Question

Cells have all the components necessary for protein synthesis but viruses do not. Complete the following sentences to indicate which gene expression components are found in virus particles. Click on a term and drag into the blank space. A term may be used more than once.

A. RNA polymerase is______ present in a cell, but present in viruses.
B. tRNA is________ present in a cell, but present in viruses.
C. Ribosomes are________ present in a cell, but present in viruses.
D. Genes are_______ present in a cell, but present in viruses.
1. Never
2. Sometimes
3. Always

Answer 1

Cells contain all components necessary for protein synthesis, including RNA polymerase, tRNA, and ribosomes, all of which are always present. Viruses sometimes have RNA polymerase but never have tRNA or ribosomes; however, they always carry their own genes.

Step-by-step explanation:

When completing the sentences to indicate which gene expression components are found in virus particles, the answers are as follows:

1. RNA polymerase is always present in a cell, but sometimes present in viruses.
2. tRNA is always present in a cell, but never present in viruses.
3. Ribosomes are always present in a cell, but never present in viruses.
4. Genes are always present in a cell, but always present in viruses.

Viruses lack many components necessary for protein synthesis and rely on host cell machinery to replicate. For example, virus particles do not contain ribosomes or tRNA, but they do contain their own genes. Some viruses bring certain enzymes necessary for replication into the host cell, such as reverse transcriptase in the case of HIV.

Answer 2

A. RNA polymerase is always present in a cell, but sometimes present in viruses.

B. tRNA is always present in a cell, but Never present in viruses

C. Ribosomes are always present in a cell, but Never present in viruses.

D. Genes are always present in a cell, but always present in viruses..

Step-by-step explanation:

A. RNA polymerase is always present in a cell, but sometimes present in viruses. RNA polymerase is the enzyme responsible for transcription in eukaryotic cells, it is the enzyme that stimulates transcription, that is, the passage from DNA to RNA. All RNA viruses encode in their genome an RNA-dependent RNA-polymerase (RdRp) that acts as a catalytic subunit, along with other viral and cellular proteins, in the replication of the viral genome. B. tRNA is always present in a cell, but Never present in viruses Transfer RNA is a type of ribonucleic acid that is responsible for transporting amino acids to ribosomes where, according to the sequence specified in a messenger RNA (transcribed, in turn , from DNA), proteins are synthesized. C. Ribosomes are always present in a cell, but Never present in viruses. Ribosomes are responsible for the granular appearance of the cytoplasm of cells. It is the most abundant organelle, several million per cell. Viruses do not have cytoplasm or ribosomes (elements necessary to form a cell), so they cannot multiply on their own and they need to infect the cell of another organism to do so.D. Genes are always present in a cell, but always present in viruses.Genes are the storage units of genetic information, they are fragments / segments of DNA that encode a specific functional product. Viruses are small pieces of RNA (ribonucleic acid) or DNA (deoxyribonucleic acid), many are encapsulated in an envelope made of base of proteins known as capsid, others protect their genetic material with a membrane or envelope derived from the cell they infect and some others also surround their capsid with a cell membrane. RNA viruses bring with them their own genetic information copying machines (eg, RNA polymerase enzyme) or possess genes (genetic information) that produce the proteins required to assemble the copying machines within the cell that they infect, thereby which makes them independent of the cellular machinery and capable of infecting cells that are not actively reproducing.