Part B: Lecture 6 Flashcards
Gene (def.)
DNA region responsible for production of an RNA molecule (mRNA, rRNA etc.)
Genes in prokaryotes + eukaryotes general difference
no difference; they work the same way
parts of gene (3)
promoter, regulatory region, transcribed region
Promoter (def.)
place where RNA pol attaches
regulatory regions (def.)
places where transcription factor proteins attach
transcribed region produces ____
RNA
regulatory region is a _____ that is ____ long
-specific DNA sequence
-10-20 bp long
positive transcription factors do what?
recruit RNA polymerase: increase gene activity by making it easier for RNA polymerase to bind
negative transcription factors do what?
block the promoter; decrease gene activity by making it harder for RNA poly to bind
example of +ve transcription factor
MyoD
transcription factors bind which form of DNA? why?
dsDNA; time and energy to open DNA is too much
How do TFs bind to DNA?
temporary base hydrogen bonds with no input of energy (spont.)
TFs bind to ____ bp to increase ___(2)
several adjacent bp to increase specificity and strength
LacZ gene in E-coli produces ____which is an enzyme that ____
-B-Gal (beta-Galactosidase)
-break down lactose brought into cell via transporter
Environmental gene expression exists because ___
different environments require different enzymes for survival
Environmental gene expression (def.)
when a gene is ‘on’ only in certain environments
LacZ gene has a ___ TF called ____
-negative
-lac repressor protein binding on regulatory regions
lac repressor protein activity when [lactose] is low
-lactose isn’t bound to protein and it has a high affinity for DNA
lac repressor protein activity when [lactose] is high
-lactose is bound to protein and it has a low affinity for DNA
Allele (def.)
different forms of gene shown with superscripts or capitalization
functional allele representation
a+ or A
non-functional allele representation
a- or a
LCT gene function (humans)
-codes for lactase: break down lactose outside cell + transporter brings monosaccharide into cell
LCT gene regulation
regulated by positive TFS
Spatial gene expression (def.)
when gene is on in only some cells; gene expression dependent on location of cell in cellular organism
Temporal gene expression (def.)
when gene is on in only some development stages (child vs adult)
genotype (def.)
all genes and alleles present in cell/organism
Homozygote (def.)
a cell/organism with identical
alleles of a gene of interest
Heterozygote (def.)
a cell/organism with different
alleles of a gene of interest
G1 & G2 representation of genotype
A/a (single letter not double letter AA/aa)
Homologous chromosomes usually have same ____ (4)
length
centromere position
bands
genes
Homologous chromosomes often have different ____ (1)
alleles
Phenotype (def.)
the physical characteristics of a cell/organism (“what we see”)
In a heterozygote the _____ allele conceals
the ______allele
-dominant
-recessive
describing allele interaction
-The A allele is dominant to the a allele
(must state two alleles)
If a cell/organism has a dominant phenotype but we don’t know if it is A / A or A / a?
A/ ___
