WEEK 19/20 - evolution of eukaryotes + cell signalling in development

properties of the LUCA

first complete cell

DNA replication, mRNA transcription, genes, operons, genetic code

rRNA, binary fission, metabolism

2 theories of evolution

macroevolution vs microevolution

what are the asgard archaea

sister group to FECA, newly sequences meta-genomes of archaea from hot springs

common features of eukarya and Asgard archaea

GTPases, actin, tubulin, histones, ESCRT systems

properties of LECA

genes with introns

cell cycle, mitosis

sex + meiosis

phagocytosis

origin of nucleus

infolding of cell membrane

origin of flagellum

symbiosis of 2 archaea, 1 with actin cytoskeleton, 1 with tubulin

origin of gamete fusino

need for cell fusion and recombination for DNA damage repair

what are chlorophyta

unicellular flagellates, colonial or multicellular (green algae, plants)

what are angiosperms

seed bearing plants that form flowers

flowers contain gametophyte

3 steps of signalling

1. signal reception

2. signal transduction

3. cellular response

what do receiving cells need for a signal to transmit

cognate receptors for the specific signals

what do different cell types result from

differential gene expression

what is a morphogen

a molecule that defines 2+ cell fates at different concentration

what can lateral inhibition do

create sharp boundaries and regular spaced patterns

3 causes of pattern formation in tissues

positional information

relay systems

lateral inhibitions

4 types of signalling

endocrine

paracrine

neurocrine

contact-dependent (juxtocrine)

what is endocrine signalling

transmits a signal over large distances via the bloodstream to target cells

what is paracrine signalling

transmits a signal locally and only affects neighbouring cells

what is neurocrine signalling

transmits a signal from a neuron over large distances via bloodstream to target cells

what is contact-dependent (juxtocrine) signalling

involves direct cell-cell contacts between neighbouring cells