell Stanley got to known that this structure is some infectious agent which has the ability  of crystallization.

Answer No 3:

The four forms of viral genomes are:

  • double-stranded DNA
  • single-stranded DNA
  • double-stranded RNA
  • single-stranded  RNA.

Answer No 4:

The capsid can be described as proteins which make up a shell to enclose the genome of a virus. Capsomeres can be described as the protein sub-units from which a capsid is made. The shapes of a capsid can be characterized into

  • rod-shaped: helical viruses, or inside spherical viruses .
  • icosohedral: icosohedral viruses or the heads of bacteriophages.

Answer No 5:

The components of a viral envelope involve phospholipids and membrane proteins and proteins and glycoproteins. The phospholipids and membrane proteins are derived from the host cell.  The proteins and glycoproteins are of the viral origin.

You might be interested in
When an ADP molecule gains a phosphate, it becomes an ATP molecule. This process is called _____.
aivan3 [116]
Phosphorylation is the correct answer.
5 0
2 years ago
Read 2 more answers
Explain the steps that the scientists probably would have used to restore sight to the dogs
sasho [114]
Scientists used gene therapy to restore the sight of the dogs who suffer from inherited blindness.

Inherited blindness is identified as retinitis pigmentosa. It is the <span>progressive loss of both the rods and the cones photoreceptors in the retina from the edge of the retina to the centre, leading to worsening tunnel vision caused by the loss of peripheral sight

</span>A human gene that enabled cells in the retina to become sensitive to light is added into the retina cells. The scientists then inject a chemical called "photoswitch" in the eye. It attaches itself to the <span>ion channel protein and enables the full conversion of light into an electrical signal relayed to the brain.</span>
3 0
2 years ago
:-) :-) :-) :-) :-) :-) :-) :-) :-)
Ugo [173]

Answer: 34

Explanation:

8 0
2 years ago
What is the nurse's priority intervention when preparing for admission of a child with acute laryngotracheobronchitis? -p=[?
andriy [413]
<span>Laryngotracheobronchitis or croup is a disease that caused by viral infection. The virus could be influenza or parainfluenza virus. The infection will cause edema of the trachea and might obstruct the airway, causing difficulty in breathing.
</span>In this case, nurse should take attention to the patient airway and breathing. Patient with dypneu should be given oxygen and racemic epinephrine nebulized. Corticosteroid also help to reduce the swelling such as dexamethasome or budesonide inhalation.
3 0
3 years ago
ANSWER PLS FAST!!!!!!
olga2289 [7]

Answer:

D: A density-independent factor.

Explanation:

An earthquake is a density-independent limiting factor

6 0
3 years ago
Read 2 more answers
Other questions:
  • Which two objects have a stronger pull of gravity?
    12·1 answer
  • Which factor would decrease an area's carrying capacity for prairie dogs? A.Decreased number of diseases B.Decreased availabilit
    7·2 answers
  • What is an accessory organ of digestion
    14·1 answer
  • In canoeing, you paddle backward to go forward. Canoeing can be explain by Newton's third law that says
    6·1 answer
  • what is your opinion on the balance of nature? should we get involved if a species is slowly disappearing?
    10·1 answer
  • Why is the rise in greenhouse gases considered harmful? A. uses all the carbon dioxide in the atmosphere B. allows more heat to
    5·2 answers
  • 3 examples of inherited variation in dragon fruit​
    14·1 answer
  • A group of deer are part of the same species
    13·1 answer
  • Can someone please help me with this asap
    8·2 answers
  • the hawthorne studies began with an investigation of the effect of changing the amount of light on workers’ productivity. which
    9·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!