Chapter 11 Flashcards
DNA structure
composed of nucleotides, which are covalently linked to form DNA strands. Two DNA strands are held together by hydrogen bonds between the bases to form a double helix.
DNA associates with various proteins to form
A chromosome
Nucleotides have 3 parts
Nucleotides are composed of a phosphate, a sugar, and a nitrogenous base. The sugar can be deoxyribose (DNA) or ribose (RNA).
Purine and pyrimidine
The purine bases are adenine and guanine, and the pyrimidine bases are thymine (DNA only), cytosine, and uracil (RNA only).
In DNA sugars are connected by a Colvalent bond in which direction
in a 5′ to 3′ direction (Figure 11.6).
DNA structure
• The X-ray diffraction data of Franklin, the data of Chargaff (that is, the amounts of A and T and those of G and C are approximately equal), and the ball-and-stick modeling of Pauling helped reveal the structure of DNA (Figure 11.7, Table 11.1).
4 criteria of genetic material
Irtv
Information
Replication
Transmission
Variation
1920s to 1940/ scientist though what would be the genetic material
The protein portion of chromosomes
Griffith bacterial transformation of streptococcus pneumoniae bacteria
What happened, what did it mean, what did he call it
Smooth(s) strain fatal in mice. Rough (r) are not fatal in mice. Heat killed S type did not kill mice, heat killed S type and living R type did kill mice
This meant some genetic material from type S had transferred to the living type R and provided it with a new trait. He called this the transformation principle.
How did Griffiths findings gir into the 4 criteria of genetic material
- Information: the transformed bacteria acquired the information to make a polysaccharide capsule from the S type
- for the bacteria to be able to kill the mouse it would have has to replicate
- The mactsria had to transmit the genetic material to the daughter cells
- VAriation existed in the ability of the two strains to either form a capsule or not form a capsule
Hershey and chase bacteriophage experiment t2 virus that infects escherichia coli
What they did what the learned
First part phage produced with sulfur 35, a radioactive amino acid.let phage infect bacteria but none of s35 got in. Part 2 involved phosphorus 32 labeled deoxyribonucleotides.resulted in the p32 showing up in the bacteria cell which told them that DNA is the genetic material
Levels of DNA structure (5)
- Nucleotides- the building blocks
- Strand- a linear polymer
- Double helix- 2 strands of DNA
- Chromosomes - DNA with An array of protein
- Genome- complete complement of genetic material
DNA Nucleotide
RNA nucleotide
5 carbon sugar, deoxyribose, a phosphate group and a nitrogenous base
4 carbon sugar, ribose, a phosphate group and a nitrogenous base
Eukaryotes have DNA in
Nucleus, mitochondria and chloroplasts
Purine bases
Pyrimidine bases
Have a double ring structure; adenine and guanine
Have a single ring structure; cytosine. Thymine in DNA and uracil in RNA
How are nucleotides bonded
Covalently
Phosphodeister bond
The bond that links the two sugars in the DNA backbone. They are linked by the phosphate group of the first nucleotide
Nucleotide numbering system
Base attaches to
Phosphate attaches to
Sugar carbons are numbered 1-5
Base attached to 1’ carbon
Phosphate attaches to 5’ carbon
What charge does the backbone of DNA/RNA have?
Negative due to the phosphate groups
Base pairs
Adenine and thymine in DNA
Adenine and uracil in RNA
And guanine and cytosine
How X-ray diffraction pattern works
When something’s exposed to X-rays the atoms in the substance cause the X-rays to be scattered. If t has a repeating structure, the X-ray will scatter in an arrangement related to the substances structure
How Rosalind franklin used d pattern
She used mathematics to conclude that DNA had a helical structure that has a uniform diameter and is too large to be single stranded.