BSC 108 EXAM 3 - UNIVERSITY OF ALABAMA QUESTIONS AND ANSWERS. VERIFIED 2025/2026.

BSC 108 EXAM 3 - UNIVERSITY OF
ALABAMA QUESTIONS AND ANSWERS.
VERIFIED 2025/2026.




What is the structure of a strand of DNA? - ANS double helix, twisted ladder



What is DNA composed of? - ANS nucleotide subunits



What is the backbone of DNA? - ANS deoxyribose and a phosphate group



What is the backbone of DNA covalently bonded to? - ANS nitrogen-containing bases



How many strands of DNA does a DNA molecule contain? - ANS two



The two strands of DNA are: - ANS complementary



What are the nitrogen-containing bases in DNA? - ANS adenine, guanine, thymine, cytosine



How are the nitrogen-containing bases held together? - ANS hydrogen bonds



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,What bases pair together? - ANS adenine=thymine

guanine=cytosine



How does DNA replicate? - ANS DNA molecule unwinds and each strand is a template for
complementary base pairing; each daughter helix contains an intact strand from the parent
helix and a newly synthesized strand therefore DNA replication is semiconservative



One parent molecule is composed of two __________________ that separate. -
ANS complementary strands



Each strand is used as a ______________ to make a new strand. - ANS template



What are the two daughter molecules composed of? - ANS One "old" (parent) strand and
one "new" (synthesized) strand



Where do parent strands separate? - ANS origins of replication



Where and how does synthesis of two new complementary strands occur? - ANS replication
bubbles, using the parent strands as templates



What do the replication bubbles do as DNA replication progresses in both directions at the
replication forks? - ANS merge



How does an organism's DNA lead to specific traits? - ANS by dictating the synthesis of
proteins



What is the structure of RNA? - ANS single-stranded nucleic acid


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, RNA contains ________ instead of thymine. - ANS Uracil



What sugar is used in RNA? - ANS ribose



What is the function of mRNA (messenger RNA)? - ANS carries the genetic message from a
gene (DNA) to ribosomes that translate it into a protein



What is the function of tRNA (transfer RNA)? - ANS translates codons into amino acids



Where does tRNA pair with mRNA? - ANS at the anitcodon



What is the function of rRNA (ribosomal RNA)? - ANS to make up ribosomes with proteins



What two processes do genes code for specific proteins? - ANS transcription and translation



What is transcription? - ANS synthesis of mRNA under the direction of DNA



Where does transcription occur? - ANS nucleus of a cell



What is translation? - ANS synthesis of a polypeptide (which will become a protein) under the
direction of mRNA



Where does translation occur? - ANS on the ribosomes in the cytoplasm




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