Saturday, May 23, 2020
School Science Fair Project Ideas Memory
What could be more fun than testing your friends and familys memory skills? It is a subject that has fascinated people for centuries and memory is the perfect topic for a middle or high school science fair project. What Do We Know About Memory? Psychologists divide memory into three stores: sensory store, short-term store, and long-term store. After entering the sensory store, some information proceeds into the short-term store. From there some information proceeds to the long-term store. These stores are referred to as short-term memory and long-term memory respectively. Short-term memory has two important characteristics: Short-term memory can contain at any one time seven, plus or minus two, chunks of information.Items remain in short-term memory around twenty seconds. Long-term memory is stored in our brains forever.à We use recall to retrieve memories. Since your experiment cannot go on forever, you should probably stick with short-term memory for your science fair project. Memory Science Fair Project Ideas Prove that people will remember more numbers if given the numbers in chunks. You can do this by giving them a list of one-digit numbers first and see how many they can remember, recording your data for each person.Then, give each person a list of two-digit numbers and see how many of those numbers they can remember. Repeat this for three- and even four-digit numbersââ¬âmost people will find four digit numbers the hardest to recall.If you use words, rather than numbers, use nouns like apple, orange, banana, etc. This prevents the person you are testing from making a sentence out of the words you have given.Most people have learned to chunk things together, so run separate tests with related words and with non-related words and compare the difference.Test gender or age differences. Do males remember more or less than females? Do children remember more than teens or adults? Be sure to log the gender and age of each person you test so you can make accurate comparisons.Test the langua ge factor. What do people remember better: numbers, words or a series of colors?For this test, you may want to use flash cards with different numbers, words or colors on each card. Begin with numbers and have each person you are testing try to memorize a series of numbers they are shown on the cards. See how many they can remember in one round. Then, do the same with nouns and colors.Can your test subjects remember more colors than numbers? Is there a difference between children and adults?Use an online short-term memory test. Within the links below, you will find two of the many memory tests available online. Have the people you are testing run through each of the tests while you watch them. Record how well they did along with data like their gender age and what time of day they took the test.If possible, test subjects twice at different times of the day. Do people remember better in the morning or the evening after a long day at work or school?Take your laptop or tablet to the sci ence fair and let people see how their own memory compares to your test group when they take the same test. Resources for a Memory Science Fair Project Penny Memory Test. DCity.orgChudler, Eric. On-line Short Term Memory Game (Grades K-12). Neuroscience For Kids. Seattle: University of Washington, 2019.
Tuesday, May 19, 2020
How Amino Acid Chirality Works
Amino acids (except forà glycine) have aà chiralà carbon atom adjacent to the carboxyl group (CO2-). This chiral center allows for stereoisomerism. The amino acids form two stereoisomers that are mirror images of each other. The structures are not superimposable on each other, much like your left and right hands. These mirror images are termedà enantiomers. D/L and R/S Naming Conventions for Amino Acid Chirality There are two important nomenclature systems for enantiomers. The D/L system is based on optical activity and refers to the Latin words dexter for right and laevus for left, reflecting left- and right-handedness of the chemical structures. An amino acid with the dexter configurationà (dextrorotary) would be named with a () or D prefix, such as ()-serine or D-serine. An amino acid having the laevus configurationà (levorotary) would be prefaced with a (-) or L, such as (-)-serine or L-serine. Here are the steps to determine whether an amino acid is the D or L enantiomer: Draw the molecule as a Fischer projection with the carboxylic acid group on top and side chain on the bottom. (The amine group will not be at the top or bottom.)If the amine group is located on the right side of the carbon chain, the compound is D. If the amine group is on the left side, the molecule is L.If you wish to draw the enantiomer of a given amino acid, simply draw its mirror image. The R/S notation is similar, where R stands for Latin rectus (right, proper, or straight) and S stands for Latin sinister (left). R/S naming follows theà Cahn-Ingold-Prelog rules: Locate the chiral or stereogenic center.Assign priority to each group based on the atomic number of the atom attached to the center, where 1 high and 4 low.Determine the direction of priority for the other three groups, in order of high to low priority (1 to 3).If the order is clockwise, then the center is R. If the order is counterclockwise, then the center is S. Although most of chemistry has switched over to the (S) and (R) designators for absolute stereochemistry of enantiomers, the amino acids are most commonly named using the (L) and (D) system. Isomerism of Natural Amino Acids All amino acids found in proteins occur in the L-configuration about the chiral carbon atom. The exception is glycine because it has two hydrogen atoms at the alpha carbon, which cannot be distinguished from each other except via radioisotope labeling. D-amino acids are not naturally found in proteins and are not involved in the metabolic pathways of eukaryotic organisms, although they are important in the structure and metabolism of bacteria. For example, D-glutamic acidà and D-alanineà are structural components of certain bacterial cell walls. Its believed D-serine may be able to act as a brain neurotransmitter. D-amino acids, where they exist in nature, are produced via post-translational modifications of the protein. Regarding the (S) and (R) nomenclature, nearly all amino acids in proteins are (S) at the alpha carbon. Cysteine is (R) and glycine is not chiral. The reason cysteine is different is that it has a sulfur atom at the second position of the side chain, which has a larger atomic number than that of the groups at the first carbon. Following the naming convention, this makes the molecule (R) rather than (S).
How Amino Acid Chirality Works
Amino acids (except forà glycine) have aà chiralà carbon atom adjacent to the carboxyl group (CO2-). This chiral center allows for stereoisomerism. The amino acids form two stereoisomers that are mirror images of each other. The structures are not superimposable on each other, much like your left and right hands. These mirror images are termedà enantiomers. D/L and R/S Naming Conventions for Amino Acid Chirality There are two important nomenclature systems for enantiomers. The D/L system is based on optical activity and refers to the Latin words dexter for right and laevus for left, reflecting left- and right-handedness of the chemical structures. An amino acid with the dexter configurationà (dextrorotary) would be named with a () or D prefix, such as ()-serine or D-serine. An amino acid having the laevus configurationà (levorotary) would be prefaced with a (-) or L, such as (-)-serine or L-serine. Here are the steps to determine whether an amino acid is the D or L enantiomer: Draw the molecule as a Fischer projection with the carboxylic acid group on top and side chain on the bottom. (The amine group will not be at the top or bottom.)If the amine group is located on the right side of the carbon chain, the compound is D. If the amine group is on the left side, the molecule is L.If you wish to draw the enantiomer of a given amino acid, simply draw its mirror image. The R/S notation is similar, where R stands for Latin rectus (right, proper, or straight) and S stands for Latin sinister (left). R/S naming follows theà Cahn-Ingold-Prelog rules: Locate the chiral or stereogenic center.Assign priority to each group based on the atomic number of the atom attached to the center, where 1 high and 4 low.Determine the direction of priority for the other three groups, in order of high to low priority (1 to 3).If the order is clockwise, then the center is R. If the order is counterclockwise, then the center is S. Although most of chemistry has switched over to the (S) and (R) designators for absolute stereochemistry of enantiomers, the amino acids are most commonly named using the (L) and (D) system. Isomerism of Natural Amino Acids All amino acids found in proteins occur in the L-configuration about the chiral carbon atom. The exception is glycine because it has two hydrogen atoms at the alpha carbon, which cannot be distinguished from each other except via radioisotope labeling. D-amino acids are not naturally found in proteins and are not involved in the metabolic pathways of eukaryotic organisms, although they are important in the structure and metabolism of bacteria. For example, D-glutamic acidà and D-alanineà are structural components of certain bacterial cell walls. Its believed D-serine may be able to act as a brain neurotransmitter. D-amino acids, where they exist in nature, are produced via post-translational modifications of the protein. Regarding the (S) and (R) nomenclature, nearly all amino acids in proteins are (S) at the alpha carbon. Cysteine is (R) and glycine is not chiral. The reason cysteine is different is that it has a sulfur atom at the second position of the side chain, which has a larger atomic number than that of the groups at the first carbon. Following the naming convention, this makes the molecule (R) rather than (S).
How Amino Acid Chirality Works
Amino acids (except forà glycine) have aà chiralà carbon atom adjacent to the carboxyl group (CO2-). This chiral center allows for stereoisomerism. The amino acids form two stereoisomers that are mirror images of each other. The structures are not superimposable on each other, much like your left and right hands. These mirror images are termedà enantiomers. D/L and R/S Naming Conventions for Amino Acid Chirality There are two important nomenclature systems for enantiomers. The D/L system is based on optical activity and refers to the Latin words dexter for right and laevus for left, reflecting left- and right-handedness of the chemical structures. An amino acid with the dexter configurationà (dextrorotary) would be named with a () or D prefix, such as ()-serine or D-serine. An amino acid having the laevus configurationà (levorotary) would be prefaced with a (-) or L, such as (-)-serine or L-serine. Here are the steps to determine whether an amino acid is the D or L enantiomer: Draw the molecule as a Fischer projection with the carboxylic acid group on top and side chain on the bottom. (The amine group will not be at the top or bottom.)If the amine group is located on the right side of the carbon chain, the compound is D. If the amine group is on the left side, the molecule is L.If you wish to draw the enantiomer of a given amino acid, simply draw its mirror image. The R/S notation is similar, where R stands for Latin rectus (right, proper, or straight) and S stands for Latin sinister (left). R/S naming follows theà Cahn-Ingold-Prelog rules: Locate the chiral or stereogenic center.Assign priority to each group based on the atomic number of the atom attached to the center, where 1 high and 4 low.Determine the direction of priority for the other three groups, in order of high to low priority (1 to 3).If the order is clockwise, then the center is R. If the order is counterclockwise, then the center is S. Although most of chemistry has switched over to the (S) and (R) designators for absolute stereochemistry of enantiomers, the amino acids are most commonly named using the (L) and (D) system. Isomerism of Natural Amino Acids All amino acids found in proteins occur in the L-configuration about the chiral carbon atom. The exception is glycine because it has two hydrogen atoms at the alpha carbon, which cannot be distinguished from each other except via radioisotope labeling. D-amino acids are not naturally found in proteins and are not involved in the metabolic pathways of eukaryotic organisms, although they are important in the structure and metabolism of bacteria. For example, D-glutamic acidà and D-alanineà are structural components of certain bacterial cell walls. Its believed D-serine may be able to act as a brain neurotransmitter. D-amino acids, where they exist in nature, are produced via post-translational modifications of the protein. Regarding the (S) and (R) nomenclature, nearly all amino acids in proteins are (S) at the alpha carbon. Cysteine is (R) and glycine is not chiral. The reason cysteine is different is that it has a sulfur atom at the second position of the side chain, which has a larger atomic number than that of the groups at the first carbon. Following the naming convention, this makes the molecule (R) rather than (S).
How Amino Acid Chirality Works
Amino acids (except forà glycine) have aà chiralà carbon atom adjacent to the carboxyl group (CO2-). This chiral center allows for stereoisomerism. The amino acids form two stereoisomers that are mirror images of each other. The structures are not superimposable on each other, much like your left and right hands. These mirror images are termedà enantiomers. D/L and R/S Naming Conventions for Amino Acid Chirality There are two important nomenclature systems for enantiomers. The D/L system is based on optical activity and refers to the Latin words dexter for right and laevus for left, reflecting left- and right-handedness of the chemical structures. An amino acid with the dexter configurationà (dextrorotary) would be named with a () or D prefix, such as ()-serine or D-serine. An amino acid having the laevus configurationà (levorotary) would be prefaced with a (-) or L, such as (-)-serine or L-serine. Here are the steps to determine whether an amino acid is the D or L enantiomer: Draw the molecule as a Fischer projection with the carboxylic acid group on top and side chain on the bottom. (The amine group will not be at the top or bottom.)If the amine group is located on the right side of the carbon chain, the compound is D. If the amine group is on the left side, the molecule is L.If you wish to draw the enantiomer of a given amino acid, simply draw its mirror image. The R/S notation is similar, where R stands for Latin rectus (right, proper, or straight) and S stands for Latin sinister (left). R/S naming follows theà Cahn-Ingold-Prelog rules: Locate the chiral or stereogenic center.Assign priority to each group based on the atomic number of the atom attached to the center, where 1 high and 4 low.Determine the direction of priority for the other three groups, in order of high to low priority (1 to 3).If the order is clockwise, then the center is R. If the order is counterclockwise, then the center is S. Although most of chemistry has switched over to the (S) and (R) designators for absolute stereochemistry of enantiomers, the amino acids are most commonly named using the (L) and (D) system. Isomerism of Natural Amino Acids All amino acids found in proteins occur in the L-configuration about the chiral carbon atom. The exception is glycine because it has two hydrogen atoms at the alpha carbon, which cannot be distinguished from each other except via radioisotope labeling. D-amino acids are not naturally found in proteins and are not involved in the metabolic pathways of eukaryotic organisms, although they are important in the structure and metabolism of bacteria. For example, D-glutamic acidà and D-alanineà are structural components of certain bacterial cell walls. Its believed D-serine may be able to act as a brain neurotransmitter. D-amino acids, where they exist in nature, are produced via post-translational modifications of the protein. Regarding the (S) and (R) nomenclature, nearly all amino acids in proteins are (S) at the alpha carbon. Cysteine is (R) and glycine is not chiral. The reason cysteine is different is that it has a sulfur atom at the second position of the side chain, which has a larger atomic number than that of the groups at the first carbon. Following the naming convention, this makes the molecule (R) rather than (S).
How Amino Acid Chirality Works
Amino acids (except forà glycine) have aà chiralà carbon atom adjacent to the carboxyl group (CO2-). This chiral center allows for stereoisomerism. The amino acids form two stereoisomers that are mirror images of each other. The structures are not superimposable on each other, much like your left and right hands. These mirror images are termedà enantiomers. D/L and R/S Naming Conventions for Amino Acid Chirality There are two important nomenclature systems for enantiomers. The D/L system is based on optical activity and refers to the Latin words dexter for right and laevus for left, reflecting left- and right-handedness of the chemical structures. An amino acid with the dexter configurationà (dextrorotary) would be named with a () or D prefix, such as ()-serine or D-serine. An amino acid having the laevus configurationà (levorotary) would be prefaced with a (-) or L, such as (-)-serine or L-serine. Here are the steps to determine whether an amino acid is the D or L enantiomer: Draw the molecule as a Fischer projection with the carboxylic acid group on top and side chain on the bottom. (The amine group will not be at the top or bottom.)If the amine group is located on the right side of the carbon chain, the compound is D. If the amine group is on the left side, the molecule is L.If you wish to draw the enantiomer of a given amino acid, simply draw its mirror image. The R/S notation is similar, where R stands for Latin rectus (right, proper, or straight) and S stands for Latin sinister (left). R/S naming follows theà Cahn-Ingold-Prelog rules: Locate the chiral or stereogenic center.Assign priority to each group based on the atomic number of the atom attached to the center, where 1 high and 4 low.Determine the direction of priority for the other three groups, in order of high to low priority (1 to 3).If the order is clockwise, then the center is R. If the order is counterclockwise, then the center is S. Although most of chemistry has switched over to the (S) and (R) designators for absolute stereochemistry of enantiomers, the amino acids are most commonly named using the (L) and (D) system. Isomerism of Natural Amino Acids All amino acids found in proteins occur in the L-configuration about the chiral carbon atom. The exception is glycine because it has two hydrogen atoms at the alpha carbon, which cannot be distinguished from each other except via radioisotope labeling. D-amino acids are not naturally found in proteins and are not involved in the metabolic pathways of eukaryotic organisms, although they are important in the structure and metabolism of bacteria. For example, D-glutamic acidà and D-alanineà are structural components of certain bacterial cell walls. Its believed D-serine may be able to act as a brain neurotransmitter. D-amino acids, where they exist in nature, are produced via post-translational modifications of the protein. Regarding the (S) and (R) nomenclature, nearly all amino acids in proteins are (S) at the alpha carbon. Cysteine is (R) and glycine is not chiral. The reason cysteine is different is that it has a sulfur atom at the second position of the side chain, which has a larger atomic number than that of the groups at the first carbon. Following the naming convention, this makes the molecule (R) rather than (S).
How Amino Acid Chirality Works
Amino acids (except forà glycine) have aà chiralà carbon atom adjacent to the carboxyl group (CO2-). This chiral center allows for stereoisomerism. The amino acids form two stereoisomers that are mirror images of each other. The structures are not superimposable on each other, much like your left and right hands. These mirror images are termedà enantiomers. D/L and R/S Naming Conventions for Amino Acid Chirality There are two important nomenclature systems for enantiomers. The D/L system is based on optical activity and refers to the Latin words dexter for right and laevus for left, reflecting left- and right-handedness of the chemical structures. An amino acid with the dexter configurationà (dextrorotary) would be named with a () or D prefix, such as ()-serine or D-serine. An amino acid having the laevus configurationà (levorotary) would be prefaced with a (-) or L, such as (-)-serine or L-serine. Here are the steps to determine whether an amino acid is the D or L enantiomer: Draw the molecule as a Fischer projection with the carboxylic acid group on top and side chain on the bottom. (The amine group will not be at the top or bottom.)If the amine group is located on the right side of the carbon chain, the compound is D. If the amine group is on the left side, the molecule is L.If you wish to draw the enantiomer of a given amino acid, simply draw its mirror image. The R/S notation is similar, where R stands for Latin rectus (right, proper, or straight) and S stands for Latin sinister (left). R/S naming follows theà Cahn-Ingold-Prelog rules: Locate the chiral or stereogenic center.Assign priority to each group based on the atomic number of the atom attached to the center, where 1 high and 4 low.Determine the direction of priority for the other three groups, in order of high to low priority (1 to 3).If the order is clockwise, then the center is R. If the order is counterclockwise, then the center is S. Although most of chemistry has switched over to the (S) and (R) designators for absolute stereochemistry of enantiomers, the amino acids are most commonly named using the (L) and (D) system. Isomerism of Natural Amino Acids All amino acids found in proteins occur in the L-configuration about the chiral carbon atom. The exception is glycine because it has two hydrogen atoms at the alpha carbon, which cannot be distinguished from each other except via radioisotope labeling. D-amino acids are not naturally found in proteins and are not involved in the metabolic pathways of eukaryotic organisms, although they are important in the structure and metabolism of bacteria. For example, D-glutamic acidà and D-alanineà are structural components of certain bacterial cell walls. Its believed D-serine may be able to act as a brain neurotransmitter. D-amino acids, where they exist in nature, are produced via post-translational modifications of the protein. Regarding the (S) and (R) nomenclature, nearly all amino acids in proteins are (S) at the alpha carbon. Cysteine is (R) and glycine is not chiral. The reason cysteine is different is that it has a sulfur atom at the second position of the side chain, which has a larger atomic number than that of the groups at the first carbon. Following the naming convention, this makes the molecule (R) rather than (S).
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