Answer:
<em>Exceptions to Mendel's principles:
</em>
Does exceptions mean that Mendel was "wrong"? The answer is "NO". It means that we know more today about diseases, genes, and heredity than compared to what he expalined 150 years ago. Here I have summerized the exceptions with examples:
<em>Incomplete dominance</em>: When an organism is heterozygous for a trait and both genes are expressed but not completely.
<em>Example</em><em>:</em> SnapDragon Flowers
<em>Codominance</em>: When 2 different alleles are present and both alleles are expressed.
<em>Example</em>: Black Feathers + Whites feathers --> Black and white speckled feathers
<em>Multiple alleles</em>: Three or more alternative forms of a gene (alleles) that can occupy the same locus.
Example: Bloodtype
<em>Polygenic traits</em>: more than one gene controls a particular phenotype
Example: human height, Hair color, weight, and eye, hair and skin color.
Excitation-contraction coupling refers to the series of events that begins with the excitation of the sarcolemma in response to stimulation by a neurotransmitter, and results in the release of calcium ions from the sarcoplasmic reticulum.
Hence, option D is the 1st process that starts the excitation-contraction coupling.
False a watershed is an area of land that contains a common set of streams and rivers that all drain into a single larger body of water
C is correct
A is incorrect because the far right lane of the road is NEVER a U-turn lane unless you can drive on the sidewalk legally (you can't)
B is incorrect it is not always the lane next to the center lane
Aneuploidy can result in the final daughter cell if the spindle fibers fail to pull a chromosome toward the pole as in case of non-disjunction.
Explanation:
Aneuploidy is a condition which arises when one or more chromosome is missing in the final daughter cells.
Non-disjunction refers to the failure of chromosomal or chromatid segregation or separation during cell division. This results in erroneous meiosis or mitosis leading to the formation of final daughter cells or gametes with an extra or missing chromosome. This condition is aneuploidy.
Failure of separation or segregation of:
- Homologous chromosomes occur in Anaphase I, affects four daughter cells.
- Sister chromatids during Anaphase II, affects two daughter cells
This failure of separation leads to aneuploidy chromosomal abnormalities like monosomy, trisomy, etc which can cause diseases like Down’s syndrome, Turner’s syndrome etc.
