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Isometric contractions are contractions in which that generate force without altering the length of the muscle. These muscles are common in body parts that are responsible for grips, such as your hands and forearms. These muscles are also prominent in maintaining posture. You experience isometric contractions when you are trying to lift items that are too heavy for you, leading to the object not being lifted. In this case, the maximum force a muscle can generate has been reached. In contrast, isotonic contractions do involve shortening. Force is generated by isotonic contractions by the change of length of muscles. These isotonic contractions can either be eccentric (the muscle lengthens) or concentric (the muscle shortens). With isotonic contractions, you are able to lift the object that you are attempting to lift, unlike isometric contractions. 

The species that should be saved is the golden retriever. This is because the golden retriever is the one of the best dog breeds out there due to its nice fur and usefulness in disability patients, along with other benefits. According to AKC.org, The American Kennel Club, golden retrievers are “friendly, intelligent, and devoted”. It is famous for its dense golden fur, which everyone loves to pet. In addition to these benefits, golden retrievers are one of the healthiest dogs, and can survive various health crisis (if saved by the scientists’ vaccines), such as the flu. 

Golden retrievers are relatively easy to train. They can be used in patients that have disabilities such as blindness, or patients who need guide dogs. Why would you not save this breed? There are plenty of other reasons that include being a man’s best friend, as well as being relatively easy to take care of. 

Isometric contractions are contractions in which that generate force without altering the length of the muscle. These muscles are common in body parts that are responsible for grips, such as your hands and forearms. These muscles are also prominent in maintaining posture. You experience isometric contractions when you are trying to lift items that are too heavy for you, leading to the object not being lifted. In this case, the maximum force a muscle can generate has been reached. In contrast, isotonic contractions do involve shortening. Force is generated by isotonic contractions by the change of length of muscles. These isotonic contractions can either be eccentric (the muscle lengthens) or concentric (the muscle shortens). With isotonic contractions, you are able to lift the object that you are attempting to lift, unlike isometric contractions. 

The lac operon is important in maintaining the breakdown of lactose. When there is no lactose to be metabolized, the Lac genes are "turned off". This is to conserve energy for other vital tasks. Genes are turned off when a lac repressor binds to the promoter region of the lac operon, disabling any ability to metabolize lactose. This inhibitory gene is the default for genes. When there is lactose, however, it must be metabolized. This is accomplished when lactose binds to the repressor, enabling the operon to work. 

Organic Molecules are everywhere around us. That human walking her dog across the street, made up of organic molecules. The dog she is walking, made up of organic molecules. The dictionary defines the word “organic” as “of or relating to living matter.” What should jump out from this definition is the word “living”. All living things are organic, which means they are made up of some combination of Carbon, Hydrogen, Nitrogen, and Oxygen. These combinations generally form the four macromolecules that are found in living organisms known as, proteins, carbohydrates, lipids, and nucleic acids. In the following experiment we set out to find out what different foods were, using a variety of tests, such as the lipid test, simple sugar test, and the protein test. These tests allowed us to find out what the different types of unknown substances were.

Materials: The materials used in this experiment are as follows: 4x4 in. Brown paper, Drop of Oil, Drop of water, drop of five unknowns (for the Lipid Test); 500ml of the following (glucose solution, distilled water, unknowns 1-5), test tubes, 1 ml of Benedict’s reagent (for the Simple Sugar Test). Seven Test tubes, 1 mL of starch, 1 mL of distilled water, 1 mL of each unknown 1-4, two drops of Lugol’s iodine reagent (for each tube) (for the Starch Test). 2 mL of each unknown (1-5), 2 mL of 2.5% NaOH, 3 drops of Biuret reagent (for each tube) (Protein Test)

    Methods: The method for the experiments in this lab are as follows:

Part 1 Identifying Lipids. To identify which unknowns are lipids, obtain a small square of brown paper, divide into seven sections. Label them, Water, Oil, Unknown #1, Unknown #2, Unknown #3,Unknown #4,Unknown #5. Put a small drop of each substance on each section of the brown paper and rub it in gently with your fingertip. Allow the substances to dry (approximately one hour), then record your results.

    Part 2 Identifying Carbohydrates. To identify carbohydrates in the unknown, two tests are done. The simple sugar test, in which you start by making a boiling bath of water. Obtain seven test tubes and label them #1-7. Put 500 mL of 0.01 M glucose in tube #1. Put 500 mL of distilled water in tube #2. In tubes #3-7, put 500 mL of the unknown substances in the tubes, each tube with only one substance. Add 1 mL of Benedict’s reagent to each tube. Place the tubes in the boiling bath for 5 minutes. After 5 minutes, remove the tubes from the water bath using tongs. Place in tube rack to cool for a 2 minutes. Record observations. The second test, Testing for Starch, goes as follows. Obtain seven tubes and label them #1-7. Put 1 mL of 1% starch solution in tube 1. Put 1 mL of distilled water in tube 2. Put 1 mL of unknowns in each of the remaining tubes. Add 2 drops of Lugol’s iodine reagent to each tube. Record your observations.

    Part 3 Identifying Proteins. To identify a protein in solution, Biuret Reagent. Obtain 7 test tubes and label them #1-7. Add 2 mL of each material to the appropriate tube. Add 2 mL of 2.5 NaOH to each tube. Add 3 drops of Biuret reagent to each tube, mix thoroughly. Hold the tubes against a white piece of paper for better contrast. Record Changes.

In the crossing of the mutant strands, there were fewer colonies observed than was expected on the control plate (one-hundred and fifty). This might have been due to a dilution error. For the MV plates, there were approximately ninety colonies observed. The reason for this proportion colonies may be due to not plating the same number of cells on the control plate as there should have been. Theoretically, there should have had a 20% survival rate if the optimal exposure was achieved. For the MV plate, the survival rate was 3.3%. This is significantly lower than expected and might be due to errors as mentioned above. There were no mutant phenotypically red colonies observed. This was expected, as you need about 10,000 surviving yeast cells for each mating type (3) to observe surviving mutant colonies that express a red color. The survival rate for our control plate was 6%. This was also much lower than the 20% expected survival rate, for reasons similar to the first plate. 

Some key principles that I remember from statistics include probability, regression, standard deviation, and the empirical rule. Probability is the chance that something will happen given certain conditions. Regression an estimation of the relationship between variables (for example X and Y). Standard deviation is a measure that is used to quantify how far a value is from the mean of the population and/or sample. The empirical rule states that 68 percent of data on a standard distribution will fall within one standard deviation from the mean, 95 percent of the data will fall within two standard deviations of the mean, and finally 99.7 percent of the values fall within three standard deviations of the mean. 

In the crossing of the mutant strands, there were fewer colonies observered than was expected on the control plate (one-hundred and fifty). This might have been due to a dilution error. For the MV plates, there were approximately ninety colonies observed. The reason for this proportion colonies may be due to not plating the same number of cells on the control plate as there should have been. Theoretically, there should have had a 20% survival rate if the optimal exposure was achieved. For the MV plate, the survival rate was 3.3%. This is significantly lower than expected and might be due to errors as mentioned above. There were no mutant phenotypically red colonies observed. This was expected, as you need about 10,000 surviving yeast cells for each mating type (3) to observe surviving mutant colonies that express a red color. The survival rate for our control plate was 6%. This was also much lower than the 20% expected survival rate, for reasons similar to the first plate. 

   An experiment to determine the effects of gene complementation when a mutation occurs was performed on Saccharomyces cerevisiae, or as it is known better by its common-use name, Yeast. The mutation was induced by UV radiation, and complementation was observed by the crossing of the resulting mutants. It was found that when there is no adenine present in a growth medium, diploid yeast cells crossed from mutant haploid cells do not grow unless there is complementation. The resulting experiment shows this through plating two haploid strands of yeast, MATa, and MATα to form diploid cells.