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8

The key here is that it is a question about mitochondrial DNA. mtDNA in humans is inherited maternally (from the mother). Both sons and daughters inherit mtDNA, but only the daughters will pass it on to the next generation. A child's mtDNA has to come from his or her mother, and all of a person's mitochondria are genetically identical. Therefore, children ...


5

Alleles are basically subtypes of a gene. At the time of Mendel, the molecular nature of inheritance was not known so the original definition of gene refers to "some" inheritable molecular entity inside the organism that is responsible for a trait. Alleles are different "flavours" of a given gene. For example there is a gene for flower colour, there can be ...


5

The answer is incomplete dominance. It can't be codominance, because codiminance involves both phenotypes being expressed in different parts of the organism: you would end up with red and yellow spotted flowers. It obviously isn't complete dominance, because the red x yellow cross produces orange flowers. Knowing that it has to be incomplete dominance or ...


3

Both genes and alleles are sequences of DNA. A gene will code for a trait, say hair colour, while an allele will be the variants of that gene (say the alleles coding for blonde, brown, black, and red hair). It's almost like cookbooks: two cookbooks (the DNA) might have a recipe (gene) for bread but they use slightly different instructions (alleles) ...


3

From what I can tell, you are not including the probability of the grandfather being a carrier (it could be the grandmother who is the carrier). Calculation should go like: P(Child is born with disorder) = P(II-2 is carrier) * P(I-2 is carrier) * P(II-3 is carrier) * P(III-2 is carrier) * P(Child is homozygous recessive) P(Child is born with disorder) = ...


2

There are species where cells and even whole organisms can go into a state called cryptobiosis where their metabolism is suspended but can be revived later. This usually happens when the conditions become too bad for survival (dry/cold etc.) and is reversed once the conditions improve again (rehydration warming up). One prominent and fascinating example are ...


2

The answer is #5, Leaflets folding after losing turgor pressure. This refers to a phenomenon called plasmolysis. 1 - positive phototropism, incorrect 2 - negative phototropism, incorrect 3 - gravitropism, incorrect 4 - thigmotropism, incorrect



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