BSC1005

BSC 1005

TEST UNIT 1

JUNE 1 2007

Topic I-Chapter 2:

Cells and the Chemistry of Life

1) What are the components of HIV?

HIV is composed of Carbohydrates, Proteins, Lipids, and Nucleic Acids. The virus is surrounded by envelope protein and carbohydrate “spikes” which attach to cells. Those “spikes” are held in a lipid envelope surrounding the cell of the virus. Beneath the lipid layer is a protein matrix, which acts as a cell wall holding in the capsid and the enzyme proteins, which in turn hold the RNA of the cell. There is a picture of what the cell looks like below.

2) How are Carbohydrates organized?

Carbohydrates are organized into either Simple or Complex categories based on the amount of sugars or starches it has. Sugars and Starches have a chemical ratio of 1:2:1, where the amount of Carbon is related to twice the amount of Hydrogen which is related to the amount of oxygen (CH₂O). Simple Carbohydrates are Monosaccharides (sugars that are stable by themselves, like fructose or glucose which is C₆H₁₂O₆), and Disaccharides (sugars made from the bonding of two monosaccharides through condensation, or the removal of water, for example the bonding of fructose and glucose create the disaccharide sucrose). Complex Carbohydrates are Polysaccharides which are like disaccharides but combining more than two sugars. More than 1000 simple sugars can be bonded together to make polysaccharides.

3) How are Proteins organized?

Proteins are separated into Primary, Secondary, Tertiary, and Quaternary categories based on organization and type of protein. Primary Proteins are amino acids like Phenylalanine (sugar substitute in diet soft drinks), Cysteine, and Glutamic acid which join together to make polypeptides (proteins). Secondary Proteins are beta sheets or alpha helix, like those in the protein matrix of an HIV cell. Tertiary Proteins are foldings of single polypeptides, and Quandary Proteins are multiple polypeptides, and the interactions between all polypeptides.

4) How are Lipids organized?

Lipids are organized into Saturated and Unsaturated fats, Triglycerides, and Phospholipids. Saturated fats are single carbon chains with only single bonds, making them harder to digest than Unsaturated fats, which contain one or two double bonds, making the chain easier to break down in the body. Triglycerides are the main components of vegetable oil and animal fats, and Phospholipids are the kinds of fats found in the lipid envelope of the HIV cell.

5) What are the differences between DNA and RNA?

DNA is a double helix, containing sugars Thymine (T), Adenine (A), Cytosine (C), and Guanine (G), where the main sugar that bonds these other sugars together is deoxyribose. RNA is a single stranded helix, containing sugars Uracil (U), Adening (A), Cytosine (C), and Guanine (G), where the main sugar that bonds these other sugars together is ribose.

6) What are all the organelles in a Cell and what are their functions?

Important organelles of the animal cell to remember are the Nucleus (where DNA is held are replicated), the Mitochondrion (where ATP’s in the Krebs Cycle and Electron Transport Chain are made), the Endoplasmic Reticulum (both Rough and Smooth, highway for nutrients in the cell), and the Ribosome (where proteins are made). A detailed picture of the animal cell is seen below.

7) What are the treatments for HIV?

Treatments are based around stopping HIV at different points of its life cycle. AZT is a nucleoside reverse transcriptase inhibitor, or NRTI, which is an antibiotic that stops the RNA in HIV from attaching with the DNA of the host cell, which in turn stops the infected cell from reproducing. Other treatments are Non-Nucleoside Reverse Transcriptase Inhibitors(NNRTI), where RNA reproduction is stopped not at the Nucleoside level, and Protease Inhibitors, which inhibits the cell from going through full mitosis by stopping the cleavage between cells from splitting.

8) What is the complete life cycle of HIV?

HIV starts by entering the blood stream, and finding a cell to attach to. The virus then attaches to a carbohydrate on the outside of a cell, and then the lipid layers bond together and the infected RNA is dumped into the cell. The RNA penetrates the nucleus and copies itself into the DNA of the cell and tricks the cell into replicating the infected RNA. It then tricks the Golgi Apparatus and Rough ER to code viral proteins, and these proteins and cells are spread throughout the body to produce more viral cells. The disease is deadly, but not infectious unless contact is made with an open wound or exchange of DNA.



	BSC 1005 BSC 1005 TEST UNIT 1 JUNE 1 2007 Topic I-Chapter 2: Cells and the Chemistry of Life 1) What are the components of HIV? HIV is composed of Carbohydrates, Proteins, Lipids, and Nucleic Acids. The virus is surrounded by envelope protein and carbohydrate “spikes” which attach to cells. Those “spikes” are held in a lipid envelope surrounding the cell of the virus. Beneath the lipid layer is a protein matrix, which acts as a cell wall holding in the capsid and the enzyme proteins, which in turn hold the RNA of the cell. There is a picture of what the cell looks like below. 2) How are Carbohydrates organized? Carbohydrates are organized into either Simple or Complex categories based on the amount of sugars or starches it has. Sugars and Starches have a chemical ratio of 1:2:1, where the amount of Carbon is related to twice the amount of Hydrogen which is related to the amount of oxygen (CH₂O). Simple Carbohydrates are Monosaccharides (sugars that are stable by themselves, like fructose or glucose which is C₆H₁₂O₆), and Disaccharides (sugars made from the bonding of two monosaccharides through condensation, or the removal of water, for example the bonding of fructose and glucose create the disaccharide sucrose). Complex Carbohydrates are Polysaccharides which are like disaccharides but combining more than two sugars. More than 1000 simple sugars can be bonded together to make polysaccharides. 3) How are Proteins organized? Proteins are separated into Primary, Secondary, Tertiary, and Quaternary categories based on organization and type of protein. Primary Proteins are amino acids like Phenylalanine (sugar substitute in diet soft drinks), Cysteine, and Glutamic acid which join together to make polypeptides (proteins). Secondary Proteins are beta sheets or alpha helix, like those in the protein matrix of an HIV cell. Tertiary Proteins are foldings of single polypeptides, and Quandary Proteins are multiple polypeptides, and the interactions between all polypeptides. 4) How are Lipids organized? Lipids are organized into Saturated and Unsaturated fats, Triglycerides, and Phospholipids. Saturated fats are single carbon chains with only single bonds, making them harder to digest than Unsaturated fats, which contain one or two double bonds, making the chain easier to break down in the body. Triglycerides are the main components of vegetable oil and animal fats, and Phospholipids are the kinds of fats found in the lipid envelope of the HIV cell. 5) What are the differences between DNA and RNA? DNA is a double helix, containing sugars Thymine (T), Adenine (A), Cytosine (C), and Guanine (G), where the main sugar that bonds these other sugars together is deoxyribose. RNA is a single stranded helix, containing sugars Uracil (U), Adening (A), Cytosine (C), and Guanine (G), where the main sugar that bonds these other sugars together is ribose. 6) What are all the organelles in a Cell and what are their functions? Important organelles of the animal cell to remember are the Nucleus (where DNA is held are replicated), the Mitochondrion (where ATP’s in the Krebs Cycle and Electron Transport Chain are made), the Endoplasmic Reticulum (both Rough and Smooth, highway for nutrients in the cell), and the Ribosome (where proteins are made). A detailed picture of the animal cell is seen below. 7) What are the treatments for HIV? Treatments are based around stopping HIV at different points of its life cycle. AZT is a nucleoside reverse transcriptase inhibitor, or NRTI, which is an antibiotic that stops the RNA in HIV from attaching with the DNA of the host cell, which in turn stops the infected cell from reproducing. Other treatments are Non-Nucleoside Reverse Transcriptase Inhibitors(NNRTI), where RNA reproduction is stopped not at the Nucleoside level, and Protease Inhibitors, which inhibits the cell from going through full mitosis by stopping the cleavage between cells from splitting. 8) What is the complete life cycle of HIV? HIV starts by entering the blood stream, and finding a cell to attach to. The virus then attaches to a carbohydrate on the outside of a cell, and then the lipid layers bond together and the infected RNA is dumped into the cell. The RNA penetrates the nucleus and copies itself into the DNA of the cell and tricks the cell into replicating the infected RNA. It then tricks the Golgi Apparatus and Rough ER to code viral proteins, and these proteins and cells are spread throughout the body to produce more viral cells. The disease is deadly, but not infectious unless contact is made with an open wound or exchange of DNA.