BIO EXAM 4 (LEARNING OUTCOMES)

DNA & RNA

Deoxyribose

Double Helix (Double Stranded

Sugar-Phosphate backbone

A pairs with T

Ribose

Single Stranded

Uracil over Thymine

A pairs with U

Purines and Pyrimidines

Adenine and Guanine

Thymine, Cytosine, and Uracil

Messenger RNA, Transfer RNA, and Ribosomal RNA

carries code from DNA to ribosome for protein synthesis

transport specific amino acid to ribosome for protein synthesis

assembles amino acids brought by tRNA in a specific order from mRNA to make proteins

made of RNA by nucleotides

Phosphate group

phosphodiester Bonds

5-carbon Sugar

5’ to 3’ orientation

removed protein from purified cell extracts

added RNA to purified cell extracts

Added DNA to purified cell extracts

Put into mouses to test

studied viruses that infect bacteria that are composed of only nucleic acids and proteins

the protein sample labeled with 35S and 32P is found in bacteria and was labeled on DNA

three different models of DNA replication {conservative, semiconservative, and dispersive} was tested

protein-transformed bacteria- Mouse died

RNA-digesting enzymes DIDN'T destroy transforming ability (Mice still died)

DNA-digesting enzymes destroyed all transforming ability (Mice didn't die)

In the protein, the 35S was found in the supernatant

in the bacteria, the 32P was found in a bacterial pellet

after one round of replication, two densities should have been observed: DNA strands would either be all-heavy (parental) or all-light (daughter): the model was rejected,

after one round of replication, a single density would be predicted because all DNA molecules would have half light strand and a heavy strand- so two densities would be observed: the model was supported

after two round of replication the dispersive model would still yield only single density; DNA strands would be composed of 3/4 light and 1/4 heavy molecules instead two densities were observed: the model was rejected

Supported DNA as the genetic material, at least in bacteria

the DNA was radioactive while the protein was not meaning that genetic material was carried in DNA not protein

DNA replicated semi-conservatively

helicase, single strand binding proteins, primase, and DNA poly III

unwinds double helix

prevents reannealing of separated strands

synthesizes RNA primers

synthesizes DNA

serves as the template of DNA replication

joins DNA segments

removes and replaces RNA primer with DNA

relaxes supercoiling

strand of daughter DNA that is synthesized discontinuously in DNA replication

- DNA-directed synthesis of RNA
- T (thymine) in DNA replaced by U (uracil) in RNA
- mRNA used to direct the synthesis of polypeptides
-RNA chain grows in the 5′-to-3′ direction as ribonucleotides are added

contains RNA polymerase, DNA template, and growing RNA transcript

5′-to-3′ direction as ribonucleotides are added

transcription

Translation

Always AUG

UAG

UGA

UAA

5’ cap

3’ Poly-A tail

Alternative Splicing

GTP is added to the 5' end, the GTP gets modified by addition of methyl group (methyl-G cap)

Associated with translation initiation, RNA stability & further processing

Created by poly-A polymerase

Other termination mechanisms exist using other factors

removal of introns

may be the cause of many human genetic disorders

non coding sequences

Post-translation regulation
Chromatin structure
Initiation Complex
Transcription factors

Mediate the binding of RNA polymerase 1 to the promoter (enhancers, promoters)

have specific promoters recognized by specific TFs

DNA organized into chromatin complicating protein-DNA interactions

Transcription occurs in nucleus while translation occurs in cytoplasm (more regulatory DNA)

Occurs in ribosomes
Several RNA and proteins work together to achieve translation (mRNA & tRNA)

Amino acids are brought to the ribosome by tRNAs and linked together to form a chain

Helicase is not used, but instead holoenzyme

The finished polypeptide is released and does its job in the cell.

Uses a hairpin loop to end the transcription process

Activators enhance the binding of RNA polymerase to promoter

Repressors bind to operators (DNA sequence) that prevent or decrease initiation frequency

alter binding/activity of repressors or activators

core polymerase

Holoenzyme

synthesizes RNA using a DNA template core subunits besides the sigma

initiates synthesis because Core polymerase can’t

4 core subunits plus Sigma factor

Only one strand of DNA copied as RNA

The strand of DNA not used as a template

Expressed sequence

forms a recognition and binding site for the RNA polymerase

Recognizes signals for the holoenzyme

a cluster of genes that are transcribed together to give a single messenger RNA

transcribes rRNA

transcribes mRNA

transcribes tRNA

silent mutation

missense mutation

nonsense mutations

same amino acid inserted, no net effect

changes amino acid inserted

changed to stop codon

made by splicing

Has 5’ cap

Has 3’ poly-A tail

No introns only EXONS

makes the protein

reads the mRNA and pushes it along

protein that allows for the termination of translation by recognizing the termination codon or stop codon in an mRNA sequence

Holds DNA pol 3 onto the thing

mutation is passed from parent to offspring

environmental agents (mutagens) damage DNA, or errors during DNA replication and recombination

Gain or loss of 1 to 50 bp

addition or deletion of base

Alter reading frame downstream

Trinucleotide repeat (TNR) or triplet repear mutation

purine to purine or pyrimidine to pyrimidine

purine to pyrimidine or pyrimidine to purine

encodes proteins necessary for the use of lactose as an energy source

lacL

Linked to the rest of the lac operon

lac repressor binds to operator to block transcription

lac repressor can no longer bind to operator

Transcription proceeds

promoter to be activated

promoter not activated

encodes genes for the biosynthesis of tryptophan

trp repressor binds to block transcription

trp repressor cant bind to operator

so transcription occurs

double-stranded, Replicated in the nucleus of eukaryotic host cell

single-stranded, Replicate in the host's cytoplasm

(Replication is error−prone, so high rates of mutation =difficult targets for the immune system and vaccines/drugs)

expresses Early genes, Intermediate genes, Late genes

allows transcription and translation

takes over host cell machinery

capsid protein production

releasing viral particles

1. Attachment

2. Penetration or injection: T4 pierces cell wall to inject viral genome,

3. Synthesis: Cell makes viral components,

4. Assembly: Put together new pages,

5. Release: Mature virus particles are released by an enzyme that lyses the host or buds through a host cell wall

1. Integration: leads to prophage,

2. Propagation: reproduction of lysogenic bacteria, 3. Induction: prophage exits the bacterial chromosome, and viral genes are expressed

Protein Shell

Helical

Icosahedral