Biochemistry Final Exam (in progress)

Front

Provide detailed Sanger's Method of DNA Sequencing "DNA ANALYSIS"

Back

Front

What are 3 Points about Transcription in Eukaryotes?

Back

1. 1. First, eukaryotic cells carry multiple specialized RNA Polymerases

2. 2. Second, chromatin containing the promoter sequence must be made accessible to the transcription machinery (carried out by specialized DNA-Remodeling complexes)

3. 3. Third, transcription factors must bind to DNA sequences in the promoter region for a gene to be active. Enhancers bind other protein factors to stimulate transcription.

Front

What are the 3 RNA polymerases?

Back

• - RNA Polymerase I and Class I transcription factors are responsible for transcribing the ribosomal RNA genes.

• - RNA polymerase II is responsible for the synthesis of mRNA (recognizes several classes of consensus sequences such as the TATA box)

• - RNA polymerase III transcribes small RNA genes (such as genes encoding tRNAs)

Front

Briefly explain Histones

Back

• - DNA wraps around histones, then condenses to protein scaffolds within chromosomes.

• - Class of specialized DNA binding protein and form core of nucleosome.

• - 2 copies of H2B,H2A,H4, and H3 which form a barrel structure

• - H1 acts as a pin stabilizing DNA enwrapped configuration

Front

Define Oncogenes

Back

• - Genes whose mutated or overexpressed products contribute to carcinogenesis

• - (First identified as products of DNA and RNA tumor viruses, but are present in normal cells)

Front

Define Protooncogenes

Back

• - Normal, non-mutated cellular analogs of oncogenes

• - Many are transcription factors

• - (Mutation into oncogenic form involves a change that makes a regulatory product less responsive to normal control)

Front

Explain p53

Back

• - "King of Tumor Suppressor"

• - Somatic mutations in DNA-binding protein p53 can be identified in about 1/2 of all human cancers

• - Wild-type p53 functions as tumor suppressor

• - A single copy of mutant p53 gene causes Li-Fraumeni syndrome

• - Linked to cell cycle control where it inhibits transcription of certain genes and promotes expression of other genes

Front

Bacterial mRNA:

• - Transcription unit?

• - 5' end?

• - Half Life?

• - 3' end?

• - 3' end Generation?

Back

• - Polycistronic

• - No cap

• - <5 min

• - No poly(A) tail

• - Termination releases mRNA

Front

Animal mRNA:

• - Transcription unit?

• - 5' end?

• - Half Life?

• - 3' end?

• - 3' end Generation?

Back

• - Monocistronic

• - Methylated cap

• - >40 hours

• - Poly(A) tail

• - Cleavage releases mRNA

Front

Explain Transcription Initiation + Termination in both Bacteria and Eukaryotes

Back