Lec 1&2 Flashcards
example of the common plant model organism
Arabidopsis thaliana
plants are sessile - explain
they are fixed/stuck (in soil) in comparison to animals which are mobile, plants being sessile means they must be very environmentally aware (not passive, they’re always perceiving and responding) to be able to respond to their environment by adjusting their pattern of growth and development
what is plant growth and development influenced by
internal (plant growth regulators ie. hormones and electrical impulses) and external (light atmospheric gases temp touch wind gravity water rocks soil, herbivores pathogens chemicals from neighbouring plants soil organisms, agricultural chemicals such as hormones) factors
how environmental factors affect plant growth and development and examples
plants must be able to first perceive these environmental signals then be able to respond to them eg. leaf morphology altered by temps and submergence, phototropism direction of plant growth in response to light, quality of light (shade, frared and infrared light), duration of light ie. day length, thigmotropism ie. response to touch, gravitropism (growth response to gravity, shoots will always grow up against gravity and roots will always grow down with gravity irrespective to pot orientation), microorganisms in their environment, waterlogging, water deficiency ie. drought, herbivores (when neighbouring plants are attacked plants may produce defensive compounds,
what plant has the smallest genome
Arabidopsis
what plant has the largest genome
lily
why is Arabidopsis a model plant organism
small genome (26000 genes, 11000 unique genes), rapid cyclers (8 week life cycle), self pollinated, thousands of seeds, bioinformatic resources, functional genomic tools, genetic resources, genetically transformed, most well researched plant
what are the levels of organisation of DNA in the nuclei
DNA double helix, DNA wound around a histone core (nucleosome), nucleosome compaction (higher order chromatin), further compaction into metaphase chromosomes
plant genes (ie. typical eukaryotic gene) structure and organisation
1-core promoter, 2-additional (upstream) regulatory regions, 3-transcribed region, 4-coding sequence (ie. exons, are typically interrupted by non-coding sequences ie. introns), 5-5’ and 3’ untranslated regions
what are transcription factors
proteins that bind to gene regulatory regions (DNA sequences) to facilitate gene transcription, composed of 2 domains - DNA-binding domain and protein-binding domain, activated by developmental or environmental signaling, cause cell differentiation (eg. what causes a kidney cell to become a kidney cell), classified based on their DNA binding domains
genes that are regulated by the same signalling mechanisms
share similar regulatory regions that are recognised by the same regulatory transcription factors
difference of signal transduction pathways in animals and plants
in animals most STPs induce a response by directly activating transcription factors that act as regulators of gene expression, this is sometimes the case in plants too but more commonly in plants STPs induce a response be removing repression of transcription factors (they inhibit the inhibitors, seen in signal pathways jasmonic acid, auxin, gibberelic, and light)
are transcription factors the only targets of signal transduction chains
no
