What are chromosomes made of?. By mass, chromosomes are about half protein and about half DNA If...
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Transcript of What are chromosomes made of?. By mass, chromosomes are about half protein and about half DNA If...
![Page 1: What are chromosomes made of?. By mass, chromosomes are about half protein and about half DNA If genes are on chromosomes, are they protein or DNA or.](https://reader036.fdocuments.in/reader036/viewer/2022081519/56649eb45503460f94bbba8f/html5/thumbnails/1.jpg)
What are chromosomes made of?
![Page 2: What are chromosomes made of?. By mass, chromosomes are about half protein and about half DNA If genes are on chromosomes, are they protein or DNA or.](https://reader036.fdocuments.in/reader036/viewer/2022081519/56649eb45503460f94bbba8f/html5/thumbnails/2.jpg)
• By mass, chromosomes are about half protein and about half DNA
• If genes are on chromosomes, are they protein or DNA or perhaps a mix?
![Page 3: What are chromosomes made of?. By mass, chromosomes are about half protein and about half DNA If genes are on chromosomes, are they protein or DNA or.](https://reader036.fdocuments.in/reader036/viewer/2022081519/56649eb45503460f94bbba8f/html5/thumbnails/3.jpg)
Basic chemistry of DNA and protein
Proteins:
• What are the subunits of protein?
• How many different types of subunit are there?
![Page 4: What are chromosomes made of?. By mass, chromosomes are about half protein and about half DNA If genes are on chromosomes, are they protein or DNA or.](https://reader036.fdocuments.in/reader036/viewer/2022081519/56649eb45503460f94bbba8f/html5/thumbnails/4.jpg)
General structure of an amino acid
![Page 5: What are chromosomes made of?. By mass, chromosomes are about half protein and about half DNA If genes are on chromosomes, are they protein or DNA or.](https://reader036.fdocuments.in/reader036/viewer/2022081519/56649eb45503460f94bbba8f/html5/thumbnails/5.jpg)
![Page 6: What are chromosomes made of?. By mass, chromosomes are about half protein and about half DNA If genes are on chromosomes, are they protein or DNA or.](https://reader036.fdocuments.in/reader036/viewer/2022081519/56649eb45503460f94bbba8f/html5/thumbnails/6.jpg)
DNA
• DNA was discovered in 1869 by Friedrich Miescher, a German Chemist. Extracted from the nucleus.
• DNA has subunits.
• How many different subunits are there?
![Page 7: What are chromosomes made of?. By mass, chromosomes are about half protein and about half DNA If genes are on chromosomes, are they protein or DNA or.](https://reader036.fdocuments.in/reader036/viewer/2022081519/56649eb45503460f94bbba8f/html5/thumbnails/7.jpg)
The basic structure of DNA and RNA determined by Levene in the 1920’s
![Page 8: What are chromosomes made of?. By mass, chromosomes are about half protein and about half DNA If genes are on chromosomes, are they protein or DNA or.](https://reader036.fdocuments.in/reader036/viewer/2022081519/56649eb45503460f94bbba8f/html5/thumbnails/8.jpg)
General structure of a nucleotide
![Page 9: What are chromosomes made of?. By mass, chromosomes are about half protein and about half DNA If genes are on chromosomes, are they protein or DNA or.](https://reader036.fdocuments.in/reader036/viewer/2022081519/56649eb45503460f94bbba8f/html5/thumbnails/9.jpg)
![Page 10: What are chromosomes made of?. By mass, chromosomes are about half protein and about half DNA If genes are on chromosomes, are they protein or DNA or.](https://reader036.fdocuments.in/reader036/viewer/2022081519/56649eb45503460f94bbba8f/html5/thumbnails/10.jpg)
![Page 11: What are chromosomes made of?. By mass, chromosomes are about half protein and about half DNA If genes are on chromosomes, are they protein or DNA or.](https://reader036.fdocuments.in/reader036/viewer/2022081519/56649eb45503460f94bbba8f/html5/thumbnails/11.jpg)
![Page 12: What are chromosomes made of?. By mass, chromosomes are about half protein and about half DNA If genes are on chromosomes, are they protein or DNA or.](https://reader036.fdocuments.in/reader036/viewer/2022081519/56649eb45503460f94bbba8f/html5/thumbnails/12.jpg)
Levene’s tetranucleotide theory
• Logic behind the theory—– Genetic information needs to be complex
– More complexity possible in proteins than in DNA—he suggests DNA plays a role as ‘scaffolding’, a repeating sequence of 4 bases
– The evidence? Approximately equal amounts of each of the 4 bases found in DNA
![Page 13: What are chromosomes made of?. By mass, chromosomes are about half protein and about half DNA If genes are on chromosomes, are they protein or DNA or.](https://reader036.fdocuments.in/reader036/viewer/2022081519/56649eb45503460f94bbba8f/html5/thumbnails/13.jpg)
Avery, MacLeod and McCarty, 1944
• Assumption: Protein is the genetic material
• Plan: if ‘transforming principle’ treated chemically to remove protein, it should lose its power – removed all but 0.02%
• Problem: It didn’t
![Page 14: What are chromosomes made of?. By mass, chromosomes are about half protein and about half DNA If genes are on chromosomes, are they protein or DNA or.](https://reader036.fdocuments.in/reader036/viewer/2022081519/56649eb45503460f94bbba8f/html5/thumbnails/14.jpg)
Avery, MacLeod and McCarty, cont.
• After chemically removing protein, ‘transforming principle’ still able to convert rough bacteria to smooth bacteria
• After treatment with proteinase, ditto• After treatment with RNAase, ditto• After treatment with DNAase –’transforming
principle’ activity destroyed• FIRST PAPER SUPPORTING DNA AS
GENETIC MATERIAL
![Page 15: What are chromosomes made of?. By mass, chromosomes are about half protein and about half DNA If genes are on chromosomes, are they protein or DNA or.](https://reader036.fdocuments.in/reader036/viewer/2022081519/56649eb45503460f94bbba8f/html5/thumbnails/15.jpg)
Tetra nucleotide theory accepted for nearly 30 years
• What finally shifted thought away from protein as the genetic material to DNA as the genetic material?
• The ‘transforming principle’ of Griffith, using ‘Rough’ and ‘Smooth’ bacteria in 1928
• Avery, MacLeod and McCarty, 1944stripped away protein without destroying the transforming principle