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38 Cards in this Set

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01:What was an early experiment regarding genes and enzymes? What was its significance?
mutants in NEUROSPORA (bread mold)

Found ORDER of mutations in biochemical pathways

SUPPORTED idea of ONE GENE-ONE ENZYME (mostly true)
02: What is our genetic material?
DEOXYRIBONUCLEIC ACID
03-What was the GRIFFITH experiment...what was its significance?
Injected SMOOTH (gene for sugar capsule to evade immune system) and ROUGH penumonia bacteria into rodents.

HEAT used to kill SMOOTH bacteria, pieces added to dish rough. Rough could then kill rodents.

Therefore TRANSFORMATION: CAPs genefrom smooth enters rough and through RECOMBINATION: replaces CAPr gene, transforming nonvirulent to virulent

DNA can SURVIVE heat that DESTROYS CELL.

OVERALL: Learned something in heat killed Smooth TRANSFORMED Rough to Smooth
04: How does DNA go from one bacteria to another?
TRANSFORMATION: ie nonvirulent strains becoming virulent

RECOMBINATION: pieces of DNA entering bacteria and replacing a gene
05: What is an experiment that showed that protein does NOT carry genetic information?
Heat-killed SMOOTH pneumonia bacteria broken down into LIPIDS, CARBS, PROTEIN, and NUCLEIC ACIDS.

each added to ROUGH cells.

found that N.A. transforms rough to smooth.
06: How do we know that DNA not RNA carries genetic info?
PANCREATIC DEOXYRIBONUCLEASE: degrades DNA but not RNA, so could tell that DNA changes rough to smooth, not RNA
07: How do we separate DNA from RNA?
DNASES and RNASES: enzymes that digest DNA or RNA only.
08: How do we know that viral genes are also nucleic acids? (experiment)
BACTERIOPHAGES: "T-Even" made of protein shell and nucleic acid.

Labeled protein w/ S35 or DNA w/ P35. Phages mixed w/ ecoli, then blended. Plaques formed where bacteria killed by phage. stopped blender at intervals before contamination occurred.

CENTRIFUGATION: DNA stays behind, Protein poured off.

Each mixed w/ bacteria and agitated. Bacteria formed NEW PHAGES only when DNA added to bacteria
09: How do we know what DNA looks like?
X-RAY DIFFRACTION: takes pictures. Shows light bouncing off at certain angles.

Shows a repeating pattern of a cross and DOUBLE HELIX, overall dimensions
10: What links nucleotides together?
PHOSPHODIESTER LINKAGES: 3' CARBON of one sugar links to OXYGEN of PHOSPHATE group, which links (via another OXYGEN) to CH2 on 5' CARBON of next sugar
11: Where does the base attach to the sugar in a nucleotide?
the 1' CARBON of the sugar.
12: What was WATSON's contribution to DNA?
he made models of DNA,
13: How do you describe the direction of the DNA strands?
ANTIPARALLEL: the 5' END of one strand matches with the 3' END of the other.
14: Where are the bases located on DNA?
on the INSIDE of the strands.
15: What are "CHARGAFF's RULES"?
the four nucleotides are present in DNA in certain ratios to each other that do not vary across species.

A:T=1 and G:C=1
16: How do the bases interact with each other? What is the significance of this?
HYDROGEN BONDS

G:C THREE hydrogen bonds

A:T uses TWO hydrogen bonds

THEREFORE: strands can be melted away (to be used as templates for replication)
17: Is DNA a perfect double helix?
NO: it has major and minor grooves
18: What makes DNA strands?
DNA POLYMERASE
19: What are the two different categories of bases? What differentiates them? Which bases are which?
PURINES: double ringed
ADENINE and GUANINE (AG)

PYRIMIDINES: single ring
CYTOSINE and THYMINE (or URACIL)
20: How is DNA structure different from RNA?
Deoxyribose vs Ribose.

Ribose has additional OH on 2' Carbon

Uracil instead of Thymine
21: What is the difference between nucleotides and nucleosides?
NUCLEOSIDE: sugar and base

NUCLEOTIDE: Sugar, Base, Phosphate group
23: What are the FULL names of all the nucleotides?
DEOXYCYTIDINE-5'-PHOSPHATE

DEOXYTHYMIDINE-5'-PHOSPHATE

DEOXYADENOSINE-5'-PHOSPHATE

DEOXYGUANOSINE-5'-PHOSPHATE
24: How does DNA POLYMERASE work?
Only works in presence of DNA (needed to set order)

takes nucleotide and BREAKS bond between 1ST (ALPHA) and 2nd (BETA) phosphate groups (arranged as P-P-P).

sheds off PYROPHOSPHATE (P-P)

forms a COVALENT BOND between the nucleotides. removes a WATER.

PYROPHOSPHATASE: breaks pyrophosphate into two phosphate groups. the ENERGY released drives reaction of DNA POLYMERASE by contributing to deltaG (NOT COUPLING)
24: What are the models for DNA replication?
SEMICONSERVATIVE: each strand acts as a template for a new strand

CONSERVATIVE: ie mona lisa. The original double helix is copied

DISTRIBUTIVE: bits and pieces of old and new DNA are put together.
25: Which DNA replication model is correct and why?
SEMICONSERVATIVE: ecoli grown in presence of N15 (heavier) for a little while, then moved to dish w/ N14. We can collect the bacteria at known generation times.

Using CESIUM CHLORIDE (to form a barrier between light and heavy DNA in centrifuge).

START: all heavy DNA
1st GEN: all semi-light DNA (supports semi and distributive)
2nd Gen: Half light, half semilight.
26: What do we know from SICKLE CELL ANEMIA?
It is caused by the change of one AMINO ACID in a protein in hemoglobin.

only observed in patients w/ S allele of BETA-GLOBIN gene.

Therefore S allele encodes the change of BETA-GLOBIN
27: What is the CENTRAL DOGMA of DNA?
DNA REPLICATES

RNA made in NUCLEUS via TRANSCRIPTION

RNA makes protein via TRANSLATION in RIBOSOMES
28: Can DNA make proteins directly?
NO: cannot order amino acids itself.

we can see that protein synthesis happens outside nucleus. RNA leaves nucleus in 1 hr (as seen w/ radioactive materials)
29: What is the CIPHER CODE?
The code that translates RNA to PROTEIN
30: Can RNA exist as a single strand?
YES
31: can RNA or PROTEIN act as a TEMPLATE?
RNA can make DNA,

Protein CANNOT act as a template
32: What is a unit of nucleotides?
CODON: 3 nucleotides
33: What are the kinds of RNA?
mRNA: short lived. carries info from DNA to ribosomes

rRNA: ribosomal RNA

tRNA: in ribosome. recognizes mRNA at anticodon, then attaches to AMINO ACID at its 3' END
34: Can TRANSLATION happen outside the cell?
YES: it can happen in test tube
35: What is the term for experiments in the body/experiments in a petri plate?
IN VITRO: in glass

IN VIVO: in life (body)
36: What helps make RNA?
RNA POLYMERASE: helps make RNA from DNA
37: How do we know that ribosomes are outside the nucleus?
PULSE-CHASE experiments:

radioactive UTP added, the ALPHA PHOSPHATE group will therefore be incorporated into RNA.

"Cold" UTP (lots!) will then be added and incorporated into RNA. can follow the radioactivity from the nucleus to other parts of cell.
38: What is the order in which proteins are made? How do we know it?
Proteins made from 5' END to 3' END

At any point in time, proteins are being made. add an antibiotic to terminate NEW protein formation (those in progress will finish up).

"HOT" amino acid added, everything finishes radioactive.

Parts of a KNOWN PROTEIN broken down. know there will be HIGH RADIOACTIVITY in the last bits made (must normalize for # of amino acids per section)

THEREFORE know which end was made last