CH 4 Nucleic Acids and Central Dogma
The information in DNA tells a cell how to make _____
-Proteins -DNA -RNA
If you were to analyze a DNA sample from a eukaryotic cell, you would find that ______
-The number of purines equals the number of pyrimidines -The number of Guanines (G) equals the number of Cytosines (C)
If a DNA sample were composed of 10% thymine, what would be the percentage of guanine?
40% Guanine (G)
Which statement expresses a real difference between DNA and RNA?
DNA is much longer than RNA
What determines the primary structure of an RNA molecule?
Sequence of ribonucleotides
Starting at the 5' end, what is the base sequence of the RNA strand shown in Figure 4.3?
UAGC
By convention, nucleotide sequences are always written from the _____.
5' end to the 3' end
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 _____.
5'TGCAAT3'
What are the complementary base pairs that form in RNA?
A-U and G-C (no T in RNA)
Which statement concerning the DNA double helix is correct?
Base pairing allows production of identical daughter molecules
Which statement is true of the TRANSCRIPTION process?
Cells do it to produce prtoteins
What is the structural feature that allows DNA to replicate?
Complementary pairing of the nitrogenous bases
The green molecules in the diagram ______
Contain the base URACIL
Which of the following are pyrimidine nitrogenous bases?
Cytosine (C) and Uracil (U) and Thymine (T)
Which statement is true of nucleic acids?
DNA carries information for making RNA
Which of the following best describes DNA's secondary structure?
Double antiparrallel helical strands
One of the primary functions of RNA molecules is to _____.
Function in the synthesis of proteins
Which of the following are purine nitrogenous bases?
Guanine (G) and Adenine (A)
In a DNA double helix, what kind of chemical bonds form between the complementary nitrogenous bases?
Hydrogen bonds
What holds the strands of the DNA double helix together?
Hydrogen bonds between purines and pyrimidines
How are nucleotides linked together to form a polynucleotide chain?
In DNA and RNA, a phosphodiester linkage connects the 3' carbon of one nucleotide and the 5' carbon of another
In a nucleic acid polymer, the bonds that help to hold regions of double-strandedness together occur between what parts of the nucleotide monomers?
Nitrogenous bases
Complementary base pairing is possible only if two DNA strands align in antiparallel—instead of parallel—fashion. Which statement best explains why?
Only antiparallel strands create the geometry that allows complementary base pairs to form via hydrogen bonding.
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
The condensation reaction that forms nucleic acid polymers occurs between a _____ group on one nucleotide and a _____ group on a second nucleotide.
Phosphate, Hydroxyl
Which statement accurately summarizes a difference between ribonucleotides and deoxyribonucleotides?
Ribonucleotides have a hydroxyl group bonded to their 2' carbon; deoxyribonucleotides have an H at the same location
What is/are the variable structure(s) of a nucleotide?
The Sugar and the Base
What feature of single nucleotides provides the energy needed for polymerization when nucleic acids are formed?
Their Phosphate groups
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 tell us there are ten rungs, or steps, on the DNA "ladder" for every turn of the helix.
In a DNA double helix an adenine of one strand always pairs with a(n) _____ of the complementary strand, and a guanine of one strand always pairs with a(n) _____ of the complementary strand.
Thymine (T); Cytosine (C)
When nucleotides polymerize to form a nucleic acid _____.
a covalent bond forms between the sugar of one nucleotide and the phosphate of a second
What are the components of a nucleotide?
a sugar, a phosphate group and a nitrogenous base
If you measure the amounts of the bases in any sample of DNA, you'll find that _____
the amount of A + the amount of G = the amount of T + the amount of C
