Bio 151 Chapter 4.1-4.2 Questions
A double-stranded DNA molecule contains a total of 120 purines and 120 pyrimidines. This DNA molecule could be composed of ________.
120 thymine and 120 adenine molecules
What feature of single nucleotides provides the energy needed for polymerization when nucleic acids are formed?
their phosphate groups
Which of the following pairs of base sequences could form a short stretch of a normal double helix of DNA?
5'-ATGC-3' with 5'-GCAT-3'
If one strand of a DNA molecule has the sequence of bases 5'ATTGCA3', the other complementary strand would have the sequence ________. Hint: you have to start in reverse because it is antiparallel.
5'TGCAAT3'
What is the difference between a ribonucleotide and a deoxyribonucleotide?
Ribonucleotides have a hydroxyl group on the 2 carbon of their sugar subunit.
Enzymes that break down DNA catalyze the hydrolysis of the covalent bonds that join nucleotides together (reverse of polymerization). What would happen to DNA molecules treated with these enzymes?
The phosphodiester linkages of the polynucleotide backbone would be broken.
What is the difference (if any) between the structure of ATP and the structure of the precursor of the A nucleotide in RNA?
There is no difference.
Franklin and Wilkins analyzed DNA by bombarding DNA crystals with X-rays. Their analysis yielded two numbers that sparked interest, 3.4 nm and 0.34 nm. What is the significance of these numbers?
These numbers demonstrate there are 10 rungs, or steps, on the DNA "ladder" for every turn of the helix.
When nucleotides polymerize to form a nucleic acid
a covalent bond forms between the sugar of one nucleotide and the phosphate of a second
When nucleotides polymerize to form a nucleic acid ________.
a covalent bond forms between the sugar of one nucleotide and the phosphate of a second
Which of the following descriptions best fits the class of molecules known as nucleotides?
a nitrogenous base, a phosphate group, and a sugar
What is/are the variable structure(s) of a nucleotide?
base and sugar
If you guys had any other questions i missed the password to edit is :
bio151
What is the structural feature that allows DNA to replicate in anti-parallel manner?
complementary pairing of the nitrogenous bases
Which of the following are pyrimidine nitrogenous bases?
cytosine and uracil
Which of the following includes all of the pyrimidines found in RNA and DNA?
cytosine, uracil, and thymine
Which of the following best describes DNA's secondary structure?
double antiparallel helical strands
Which of the following are purine nitrogenous bases?
guanine and adenine
DNA double helices are soluble in water because of all the following except ________ (This has an important practical application for DNA isolation (extraction): when DNA is in alcohol, it is insoluble white-powder-like material that biologists and chemists call "precipitate")
hydrogen at 2' C
If cells are grown in a medium containing radioactive 32P-labeled phosphate, which of these molecules will be labeled?
nucleic acids
Nucleic acids are polymers made up of which of the following monomers?
nucleotides
Like many molecules, nucleotides have asymmetry. This gives nucleic acids a specific direction for polymerization. The 3' carbon of a nucleotide has a hydroxyl group, while the 5' carbon is covalently bonded to _____.
phosphate group
Some viruses consist only of a protein coat surrounding a nucleic acid core. If you wanted to radioactively label the nucleic acids separately from the protein, you would use radioactive ________. (Which atom is in nucleotides but not proteins?)
phosphorus
Which of the following did Watson and Crick already know when they were trying to determine the structure of DNA? The number of ________.
purines is always the same as pyrimidines
