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28 Cards in this Set
- Front
- Back
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what did Frederick Giffitch want to learn about bacteria?
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how certain types of bacteria produce pneumonia
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the strain of the bacteria that caused pneumonia grew into ____ colonies on culture plates; harmless bacteria produced colonies with ____ edges
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smooth, rough
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what's the result of Griffith's experiment?
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bacteria with smooth colonies --> died
bacteria with rough colonies --> lived bacteria with heat-killed smooth colonies --> lived bacteria with heat-killed smooth and rough --> died |
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what result from Griffith's experiment suggested that the cause of pneumonia was not a chemical poison released by the disease-causing bacteria?
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when heat-killed disease-causing bacteria didn't kill the mice.
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what is transformation?
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when some traits/genes was inherited by the transformed bacteria's offspring
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what hypothesis did Griffith form from the results of his experiments?
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some factors was transferred from heat-killed cells into live ones; that factor must be a gene
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T or F?
Avery and his colleagues thought that the molecule required in transformation might also be the molecule of the gene. |
True
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How did Avery and his group determined which molecule was most important for transformation?
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Used enzymes that destroy either RNA or DNA, and see if transformation occurred
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Transformation did not occur when ____ was destroyed.
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DNA
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what was the conclusion from Avery's experiments?
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DNA stores and transmits genetic info. from one generation of an organism to the next
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bacteriophage
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a kind of virus that infects bacteria
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what makes up a bacteriophage?
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protein coat and DNA core
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what happens when a bacteriophage infects a bacterial cell?
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the viral genes produce new bacteriophages and destroy the bacterium, then when the cell opens, hundreds of new viruses burst out
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how would hershey and chase learn whether genes were made of protein or DNA?
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uses 32P as radioactive DNA marker and 35S as radioactive protein marker. they put it into 2 bacteriophages and see if the 32P or the 35S are injected into the bacterium.
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what results did Hersey and Chase observe?
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Nearly all the radioactivity in the bacterium was from 32P
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what did Hershey and Chase conclude?
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the genetic material of the bacteriophage was DNA
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the 3 critical things that genes were known to do
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1-carry information from one generation to the next
2-determines heritable characterisitics of organisms 3-easily copy its information for cell division |
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what are the 4 nitrogenous bases in DNA?
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adenine, guanine, cytosine, and thymine
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what group does adenine and guanine belong to?
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purines
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what group does cytosine and thymine belong to?
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pyrimidines
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what's the difference between adenine + guanine and cytosine + thymine?
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adenine and guanine has 2 rings.
cytosine and thymine has 1 ring. |
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does the nucleotides must be joined together in a specific order?
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no
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according to Chargaff's rules, the percentages of ____ are equal to ____ and the percentages of ____ are equal to ____ in the DNA molecule
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adenine + thymine
cytosine + guanine |
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Rosalind Franklin's work with X-ray diffraction showed that the DNA molecule is shaped like a(an) ____ and contains ____ strands
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helix, double
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what did Franklin's work show?
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the DNA molecule is shaped like a(an) helix and contains double strands
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how did Francis Crick and James Watson try to understand the structure of DNA?
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by building 3-D models
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How did watson and crick describe the structure of DNA?
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double helix with 2 strands wound around each other with nitrogenous base close to the center, having hydrogen bonds holding it together
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T or F?
according to the principle of base pairing, hydrogen bonds could form only between adenine and cytosine |
False
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