View
- Term
- Definition
- Both Sides
Study
- All (62)
Shortcut Show
Next
Prev
Flip
Biochem 275: Exam 1
Griffith, 1928
Rough & Smooth Bacteria |
Rough wasn't harmful while smooth killed mice
both heated -> mice survived
heat R, not S -> mouse died
heat S, not R -> mouse still died and S was present |
Avery, 1944
DNA vs Protein |
broke up the smooth bacteria into protein and DNA
DNA was the genetic material because when put into the R bacteria it killed the mouse |
Hershey, 1952
Bacteriophage |
Bacteriohage head contains the DNA
Radioactive phosphorus and sulfur to determine that DNA was the genetic material |
Nucleotide |
Deoxyribose + base + phosphoric acid |
Nucleoside |
Deoxyribose + base |
Linus Pauling, 1951 |
First helical structure |
Franklin and Gosling, 1951
XRay Diffraction |
concluded there are about 10 base pairs per 360 degrees |
Chargaff's Rule |
1:1 Ratio of purines:pyramidines |
Forces within DNA in increasing order |
Dispersion, Hydrogen, Ionic, Covalent |
G-C bonds vs A-T bonds
|
The G-C bonds are about 3 kcals stronger than the A-T bond |
Restriction Enzymes |
Like ecoRI, cut DNA after recognizing specific sequences |
Base + deoxyribose |
-osin
EX: adenosine |
Base + deoxyribose + 1 phosphate |
base-osine monophosphate
Ex: adenosine monophosphate |
Base + deoxyribose + 2 phosphates |
adenosine diphosphate (ADP) |
Base + deoxyribose + 3 phosphates |
Adenosine Triphosphate (ATP) |
ATP, TTP, GTP, CTP |
Building blocks because they link together for the backbone.
Forms 2 phosphate groups |
Type I Restriction Enzymes |
cut at random positions far fro the recognition sequences so they're not used in labs |
Type II Restriction Enzymes |
cut at defined points close to or within the recognition sequences (often used in labs) |
How do bacteria protect their DNA? |
Methylated DNA cannot be recognized or cleaved by the restriction enzymes like ecoRI |
Where does cleavage occur in DNA? |
Phosphate backbone and it regenerated a hydroxyl group |
Sticky Ends: Blunt Ends |
cut in the same spot on both sides and can be ligased back with many other sequences |
Sticky Ends: Cliffs |
strands are uneven and cut at same base resulting in pre-determined binding to specific strands |
Features of Bacterial Plasmid (2) |
origin of replication that is <100 bps
Promote genes of antibiotic resistance |
β-lactam |
Antibiotic resistant gene |
Cloning |
Cleaving DNA and using DNA ligase to add in an antibiotic gene, now some DNA has the resistance |
Gel Electrophoresis |
Agarose gel where smaller strands go farther towards positive charge. Mix DNA with ethidium bromide to make it visible |
mRNA |
Messenger
intermediate between DNA and protein |
tRNA |
Transfer
bind to amino acids and mRNA to link protein
anticodon on one end and a protein on the other to bind together to make polypeptide chains of amino acids |
rRNA |
Ribosomal
Interacts with proteins |
miRNA |
Micro (20 bps)
Tandemly repeated DNA |
snoRNA |
Small Nucleolar (Guide)
Modifies mRNA |
snRNA |
Small Nuclear
Helps proteins cut RNA and put it together |
RNA vs DNA (3 differences) |
RNA uses ribose not (deoxy)
uracil not thymine
RNA is single stranded and can fold on itself |
AU Bond |
Doesn't form a major/minor groove
2 Hydrogen bonds are formed |
UAU Triplet |
now possible because RNA strand can twist |
Genome |
All DNA (bases) |
Isoforms |
Genes encoding for multiple, similar proteins |
Gene |
DNA sequences coding for 1 protein that influences a trait |
Chromatin |
DNA an its associated proteins |
Compactors of DNA |
Histones |
Find binding sites and bring in assembly team |
transcription factors |
Protect DNA from degredation |
DNAse |
Other proteins in Chromatin |
allow DNA to be separated and proteins that keep pairs together |
Nucleosome
|
DNA bound to histones |
Gene Density |
Decreases as the complexity increases a lot |
Noncoding DNA in bacteria |
Regulatory sequence that determines expression |
Noncoding sequences in prokaryotes |
introns |
What do we achieve by coding from both 5' to 3' and 3' to 5'? |
There can be many genes overlapping coding for different things |
Base and Ribose modifications result in... |
New functionality |
Pseudouridylation |
uracil mirrors and spins to create a new base pair bond
|
2'-O-Methylation |
adds a CH3 to where the H was on the 2' position |
Secondary Structure of RNA |
The folding allows for important purposes
|
10 nm fibers |
DNA is wrapped around histones |
30 nm fibers |
DNA is wrapped around histones and then this refolds onto more histones |
Core DNA |
is wrapped around core histones and is 147 base pairs long |
Linker DNA |
is between histones, is 20-60 base pairs long and allows DNA to fold into 30 nm fibers |
The Positive Amino Acids |
lysine and argenine |
Dimers |
H2A and H2B |
Tetramers |
H3 and H4 that are attracted to DNA's negative charge |
Intermediate Stage |
DNA wrapped around tetramer |
Final Stage of DNA Packing |
Two dimers add onto the tetramer and DNA for 8 protein |
N-Tails |
N-Tails are hanging off (as proved by use of protease)
Tails can be methylated or acetylated through these tails, modifying the hisotnes |