AP Biology Molecular Genetics Flashcards

5010774611	Define DNA	Deoxyribonucleic acid; a double-stranded, helical nucleic acid molecule that determines the structure of proteins	0
5010774612	Define chromosome	These consist of DNA wrapped around proteins called histones; located in the nucleus	1
5010774613	Define euchromatin	The state of genetic material in its loose form in the nucleus	2
5010774614	Define heterochromatin	The state of genetic material and its fully condensed coils	3
5010774615	Define double helix	The structure of DNA where two strands wrap around each other to form a long, twisted ladder	4
5010774616	Who are Watson & Crick?	These two scientists were the first to define the structure of a DNA molecule	5
5010774617	Define nucleotide	The monomers of nucleic acid; the repeated subunits of DNA molecules. Each contains a five-carbon sugar, a phosphate group, and a nitrogenous base.	6
5010774618	Define purine and give two examples	A nucleotide with a double-ringed nitrogenous base; the two in DNA are adenine and guanine	7
5010774619	Define pyrimidine and give two examples	A nucleotide with a single-ringed nitrogenous base; the two in DNA are cytosine and thymine	8
5010774620	Define phosphodiester bonds	Bonds that link nucleotides of a DNA strand together. The 3′ and 5′ carbons of sugars of two respective nucleotide subunits are linked together, and the phosphate group of the bottom nucleotide lies in between.	9
5010774621	Define dioxyribose	The five-carbon sugar in a DNA nucleotide	10
5010774622	Define the role of hydrogen bonds in DNA	This type of bond holds together the two DNA strands by linking complementary nitrogenous bases; this contributes to DNA's secondary structure, a double helix	11
5010774623	Which bases are complements in DNA base pairing?	Adenine pairs with thymine Cytosine pairs with guanine	12
5010774624	Define antiparallel	Running alongside but in an opposite orientation. The term is used to describe the relative orientation of the two strands of a DNA molecule, which run in opposite directions (5′ to 3′ and 3′ to 5′).	13
5010774625	A-T and T-A requires how many H-bonds?	Two	14
5010774626	C-G and G-C requires how many H-bonds?	Three	15
5010774627	What is DNA main role?	Directing the manufacture of proteins	16
5010774628	Define DNA replication	The copying of DNA to pass on information	17
5010774629	Define conservative replication	A proposed mechanism for DNA replication that suggested replication resulted in a DNA molecule consisting of two new, and no parental, strands. The mechanism has been disproven.	18
5010774630	Define dispersive replication	A proposed mechanism of DNA replication, suggesting that segments of both parental strands act as templates for a new strand. The resulting daughter strands contain a mixture of old and newly synthesized DNA.	19
5010774631	Define semi-conservative replication	A model (born out by experimental evidence) for DNA replication in which each DNA strand acts as a template for the synthesis of a new complementary strand.	20
5010774632	Define the role of helicase	This enzyme unwinds our double helix into two strands	21
5010774633	Define the role of DNA polymerase	This enzyme adds nucleotides to an existing strand	22
5010774634	Define the role of ligase	This enzyme brings together the Okazaki fragments	23
5010774635	Define the role of topoisomerase	This enzyme cuts and rejoins the helix	24
5010774636	Define the role of RNA primase	This enzymes catalyzes the synthesis of RNA primers	25
5010774637	Define origins of replication	The specific sites at which DNA replication begins	26
5010774638	Define leading strand	During replication, the strand of DNA that is synthesized continuously in the direction of the replication fork.	27
5010774639	Define replication fork	One half of a replication bubble; a y-shaped structure on the DNA molecule along which replication takes place	28
5010774640	Define replication bubble	A portion of the DNA molecule that has opened, providing a site for two replication forks. Multiple replication bubbles along the DNA molecule speed of the process of replication.	29
5010774641	Define lagging strand	During replication, the DNA strand that grows discontinuously and in the direction opposite of the replication fork.	30
5010774642	Define Okazaki fragments	The noncontinuous segments of newly synthesized DNA along the lagging strand	31
5010774643	How is RNA different from DNA?	1. RNA is single-stranded, not double stranded 2. The five-carbon sugar is ribose instead of deoxyribose 3. The nitrogenous base uracil replaces the DNA base thymine	32
5010774644	Define messenger RNA (mRNA)	The type of RNA that copies the information stored in the strand of DNA	33
5010774645	Define ribosomal RNA (rRNA)	The type of RNA, produced in the nucleolus, that makes up part of the ribosomes	34
5010774646	Define the role of a ribosome	These cellular organelles are the sites of protein synthesis	35
5010774647	Define transfer RNA (tRNA)	The type of RNA that shuttles amino acids to the ribosomes;it functions as the translator from nucleotide into amino acid in protein synthesis	36
5010774648	What are the three basic steps of protein synthesis?	1. Transcription 2. RNA processing 3. Translation	37
5010774649	Define transcription	The process of copying the genetic code from DNA into the form of mRNA	38
5010774650	What are the three phases of both transcription and translation?	1. Initiation 2. Elogation 3. Termination	39
5010774651	Define promoter	A sequence of DNA nucleotides that signals where transcription will begin and where RNA polymerase binds	40
5010774652	Define sense strand	The strand in transcription that serves as the template for mRNA	41
5010774653	Define antisense strand	The strand in transcription that lies dormant, aka the one that is not being used to make mRNA	42
5010774654	Define RNA polymerase	An enzyme that catalyzes the synthesis of the mRNA strand during transcription	43
5010774655	Define heterogeneous nuclear RNA (hnRNA)	The newly made RNA molecule	44
5010774656	Define exon	A coding segment in a eukaryotic gene	45
5010774657	Define intron	Noncoding sequences within genes that are between 20-40 nucleotides long that exist in pairs of upside-down and backward versions of each other	46
5010774658	Define spliceosome	An assembly of proteins and RNA that function in the removal of introns from an mRNA strand	47
5010774659	Define poly(A) tail	The section of adenine nucleotides from 30-200 base pairs long that is added to the 3′ end of a newly synthesized mRNA strand for protection from degradation and to aid in export from the nucleus	48
5010774660	Define mRNA processing	Final changes that are made in a mRNA strand, such as 5′ capping, adding a poly(A) tail, and removing segments of the strand	49
5010774661	Define 5' cap	Methylated guanine nucleotide that is added to the 5′ end of a newly synthesized mRNA strand for protection from degradation	50
5010774662	Define codon	A sequence of DNA, three nucleotides in length, that translates into a single amino acid	51
5010774663	Define anticodon	A sequence of three nucleotides on a transfer RNA molecule that is complementary to a nucleotide sequence on a messenger RNA molecule; they are specific to the amino acid carried by tRNA	52
5010774664	Define initiation	The beginning of translation, characterized by the formation of an initiation complex, the messenger RNA strand, a charged tRNA, and the small ribosomal subunit	53
5010774665	What three binding sites do ribosomes contain?	An A site, a P site, and an E site	54
5010774666	Define A site	The site for the attachment of new tRNA	55
5010774667	Define P site	The site occupied by the initator tRNA; P stands for polypeptide	56
5010774668	Define E site	The site for the exiting of tRNA	57
5010774669	What is the codon for the initiation of protein synthesis?	A-U-G, which codes for the amino acid methionine	58
5010774670	Define elongation	The addition of amino acids to mRNA	59
5010774671	Define termination	The end of the synthesis of a polypeptide, caused by a stop codon	60
5010774672	Define stop codon, and give three examples	Sequences of nucleotides on the messenger RNA strand, such as U-G-A, U-A-A, and U-A-G, that signal the end of translation	61
5010774673	Define primary structure	The linear sequence of amino acids in a protein	62
5010774674	Define secondary structure	The twisting of a polypeptide into either an alpha helix or beta-pleated sheets	63
5010774675	Define tertiary structure	The folding of a polypeptide into a three-dimensional structure	64
5010774676	Define quaternary structure	When two or more polypeptides get together	65
5010774677	Define chaperon proteins (aka chaperonins)	Proteins that help other proteins fold properly and make the process of folding more efficient	66
5010774678	Define mutation	A defect in the chromosome or changes in the normally occurring DNA sequence	67
5010774679	Define base substitution (point) mutation	A mutation when one base is substituted for another	68