Your lazy labmates need your ! they set up a 10-ml culture of myxococcus xanthus yesterday, but then they decided to stay up late playing overwatch. overwatch led to oversleep, and they are worried that their culture grew too much. they call you in laband ask you to take an od reading for them. you do this favor for them, and do the conversion into cells/ml, finding that they are currently sitting at about 6.5 x108cells per ml. your labmates are horrified: they won’t be back in time before the cells hit stationary phase, since they double every 2 hours. they beg you to make a new culture using these cells and set it up to reach the same cell density tomorrow morning. that’s 13 hours away. if the cells usually lag for one hour after dilution, what cell density should you dilute the culture to?

humans are now responsible for causing changes in the environment that hurt animals and plant species. we take up more space on earth for our homes and cities. we pollute habitats. human activity often changes or destroys the habitats that plants and animals need to survive.

increase soil erosion                                             reduce soil erosion

cattle grazing                                                         hydroseeding

deforestation                                                         contour plowing

                                                                                planting vegetation

plant roots basically hold the top soil

together and stop soil erosion because

in such situation top soil is not removed

during flood but cattle grazing causes

soil erosion because cattle consume the

grasses and herbs and top soil is exposed.

same situation occurs because of

deforestation, the trees and plants are cut

down to expose top soil which causes soil

erosion

prophase: we can observe the chromosomes to coil up and condense. they become visible. nuclear membrane and envelope disintigrate.s

metaphase: chromosomes align at the center, the metaphase plate. spindle fibers attach to centromeres of the sister chromatids. they meet at kinetochores.

anaphase: sister chromatids are pulled towards each opposing centromere, set on different poles.

telophase: chromosomes are now clustered up only on either sides of the cell. nuclear membranes reform, and a new cell wall forms along the cell plate. this will lead to cytokinesis, the process that divides the cell membrane and forms the cell wall.