View Full Version : Ap Bio summer hw

05-20-2008, 04:03 AM
Ok next year in my sophmore year of high school im taking AP bio and we have a summer homework packet pertaining to the first 5 chapters of the book. The bad thing is some questions I can't find the answers to. Like this one:

How do DNA nucleotides relate to proteins?
any help on this would be helpful because my book doesn't say anything (that I saw) about DNA nucleotides(so far).

05-20-2008, 04:54 AM
Well based on what you know (or should know) about DNA, and what you know about proteins, you could instead of linking them directly together, find a topic that they both link to, and compare them using that as the basis of your argument (answer, whatever). If we know that both parts X and Y affect structure or process Z, then they are related because of Z. A more concrete example I can think of is that the arrangement of DNA tides affects the production of certain chemicals, which may or may not be proteins. Like, if you have something out or order, you could accidentally create Valium or such thing when something else is needed. A skim of Wikipedia shows one that nucleotides have something to do with replication, so perhaps that might lead you to a more solid conclusion.

This is of course, based solely on the recollection of the instruction of my Honors Biology teacher from my Freshman year. And Wiki. Sorry I can't give you a more definitive answer, but AP classes do imply at least some level of concept connection. Maybe not, who knows? Maybe your teacher is so good that you don't have to connect concepts at all; you would just know it instantly because of awesome that radiates.

05-20-2008, 04:57 AM
Good luck, you will need it.

There is some vocab that you will need to know. I've put those terms in bold. :p

DNA nucleotides are Adenine (A), Thymine (T), Cytosine (C), and Guanine (G). A pairs up with T, and C with G. To make a protein, first an enzyme called DNA Heliase unzips the DNA. Then mRNA is brought in for the process of Transcription. Basically the DNA ATCG is linked with the RNA's AUCG. ( U is Uracil, a nucleotide that replaces Thymine in RNA) This mRNA then leaves the nucleus and goes to to the ribosome for the second part of protein synthesis, Translation. Translation is that there is tRNA that carries a specific amino acid based on the codon and then peptide bonds form between the amino acids brought by the tRNA to form a protein. A codon is a set of three nucleotides, and each codon signals a different amino acid. This sequence is based on the original DNA sequence. (AAA codes Lysine, while GGG codes for Glycine.) I can explain in greater detail if you need it and help with any other questions.

05-20-2008, 05:23 AM
I pretty much summed this up to

"information" from the nucleotides are "read" and this specifies the sequence of amino acids in proteins. Is that about right?

05-20-2008, 05:49 AM
Yup. The AP likes to ask some kind of question relating to protein synthesis, so make sure you know it for may.

05-20-2008, 10:51 AM
Oooh, Im gonna write the answer because it'll be good practice for my Biology exam thats coming up. Here I go...

DNA Nucleotides are formed from a phosphate, a pentose sugar called deoxyribose and an organic nitrogenous base. DNA has four possible bases, Adenine and Guanine which are purines and Cytosine and Thymine which are pyrimidines. During complimentary base paring, Adenine joins with Thymine and Cytosine joins with Guanine.

Nucleotides are an essential part of protein synthesis. First, transcription occurs and the DNA unwinds and unzips. It is able to unzip because its hydrogen bonds are disrupted. After unzipping, the coding strand provides a template for a new messenger RNA strand to form. The RNA nucleotides join up by complimentary base pairing with Uracil joining to Adenine instead of Thymine. It is 'glued' together by RNA polymerase. When the mRNA strand is formed, it leaves the nucleus through the pores in the nuclear membrane.

The next process is translation. The Messenger RNA enters the cytoplasm and attaches to a ribosome that is either free in the cytoplasm or one in the rough endoplasmic reticulum. By now I should mention that three bases in a row form a codon, which codes for one amino acid. Two codons are able to attach to a ribosome at any given time. Somewhere else in the cytoplasm is a transfer RNA molecule. This contains an anti-codon at one end, and the relevant amino acid at the other. The transfer RNA strand with its anti-codon attaches to a codon on the messenger RNA (held by the ribosome). Another transfer RNA strand attaches to the next codon, and a peptide bond forms between the amino acids. The ribosome then moves along the messenger RNA strand until a long chain of peptide bonded amino acids is formed. This is called a protein. Sometimes a bunch of ribosomes form a polysome which can form proteins at a faster rate.

So in summary, note how the bases on the DNA nucleotides codes for the messenger RNA. And how the messenger RNA codes for the amino acids. This ensures that the right number and sequence of amino acids is present in the protein.

Hope I helped. Qwertxsora gave a good explanation as well.