Question

7) Which of the four major types of cell communication requires both signal and target cell to use transmembrane proteins during their communication event?

A) Paracrine B) Neuronal C) Endocrine D) Contact-Dependent

8) When a ligand from a signal cell binds to a receptor on a target cell- the target cell processes the message and responds to it with the appropriate cellular actions via a process called:

A) Signal Transduction B) Gene Transcription C) Second Messengers D) The Central Dogma

9) When a target cell needs to make a new protein so it can do a NEW job-- the gene for that protein (the protein’s DNA code) is turned ON-ie. It is expressed, which means that the gene will undergo THIS reaction:

A) Replication B) Transcription C) Translation D) Phosphorylation

Answer 1

7. The four major types of cell communication requires both signal and target cell to use transmembrane proteins during their communication event is CONTACT DEPENDENT.

In contact dependent signalling or Juxtacrine signalling, uses a membrane ligand (molecule that binds to the receptor protein) and a membrane protein for the interaction of two cells. This type of communication plays an important role in immune responses. It is a type of cell to cell or extracellular matrix signalling in the cells of close contact.

8. When a ligand from a signal cell binds to a receptor on a target cell- the target cell processes the message and responds to it with the appropriate cellular actions via a process called SIGNAL TRANSDUCTION.

Cell signalling encompasses the generation and transmission of a signal, the reception of the signal and the propogation of the signal within the receiving cells.

Signal Transduction is the process whereby an extracellular signal is converted or tranduced into a different form of intracellular signal. It results in the amplification of the signal and is a multi step process. It regulates the functions such as growth, differentiation, metabolism and survival. The two major signal transduction pathways are

1. cAMP dependent pathway and
2. Mitogen activated protein kinase (MAPK) pathway

9. When a target cell needs to make a new protein , the gene for that protein (the protein’s DNA code) is turned on. It is expressed, which means that the gene will undergo REPLICATION.

For the protein synthesis to occur, the first step is formation of DNA template for transcription process to start. DNA replication is the process of making two daughter strands where each daughter strand contains half of the original DNA double helix. Hence DNA will undergo replication process and then followed by transcription and translation. Both transcription and translation are equally important in the process of genetic flow of information starting from Genes in DNA to protein synthesis and these steps follows the DNA replication. The synthesis of ribosomal RNA, transfer RNA, messenger RNA under the direction of DNA templates and the information in a strand of DNA is transcribed into a new molecule of messenger RNA (mRNA) is called Transcription. double helix.