A cell is alive.
A protein is definitely not alive.
A virus - well, that depends on who you ask.
Viruses are typically composed of RNA surrounded by a capsid (protein shell). This would mean by definition that the virus molecule, which is technically considered nonliving, is larger than a protein strand (because the capsid is made of protein).
Either DNA, or RNA, depending on the virus.
The nucleic acid of a virus is covered by a protein capsid.
A virus is an obligate intracellular parasitic acellular microorganism, consisting of protein coat and nucleic acid DNA or RNA and may be enveloped or not. It is a particle that is not defined as being alive, that goes inside you and attacks your cells, and inserts their DNA into your cell, so that your cell makes more of the virus instead of making more of itself. If you mean in computers, its when malicious code is running in your computer and doing damage. Just like a biological virus, computer viruses alter existing code and produce more copies of itself. But it is just computer code and not anything that is alive. If you have this, you should run antivirus software or get help from a computer professional.
Haemagglutinin (HA) is a surface protein on viruses which assits the virus in attaching to host cells.
II and III only
No. There is no central nervous system - its just a DNA or RNA molecule coiled up in a protein.
Viruses are typically composed of RNA surrounded by a capsid (protein shell). This would mean by definition that the virus molecule, which is technically considered nonliving, is larger than a protein strand (because the capsid is made of protein).
virions i.e. a virus protein
The retroviruses are enveloped viruses that have two complete copies of RNA. They also contain the enzyme reverse transcriptase.
Only through the "hijacking" of the host cell DNA can the virus make protein.
If a virus has one, yes, and it's often referred to as a "protein coat."
protein
protein
Either DNA, or RNA, depending on the virus.
Protein capsid.
The nucleic acid of a virus is covered by a protein capsid.