Chapter 16 Flashcards
Differentiation
Cells become specialized in structure and function
Morphogenesis
Development of the form of an organism and its structures.
Cytoplasmic determinants
A protein, or rna that is placed in an egg and influenced the early development by regulating the expression if genes that affect the developmental fate of cells.
Induction
A group of embryonic cells influence the development of each other, usually by causing changes in gene expression.
-contact with cell surface molecules in neighbouring cells and the being of growth factors secreted by neighbours
Determination
Point at which an embryonic cell is irreversibly committed to being a specific cell type.
Apoptosis
Programmed cell death where cellular agents chop up the DNA and fragment the organelles and other cytoplasmic components.
Cells become multilobed “bleebing”
Responsible for webbed fingers
Pattern formation
Tissues and organs are all in their characteristic places due to cytoplasmic determinants and inductive signals
Positional information
Molecular cues that control pattern formation in an embryonic structure by indicating a cells location relative to the organisms body axes.
Nurse and follicle cells
Support cells that supply the egg with nutrients and mRNAs
Homeotic genes
Regulatory genes that control pattern formation in late embryo, larva and adult.
Embryonic lethals
Mutations with phenotypes causing death at the embryonic or larval stage
Maternal effect gene
A gene that, when mutant in the mother results in a mutant phenotype in the offspring, regardless of offsprings genotype
Bicoid
A meter al effect gene that codes for a protein responsible for specifying the anterior end in flies.
Bicoid mRNA deposited in high concentration in anterior end and diffuse to posterior.
-embryo with two mutant bicoid ales has posterior at both ends of organism
Morphogens
A substance that provides positional information on the form of a concentrated gradient along the embryonic axis.
Maternal mRNAs determines what
Anterior, posterior, dorsal and ventral areas of offspring
Does maternal mRNA continue through organisms life?
No, maternal mRNA stops after embryonic phase and gene expression takes over
Stem cells
Unspecialized cells that can both reproduce themselves and even differentiate into many tissues.
Totipotent
In plants, mature cells can dedifferentiate and then give rise to all the specialized cell types of an organism.
Nuclear transplantation
Scientists replace nucleus of an egg with the nucleus of a differentiated cell
Where can stem cells be isolated
Early embryos at blastula stage or blastocyst stage.
Pluripotent
Capable of differentiating into many cell types
Therapeutic cloning
When aim of cloning is to produce stem cells to treat disease.
Induced pluripotent stem cells
Deprogrammed Cell
Oncogenes
Proto-oncogenes
A gene found in viral or cellular genomes that is involved in triggering molecule events that can lead to cancer.
Code for normal cell growth and division.
Three types of changes to proto-oncogenes to turn to oncogenes
Movement of DNA within genome
Amplification of a proto-oncogene
Point mutation in a control element or in proto-oncogene itself
What happens to translocated chromosome ps that can cause cancer
Translocated porto-oncogene ends up near active promoter and its transcribed more.
Increases copies of proto-oncogene results in more proteins
Tumor suppressor gene
Gene whose normal products inhibit cell division
Mutation of this =cancer
Adult stem cells do…
Replenish specialized, no reproducing cells types
Benign vs, Malignant
Metastasize
No cancer
Cancerous, continue to grow, invade surroundings and spread
Art of tumour breaks off and spreads
What is meant by cancer is a multi step model
Requires 1 active oncogene and loss of several tumor suppressor genes
Means different treatments must be used
