5. TIMING = 24 HOURS
INTERPHASE (18-20 hours)
G1 (10 hours) is typically the longest phase of the cell
cycle since it follows cell division in mitosis; first chance
for new cells have to grow.
S (5 to 6 hours) phase varies according to the total DNA
that the particular cell contains which is fairly constant
between cells and species
G2 (3 to 4 hours)
MITOSIS (2 hours)
the cell makes preparations for and completes cell
division only takes about 2 hours
15. BINOMIAL EXPANSION
Mathematical way to determine or
project combinations
Let a = probability of first event; b =
probability of the alternative event; and
a+b=1
THUS...a 50% probability or chance
that one character will appear over the
other
17. What if you are only after a certain combination?
use of FACTORIAL
P = [n!/x! (n-x)!] pxqn-x
What is the probability is that a monohybrid
cross yielding a litter of four pups will
produce three agouti and one black pup?
B (agouti) and b (black)
P=
n = # trials (births) (4)
s = agouti (p = 3/4 = .75)
t = black (q = 1/4 = .25)
Therefore,
P = [4!/3!1!](.75)3(.25)1 = 0.42
18. MUTUALLY EXCLUSIVE EVENTS
Either one or the other will occur
focus is on the concept of outcome A or B
Example: In rolling a dice: calculate the probability of either two 4s or two
5s
Because these outcomes are mutually exclusive, the sum rule can be used
to tell us that the answer is 1/36 + 1/36 which is 1/18. This probability can
be written as follows:
19. What if: chances of both?
The product rule states that the probability of independent events
occurring together is the product of the probabilities of the
individual events.
consider two dice and calculate the probability of rolling a pair of
4s
The probability of a 4 on one die is 1/6 because the die has six
sides and only one side carries the 4
Therefore, with the use of the product rule, the probability of a 4
appearing on both dice is 1/6 × 1/6 = 1/36
28. DOMINANT EPISTASIS: CASE 1
W is dominant to w (W white)
Y is dominant to y (Y yellow)
W is epistatic to Y and y
In the absence of a dominant allele, the YY or Yy yellow while yy another phenotype which is green)
29. DOMINANT EPISTASIS: CASE 2
If W is white and Y is
WHITE yellow
W is dominant to w
WHITE
Y is dominant to y
YELLOW W is epistatic to Y and y
Y is epistatic to ww
WHITE
W and yy same expression
30. RECESSIVE EPISTASIS
B_: agouti
bb: brown
Presence of one C: allows
pigmentation to occur
Presence of cc: albino
Ratio: 9:3:4 (example:
mouse coat color)
31. DUPLICATE RECESSIVE GENES
W dominant to w
ww epistatic to P
P dominant to p
pp epistatic to W
The presence of at least one dominant allele of each two gene pairs is essential for flower to be purple
Ratio: 9:7 (Sweet Pea flower color)
