AP Bio DNA

The process of transcription results in the formation of

• DNA
• Proteins
• lipids
• RNA

Cytosine makes up 38% of the nucleotides in a sample of DNA from an organism. approximately what percentage of the nucleotides in this sample will be thymine?

• 12
• 24
• 31
• 38

Chargraff's analysis of the relative base composition of DNA was significant because he was able to show that

• the relative proportion of each of the four bases differs within individuals of a species
• the human genome is more complex than that of other species
• The amount of A is always equivalent to T, and C to G
• the amount of ribose is always equivalent to deoxyribose

. What is meant by the description "antiparallel" regarding the strands that make up DNA?

• The twisting nature of DNA creates nonparallel strands.
• The 5' to 3' direction of one strand runs counter to the 5' to 3' direction of the other strand.
• Base pairings create unequal spacing between the two DNA strands
• One strand contains only purines and the other contains only pyrimidines

A particular triplet of bases in the template strand of DNA is 5' AGT 3'. The corresponding codon for the mRNA transcribed is

• 3' UCA 5'.
• 3' UGA 5'
• 5' TCA 3'
• 3'ACU 5'. 

Introns are significant to biological evolution because

• their presence allows exons to be shuffled.
• they protect the mRNA from degeneration.
• they are translated into essential amino acids.
• they maintain the genetic code by preventing incorrect DNA base pairings

Why does the DNA double helix have a uniform diameter?

• Purines pair with pyrimidines
• C nucleotides pair with A nucleotides
• Deoxyribose sugars bind with ribose sugars
• Nucleotides bind with nucleoside triphosphates

Replication in prokaryotes differs from replication in eukaryotes for which of these reasons?

• The prokaryotic chromosome has histones, whereas eukaryotic chromosomes do not
• Prokaryotic chromosomes have a single origin of replication, whereas eukaryotic chromosomes have many. 
• The rate of elongation during DNA replication is slower in prokaryotes than in eukaryotes.
• Prokaryotes produce Okazaki fragments during DNA replication, but eukaryotes do not

Considering the structure of double stranded DNA, what kinds of bonds hold one complementary strand to the other?

• ionic
• covalent
• Van der Waals
• hydrogen

E. coli genomic DNA differs from a eukaryotic chromosome in that E. coli DNA

• has a single centromere
• has telomeres
• is circular
• does not undergo supercoiling