A Punnett square is a graphical representation of the possible genotypes of an offspring arising from a particular cross or breeding event. Creating a Punnett square requires knowledge of the genetic composition of the parents.
Explanation:
The classical cell theory was proposed by Theodor Schwann in 1839. There are three parts to this theory. The first part states that all organisms are made of cells. The second part states that cells are the basic units of life. These parts were based on a conclusion made by Schwann and Matthias Schleiden in 1838, after comparing their observations of plant and animal cells. The third part, which asserts that cells come from preexisting cells that have multiplied, was described by Rudolf Virchow in 1858, when he stated omnis cellula e cellula (all cells come from cells).
Since the formation of classical cell theory, technology has improved, allowing for more detailed observations that have led to new discoveries about cells. These findings led to the formation of the modern cell theory, which has three main additions: first, that DNA is passed between cells during cell division; second, that the cells of all organisms within a similar species are mostly the same, both structurally and chemically; and finally, that energy flow occurs within cells.
Answer:
1. Inhibiting IP3 channels, leading to decreased Ca2 in the sarcoplasm and reduced contraction.
2. Increasing the relative activity of MLCP, leading to a decrease in tension.
3. Activating K channels, increasing K leaking out of the cell which hyperpolarizes it and decreases the likelihood of Ca2 entry.
Explanation
In smooth muscle, cyclic AMP (cAMP) mediates relaxation because cAMP inhibits a specific kinase required for myosin light chain protein (MLCP) phosphorylation, thereby triggering contraction in the smooth muscles. It has been shown that cAMP inhibits 1,4,5-trisphosphate (IP3)-dependent calcium ions (Ca 2+) release by activation of the cGMP-dependent protein kinase (PKG). PKG proteins act to modulate Ca2+ oscillations by stimulating sarcoplasmic Ca2+-ATPase membrane proteins, increasing Ca2+ in the sarcoplasmic reticulum stores and Ca2+ efflux from the cells, and activate voltage-gated potassium (K) channels, thereby leading to membrane hyperpolarization and reducing Ca2+ entry through Ca2+ channels.
Answer: B). Primary succession takes place over a long period of time on a newly formed land, while secondary succession occurs quickly in areas that have disrupted by a natural disaster.
Explanation:
A succession is a gradual change that occur within the biotic community due to change in the non-living environmental factors with respect to time until the community establish stability.
A primary succession occurs over a land which was not previously occupied by any living species. The land can be primitive, environmental factors like soil, air and others are not supportive initially. Thus, it takes long time to establish a biotic community.
A secondary succession occurs over a region which was previously inhabitated by colonies of species but disturbed due to natural calamity or human induced disaster. Some of the precursors of life can be found in such region like seeds, spores, roots and others which support new growth and the environmental factors are suitable to support re-establishment of living species. Hence, secondary succession takes place quickly as compared to primary succession.
<span>1 x Ethmoid Bone
1 x Frontal Bone
1 x Occipital Bone
2 x Parietal Bones
1 x Sphenoid Bone
2 x Temporal Bones
:)
</span>
