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Flashcards / Science / Biology / biology 121 exam 4 note cards

biology 121 exam 4 note cards

biology 121 exam 4 note cards


School: Wilkes University
Tags: Wilkes University
Cost: 25
Name: biology 121 exam 4 note cards
Uploaded: 03/23/2016
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Gene Expression

Goals: Control of Amount and Activity of Proteins, Which proteins to make, and how much of each to make

Regulating Gene Expression

Most Important Step in * * * : controlling transcription because it comes first, you don't copy a gene unless you need its products (i.e: a protein)

Transcription Factor

all help recrui RNAase


What enzyme melts DNA?


DNA replication is classified as ****

Aging Theory

"Mature" cells lose telomerase, lose DNA each cell cycle >> die when lose too much

cancer cells

these type of cells reactivate telomerase


allows you to make enough DNA to analyze starting from very small samples


Photolyase uses this to fix dimers

Nucleotide Excision Repair

fixes chemical damage


"black urine"

Beadle and Tatum

tested the one gene-one enzyme hypothesis


making RNA copy of a DNA sequence


The process of removing introns and rejoining cut ends.

frame-shift mutation

A mutation occurring when the number of nucleotides inserted or deleted is not a multiple of three, resulting in the improper grouping of the following nucleotides into codons.

genetic transformation

Process of inserting DNA from one species into another species to create a transgenic organism.

activating enzymes

deciphers the genetic code

activating enzymes

decide which amino acid goes on each tRNA


site of protein synthesis

protein synthesis

3 PHASES - (1) initiation (2) elongation (3) termination


stop of mRNA synthesis (i.e., transcription) at the terminator site

transcription factors

bind DNA and regulate initiantion of transcription


a segment of DNA containing adjacent genes including structural genes and an operator gene and a regulatory gene


protein that binds to the operator in an operon to switch off transcription


region of DNA that indicates to an enzyme where to bind to make RNA

lac operon

a gene system whose operator gene and three structural genes control lactose metabolism in E. coli

cap site

the place where the promoter isn't active until CAP binds


it blocks transcription if no lactose

transcriptional control

it is exerted by means of DNA sequences that are not transcribed


RNA polymerase binding site

core promoter

recruits RNA polymerase


this scientist demonstrated that proteins are strings of amino acids arranged in a specific order by sequencing insulin

transcription and translation

gene expression includes two processes called


used frameshift mutations to show the code consists of three letter "words" with no punctuation


the tRNA nucleotide sequence that pairs with the mRNA is called -

5' -AUG- 3'

What is the sequnce of anticodon that binds to the mRNA codon 5'-CAU-3'

the ribosomes and translation factors

2 differences in bacteria and eukaryotes show how antibiotics which poison bacterial protein synthesis affect humans

transcription, translation, and DNA replication

(1) all three use a nucleic acid template to decide which component to add next to a growing macromolecule, all three are catalyzed by dumb enzymes which need to be told where to start, all three processes can be separated into initiation and elongation phases, all three processes are regulated by proteins which bind to specific nucleic acid sequences

mRNA processing

In eukaryotes , includes the events of capping 5' end and adding a poly A tail to the 3' end

structural motifs employed by regulatory proteins

zinc finger, helix-turn-helix, homeodomain, and leucine zipper are all :

regulatory proteins

these bind to specific DNA sequences through forming H-bonds with specific comvinations of H-bond donors and acceptors exposed in teh major groove by each base pait

transcriptional control

This is exerted by DNA sequences that are not transcribed

trp operon regulation

this happens when the trp operon is only transcribed if [trp] is low because the trp repressor senses the [trp] and binds to the operator when [trp] is high


What will happen to the trp operon (all the time) if you mutate the trp repressor so that it can no longer bind DNA?

eukaryotic transcription

Steps: -RNA polyermase binds to the promoter and begins synthesizing the primary transcript using the complementary DNA strand as template -the initiation complex assembles on the core promoter and recruits RNA polymerase -The region of DNA containing the gene and its promoter are located and decompressed -Regulatory proteins bind to specific DNA sequences and assemble an initiation complex


Deletion of a single base near the start of the coding sequence would be lethal or ok for an organism


Many retroviruses cause this because they have added an oncogene from a former host to their genome which they then add to the genome of each new host