Download ISE 362 HOMEWORK SEVEN Due Date: Tuesday 12/15 1. Water

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Due Date: Tuesday 12/15
11.. Water aeration is often required in water bodies that suffer from anoxic conditions, usually
caused by adjacent human activities such as sewage discharges, agricultural run-off, or overbaiting a fishing lake. Aeration can be achieved through the infusion of air into the bottom of
the lake or pond by surface agitation from a fountain (see below) or spray-like devices to allow
for oxygen exchange at the surface and the release of noxious gasses such as carbon dioxide or
methane. Natural aeration is a type of both sub-surface and surface aeration. It can occur
through sub-surface aquatic plants. Through the natural process of photosynthesis, pond plants
restore oxygen to the water, and thus aerate the pond, providing it with the oxygen necessary for
fish to live and aerobic bacteria to break down excess nutrients. A recent study reports data on
the rate of oxygenation in streams at 20oC in the upstate New York regions. The sample mean
and standard deviation were computed as x_bar = .173 and s = 0.066, respectively. Based on
the accompanying frequency distribution, can it be concluded that the oxygenation rate is a
normally distributed variable? Use the chi-squared goodness-of-fit test with α =0.05.
Rate (per day)
Frequency
Below .100
14
.100-below .150
24
.150- below .200
28
.200 –below .250
18
.250 or more
16
ANS:
Fountains aerate the lakes…
88.. Genetics has shown us that many of the differences between organisms are the result of
differences in the genes they carry. The principles of heredity were first written by Gregor
Mendal in the 1860s. (The importance of his findings was not recognized in his lifetime). The
genetic material of all living organisms is DNA. DNA strands are made of a sequence of
ATCG. In a nucleus, genetic material is complexed with protein and is organized into a number
of linear structures called chromosomes. Chromosome means colored body and is so named
because these threadlike structures are visible under the microscope only after they are stained
with dyes. Chromosomes are the essential unit for cellular division and must be replicated.
Compaction of the duplicated chromosomes during mitosis and meiosis results in the classic
four-arm structure pictured below. Chromosomal recombination plays a vital role in genetic
diversity. If these structures are manipulated incorrectly, through processes known as
chromosomal instability and translocation, the cell may undergo mitotic catastrophe and die, or
it may unexpectedly evade apoptosis leading to the progression of cancer. In an experiment
reported in Genetics, investigators looked at 300 metacentric chromosomes and then counted
the number of sister-chromatid exchanges on each. (Sister-chromatids are ones that are
identical). A Poisson model was hypothesized for the distribution of the number of exchanges.
Test the fit of a Poisson distribution to the data by first estimating λ and then combining the
counts for x = 8 and x = 9 into one cell.
X = number of exchanges>> 0
1
2
3
4
5
6
7
8
9
Observed Counts >>> 6
24 42 59 62
44 41 14
6
2
Ans:
Diagram of a replicated and condensed metaphase eukaryotic chromosome. (1)Chromatid – one of the two
identical parts of the chromosome after S phase. (2) Centromere – the point where the two chromatids touch,
and where the microtubules attach. (3) Short arm. (4) Long arm.
THE END