Answer:
With respect to the composition of DNA, in an analysis it can be found that the proportions of nucleotides are A + C = G + T (option a).
Explanation:
The proportion of nucleotides in a DNA molecule can be established according to the sequence of these nucleotides on both complementary strands, since the purinic bases of one strand are complemented by the pyrimidinic bases of another:
- <em>Adenine is complemented with Thymine A=T</em>
- <em>Guanine is complemented with Cytosine G=C</em>
From this we can deduce that in a DNA molecule with two chains there will be the same amount of adenine and thymine, as well as the same number of guanine with respect to cytosine, so:
<em> A + C = G + T</em>
An example of this would be a known DNA molecule (hypothetical), with 5 molecules of Adenine and 7 molecules of Guanine. In this case there are 5 Thymines, complementary with Adenine, and 7 Cytosines like Guanine:
<em> A + C = G + T</em>
<em> 5 + 7 = 7 + 5</em>
Answer:
The correct answer is - qualitative measurements.
Explanation:
When the information about characteristics is tough to describe of define by measuring or represent numerically, qualitative measurements are used to describe it.
These measurements are carried out by information collected through all senses such as vision, hearing, touch, smell, and taste. For example softness of the skin, the color of hair.
Thus, the correct answer is - qualitative measurements.
Answer:
The options
a. New combinations of genes yielding genotypes of greater fitness
b. Few heterozygotes because of underdominance
c. Frequency-dependent selection, leading to fluctuations in fitness
d. Heterozygotes with greater fitness, owing to overdominance
e. A random assortment of genotypes because of genetic drift
The CORRECT ANSWER IS b.
b. Few heterozygotes because of under dominance
Explanation:
In genetics, underdominance (at times called "negative overdominance") is the opposite of overdominance.
It is the selection against the heterozygote, that leads to disruptive selection and divergent genotypes. It occurs in cases of inferior and reduced fitness (As in our case study, it is the different chromosomal fusions and inversions)
of the heterozygotic genotype to the dominant or recessive homozygotic genotype. It is unstable as it causes fixation of either allele.
Another example is the African butterfly species Pseudacraea eurytus, which makes use of Batesian mimicry to avoid predation. This species carries two alleles that gives a coloration that is alike to a different local butterfly species that is harmful to its predator. The butterflies who are heterozygous for this trait are observed to be intermediate in coloration and thus encounter an higher risk of predation and a decrease in the total fitness.
Answer:
Incomplete dominance is the inheritance pattern where the dominant allele did not mask the recessive allele completely and form a mix of both alleles. Here the inheritance is the incomplete inheritance. The ratio of F2 generation is 1:2:1.
Given:
R1R1 = 42
R2R2 = 39
R1R2 = 86
Total R1 alleles = 2*42+86 = 170
Total R2 alleles = 2*39+86 = 164
Total alleles = 334
Frequency of allele R1 = 170/334 = 0.51
Frequency of allele R2 = 164 / 334 = 0.49
Expected number of each phenotype:
Total population = 167
Blue = R1R1 = 0.51 * 0.51 * 167 = 43.44
Green = R2R2 = 0.49 * 0.49 * 167 = 40.10
Cyan = 2*R1*R2 = 2*0.51*0.49*167 = 83.46
Phenotype Observed(O) Expected (E) O-E (O-E)2 (O-E)2/E
Blue 42 43.44 -1.44 2.0736 0.0477
cyan 86 83.46 2.54 6.4516 0.0773
green 39 40.1 -1.1 1.2100 0.0302
Total 167 167 0.1552
Chi-square value = 0.155
Degrees of freedom = no. of phenotypes – 1
Df = 3-1 = 2
Critical value = 5.99
Chi-square value of 0.155 is less than the critical value of 5.99. So we accept the null hypothesis.
Answer:
In eukaryotic cells you find core and proximal promoters.
Promotors are specific DNA sequences where transcription factors (proteins) and RNA polymerase binds to initiate transcription. Promotors are located upstream the coding sequence
Core promoters are where RNA polymersae binds and proximal promoters are where transcription factors bind.
Enhancer elements are DNA sequences where transcription factors (proteins) bind to increase the rate of expresion of an specific gene. Enhancers can be located either upstream, downstream or thousands of nucleotids away from the of the coding region.
Explanation:
Promoters and enhancer are key elements for controling gene regulation. Transcription begins when chromatin rearranges from a condensed state to a accesible state, this allow to transcrition factors and RNA polymerase to bind specif DNA sequences (promotors). Proteins bind to enhancers , this complex develops a DNA loop, so that the protein that is bound to the enhancer interacts with the RNA polymersase. When this interaction is made, the activity of the RNA polymerase is increased.
