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Nucleic Acids and Proteins
1. Test your vocabulary by matching each term to its correct definition, as identified by its preceding letter code.
anticodon
base-pairing rule
coding strand
DNA
gene expression
genetic code
hydrogen bond
nucleic acids
nucleotides
RNA
template strand A Single stranded nucleic acid that consists of nucleotides containing ribose sugar.
B A set of rules by which information encoded in DNA or mRNA is translated into proteins.
C The rule governing the pairing of complementary bases in DNA.
D The structural units of nucleic acids, DNA and RNA.
E Intermolecular bond between hydrogen and an electronegative atom such as oxygen.
F The process by which genetic information is used to produce a functional gene product.
G The sequence of DNA that is read during the synthesis of mRNA.
H Universally found macromolecules composed of chains of nucleotides. These molecules carry genetic information within cells.
I The DNA strand with the same base sequence as the RNA transcript produced (although with thymine replaced by uracil in mRNA).
J Macromolecule consisting of many millions of units containing a phosphate group, sugar and a base (A,T, C or G). Stores the genetic information of the cell.
K The region of a transfer RNA with a sequence of three bases that is complementary to a codon in the messenger RNA.
2. A grasshopper has the following percentages of nucleotides in its DNA: A = 29.3, G = 20.5, C = 20.7, T = 29.3, %GC = 41.2, %AT = 58.6. For a rat, the percentages are A = 28.6, G = 21.4, C = 20.5, T = 28.4, %GC = 42.9, %AT = 57.0.
Use the base pairing rule to explain this data:
3. For the following DNA sequence on the template strand, give the mRNA sequence and then Identify the amino acids that are encoded. For this question you may consult the mRNA-amino acid table earlier in the chapter.
DNA (template strand): G A A AC C C T TAC ATAT C G T G C T
mRNA:
Amino acids:
4. Complete the following paragraph by deleting one of the words in the bracketed () pairs below:
In eukaryotes, gene expression begins with (transcription/translation) which occurs in the (cytoplasm/nucleus). (Transcription/Translation) is the copying of the DNA code into (mRNA/tRNA). The (mRNA/tRNA) is then transported to the (cytoplasm/nucleus) where (transcription/translation) occurs. Ribosomes attach to the (mRNA/tRNA) and help match the codons on (mRNA/tRNA) with the anticodons on (mRNA/tRNA). The (mRNA/tRNA) transports the animo acids to the ribosome where they are added to the growing (polypeptide/carbohydrate) chain.
5. Decide if the nucleotide shown right is from DNA or RNA. Explain your choice:
