Ch12 - DNA & RNA Flashcards
What happens in transformation?
One thing/strain is changed to another
What experiment did Griffith do?
- Goal: vaccine of pneumonia
- used 2 bacteria strains
- R strain - does not cause pneumonia
- S strain - causes pneumonia
- He tested to find that when R strain & heat-killed S strain are together, the organism dies of pneumonia
What is the structure of a virus?
DNA on the inside
protein on the outside
Who initially discovered DNA? How?
Oswald Avery (1944)
Goal: determine what caused the transformation principle
- He enzymatically destroyed certain components to find that DNA caused this change
- He double checked using nitrogen and phosphorus concentration
What did Hershey-Chase do/find?
Studied bacteriophage
Goal: was genetic material made of protein or DNA
- Used radioactive isotopes to identify whether the virus injected sulfer or phosphorus
Result: genetic material is made of DNA
What are the 3 main roles of genes?
- Carry information
- Help information come to use
- easily replicated
What are the components of DNA?
nucleotides
- 5 carbon sugar (deoxyribose)
- phosphate group
- nitrogenous bases
What are bacteriophage?
bacteria eaters
Who discovered base pairing rule & what is the rule?
Erwin Chargaff
Adenine – Thymine
Cytosine — Guanine
A & G - purines
T & C - pyrimidines
What did Rosalind Franklin do/find?
Worked with X-ray crystallography to identify structure of DNA
- found X shape which suggested helical 2 stranded structure
What did Francis Crick & James Watson do/find?
used 3d model to add on to franklins work
- found out about antiparallel structure
- right handed helical
- sugar & phosphate backbone + nitrogenous base inside
What is DNA’s antiparallel structure?
3’<–>5’
3’ = hydroxyl group
5’ = phosphate group
What is the structure of chromosomes/dna?
chromatin tightly condensed around histone (proteins)
Structure of chromosomes in eukaryotes vs. prokaryotes?
Eukaryotes: 1000x amt of dna in nucleus
Prokaryotes: circular DNA in cytoplasm
When does DNA replication occur?
S phase of interphase
What are telomeres? Enzyme function?
telomeres- tips of dna that are very difficult to replication
telomerase assists this replication
DNA replication in eukaryotes vs. prokaryotes
eukaryotes: starts at many sites
prokaryotes: circular dna - starts at 1 point and goes in 2 directions
Transcription? Enzyme used?
copying DNA to make mRNA
using RNA polymerase, primase, and promoter section
Translation?
translating the codons from mRNA into amino acids/ polypeptide chain
What are promoters?
section of DNA strand that is used to bind polymerase
Types of mutations
Gene mutations & Chromosomal mutations
Point mutations vs frameshift
point mutation: affects a single/few nucleotides
- substitution, insertion, deletion
frameshift: affects large section and alters protein production
Types of chromosomal mutations
Deletion:
Duplication
Inversion: reverse the direction of parts of chromosome
translocation: part of 1 chromosome attaches to another
Causes of mutation
Environment - UV, radiation
DNA replication errors
