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3 years ago

Which of the following contradicts the "one-gene, one-enzyme hypothesis"?

Biology

1 answer:

Pepsi [2]3 years ago

7 0

Answer:

A single antibody gene can code for different related proteins, depending on the splicing that takes place post-transcriptionally.

Explanation:

According to the "one-gene, one-enzyme hypothesis", a gene code for single specific enzyme only. Beadle and Tatum proposed the one-gene, one-enzyme hypothesis that states that a gene encodes the genetic information for the synthesis of one enzyme only. However, alternative splicing in eukaryotes allows the formation of more than one related proteins/enzymes from a single gene.

For instance, alternative splicing of single primary transcript transcribed from an antibody gene allows the formation of multiple proteins. The primary transcript encoded by this gene has a segment of the gene that serves as either intron or exon. Depending on particular combinations of exons retained after splicing, multiple related proteins are formed by respective mRNA.

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What statement best compares photosynthesis and cellular respiration?

Paladinen [302]

Answer:

Explanation:

Photosynthesis only takes place in the light, while cellular respiration takes place in the light and dark.

https://youtu.be/xmfhKbmQhq0

Photosynthesis vs. Cellular Respiration Comparison

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3 years ago

Read 2 more answers

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erica [24]

Was AA, KK, and TT correct?

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3 years ago

Cystic fibrosis (CF) is one of most common recessive disorders among Caucasians it affects 1 in 1,700 newborns. What is the expe

Phantasy [73]

Answer: The expected frequency of carriers is P(Aa)=0.046.

The proportion of childs with CF is P(aa)=0.024.

25% of having a child with CF (aa).

Explanation:

Hardy-Weinberg's principle states that in a large enough population, in which mating occurs randomly and which is not subject to mutation, selection or migration, gene and genotype frequencies remain constant from one generation to the next one, once a state of equilibrium has been reached which in autosomal loci is reached after one generation. So, a population is said to be in balance when the alleles in polymorphic systems maintain their frequency in the population over generations.

Given the gene allele frequencies in the gene pool of a population, it is possible to calculate the expected frequencies of the progeny's genotypes and phenotypes. If P = percentage of the allele A (dominant) and q = percentage of the allele a (recessive), the checkerboard method can be used to produce all possible random combinations of these gametes.

Note that p + q = 1, that is, the percentages of gametes A and a must equal 100% to include all gametes in the gene pool.

The genotypic frequencies added together should also equal 1 or 100%, and all the equations can be summarized as follows:

$p+q=1\\(p+q)^{2} = p^{2} +2pq+q^{2} = 1\\P(AA)=p^{2} \\P(aa)=q^{2} \\P(Aa)=2pq1$

So, there are 1700 individuals and only one is affected. Since it is a recessive disorder, the genotype of that individual must be aa. So the genotypic frequency of aa is 1/1700=0.000588.

Then, $P(aa)=q^{2}=0.000588$ . And with that we can calculate the value of q,

$P(a)=q=\sqrt{0.000588}=0.024$

And since we know that p+q=1, we can find out the value of p.

$p+0.024=1\\1-0.024=p\\p=0.976$

Next, we find out the genotypic frequency of the genotype AA:

$P(A)=p=0.976\\P(AA)=p^{2} = 0.976^{2}=0.95$

Now, we can find out the genotypic frequency of the genotype Aa:

$P(Aa)=2pq=2 x 0.976 x 0.024 = 0.046$

Notice than:

$p^{2} + 2pq + q^{2} = 1\\x^{2} 0.976^{2} + 2 x 0.976 x 0.024 + 0.024^{2} = 1$

Then, the expected frequency of carriers is P(Aa)=0.046

The proportion of childs with CF is P(aa)=0.024

If two parents are carriers, then their genotypes are Aa.

Gametes produced by them can only have one allele of the gene. So they can either produce A gametes, or a gametes.

In the punnett square, we can see that there genotypic ratio is 2:1:1 and the phenotypic ratio is 3:1. So, there is a probability of 25% of having an unaffected child, with both normal alleles (AA); 50% of having a carrier child (Aa) and 25% (0.25) of having a child with CF (aa).

5 0

3 years ago

In the study of human evolution, scientists define modern in terms of:

Lina20 [59]

Answer: a) a series of anatomical traits that distinguish Cro-magnon features from Neandertals.

Neanderthals (Homo neanderthalensis) were first discovered in Germany in 1856 and are believed to emerged between 100,000 and 200,000 years ago.

Significant differences found in the human and Neanderthal includes: 1) their DNA, 2) the brain of a Neanderthal had a raised larynx and was also bigger, and 3) Compared to modern humans, Neanderthals had bigger and muscular body but with shorter legs.

Cro-magnon is the earliest known Western European example of our species who lived 35,000 and 10,000 years ago. They are believed to be actually modern in every anatomical respect. They are much like us.

Neanderthal and Cro-magnon were believed to overlap in Europe for a thousand years but long-term interbreeding was not seen.

6 0

3 years ago

An atom on the periodic table can be identified by its

zaharov [31]

Answer:

The number of protons in it.

Explanation:

There are two properties that can be used to identify an element:

the atomic number
the number of protons in an atom.

The number of neutrons and number of electrons are frequently equal to the number of protons, but can vary depending on the atom in question

4 0

2 years ago