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Exam 3
Case Study 5 & 6
32
Biology
Undergraduate 2
11/11/2013

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Term
recombination
Definition
new "arrangements" of alleles due to independent assortment or crossing over (AB --> Ab)
Term
when does crossing over occur?
Definition
prophase I of meiosis
Term
recombinant vs parental offspring
Definition
recombinant - offspring in which cross-overs occurred in the gametes that produced them; parental - offspring did not experience crossing over
parentals are much more abundant
Term
linked genes
Definition
genes located on the same chromosome that do not appear to assort independently
Term
repulsion vs coupling
Definition
Ab/aB; AB/ab
Term
promoter
Definition
sequence upstream of the start of the gene that encodes the RNA
Term
terminator
Definition
specifies where transcription stops
Term
-35 box
Definition
5'-TTGACA-3', -35 nucleotides upstream from transcription start site in bacteria
Term
-10 box (Pribnow box)
Definition
5'-TATAAT-3', -10 nucleotides upstream from transcription start site in bacteria
Term
core enzyme
Definition
holoenzyme, initiates transcription in bacteria
Term
sigma factor
Definition
ensures that RNA polymerase binds in a stable way only at promoters (prokaryotes)
Term
RNA polymerase I
RNA polymerase II
RNA polymerase III
Definition
I - catalyzes synthesis of three of the RNAs found in ribosomes, located in nucleolus
II - synthesizes mRNAs and some snRNAs, located in nucleoplasm
III - synthesizes tRNAs, snRNAs not made by RNA pol II, located in nucleoplasm
Term
TATA box
Definition
5'-TATAAAA-3' specifies where the transcription machinery assembles and determines where transcription will begin (eukaryotes)
Term
CAAT box (-75) and CG box (-90)
Definition
work in either orientation, play a role in determining the efficiency of the promoter
Term
5' untranslated region (leader sequence)
Definition
untranslated part of an mRNA molecule extending from the 5' end to the first start codon; contains info for directing initiation of protein synthesis at the translation start site
Term
3' untranslated region (trailer sequence)
Definition
untranslated part of an mRNA molecule beginning at the end of the amino acid-coding sequence and extending to the 3' end of the mRNA
Term
role of enhancer in regulating transcription
Definition
enhancers are sequences (elements) needed for maximal transcription; cis-acting (same strand); not genes, no products, not a modifier gene subtype
enhancers interact with activators and co-activators, basal TFs, and RNA pol in 3D structure with DNA to cause maximal transcription
Term
constitutive genes
Definition
genes whose products are essential to the normal functioning of a growing and dividing cell, no matter what the conditions are; always active in growing cells
Term
operon
Definition
cluster of genes, the expressions of which are regulated togethr by operator-repressor protein interactions, plus the operator region itself and the promoter
Term
steps of transcription
Definition
initiation - (prokaryotes) core enzyme directed to promoter by sigma factor, (eukaryotes) RNA pol directed to promoter by transcription factors
elongation - RNA pol builds mRNA, some proofreading
termination - (prokaryotes) rho dependent or rho independent with hairpin + U=A string, (eukaryotes) poly site 5'-AAUAA-3'
Term
genes in lac operon
Definition
lac I+ - repressor binds allolactose (inducer)
lac O+ - binds operator as long as repressor bound to operator RNA pol will not trancribe lac operon
lac Z+ - beta-galactosidase converts lactose into galactose and glucose
lac Y+ - permease allows lactose into the cell
lac A+ - acetylase seems to insure that beta gal. works on lactose and doesn't metabolize the "wrong" sugar
Term
acetylation
Definition
histones are acetylated by lysine acetyl transferases (KATs), neutralizes the positive charge of lysine residues
Term
nucleosome remodeling
Definition
remodeling by using the energy of ATP hydrolysis; complex may slide nucleosome along DNA exposing sites for DNA binding proteins, restructure the nucleosome in place, or transfer the nucleosome from one DNA molecule to another
Term
DNA methylation
Definition
silencing involving DNA methyltransferases modifying cytosines to produce 5-methylcytosine
Term
genomic imprinting
Definition
expression of certain genes is determined by whether the gene is inherited from the female or male parent
Term
alternate splicing
Definition
using different exon combinations from the same gene to make more than one protein
Term
alternate polyadenylation
Definition
polyadenylation on a different exon on one protein than another from the same gene
Term
transposable elements
Definition
DNA sequence that can change its position within the genome, sometimes creating or reversing mutations and altering the cell's genome size
Term
transposase
Definition
recognizes the IR sequences of the element to initiate transposition
Term
autonomous vs nonautonomous elements
Definition
can transpose by themselves, cannot transpose by themselves because they lack the gene for transposition, often defective derivative of the autonomous element in the family
Term
epigenetics
Definition
heritable changes in gene expression or cellular phenotype caused by mechanisms other than changes in the underlying DNA sequence
Term
what effect did genistein have on offspring?
Definition
brown fur (pseudoagouti), less likely to be obese
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