Stress 2

Question 1

what happens in hyper-osmotic stress/ how does it effect the cell

Answer 1

happens if the cell goes from low to high osmotic stress - so water leaves the cell - cell shrinks - passively diffuses out

Question 2

what happens in hypo-osmotic stress/ how does it effect the cell

Answer 2

cell conditions go from salty to low osmolarity

water flows into the cell - strain on the cell wall - damages

Question 3

what is a cells response to changes in osmolarity

Answer 3

solutes synthesised/accumulated to help maintain balance

Question 4

name 4 solutes that may be accumulated for balance

Answer 4

glycerol
sugars
potassium
amino acids

Question 5

what other important molecule is synthesised and used widely for stress responses

Answer 5

trehalose

Question 6

improvement to osmotic stress is usually a …. trait

Answer 6

polygenic

controlled by many genes

Question 7

what is gTME

Answer 7

the random mutagenesis of multiple transcription factors at once, instead of manipulating many genes one after another
(TFs regulate genes)

Question 8

what is oxidative stress

Answer 8

inability to counteract or detoxify harmful effects of free radicals through neutralization by antioxidants

Question 9

what are free radicals

Answer 9

unstable molecules that damage/ oxidise cells

Question 10

what are ROS

Answer 10

Reactive Oxygen Species - chemically reactive chemical species containing oxygen eg peroxides

Question 11

how are ROS formed

Answer 11

as a natural bi-product of metabolism of oxygen generated in respiration
we have defence mechanisms, but can exceed antioxidant capacity of cells

Question 12

what is the stress response for oxidative stress

Answer 12

up-regulation of scavengers eg catalase

up regulation of enzymes that repair oxidative damage