What Determines The Shape Of A Virus

What Determines The Shape Of A Virus?

The amount and arrangement of the proteins and nucleic acid of viruses determine their size and shape. The nucleic acid and proteins of each class of viruses assemble themselves into a structure called a nucleoprotein or nucleocapsid.

What keeps the structure or shape of a virus?

A complete virus particle known as a virion consists of nucleic acid surrounded by a protective coat of protein called a capsid. These are formed from identical protein subunits called capsomeres. Viruses can have a lipid “envelope” derived from the host cell membrane.

How is the structure of a virus determined?

All viruses contain nucleic acid either DNA or RNA (but not both) and a protein coat which encases the nucleic acid. Some viruses are also enclosed by an envelope of fat and protein molecules. In its infective form outside the cell a virus particle is called a virion.

Why do viruses change their shape?

These altered virus particles are known as A-particles or virus entry intermediates. In previous experiments exposing a virus to extreme heat or proteins caused the shape of the entire capsid to change. These were the closest observable simulations to a virus invading a cell that had been devised at the time.

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What determines the shape of the capsid or core?

What determines the shape of the capsid or core? Structure: The order of the individual proteins and if they are symmetrical determine the the shape.

What is lacking in a virus which makes it?

1) Despite the fact that viruses carry their own genome in the form of DNA or RNA molecules they lack the necessary ribosomal RNAs and ribosomal proteins required for the process of replication. This is why viruses take up the cells host protein building mechanisms to form their own viral copies.

What are the three parts that make up the structure of most viruses?

The correct answer is (d) Nucleic acid (either DNA or RNA) a capsid and recognition spikes.

What are the three main criteria used to classify viruses?

Viruses are classified by factors such as their core content capsid structure presence of outer envelope and how mRNA is produced.

What best describes a virus?

virus. Viruses are microscopic biological agents that invade living hosts and infect their bodies by reproducing within their cell tissue. Viruses are tiny infectious agents that rely on living cells to multiply. They may use an animal plant or bacteria host to survive and reproduce.

What are the basic characteristics of a virus?

  • Non living structures.
  • Non-cellular.
  • Contain a protein coat called the capsid.
  • Have a nucleic acid core containing DNA or RNA (one or the other – not both)
  • Capable of reproducing only when inside a HOST cell.

Which is the biggest virus?

Comparison of largest known giant viruses
Giant virus name Genome Length Capsid diameter (nm)
Megavirus chilensis 1 259 197 440
Mamavirus 1 191 693 500
Mimivirus 1 181 549 500
M4 (Mimivirus “bald” variant) 981 813 390

What contributes to antigenic shift in influenza viruses?

Influenza viruses constantly change through a process called antigenic drift. This is the random accumulation of mutations in the haemagglutinin (HA) and to a lesser extent neuraminidase (NA) genes recognized by the immune system. It is most pronounced in influenza A viruses.

Do all viruses replicate the same way?

Replication between viruses is greatly varied and depends on the type of genes involved in them. Most DNA viruses assemble in the nucleus while most RNA viruses develop solely in cytoplasm.

Do all viruses have a capsid?

Each virus possesses a protein capsid to protect its nucleic acid genome from the harsh environment. Virus capsids predominantly come in two shapes: helical and icosahedral.

What is lacking in viruses which make it dependent on a living cell to multiply?

1) Despite the fact that viruses carry their own genome in the form of DNA or RNA molecules they lack the necessary ribosomal RNAs and ribosomal proteins required for the process of replication. …

What is lacking in virus for it to dependent on a living cell?

1)Viruses are dependent on living cells because they lack the sophisticated machinery that a cell possesses. Thus it breaks into a host cell and injects its own DNA or RNA into it. This new DNA makes the cell create new viruses and protein coats for them.

What is lacking in a virus which makes it dependent on a living cell to multiply explain Class 9?

Viruses lack cellular machinery and hence do not show any characteristics of life until they enter a living body/host and use the host cell to multiply.

What is the composition of virus?

In the simpler viruses the virion consists of a single molecule of nucleic acid surrounded by a protein coat the capsid the capsid and its enclosed nucleic acid together constitute the nucleocapsid. In some of the more complex viruses the capsid surrounds a protein core (Fig.

What are 5 characteristics of viruses?

These are: 1) attachment 2) penetration 3) uncoating 4) replication 5) assembly 6)release. As shown in the virus must first attach itself to the host cell.

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What is not true about a virus?

Unlike true organisms viruses cannot synthesize proteins because they lack ribosomes (cell organelles) for the translation of viral messenger RNA (mRNA a complementary copy of the nucleic acid of the nucleus that associates with ribosomes and directs protein synthesis) into proteins.

What is the most important factor of virus classification?

Because the viral genome carries the blueprint for producing new viruses virologists consider it the most important characteristic for classification.

Why is it difficult to classify viruses?

Viruses are notoriously difficult to classify due to their enormous diversity high rates of change and tendency to exchange genetic material.

Which component of a virus is lacking in a cell?

protein shell

The component present in a virus that is lacking in a cell is the protein shell also called a capsid.

Can a virus have both DNA and RNA?

Virus genomes

We often think of DNA as double-stranded and RNA as single-stranded since that’s typically the case in our own cells. However viruses can have all possible combos of strandedness and nucleic acid type (double-stranded DNA double-stranded RNA single-stranded DNA or single-stranded RNA).

Do viruses have homeostasis?

Viruses have no way to control their internal environment and they do not maintain their own homeostasis.

Is our DNA made up of viruses?

Eight percent of our DNA consists of remnants of ancient viruses and another 40 percent is made up of repetitive strings of genetic letters that is also thought to have a viral origin.

Is a virus a living?

Viruses are not living things. Viruses are complicated assemblies of molecules including proteins nucleic acids lipids and carbohydrates but on their own they can do nothing until they enter a living cell. Without cells viruses would not be able to multiply.

Where did viruses evolve from?

Viruses may have arisen from mobile genetic elements that gained the ability to move between cells. They may be descendants of previously free-living organisms that adapted a parasitic replication strategy. Perhaps viruses existed before and led to the evolution of cellular life.

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How do we get antigenic shift?

Antigenic shift occurs when a nonhuman influenza virus directly infects human hosts or when a new virus is generated by genetic reassortment between nonhuman and human influenza viruses.

What causes antigenic drift to occur in viral infections?

Infectious Diseases

Antigenic drift: A subtle change in the surface glycoprotein (either hemagglutinin or neuraminidase) caused by a point mutation or deletion in the viral gene. This results in a new strain that requires yearly reformulation of the seasonal influenza vaccine.

What are the major steps in viral reproduction?

Key Points
  • Viral replication involves six steps: attachment penetration uncoating replication assembly and release.
  • During attachment and penetration the virus attaches itself to a host cell and injects its genetic material into it.

Why do RNA viruses replicate in the cytoplasm?

There are exceptions notably the smallpox DNA virus encodes its own DNA replication machinery and thus remains in the cytoplasm. Most RNA viruses replicate in the cytoplasm because the enzymes used to replicate viral RNA are virally encoded.

Why can’t viruses reproduce on their own?

“The virus cannot reproduce itself outside the host because it lacks the complicated machinery that a [host] cell possesses.” The host’s cellular machinery allows viruses to produce RNA from their DNA (a process calledtranscription) and to build proteins based on the instructions encoded in their RNA (a process called …

How does a virus replicate in a human cell?

Viruses cannot replicate on their own but rather depend on their host cell’s protein synthesis pathways to reproduce. This typically occurs by the virus inserting its genetic material in host cells co-opting the proteins to create viral replicates until the cell bursts from the high volume of new viral particles.

Introduction to Virology and Viral Classification

4 Virus shape and structure

Viral Structure and Functions

Viruses (Updated)

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