Chapter 3 - bio
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- Give an example of the ultimate parasite. List the characteristics of a virus.
- Virus = simplist organisms. They are called the ultimate parasites because they cannot survive on their own. Ex. = influenza
- The Spanish Flu killed over ____ people worldwide.
- 50 million people
- The influenza virus differs from out cells in that it uses _____ instead of DNA as its genetic material.
- Host's cells
- The surface of a virus is covered with two types of _____, abbreviated H and N.
- hydrogen and nitrogen
- Once inside a host cell, how does the influenza virus use the cell to reproduce itself?
- Once inside the host cell, the viral RNA replicates itself and mRNA is made which in turn is used by the cells machinery to make viral proteins including hemofflutanin and neuromindase, which inserts in the host cell membrane. The newly formed RNA genome and proteins migrate to the membrane and are pinched off in host cell membrane already containing the newly formed hemagglutanin and neuraminidase.
- Describe the common characteristics of life. What are the building blocks of life? What are the three common elements that comprise life?
- Same building blocks are used for constructing biological molecules, same genetic code is used, same biosynthetic process and machinery is used, and the same enzymes serve as a catalyst for similar biological reactions.
- _____, _____, and _____ are the most common elements in the universe and in biological molecules.
- hydrogen, oxygen, and carbon
- Biological membranes are "fluid" structures which can contain proteins that sense the outside environment. Explain membrane proteins in this role using the influenza virus as an example.
- Proteins can be located within cellular or viral membranes with portions of those proteins protruding outward into the surrounding environment. One such membrane protein in the influenza virus, hemagglutanin, can recognize surface membrane proteins of a host cell and then initiate the process of entering the cell, thus beginning infection.
- Name the four major biological molecules used to make a virus. Give and example of how each of those three is used specifically in the influenza virus.
- The four major biological molecules are lipids, nucleic acids, proteins and carbohydrates. Proteins are used in binding to host cells, lipids are used to make the membrane of the virus, RNA is used as the genetic material of the flu virus.
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Explain how protein synthesis occurs in a cell.
What is the most important function of proteins? - Protein synthesis is based on a 3-letter code, which represents the 20 amino acids. Influenza viruses belong to a group of viruses that use RNA instead of DNA for its genetic materials. The influenza viral genome contains eight discrete RNA molecules, each coding for different proteins, including the hemagglutanin, found on the viral surface. The other proteins include a necleoprotein and a matrix protein that wraps around the viral RNA. These eight proteins are sufficient for the virus to enter into and take over a host cell.
- _____ is the process of making an RNA copy of a gene.
- Transcription
- the intermediary molecule between those steps?
- Transcription takes place in the nucleus of the cell and is where an RNA copy of the gene is produced. This intermediary RNA molecule then passes form the nucleus to the cytoplasm where translation occurs.
- Genes encode proteins but not directly, therefore an intermediate molecule is involved. Address the topic while describing transcription.
- During transcription, the sequence of bases in a portion of DNA that contains a gene is read and an RNA copy is made based on that sequence. This RNA copy is known as messenger RNA or mRNA. This mRNA molecule serves as the intermediate molecule, traveling to the cytoplasm for translation.
- All living organisms on Earth employ nucleic acids as the informational system to direct the reproduction of the next generation. Name the 4 nucleic bases and which bases are complementary. Who discovered the structure of DNA and what form does DNA take?
- A(adenine, T(thymine), G(guanine), and C(cytosine). Complementary bases are Adenine and Thymine, Guanine and Cytosine. Watson and Crick discovered that DNA has a double helix structure. A short segment of the DNA corresponding to the region of interest is copied to another type or nucleic acid known as RNA. This process is known as transcription. A DNA molecule is a hundred million bases in length and too cumbersome to work with directly for protein synthesis.
- How was genetic engineering used to produce insulin for diabetics?
- Using restriction enzymes like Boyer and Cohen had done, people were able to cut the hunam insulin gene out of human DNA and insert that gene into the genone of bacteria. Because of the commonality of life, the bacteria is treated the gene as its own and produced human insulin which was the purified and sold for use by diabetics.
- How is Bt corn different from regular corn and how is that difference beneficial to the plant?
- Bt corn contains a toxin from bacteria known as the Bt toxin. The plant produces this toxin, which is lethal to some insect larvae, in its own tissues. When larvae feed on the corn plant, they ingest the the toxin and die. This results in less damage to plants from the larvae and an increased yeild in crop.
- Describe how new genes are introduced into genetically engineered plants. Give one example of genetically engineered plants that can a) resist pests and b) resist herbicides. Describe how the new gene helps the plants a)resist pests and b) resist herbici
- A bacterium which normally causes a tumor-like disease known as crown-gall in plants is used to introduce genes into plants. The bacteria cause the disease by inserting a piece of its DNA into the plant genome. Therefore, the genetic engineering of plants could be carried out by splicing a desirable foreign gene into the bacterium, thus infecting the plant.