BISC 1111 - mitosis & intro to stat analyses

field of view

largest on lowest power objective, when you switch to higher power, field of view closes in toward centerm you will see more of an object on low power

best to find an oject on low power, center it, the switch to next higher power and repeat

depth of focus

greatest on lowest power objective, each time you switch to higher power, depth of focus is reduced

cell cycle

organismal growth regulated by cell cycle

events that happen as cell grows and divides

Gap 1

S

Gap 2

M

Gap1

cell increases in size

cell contents duplicated

period before synthesis

S

DNA replication

each of 46 chromosomes (23 pairs) replicated by cell

dna synthesis takes place

Gap2

organelles and proteins develop in preparation for cell division

period between end of DNA synthesis and beginning of prophase

M

formation of daughter cells

mitosis

cell devision two daughter cells formed from a parent cell

• chromosome number in parent and daughter cells are the same

ongoing continues cycle

interphase

cells spend most of their life here

preparations for mitosis occur here (is not itself a step of mitosis)

DNA replicates to prepare for mitosis

chromosomes not clearly seen in nucleus, but dark spot called nucleolusmay be visible

prophase 

immediately after S and G2 phases

in nucleus: chromatin begins to condense

nuclear envelope dissolves

proteins attach to centromeric region, creating kinetochores

microtubules attach at kinetochores → chromosomes begin moving 

pro-metaphase

nuclear envelope has disintegrated

microtubules extend from centromere on chromosome to poles of the cell

allows cell to move chromosomes around 

metaphase

spindle fibers align the chromosomes along middle of cell —> metaphase palte

microtubules pull chromosomes with equal force

anaphase

sister chromatids separate at kinetochores

chromosomes move to opposite sides of cell

motion results from combination of kinetochore movement along spindle microtubules and through physical interaction of polar microtubules 

telophase

new membranes form around daughter nuclei

chromosomes disperse and are no longer visible under light microscope 

cytokinesis

partitioning of the cell

two daughter cells are formed

mitotic index

#cells in mitosis/total# cells) x 100 = % cells dividing

% cells at rest in normal tissue

#cells in interphase/total# cells) x 100 = % cells at rest

t-test

tells you if there is a signficant difference between the means of two groups

assumptions

• data are independent

• norm dist

• homogeneity of variance across groups

types

• independent - compares means of 2 groups

• paired 1 sample t-test

• one sample t-test - tests mean of a group against a known mean (previous research or normal)

two tailed t-test

used to determine if there is a difference between groups being compared

one tailed t-test

used to determine if there is a difference between groups in a specific direction

p values

probability that your results happened by chance

• usually written as a decimal 

  • p valye of 5% is 0.05

• low p value indicated that your results didn’t occur by chance