Wednesday, May 18, 2011
Catalase Lab:Temperature Group 1
Amount of gas measured in mL.
0 degrees Celsius – 75mL
15 degrees Celsius- 70ml
20.2 degrees Celsius- 95mL
37 degrees Celsius – 90mL
50 degrees Celsius – 0mL
0 degrees Celsius – 75mL
15 degrees Celsius- 70ml
20.2 degrees Celsius- 95mL
37 degrees Celsius – 90mL
50 degrees Celsius – 0mL
Tuesday, April 5, 2011
Entropy
-Entropy is a measure of randomness.
-Exothermic rnx are mostly spontaneous and entropy will always increase
-Endothermic rnx are not spontaneous and entropy will decrease in the system, but still increases the entropy in the universe
-Entropy is based on human experiences. i.e. a bag of marbles spilled on the floor will roll in different, random directions
-All reactions contribute to the overall increase of entropy in the universe.
Monday, March 7, 2011
Monday, February 21, 2011
10 things about replication
1.When a cell divides, an exact copy of DNA must be created prior to cell division. Any errors represent genetic mutations.
2.Helicase untwists the DNA strand, and create 'bubbles' where A-T pairs are rich.
3.SS(single strand) binding proteins stabilize the single stand of DNA.
4.Gyrase releases tension on the DNA. (The bubbles create tension at the ends of DNA)
5.RNA primase insert RNA primers as soon as the bubbles open up. This signals the Polymerase III
6. Pol. III recognizes the RNA primers and binds a complementary 'leading' strand of DNA nucleotides at the 3' end of the RNA primer.
7. The 'lagging' strands begin to form as the bubble opens up more. They also grow from 5' to 3' and are called okazaki fragments. Pol III is also what initiated the lagging strands.
8.DNA Polymerase I replaces RNA primers with DNA. It also functions as a proof-reader to insure there aren't any mistakes.
9. Ligase inserts phosphate into any remaining gaps in the sugar-phosphate backbone
10.Each of the two new strands of DNA are composed of one new and one old chain of nucleotides.
* 1-5 = Initiation
* 6-7 = Elongation
* 8-9 = Termination
see animation: http://www.johnkyrk.com/DNAreplication.html
Sunday, February 13, 2011
Vocab
RNA: Ribonucleic acid
Many people are familiar with deoxyribonucleic acid (DNA), a nucleic acid which is often referred to as the “building blocks of life” because it contains the genetic material for its parent organism. RNA is equally important, even if it is lesser known, because RNA plays a critical role in helping DNA to copy and express genes, and to transport genetic material around in the cell. RNA also has a number of independent functions which are no less important.
RNA strands have a backbone made from groups of phosphates and ribose, to which four bases can attach. The four bases in RNA are adenine, cytosine, guanine, and uracil. Unlike DNA, RNA consists of a single strand, with strands of RNA folding to compact themselves into the tight space of the cell. Many viruses rely on RNA to carry their genetic material, using their RNA to hijack the DNA of infected cells in order to force those cells to do what the virus wants them to do.
Cytosol
The cytosol is the "soup" within which all the other cell organelles reside and where most of the cellular metabolism occurs. Though mostly water, the cytosol is full of proteins that control cell metabolism including signal transduction pathways, glycolysis, intracellular receptors, and transcription factors. Cytoplasm is a collective term for the cytosol plus the organelles suspended within the cytosol.
Histones
Histones are proteins around which DNA can wind. They play an important role in gene regulation in eukaryotic cells and in the Euryarchaea bacteria of the family Archaea. Histones are highly water soluble. Responsible for the structure of chromatin
London Forces: Van der waals Force
We know that polar molecules are attracted to each other by dipole-dipole attractions between the partial negative charge of one polar molecule and the partial positive charge on another polar molecule. Experiments have shown, though, that the actual strengths of the attractions between polar molecules are greater than we would predict from the polarity of the isolated molecules. The additional attraction is the result of London forces, which contribute to the attractions between polar molecules as well as nonpolar ones.
Consider a sample of hydrogen chloride gas, HCl, being cooled to the point where the molecules begin to form mutual attractions. Because HCl contains polar molecules, we would predict the attractions to be dipole-dipole forces, but in fact, they are actually dipole-dipole forces that have been enhanced by London forces. Some of the collisions between polar HCl molecules shift the electron clouds further toward the particles partial negative ends. Molecules that undergo this instantaneous increase in their dipole are then able to induce an increase in the dipoles of other molecules. The increased attractions that result from these instantaneous and induced increases in dipoles are also called London forces. Therefore, polar molecules like HCl are held together by both dipole-dipole attractions and London forces.
Alleles
An allele is an alternative form of a gene (one member of a pair) that is located at a specific position on a specific chromosome. These DNA codings determine distinct traits that can be passed on from parents to offspring.
Somatic Cells
Somatic cells are all the cells that make up an organism except for the germ cells. Germ cells are the sexually reproductive cells, for example the egg and sperm in mammals, including humans. Even though somatic cells can differ throughout an organism, they all contain the same DNA. Germ cells contain half the amount of DNA that is found in the somatic cells.
In humans, somatic cells contain 46 chromosomes or 23 homologous pairs of chromosomes. A homologous pair of chromosomes contains the same genes in the same location, even if the genes are for different conditions of the characteristic they code for. Sex cells only contain 23 chromosomes, or a single copy of each pair. During fertilization, the egg and sperm cell fuse to create a zygote, which will have the full complement of 46 chromosomes. The zygote has one set of 23 chromosomes from the mother and one from the father.
Cytokinesis
During cell division, there are two separate nuclei, but they are in the same cell. The cell now needs to be split in half. Cytokenesis begins in anaphase and continues on through telophase. The first visible sign of cytokenesis is when the cell begins to pucker in, a process called furrowing. Furrowing tends to take place at right angles to the axis of the spindle (so that each nucleus is placed in a different cell of course!). The cytoskeleton is reused to build the next spindle for mitosis. Now the two cells will continue the cell cycle and begin their interphase again!
Eukaryotes/Prokaryotes
Eukaryotes are organisms whose cells contain membrane-bound nucleus, as opposed to prokaryotes whose cells do not have nucleus or other membrane-bound organelles.
Eukaryotes (also referred to as the Eukaryota or the Eukarya) comprise one of the three recognized domains of cellular life, the other two being the Archaea (or Archaebacteria) and the Eubacteria (or Bacteria).
Archaea and Eubacteria in many different ways, but most importantly, the cells of eukaryotes display a much greater degree of structural organization and complexity. Archaeal and eubacterial cells generally lack internal structural organization (with a few notable exceptions, like the cyanobacteria). Eukaryotic cells, by contrast, share several complex structural characteristics. Most of these are parts of two interrelated systems: the cytoskeletal system and a system of membrane-delimited compartments. The cytoskeleton is an elaborate and highly organized internal scaffolding of proteins, such as actin-based microfilaments and tubulin-based microtubules.
Replicated/Unreplicated Chromosomes
Replicated - chromosomes which have undergone DNA replication and contain two sister chromatids.
Unreplicated - chromosomes that have not undergone replication and contain just one DNA double helix.
Metallic Bonds
Metals tend to have high melting points and boiling points suggesting strong bonds between the atoms. Even a metal like sodium (melting point 97.8°C) melts at a considerably higher temperature than the element (neon) which precedes it in the Periodic Table.
Sodium has the electronic structure 1s22s22p63s1. When sodium atoms come together, the electron in the 3s atomic orbital of one sodium atom shares space with the corresponding electron on a neighbouring atom to form a molecular orbital - in much the same sort of way that a covalent bond is formed.
The difference, however, is that each sodium atom is being touched by eight other sodium atoms - and the sharing occurs between the central atom and the 3s orbitals on all of the eight other atoms. And each of these eight is in turn being touched by eight sodium atoms, which in turn are touched by eight atoms - and so on and so on, until you have taken in all the atoms in that lump of sodium.
All of the 3s orbitals on all of the atoms overlap to give a vast number of molecular orbitals which extend over the whole piece of metal. There have to be huge numbers of molecular orbitals, of course, because any orbital can only hold two electrons.
The electrons can move freely within these molecular orbitals, and so each electron becomes detached from its parent atom. The electrons are said to be delocalised. The metal is held together by the strong forces of attraction between the positive nuclei and the delocalised electrons.
Many people are familiar with deoxyribonucleic acid (DNA), a nucleic acid which is often referred to as the “building blocks of life” because it contains the genetic material for its parent organism. RNA is equally important, even if it is lesser known, because RNA plays a critical role in helping DNA to copy and express genes, and to transport genetic material around in the cell. RNA also has a number of independent functions which are no less important.
RNA strands have a backbone made from groups of phosphates and ribose, to which four bases can attach. The four bases in RNA are adenine, cytosine, guanine, and uracil. Unlike DNA, RNA consists of a single strand, with strands of RNA folding to compact themselves into the tight space of the cell. Many viruses rely on RNA to carry their genetic material, using their RNA to hijack the DNA of infected cells in order to force those cells to do what the virus wants them to do.
Cytosol
The cytosol is the "soup" within which all the other cell organelles reside and where most of the cellular metabolism occurs. Though mostly water, the cytosol is full of proteins that control cell metabolism including signal transduction pathways, glycolysis, intracellular receptors, and transcription factors. Cytoplasm is a collective term for the cytosol plus the organelles suspended within the cytosol.
Histones
Histones are proteins around which DNA can wind. They play an important role in gene regulation in eukaryotic cells and in the Euryarchaea bacteria of the family Archaea. Histones are highly water soluble. Responsible for the structure of chromatin
London Forces: Van der waals Force
We know that polar molecules are attracted to each other by dipole-dipole attractions between the partial negative charge of one polar molecule and the partial positive charge on another polar molecule. Experiments have shown, though, that the actual strengths of the attractions between polar molecules are greater than we would predict from the polarity of the isolated molecules. The additional attraction is the result of London forces, which contribute to the attractions between polar molecules as well as nonpolar ones.
Consider a sample of hydrogen chloride gas, HCl, being cooled to the point where the molecules begin to form mutual attractions. Because HCl contains polar molecules, we would predict the attractions to be dipole-dipole forces, but in fact, they are actually dipole-dipole forces that have been enhanced by London forces. Some of the collisions between polar HCl molecules shift the electron clouds further toward the particles partial negative ends. Molecules that undergo this instantaneous increase in their dipole are then able to induce an increase in the dipoles of other molecules. The increased attractions that result from these instantaneous and induced increases in dipoles are also called London forces. Therefore, polar molecules like HCl are held together by both dipole-dipole attractions and London forces.
Alleles
An allele is an alternative form of a gene (one member of a pair) that is located at a specific position on a specific chromosome. These DNA codings determine distinct traits that can be passed on from parents to offspring.
Somatic Cells
Somatic cells are all the cells that make up an organism except for the germ cells. Germ cells are the sexually reproductive cells, for example the egg and sperm in mammals, including humans. Even though somatic cells can differ throughout an organism, they all contain the same DNA. Germ cells contain half the amount of DNA that is found in the somatic cells.
In humans, somatic cells contain 46 chromosomes or 23 homologous pairs of chromosomes. A homologous pair of chromosomes contains the same genes in the same location, even if the genes are for different conditions of the characteristic they code for. Sex cells only contain 23 chromosomes, or a single copy of each pair. During fertilization, the egg and sperm cell fuse to create a zygote, which will have the full complement of 46 chromosomes. The zygote has one set of 23 chromosomes from the mother and one from the father.
Cytokinesis
During cell division, there are two separate nuclei, but they are in the same cell. The cell now needs to be split in half. Cytokenesis begins in anaphase and continues on through telophase. The first visible sign of cytokenesis is when the cell begins to pucker in, a process called furrowing. Furrowing tends to take place at right angles to the axis of the spindle (so that each nucleus is placed in a different cell of course!). The cytoskeleton is reused to build the next spindle for mitosis. Now the two cells will continue the cell cycle and begin their interphase again!
Eukaryotes/Prokaryotes
Eukaryotes are organisms whose cells contain membrane-bound nucleus, as opposed to prokaryotes whose cells do not have nucleus or other membrane-bound organelles.
Eukaryotes (also referred to as the Eukaryota or the Eukarya) comprise one of the three recognized domains of cellular life, the other two being the Archaea (or Archaebacteria) and the Eubacteria (or Bacteria).
Archaea and Eubacteria in many different ways, but most importantly, the cells of eukaryotes display a much greater degree of structural organization and complexity. Archaeal and eubacterial cells generally lack internal structural organization (with a few notable exceptions, like the cyanobacteria). Eukaryotic cells, by contrast, share several complex structural characteristics. Most of these are parts of two interrelated systems: the cytoskeletal system and a system of membrane-delimited compartments. The cytoskeleton is an elaborate and highly organized internal scaffolding of proteins, such as actin-based microfilaments and tubulin-based microtubules.
Replicated/Unreplicated Chromosomes
Replicated - chromosomes which have undergone DNA replication and contain two sister chromatids.
Unreplicated - chromosomes that have not undergone replication and contain just one DNA double helix.
Metallic Bonds
Metals tend to have high melting points and boiling points suggesting strong bonds between the atoms. Even a metal like sodium (melting point 97.8°C) melts at a considerably higher temperature than the element (neon) which precedes it in the Periodic Table.
Sodium has the electronic structure 1s22s22p63s1. When sodium atoms come together, the electron in the 3s atomic orbital of one sodium atom shares space with the corresponding electron on a neighbouring atom to form a molecular orbital - in much the same sort of way that a covalent bond is formed.
The difference, however, is that each sodium atom is being touched by eight other sodium atoms - and the sharing occurs between the central atom and the 3s orbitals on all of the eight other atoms. And each of these eight is in turn being touched by eight sodium atoms, which in turn are touched by eight atoms - and so on and so on, until you have taken in all the atoms in that lump of sodium.
All of the 3s orbitals on all of the atoms overlap to give a vast number of molecular orbitals which extend over the whole piece of metal. There have to be huge numbers of molecular orbitals, of course, because any orbital can only hold two electrons.
The electrons can move freely within these molecular orbitals, and so each electron becomes detached from its parent atom. The electrons are said to be delocalised. The metal is held together by the strong forces of attraction between the positive nuclei and the delocalised electrons.
Tuesday, February 8, 2011
Thomas Hunt Morgan
September 25, 1866 – December 4, 1945
The importance of Morgan's earlier work with Drosophila (fruit flies) was that it demonstrated that the associations known as coupling and repulsion demonstrated using the Sweet Pea, are in reality the obverse and reverse of the same phenomenon, which was later called linkage. Morgan's first papers dealt with the demonstration of sex linkage of the gene for white eyes in the fly, the male fly being heterogametic. His work also showed that very large progenies of Drosophila could be bred. The flies were, in fact, bred by the million, and all the material thus obtained was carefully analysed. His work also demonstrated the important fact that spontaneous mutations frequently appeared in the cultures of the flies. On the basis of the analysis of the large body of facts thus obtained, Morgan put forward a theory of the linear arrangement of the genes in the chromosomes, expanding this theory in his book, Mechanism of Mendelian Heredity (1915).
Morgan was able to demonstrate that genes are carried on chromosomes and are the mechanical basis of heredity. These discoveries formed the basis of the modern science of genetics. He was the first person to be awarded the Nobel Prize in Physiology or Medicine for his work in genetics.
Hershey & Chase
Hershey and Chase concluded that DNA must be the genetic code material, not protein as many poeple believed. When their experiment was published and people finally acknowledged that DNA was the genetic material
1952- Hershey-Chase Experiment
Hershey and Chase sought an answer to the question, “Is it the viral DNA or viral protein coat (capsid) that is the viral genetic code material which gets injected into a host bacterium cell? They were using a bacterium named Escherichia coli, or E. coli and a virus called T2 (bacteriophage that infects E. Coli)
Frederick Griffith
In 1928, Frederick Griffith performed an experiment using pneumonia bacteria and mice. This was one of the first experiments that hinted that DNA was the genetic code material. Click on the “mouse button” to study his experiment. He used two strains of Streptococcus pneumoniae: a “smooth” strain which has a polysaccharide coating around it that makes it look smooth when viewed with a microscope, and a “rough” strain which doesn’t have the coating, thus looks rough under the microscope.
Griffith concluded that the live R strain bacteria must have absorbed genetic material from the dead S strain bacteria, and since heat denatures protein, the protein in the bacterial chromosomes was not the genetic material. This evidence pointed to DNA as being the genetic material. Transformation is the process whereby one strain of a bacterium absorbs genetic material from another strain of bacteria and “turns into” the type of bacterium whose genetic material it absorbed.
Erwin Chargaff
He took samples of DNA of different cells and found that the amount of adenine was almost equal to the amount of thymine, and that the amount of guanine was almost equal to the amount of cytosine. Thus you could say: A=T, and G=C. This discovery later became Chargaff’s Rule.
The adenine and thymine are connected together through hydrogen bonds and also connected to the sugar phosphate spine. Erwin found this to be true by using the percent of adenine in the DNA molecule commpared to that of the thymine. With these results he found that %A and %T were the same. Therefore %A=%T. This also concluded that the remaining nucleiotides were paired together as well. %C=%G.
Wilking & Franklin
By using a technique called X-ray diffraction, Franklin obtained results which led to the realization that a DNA molecule consists of an intertwined double helix of atoms. An X-ray diffraction experiment directs a beam of X-rays through a sample of a substance onto a screen. A pattern of spots is formed. This is recorded, and used to calculate the arrangement of atoms in the sample
Watson & Crick
In 1953, James Watson and Francis Crick determined the structure of DNA, in what is one of the most significant biological discoveries ever made. An examination of x-ray crystallography work by another researcher allowed the duo to determine that DNA is a double-helical molecule – a helical structure with two DNA strands, each with a carbon-phosphate backbone, and pairs of nucleotides arranged like rungs on a ladder.
This discovery was important not only for its own sake but also because it suggested two important facts about genetic inheritance:
1.That genetic information was carried by the sequence of nucleotides on the DNA strands
2.That DNA replication could be achieved if the strands were unwound, with each single strand used as the template for a new strand
September 25, 1866 – December 4, 1945
The importance of Morgan's earlier work with Drosophila (fruit flies) was that it demonstrated that the associations known as coupling and repulsion demonstrated using the Sweet Pea, are in reality the obverse and reverse of the same phenomenon, which was later called linkage. Morgan's first papers dealt with the demonstration of sex linkage of the gene for white eyes in the fly, the male fly being heterogametic. His work also showed that very large progenies of Drosophila could be bred. The flies were, in fact, bred by the million, and all the material thus obtained was carefully analysed. His work also demonstrated the important fact that spontaneous mutations frequently appeared in the cultures of the flies. On the basis of the analysis of the large body of facts thus obtained, Morgan put forward a theory of the linear arrangement of the genes in the chromosomes, expanding this theory in his book, Mechanism of Mendelian Heredity (1915).
Morgan was able to demonstrate that genes are carried on chromosomes and are the mechanical basis of heredity. These discoveries formed the basis of the modern science of genetics. He was the first person to be awarded the Nobel Prize in Physiology or Medicine for his work in genetics.
Hershey & Chase
Hershey and Chase concluded that DNA must be the genetic code material, not protein as many poeple believed. When their experiment was published and people finally acknowledged that DNA was the genetic material
1952- Hershey-Chase Experiment
Hershey and Chase sought an answer to the question, “Is it the viral DNA or viral protein coat (capsid) that is the viral genetic code material which gets injected into a host bacterium cell? They were using a bacterium named Escherichia coli, or E. coli and a virus called T2 (bacteriophage that infects E. Coli)
Frederick Griffith
In 1928, Frederick Griffith performed an experiment using pneumonia bacteria and mice. This was one of the first experiments that hinted that DNA was the genetic code material. Click on the “mouse button” to study his experiment. He used two strains of Streptococcus pneumoniae: a “smooth” strain which has a polysaccharide coating around it that makes it look smooth when viewed with a microscope, and a “rough” strain which doesn’t have the coating, thus looks rough under the microscope.
Griffith concluded that the live R strain bacteria must have absorbed genetic material from the dead S strain bacteria, and since heat denatures protein, the protein in the bacterial chromosomes was not the genetic material. This evidence pointed to DNA as being the genetic material. Transformation is the process whereby one strain of a bacterium absorbs genetic material from another strain of bacteria and “turns into” the type of bacterium whose genetic material it absorbed.
Erwin Chargaff
He took samples of DNA of different cells and found that the amount of adenine was almost equal to the amount of thymine, and that the amount of guanine was almost equal to the amount of cytosine. Thus you could say: A=T, and G=C. This discovery later became Chargaff’s Rule.
The adenine and thymine are connected together through hydrogen bonds and also connected to the sugar phosphate spine. Erwin found this to be true by using the percent of adenine in the DNA molecule commpared to that of the thymine. With these results he found that %A and %T were the same. Therefore %A=%T. This also concluded that the remaining nucleiotides were paired together as well. %C=%G.
Wilking & Franklin
By using a technique called X-ray diffraction, Franklin obtained results which led to the realization that a DNA molecule consists of an intertwined double helix of atoms. An X-ray diffraction experiment directs a beam of X-rays through a sample of a substance onto a screen. A pattern of spots is formed. This is recorded, and used to calculate the arrangement of atoms in the sample
Watson & Crick
In 1953, James Watson and Francis Crick determined the structure of DNA, in what is one of the most significant biological discoveries ever made. An examination of x-ray crystallography work by another researcher allowed the duo to determine that DNA is a double-helical molecule – a helical structure with two DNA strands, each with a carbon-phosphate backbone, and pairs of nucleotides arranged like rungs on a ladder.
This discovery was important not only for its own sake but also because it suggested two important facts about genetic inheritance:
1.That genetic information was carried by the sequence of nucleotides on the DNA strands
2.That DNA replication could be achieved if the strands were unwound, with each single strand used as the template for a new strand
Thursday, February 3, 2011
Ideas for Sci Fair
Day 1 of SBI4U1-05!
Time to start brainstorming ideas for the science fair.
-a study on neuro-recognition of mammals (hamsters set in a maze)
-does gaming make you have faster reflexes or playing sports?
-can energy-saving light bulbs provide plants with sufficient light
-can fish be trained to do tricks?
-algae and fresh water systems->algae blooms where there is too much light, easy to set up a mini aquarium
-can normally territorial animals(betta fish) be trained to get along?
Decide on a date to present the article sometime soon!
mar. 30?
Time to start brainstorming ideas for the science fair.
-a study on neuro-recognition of mammals (hamsters set in a maze)
-does gaming make you have faster reflexes or playing sports?
-can energy-saving light bulbs provide plants with sufficient light
-can fish be trained to do tricks?
-algae and fresh water systems->algae blooms where there is too much light, easy to set up a mini aquarium
-can normally territorial animals(betta fish) be trained to get along?
Decide on a date to present the article sometime soon!
mar. 30?
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