Lab 4

Question 1

Cyrobiology is the biological study of the effects of

Answer 1

low temp on organisms

Question 2

At temperatures below___ the glass transition phase is reached preventing diffusion and thus halting all biological actvity

Answer 2

-130C

Question 3

When cells are cooled belwo 0C what happens

Answer 3

ice crystals form outisde the cell raising concentration of dissolved solutes. This cause a loss of weater from osmosis and cells shrink becoming more dehydrated. If cells are cooled to fast or slow is damages cells thus why wwe use cryoprotective agents

Question 4

Cryoprotective agnets(CPAs) are highly _____ and can act in either the intracelluklar or extracellular space.

Answer 4

hydrophilic, this helps cells becuse thay bind to water pr4eventing dehydration

Question 5

What are the two most used CPAs?

Answer 5

DMSO-dimethylsulfoxide
glycerol

they decrease freezing point lessening salt concntrations and pr4eventing osmotic shock

Question 6

_____containsers ar4e appropraite long-term storage devices that are able to continually maintain temp of -196C

Answer 6

Liquid nitrogen

Question 7

How can the viability of yeast be assessed?

Answer 7

using methylene blue dye we can see the living and died cells, dark blue are died

this is critizes b/c the redox-reaction that converts the blue dye to colo9urless can be reversed in the presence of oxygen.Thus in lots of oxygen living cells look blue