METHOD 1:
. Less inbreeding/ more outbreeding so more hybrid vigour
. greater genetic variation
METHOD 2:
. Does not lead to offspring getting unwanted genes from wild plant
species
. Does not require a wild plant to proceed
. No risk of disease transfer
COMPARE BACTERIA AND ARCHEA
SIMILARITIES:
Both are prokaryotes.
Both have smaller ribosomes (70S) compared to prokaryotes.
Both divide by binary fission; not mitosis
Both exists as unicellular organisms or group of of cells.
Both do not have membrane-bound organelles
DIFFERENCES:
Archea’s 70S ribosomes small subunit is More similar to that of eukaryotic
ribosomes. As well as the rRNA and the primary structure of ribosomal proteins
is similar to that of eukaryotes
Archea’s DNA exists as circular chromosomes with histone proteins associated
with it. Bacteria have circular DNA with no histone proteins associated.
Archea’s cell wall is made up of material that is not peptidoglycan.
HOW CAN CHLOROPLAST PIGMENTS BE IDENTIFIED IN A LEAF?
Crush the leaf in a solvent made up of propane and petroleum ether. Propane is
a polar solvent and since leaves contain nitrogen-containiubgn compounds that
are polar, it dissolves well in propane. Make sure to use less amount of solvent
to make a concentrated solution. Crush the leaves properly.
Can carry out TLC or paper chromatography. I’m gna write about TLC cz it
makes me sound smarter hehehe
Place a small spot of sample on the TLC plate, let it dry and place more of the
sample in the spot. Repeat until the spot is concentrated. Since the TLC plate is
coated with SiO2 or Al2O3, which is polar, use an inorganic solvent as the
mobile phase. Place the TLC plate in the organic solvent in a beaker, making
sure the solvent does not touch the sample spot.
The sample will separate into different pigments on the TLC plate that can be
seen as spots. Separation happens on the basis of the different solubilities of
the pigments in the mobile or stationary phase or simply the solvent. After the
solvent has travelled nearly to the top of the TLC plate, stop the experiment
and measure the distance travelled by each spot and the distance travelled by
the solvent front. Calculate the Rf values for each spot and compare with the
standardised or known Rf of values of certain pigments.
MARK-RELEASE-CAPTURE METHOD
MICROARRAYS
Microarrays have a small plastic chip of about 2cm2, with small strands of
single-stranded, complementary DNA to the genes being tested for, called DNA
probes. Several of these DNA probes are present on every unit of the
microarray.
The DNA is obtained from the organism and DNA that needs to be tested for
the presence of a gene, is first treated restriction endonucleases to cut them
into fragments. These small, double-stranded DNA fragments are denatured to
give small, single-stranded DNA fragments. These fragments are marked with
fluorescent tags. DNA hybridisation takes place as 2 single stranded DNA
molecules bind with each other by complementary base pairing.Allow these
strands of DNA to hybridise with the gene probes on the microarray; wash off
any DNA that does not hybridise. UV light can be used too detect presence of
the genes, if the genes present, they hybridise and fluoresce under UV light.
SOCIAL BENEFITS OF GM CROPS
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Increased crop yield
Low cost of food
Resolves global hunger, more food available\
More income for farmers as more yield
Less land has to be evacuated for increasing yield of crop, less
harm to habitats of other animal/plant species
ADVANTAGES OF USING mtDNA RATHER THAN NUCLEAR DNA
. mtDNA is high in number; many in a single cell
. It is small so can be easily analysed and quickly
. Mutations occur at a constant rate so can be compared with the
molecular clock to find rate of mutation and compare them
. mtDNA does not have histone proteins attached
. No crossing over or recombination, only inherited from the mother
MOLECULAR CLOCK HYPOTHESIS
Assumes that the rate of mutation in mtdna remains constant over time and the
greater the difference nucleotide sequences, the longer ago they shared a
common ancestor
The clock can be calibrated by obtaining nucleotide sequences of species
whose date of speciation can be estimated from fossil evidence such as
through carbon dating
PEARSON’S LINEAR CORRELATION
This can be used to calculate a correlation coefficient when:
. Quantitative data is collected as measurements ( such as height,
mass, length, depth, light intensity) or counts (such as number of
species in a quadratic)
. You have an idea that it is a linear correlation
. Normal distribution of data
SPEARMAN’S RANK CORRELATION
This is used to calculate a correlation coefficient when:
. The data collected is not quantitative but according to an abundance
scale
. Quantitative data collected but not sure if it has a normal distribution
. There is correlation between the two variables but it is not linear
HBB ALLELE MUTATION