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________ _______ is the study of DNA and how it serves as the chemical basis of heredity
Molecular biology
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_______ ______, the causal agent of cold sores, chicken pox, etc
herpes virus
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________ are viruses that infect bacterial cells.
Bacteriophages
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The monomer unit of DNA and RNA is the nucleotide, containing:
- - Nitrogenous base (G, C, A, T or U)
- - 5-carbon sugar (ribose or deoxyribose)
- - Phosphate group
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Thymine, cytosine, and uracil are single-ring structures called ______
pyrimidine
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Adenine and guanine are larger, double-ring structures called _____
purines
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DNA is composed of two __________ chains joined together by hydrogen bonding between bases, twisted into a helical shape.
polynucleotide
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Guanine pairs with ______, forming three hydrogen bonds
cytosine
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DNA replication occurs in the______ direction
5' to 3'
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Replication is discontinuous on hte ______ template, forming short segments.
5' to 3'
-
What is the central dogma of molecular biology?
DNA-RNA-PROTEIN
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DNA replication follows a _________ model because half of the parental molecule is conserved in each daughter molecule
semiconservative
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DNA replication begins at the origins of ______
replication
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The primed #s refer to the C atoms of the nucleotide sugars. At one end of each DNA strand, the sugar’s 3’ C is attached to a hydroxyl group; at the other end, the sugar’s 5’ C has a _______group
phosphate
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Replication is continuous on the _______ template
3’ to 5’
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DNA _______ adds nucleotides to a growing chain
polymerase
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DNA _______ joins small fragments into a continuous chain
ligase
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The DNA genotype is expressed as _______, which provide the molecular basis for phenotypic trait
proteins
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A gene is a sequence of ____that directs the synthesis of a specific protei
DNA
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DNA is transcribed into RNA. - in the _____
nucleus
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RNA is translated into protein. - in the _____
cytoplasm
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Protein construction requires a conversion of a nucleotide sequence to an _____ ______ sequence
amino acid
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Transcription rewrites the DNA code into _____, using the same nucleotide “language”. Each “word” is a codon, consisting of three nucleotide
RNA
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Translation involves switching from the ______ “language” to amino acid “language
nucleotide
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Each amino acid is specified by a codon. ____codons are possible
64
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A ________is a specific DNA sequence that signals the beginning of a gene/ where to start transcribing a gene
promoter
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A ________is a specific DNA sequence that signals the end of a gene/ where to stop transcribing a gene
terminator
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The RNA nucleotides are linked by the transcription enzyme RNA _______
polymerase
-
3 Phases of Transcription
Initiation RNA polymerase binds to a promoter, where the helix unwinds and transcription starts.
Elongation RNA nucleotides are added to the chain
Termination RNA polymerase reaches a terminator sequence and detaches from the templat
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RNA ______ removes introns and joins exons to produce a continuous coding sequence
splicing
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_____ ______ is a molecular interpreter to convert a3-nucleotide mRNA codon sequence to 1 amino acid
Transfer RNA (tRNA)
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Cells have a supply of amino acids in the ______ that areobtained from food or other chemical
cytoplasm
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____ molecules match an amino acid to its corresponding mRNA codon
tRNA
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Ribosomes build _______
polypeptides (proteins)
-
Translation occurs on the surface of the ribosome
ribosome
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Ribosomes have two subunits: ____ and _____
small and large
-
Each subunit is composed of _____ ______ and proteins
ribosomal RNAs and proteins
-
Ribosomal subunits come together during ______
translation
-
_________ have binding sites for mRNA and tRNAs
Ribosomes
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Translation can be divided into the same 3 phases as transcription:________,_______,______
initiation, elongagtion, & termination.
-
Transcriptional initiation brings together the components needed to begin ________ ______
RNA synthesis
-
A large ribosomal subunit joins the small subunit, allowing the ribosome to function. The first tRNAoccupies the ___ site, which will hold the growing peptide chain. The___ site is available to receive the next tRNA
-
Elongation adds _____ _____ to the ______ chain until a stop codonterminates translation.
-
Each amino acid addition occurs in a 3-step elongation process.
1) Codon recognition: the anticodon of an incoming tRNAmolecule, carrying its amino acid, pairs with the mrNA codonin the A site of the ribosome.
2) Peptide bond formation: the growing polypeptide separates from the tRNA in the P site & attaches to the newly added amino acid in the A site.
3) Translocation: The “empty”tRNA in the P site leaves the ribosome & the growing polypeptide attached to the tRNA in the A site moves to the P site.
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