Genetics Test Flashcards
What did Meischer study? What did he discover?
- studied pus
- identified substance in cells he called ‘nuclein’
What did Briggs + King study?
- frog eggs
What was Briggs + King’s first experiment?
- they removed nucleus from frog egg
- no frog grew
What was Briggs + King’s second experiment?
- used 2 different frogs
- they placed nucleus of frog B into egg of frog A
- frog b grew
What was Briggs + Kings conclusion?
- genetic material is in the nucleus
What did Griffith study?
- mice/pneumonia
-2 strains of pneumonia
A) S strain (smooth -> capsule)
B) R strain (rough -> no capsule)
What were the findings of Griffith’s experiments?
1) mice + S strain -> death
2) mice + R strain -> live
3) mice + heat killed S strain -> live
4) mice + heat killed S strain + R strain -> death
- Transforming Principle*
What did Avery, Mcleod, and McCarty study? What was their conclusion?
- streptococcus
1) heat killed S strain + digested RNA and protein of R strain -> death
2) heat kill S strain + digested DNA of R strain -> live
3) heat kill S strain + digested RNA and DNA of R strain -> live - concluded DNA is genetic material
What did Hershey/Chase study? What was their conclusion?
- radio isotopes/bacteriophage
Labelled: DNA - P32
Protein - S35
-after infection they found P32 in the cells - concluded DNA is the genetic material
What was Chargraff’s contribution?
- chemical analysis of DNA
- A,T,G,C
- A proportional to T
- G proportional to C
What did Franklin (Wilkins) do?
- X ray crystallography
- Double helix shape
What did Watson/Crick conclude?
- structure of DNA
*NOT 1 experiment
1)Phosphate-sugar backbone
2) Rungs of ladder are N bases - held by H bonds
A-T (2H), G-C (3H)
3) Double helix
4) Antiparallel
Is DNA replication conservative, semiconservative, or disruptive?
- DNA replication is semiconservative
What are the 3 steps of DNA replication?
1) Strand separation: unwind, break H bonds
2) Build complementary strand
3) Fix errors - edit
What is the location and function of Topoisomerase?
Location - above replication fork
Function - eases tension of unwound strand
What is the location and structure of Helicase?
Location - at replication fork
Function - breaks H bonds
What is the location and function of SSB’s (single stranded bonding protein)?
Location - attach to open strands below replication fork
Function - prevents reannealing
What is the location and function of RNA primase?
Location- at end of leading strand
-many points of lagging strand
Function - adds RNA primer
What is the location and function of RNA primer?
Location - end of leading
-many on lagging
Function - starting point for DNA polymerase III
What is the function of DNA Polymerase III?
Function - add N bases to new strand
- works in 5’ to 3’ direction
What is the location and function of DNA Polymerase I and II?
Location - follow DNA polymerase III
Function - proof read
-fix errors
What is the function of ligase?
Function - glue okasaki fragments together
What is a codon?
3 nitrogen bases - codes for 1 amino acid
What is transcription and where does it occur?
- copy DNA into RNA
- in the nucleus
What enzyme is involved in transcription?
RNA polymerase
What are the 3 steps of transcription?
- Initiation
- Elongation
- Termination
What are the 3 post transcriptional modifications?
- cut out introns, add 5’ cap, add Poly A tail
What is tRNA also called?
- also called anticodon
What is translation?
Reading mRNA and making protein
Where does translation occur?
On the ribosome
What 3 types of RNA are involved in translation?
1.mRNA - message from the DNA
2. tRNA - bring the amino acid’s down
3. rRNA - site on ribosome
What is a mutation?
- any change to the DNA
What is a small scale mutation? What is it also known as?
- a change in a single base pair or small group
- also know as point mutations
What are the 4 types of small scale mutations?
1) Missense
2) Nonsense
3) Silent
4) Frameshift
What is a large scale mutation?
Affects multiple codons, entire genes, or large regions of a chromosome
What are the 5 types of large scale mutations?
1) Amplification (aka duplication)
2) Deletion
3) Translocation
4) Transposition
5) Trinucleotide repeat
What are the 2 causes of mutations?
1) Spontaneous Mutations - mistakes during DNA replication
2) Induced Mutation - caused by an environmental factor
-Mutagen - causes induced mutations
-Carcinogen - causes a mutation which leads to cancer
What are operons?
- control transcription
- beginning of every gene
