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Water Molecular Structure, Protists and Eukaryotes

1. Select a molecule. List the atoms that that molecule is composed of and describe the type of bond that holds those atoms together. Be sure to explain how this bond works.

2. Often, prokaryotic cells exist as simple unicellular organisms, but in some species, prokaryotic cells can grow together in colonies or filaments. In addition, some species, such as Cynaobacteria or Myxobacteria, demonstrate intercellular communication, or might even produce specialized cells and structures. However, only eukaryotic cells form the bodies of multicellular organisms with complex internal specialization. Develop one or two hypotheses explaining why only eukaryotic cells are found in multicellular organisms.

3. Today, scientific advances are being made at an astounding rate, and nowhere is this more evident than in our understanding of the biology of heredity. Using DNA as a starting point, do you believe there are limits to the knowledge people should acquire? Defend your answer.
Because genetics is important to so many aspects of human behavior, defense attorneys might consider using a defendant's genetic constitution as a strategy to excuse criminal behavior. Take one of the two sides listed below:
Present an argument about why a defendant's genes should be considered as a factor in the criminal behavior.
Present an argument about why a defendant's genes do not excuse criminal behavior.

4. Argue for or against the statement, "Viruses are alive." The internal structure of many protists is much more complex than that of cells of multicelluar organisms. Does this mean that the protist is engaged in more complex activities than the multicellular organism? If not, why should the protistan cell be much more complicated?

5.You are a geneticist working for a firm that specializes in plant biotechnology. Explain what specific parts (fruit, seeds, stems, roots, etc.) of the following plants you would try to alter by genetic engineering, what changes you would try to make, and why, on a) corn, b) tomatoes, c) wheat, and d) avocados.
Only a few hundred of the hundreds of thousands of species in the plant kingdom have been domesticated for human use. One example is the almond. The domestic almond is nutritious and harmless, but its wild precursor can cause cyanide poisoning. The oak makes potentially nutritious seeds (acorns) that contain very bitter-tasting tannins. If we could breed the tannin out of acorns, they might become a delicacy. Why do you suppose we have failed to domesticate oaks?

Solution Preview

1. Water is composed of hydrogen and oxygen, H2O. The bonds are covalent involving the sharing of electrons. In addition, the molecules of water are held together by hydrogen bonds, an electrostatic interaction between the partially negative oxygen atom in one water molecule and a partially positively charged hydrogen in another water molecule. This polarity is caused by the high electronegativity of oxygen which causes the covalent bond between each hydrogen and the oxygen to be polarized, hence, it is called a polar covalent bond.

2. Only eukaryotic cells form the bodies of multicellular organisms with complex internal specialization. Why is this so? Think about it. Larger cell types can specialize. Smaller cell types can't specialize as much. Why not? Larger cells (eukaryotic cells) can have many separate internal structures and compartments where different biochemical functions can take place. For example, you can have cells that specialize in the formation of ATP because they may have lots of mitochondria. Other cells may specialize in contraction, because they have lots of intracellular filaments and sarcoplasmic reticulum. Other cells may specialize in neural signalling because they have neurotransmitters and long axons. On and on we could go. Prokaryotic cells don't have this flexibility. Their cells are just too small and they lack internal membrane structures. Eukaryotic cells, on the other hand, have internal membranes and it is on these internal membranes and within compartments bounded by these internal membranes where special functions can occur.

Another reason one could postulate is due to the volume/surface area constraint. Eukaryotic cells are larger, but they can't become too large or else their surface area would not be sufficient to maintain such a large volume. However, if there are lots of eukaryotic cells with convoluted shapes, etc. then there might be sufficient surface area throughout the entire organism to supply the needs of the internal volumes. On the other hand, prokaryotic cells are small and their internal volume is not that big when compared to their surface area. Therefore, they don't need to assembly in multicellular organisms in order to overcome this limitation.

3. This question is very good, because it's quite relevant in the world we live in. This sort of thing is not just speculation, because it will be used (if it hasn't been already!).

Are we merely "biochemical bags"? Are we just machines? Or are we something else? Something more? Where did we come from? Where are we going? Can we tell? Is there a source of "revelation" that might help us out with these questions?

Augros and Stanciu in their book "The New Biology" ( argued very strongly for their belief that life is more than just machine. Physicists had to undergo a revolution when they began to understand that "the mechanical model" (Newtonian mechanics) wasn't the answer to explain all universal phenomena. Chemists have undergone a revolution too because they had to deal with electrical and magnetic issues in the atom. Quantum theory needed to come along to help explain phenomena that could not be explained by classical mechanics. Well, biology has yet to undergo its revolution. It's still stuck in 19th century thinking - specifically the ...

Solution Summary

This solution discusses the molecular structure of water and the specializations of protists and eukaryotes. It also uses outside references to explain the mechanism of viruses and also focuses on the structure of corn in plant biotechnology.