bio test 4 Flashcards
definition of heterochromatin
densely staining chromatin that appears as nodules in or along chromosomes and contains relatively few genes.
euchromatin definition
It represents the major genes and is involved in transcription. chromosome material that does not stain strongly except during cell division.
difference between euchromatin and heterochromatin
Heterochromatin is highly condensed, gene-poor, and transcriptionally silent, whereas euchromatin is less condensed, gene-rich, and more easily transcribed
Gurdon’s nuclear transplant experiment
transplanted nuclei from tadpole cells of Xenopus, and other frog species, into unfertilized Xenopus eggs and observed how the modified eggs proceeded to develop. Gurdon stopped the development of some of the modified eggs, or fixated them, and allowed others to build as far as possible.
General CpG
useful markers for genes in organisms containing 5-methylcytosine in their genomes. In addition, CpG islands located in the promoter regions of genes can play important roles in gene silencing during processes such as X-chromosome inactivation, imprinting, and silencing of intragenomic parasites.
Positive regulation
increased rate of gene expression
negative regulation
inhibits or lowers odds of that specific gene
what conditions must be met for the lac operon to be fully functional
Low glucose
High cAMP
lactose
what CRP-cAMP does
cAMP readily binds with CAP, and the CAP-cAMP complex binds DNA at a position upstream of the lac operon. The association between RNA polymerase and DNA is enhanced when the CAP-cAMP complex is present.
high glucose low cAMP
low glucose high cAMP
totipotent
isolated cell that is able to produce a fertile adult individual
where are totipotent stem cells found
only in early embyotic tissues
pluripotent
A cell that is able to develop into many different types of cells or tissues in the body.
where are pluripotent found
Found in bone marrow, blood and adipose tissue.
multipotent stem cells
have the ability to differentiate into all cell types within one particular lineage. There are plentiful advantages and usages for multipotent stem cells. Multipotent Stem cells act as a significant key in procedure of development, tissue repair, and protection.
where are multipotent stem cells found
Found in bone marrow, fat tissue, dental pulp, heart tissue, and many other places.
pax6 gene
play a critical role in the formation of tissues and organs during embryonic development. The members of the PAX gene family are also important for maintaining the normal function of certain cells after birth
enhancers in transcription regulation
help establish the transcriptional program of cells by increasing transcription of target genes.
activators in transcription regulation
turn on the expression of genes in a eukaryotic cell.
mediators in transcription regulation
relaying signals from TFs directly to the pol II enzyme, thereby facilitating TF-dependent regulation of gene expression.
evolution definition
a change in allele or genotype frequency in a population over time
difference between natural selection and genetic drift
Genetic drift causes evolution by random chance due to sampling error, whereas natural selection causes evolution on the basis of fitness.
three types of selection
Stabilizing selection
Disruptive selection
Directional selection.
reproductive isolation
the inability of a species to breed successfully with related species due to geographical, behavioral, physiological, or genetic barriers or differences.
adaptation for apes
Having long arms and short legs gives the species a natural quadrupedal posture, which helps reduce stress on their bones and joints due to their great mass. They normally “knuckle walk” on the knuckles of their hands and the palms of their feet, but are also capable of walking bipedally for limited periods.
