Scientists have engineered bacteria to produce human proteins, such as factor VIII, a blood clotting factor used to treat hemophilia. Suppose the unmodified eukaryotic gene coding for factor VIII is inserted directly into a bacterial chromosome. Select the reasons why no expression would be seen in the bacterial cell for the factor VIII gene. Bacteria cannot remove intronic sequence from a gene, so if the gene for factor VIII were transcribed, it would translate to a nonfunctional protein. The bacterial nucleoid does not have the proper proteins to transcribe the eukaryotic gene. The gene will induce attenuation in the bacterial cell, which will cause a delay in the transcription and translation of the factor VIII gene. The bacteria will not recognize the eukaryotic promoter to transcribe the gene. Arrange the steps that would be used in a laboratory to engineer a bacterium that could express the human gene coding for factor VIII. Not all steps will be placed.

- Bacteria cannot remove intronic sequence from a gene, so if the gene for factor VIII were transcribed, it would translate to a nonfunctional protein.  

- The bacteria will not recognize the eukaryotic promoter to transcribe the gene.

Genome engineering steps:

I. Isolate by PCR the mature mRNA of the target factor VIII gene

II. Synthesize a complementary DNA (cDNA) for this mRNA by using a reverse transcriptase enzyme

III. Insertion of the cDNA into a plasmid vector

IV. Expression of the protein in the host bacterial cell through transformation

Explanation:

Bacteria lack the spliceosome (ie., the eukaryotic machinery required to remove introns from the primary mRNA), because bacterial genes do not have introns. Moreover, eukaryotic organisms require several proteins that bind to the promoter sequence and subsequently recruit the RNA polymerase to initiate this process. In bacteria, transcription is controlled by proteins that bind to cis-acting sequences which regulate the transcription of adjacent genes. In contrast to bacteria, eukaryotic genes have many classes of promoter and enhancer elements.

Genome engineering technologies can be used to produce bacteria expressing human proteins derived from synthetically introduced human genes (see steps above). For example, recombinant bacteria expressing the human insulin gene have already been designed by using E. coli as cell factories.

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question#1

ans:

cell is the basic unit of organization of all living things. cells are often called the building block of life and it is the smallest unit of life. the study of cell is called cell biology. cell consists of cytoplasm enclosed within membrane, which contain bio-molecules such as proteins and nucleic acid.

two third of cell is water, which means that two-third of your whole body is water. the rest is the mixture of molecules, mainly proteins, lipids and carbohydrates.

question#2

ans:

organ:

an organ is a group of tissues specialized to form a functional unit. an example is the heart in animals.

organ system:

an organ system is a group of several organs whose functions are synchronized to release an effective action in a living organism. an example is digestive system.

question#3

different systems perform different function at tissue level. for example, the respiratory system facilitates breathing. in the alveoli tissue of the lungs, the exchange of oxygen and carbon dioxide molecules between the air and the bloodstream occurs by passive transport, so that oxygen is taken in and carbon dioxide and water are removed. different systems of the body carry out different functions. for example, your digestive system is responsible for taking in and processing food, while your respiratory system working with your circulatory system is responsible for taking up oxygen and getting rid of carbon dioxide.

question#4

different systems perform different function at tissue level. for example, the respiratory system facilitates breathing. in the alveoli tissue of the lungs, the exchange of oxygen and carbon dioxide molecules between the air and the bloodstream occurs by passive transport, so that oxygen is taken in and carbon dioxide and water are removed. different systems of the body carry out different functions. for example, your digestive system is responsible for taking in and processing food, while your respiratory system—working with your circulatory system is responsible for taking up oxygen and getting rid of carbon dioxide.

question#5

our body works because of the interactions that happen between organs and organ systems.  

for example:  

the heart to regulate blood flow throughout the body. the blood carries oxygen and nutrients to the cells and carries carbon dioxide and waste away from the cells. body systems work together in maintaining a constant internal environment. when this balance is disrupted, the body systems may not function properly, and human health can suffer.   you start to feel bad.