Enthalpies of Formation (Section)
For each of the following compounds, write a balanced thermochemical equation depicting the formation of one mole of the compound from its elements in their standard states and then look up ΔHf° for each substance in Appendix C (a) NO2(g), (b) SO3(g), (c) NaBr(s), (d) Pb(NO3)2(s).
Exam 2 study guide Human Biology 100E Reminder: We did not have Class on Monday due to a Spthker, therefore, are test was moved to March 9 . 1) Be able to explain cell theory and discuss where the knowledge for the theory came from. All living things are made of one or more cells. Cells are the fundamental unit of life. Later the cell theory was modified to include: All cells come from previously existing cells, they do not arise spontaneously. 2) What was spontaneous generation The thought that life arises if the right ingredients were put together the right way, life would emerge a. What evidence was provided against this theory Francesco Redi He put some pieces of raw meat into jars that were covered with fine gauze prevented flies from getting to the meat, but the air could circulate freely in the jars. No maggots resulted, so he proved that the air did not contain a vital element which gives rise to maggots, when reacted with raw meat. 3) Why were sugar fermenting beet vats becoming contaminated, and how did Louis Pasteur solve this problem Pasteur found that some bacteria from the air were getting into the vats and spoiling the fermentation reactions. He recommended covering the vats, which eliminated the contamination and the spoilage. a. What did his solution provide evidence for in regards to cell theory Pasteur later proved that bacteria were in the air. 4) Explain how Louis Pasteur provided evidence through an experiment that bacteria do not “spontaneously generate.” a. Draw a diagram if it helps you, but EXPLAIN how what you drew provided evidence. 1. Louis Pasteur designed an experiment to test whether sterile nutrient broth could spontaneously generate microbial life. To do this, he set up two experiments. In both, Pasteur added nutrient broth to flasks, bent the necks of the flasks into S shapes, and then boiled the broth to kill any existing microbes. 2. After the broth had been sterilized, Pasteur broke off the swan necks from the flasks in Experiment 1, exposing the nutrient broth within them to air from above. The flasks in Experiment 2 were left alone. 3. Over time, dust particles from the air fell into the broken flasks of Experiment 1. In Experiment 2, dust particles remained near the tip of the swan necks, but could not travel against gravity into the flasks, keeping the nutrient broth sterile. 4. The broth in the broken flasks quickly became cloudya sign that it teemed with microbial life. However, the broth in the unbroken flasks remained clear. Without the introduction of duston which microbes can travelno life arose. Thus, the Louis Pasteur experiment refuted the notion of spontaneous generation. 5) Friedrich Wöhler discovered a method to produce organic molecules from inorganic molecules. Emil Fischer showed, through experimentation, that organic molecules behaved (followed the same chemical and physical laws) the same as inorganic molecules. a. Explain what these two scientists’ work meant to cell theory and to current biology. Friedrich Wöhler: He was able to produce an organic compound for the first time in the laboratory. He did this by using inorganic compounds as the starting material. He produced urea, which was found in the urine, and was previously thought to be produced ONLY by living beings. After Wöhler’s work some people began to realize that life could be based on regular chemistry, and did not need a vital force to explain it. Emil Fischer: He conducted experiments with enzymes and studied the structures of many different biological molecules. He found that they behaved according to regular laws of chemistry. Today, the name organic chemistry still exists, but now it refers to the chemistry of carbon containing compounds, many of which are biological molecule. 6) Provide 3 differences between Eukaryotic and Prokaryotic cells. Eukaryotic cells contain membranebound organelles, including a nucleus. Eukaryotes can be singlecelled or multicelled, such as you, me, plants, fungi, and insects. Bacteria are an example of prokaryotes. Prokaryotic cells do not contain a nucleus or any other membranebound organelle. Along with their sizes Prokaryotic is 12 Um in diameter and Eukaryotic is 10200 Um in diameter. 7) Why are there no 1 meter tall singlecelled organisms A meter is a standard metric unit of length. One meter is equal to 100 centimeters or 1,000 millimeters. It is equal to about 39 inches. That is just a bit longer than a yard stick. But meters are still way too big for measuring bacteria. So are centimeters and even millimeters. Scientists use the terms microns or micrometers to measure microbes. One micrometer is the same as one micron. One micron is equal to one millionth of a meter. Most bacteria are from 1 to 10 micrometers long. 8) Provide three functions of the cell membrane. The cell membrane (plasma membrane) is a thin semipermeable membrane that surrounds the cytoplasm of a cell. Its function is to protect the integrity of the interior of the cell by allowing certain substances into the cell, while keeping other substances out. It also serves as a base of attachment for the cytoskeleton in some organisms and the cell wall in others. Thus the cell membrane also serves to help support the cell and help maintain its shape. 9) What macromolecule makes up most of the cell membrane Lipidsphospholipids 10)Explain why the polar and nonpolar portions of the cell membrane are beneficial to the cell. It helps you know if it is going to be hydrophobic (repel to mix with water) or hydrophilic (tendency to mix with water). 11)Provide some of the functions of membrane proteins (proteins found connected to the cell membrane. Membrane proteins allow for many of the interactions that occur between cells. Membrane proteins are free to move within the lipid bilayer as a result of its fluidity. They can also be confined to certain areas of the bilayer with enzymes. Membrane proteins perform various functions, and this diversity is reflected in the significantly different types of proteins associated with the lipid bilayer. 12)Be able to talk about the two types of endoplasmic reticulum and what the function of each type is. Smooth ER: It synthesizes lipids, phospholipids, and steroids. Cells which secrete these products, such as those in the testes, ovaries, and sebaceous glands have an abundance of smooth endoplasmic reticulum. Rough ER: Rough ER is found throughout the cell but the density is higher near the nucleus and the Golgi apparatus. Ribosomes on the rough endoplasmic reticulum are called 'membrane bound' and are responsible for the assembly of many proteins. This process is called translation. 13)What is the main function of a ribosome Are a cell structure that makes the proteins are needed for many cell functions such as repairing damage or directing chemical processes. Ribosomes can be found floating within the cytoplasm or attached to the endoplasmic reticulum. 14)What is the main function of the Golgi apparatus A major function is the modifying, sorting and packaging of proteins for secretion. It is also involved in the transport of lipids around the cell, and the creation of lysosomes. The sacs or folds of the Golgi apparatus are called cisternae. 15)Provide two functions of the lysosome. Inside a cell, numerous organelles function to remove wastes. One of the key organelles involved in digestion and waste removal is the lysosome. Lysosomes are organelles that contain digestive enzymes. They digest excess or worn out organelles, food particles, and engulfed viruses or bacteria. 16)Draw a mitochondria and label the different parts On 16 and 17 it would not be worded like that it would be like the one we did in class on the cell membrane and then you would just have to explain them briefly. 17)Draw a chloroplast and label the different parts. On 16 and 17 it would not be worded like that it would be like the one we did in class on the cell membrane and then you would just have to explain them briefly. 18)What is the function of the cytoskeleton It forms a framework for the movement of organelles around the cytoplasm most of the organelles are attached to the cytoskeleton. The network consists of protein microfilaments, intermediate filaments, and microtubules. The cytoskeleton provides an important structural framework for: Cell shape. 19)What macromolecule composes most of the cytoskeleton Proteins 20)Provide three structures or molecules you would expect to find in the nucleus. Chromosomes are the most important structure in the nucleus as they are made of DNA. DNA contains all the instructions that tell the cell how to grow, reproduce and develop. If the DNA is damaged, the cell cannot function correctly. The nucleolus is also vital for proper cell function. It is found within the nucleus, and is made of a variety of proteins and RNA. The function of the nucleolus is to create a special type of product called ribosomes, which produce proteins that are required for many cell functions. An important role of the nucleus is to control the cell's production of proteins. It does this by sending messenger RNA, which is a template for creating certain proteins, throughout the cell. Messenger RNA is initially found in the nucleus, but is sent to the cytoplasm when protein production is required. Without the nucleus to regulate protein production, the cell would not produce the correct proteins for survival. 21)Be able to demonstrate understanding of the differences between diffusion, osmosis, active transport and Endo/exocytosis. a. Think about using drawings to help you keep them straight, also remember which forms of movement require energy, and which are passive. Diffusion: molecules moving from an area with high concentration to an area with lower concentration. Osmosis: molecules moving from an area with lower concentration to an area with higher concentration. Active Transport: movement of molecules or ions across the cell membrane into an area with higher concentration, assisted by enzymes and required energy. Endocytosis: Moving large molecules or even their sets of molecules into the cell (remember there are three types of these that might be on the test) Exocytosis: moving large molecules or even their sets of molecules outside of the cell.