1. Explain the process that DNA replicates by. Why is it so important that it is carried out in this matter? In explaining the actual process, refer to the possible choices that the scientist considered: conservative, semi-conservative and dispersive.
2. Speciation is a concept that mean one species becoming 2 or more by a progression of different factors (that are key to the theory behind evolution that Darwin proposed) Some biologists classift dogs, wolves, and coyotes as the same species (Canis familiaris). Other seperate coyotes from these group, even though dogs and coyotes can breed in captivity. For what reason would either idean more accepted?
3. Give and describe three categories of evidence that are primarily used in support of Darwin's evolutionary theories.
4. Define symbiosis. Give three types and give 2 examples of each, explaining with each one how the situation applies the example that you give me
5. Name at least 2 major and 2 minor effects that human development and industrialization have had on ecosystems and explain the impact that each has had on both the environment and life in them.© BrainMass Inc. brainmass.com October 24, 2018, 7:13 pm ad1c9bdddf
1. DNA forms a double helix defined by its base pairs Adenine coupled to Thymine and Cytosine coupled to Guanine. These base pairs hold the helixes togeter and also form the genetic code. This means that when DNA replicates its double helix splits up into 2 helixes. By attracting and recoupling to free bases according to the scheme above each helix forms a new double helix identical to the original one. The whole process can to some extent be compared to the zipping and unzipping of a pair of jeans. The base pairs fit together as if they had been zipped into place. Yet the process forms 2 identical double helixes out of one and they are also identical to the original one (unless a mutation occurs somewhere in the structure). The importance of the process is based on the fact that it gives you a very high security in faithfully duplicating the genetic code present in the structure. There can be mishaps though and those form the basis of mutations. I am not familiar with the 3 mentioned historical alternatives to the real process, but now when you do know how it really works and having your textbook on the subject I hope you can construct that part on your own.
2. The normal definition ...
1.The basic differences between RNA and DNA are:
a.The organic bases only
b.Bases, ribose units, and the phosphodiester linkage
c.Bases, ribose units, and the glycosidic bond type
d.Bases and the ribose units only.
2.The solubility characteristics of the pyrimidine or purine bases and the corresponding nucleosides differ greatly. Which of the following statements is not true?
a.purine bases are quite soluble in water.
b.Nucleosides are much more soluble than the corresponding bases.
c.Nucleosides and nucleotides are quite soluble in water.
d.Ribose units are very soluble in water.
3.Adenosine and guanosine are found predominantly in which tautomeric forms, respectively?
a.Amino & keto, respectively
b.Imino & keto, respectively
c.Amino & enol, respectively
d.Imino & enol, respectively
4.The component(s) of DNA which is (are) responsible for the absorbance band at 250-270 nmis:
a.Bases, pentoses. and phosphates all contribute
c.Only bases and pentoses
d.Only pentoses and phosphates
5.AMP has three relevant ionizable groups. NI of adenine has pKa 4.0 and the phosphomonoester has pKas at 1.0 and 6.0 the net charge on AMP at pH 7.0 is approximately:
6.The thermodynamically most favorable form for pyrimidine nucleotides is:
c.Both are equally favored
d.Cannot be predicted
7.Which molecule contains an acid anhydride bond?
8.All the NTPs are essential for RNA synthesis but GTP is also essential in:
d.Fatty acid biosynthesis
9.The oligonucleotide, AUGGp, has all these properties except
a.Composed of ribonucleotides
b.Contains a 3' phosphate
c.Has a net charge pf -2 at pH 8.5
d.Contains three phosphodiester bonds.
10.To what target sequence on DNA is the oligonucleotide pAATTCCGG complementary?
11.Which of the following characterizes the DNA in human cells?
a.DNA is located at a mesosome.
b.DNA is complexed with nonhistone proteins to form a nucleosome.
c.DNA is complexed with histone proteins with the DNA residing in the interior of the nucleosome.
d.DNA is complexed with the basic histone proteins and winds around the exterior of the histone protein "core".
12.An individual heterogeneous nuclear RNA (hnRNA):
a.Contains intron sequences not found in the final mature mRNA.
b.Contains exon sequences which are removed prior to translation.
c.Encodes more than one protein.
d.Can be found in the cytoplasm.
13.The RNA molecules which are involved in processing the hnRNA are:
14.RNA is hydrolyzed in basic solution but DNA is not. This occurs because:
a.Thymine is found in DNA, but uracil is not.
b.DNA is double stranded. while RNA is single stranded.
c.DNA contains a 2'-deoxyribose, while RNA does not.
d.RNA has modified bases, while DNA does not
15. What statement is incorrect about the different RNA molecules?
a.tRNA contain numerous intramolecular hydrogen bonds between bases.
b.There are more distinct tRNA molecules than there are rRNA molecules.
c.rRNA are complexed to proteins in the ribosomes.
d.The most abundant RNA molecule in the cell is mRNA.