BASIC MOLECULAR GENETIC MECHANISMS Flashcards

1633876109	DNA, the genetic material, is transcribed into several types of RNA, including _____, ______, ______, which function in protein synthesis.	mRNA, tRNA, rRNA	0
1633876110	A nucleic acid strand is...	a linear polymer with end-to-end directionality	1
1633876111	All DNAs and most RNAs are long unbranched polymers of nucleotides, which consist of...	phosphorylated pentose linked to an organic base, either purine (A and G) or pyrimidine (C, T and U).	2
1633876112	Native DNA is a _____ helix of ________________________ strands.	double, complimentary antiparallel	3
1633876113	Natural DNA (B-type) is a regular____________________ with the bases ____________________________________________________________________	right-handed double helix, on the inside and the two sugar-phosphate backbones on the outside.	4
1633876114	The bases in nucleic acids can interact....	via hydrogen bonds.	5
1633876115	The standard Watson-Crick base pairs are _____________ in DNA, and ____________ in RNA.	G-C/A-T, G-C/A-U	6
1633876116	DNA can undergo....	reversible strand separation	7
1633876117	Different types of RNA exhibit various conformations...	related to their function	8
1633876118	Cellular RNAs are _____________, some of which form_________________.	single-stranded polynucleotides, well-defined secondary and tertiary structures	9
1633876119	Some RNAs, called ______________, have _________________.	ribozymes, catalytic activity	10
1633876120	Secondary RNA structures:	hairpin, stem-loop	11
1633876121	Tertiary Structure	Pseudoknot	12
1633876122	DNA is more stable than RNA due to...	a hydroxyl group	13
1633876123	A template DNA strand is transcribed into a complimentary RNA chain by ________________.	RNA polymerase	14
1633876124	__________________ are added one at the time to the 3' end of a growing RNA	Ribonucleotides	15
1633876125	The sequence of the template DNA strand determines the order in which ______________________________________________.	ribonucleotides are polymerized to form an RNA	16
1633876126	Organization of genes differs in ______________________________	prokaryotic and eukaryotic DNA	17
1633876127	In prokaryotes several protein-coding genes are commonly clustered into ____________________________.	an operon, which is transcribed from a single promoter into one mRNA	18
1633876128	In eukaryotes each protein-coding gene is _____________________________	transcribed from its own promoter	19
1633876129	Eukaryotic precursor mRNAs are processed to form __________________________.	functional mRNAs	20
1633876130	Alternative RNA splicing increases __________________________.	the number of proteins expressed from a single eukaryotic gene	21
1633876131	Three stages in RNA transcription	Initiation, elongation, termination	22
1633876132	In prokaryotes all the genes are transcribed ___________, in eukaryotes, they are _________	together, separate	23
1633876133	Messenger RNA carries information from DNA in a _________________	three-letter genetic code	24
1633876134	Genetic information is transcribed from DNA into RNA in the form of a(n) ____________________________	overlapping, degenerate triplet code	25
1633876135	Each amino acid is encoded by _______________________.	one or more codons in mRNA	26
1633876136	Each codon specifies ________________.	one amino acid	27
1633876137	The folded structure of tRNA promotes its ______________________	decoding function	28
1633876138	Three-dimensional structure of tRNA includes an acceptor arm for attachment of a _____________________________________	specific amino acid and a stem-loop with a three-base anticodon sequence at its end	29
1633876139	The tRNA anticodon can base-pair with __________________________________________	its corresponding codon on mRNA	30
1633876140	Nonstandard base pairing often occurs between _____________________________________	codons and anticodons	31
1633876141	Amino acids become activated when _____________________________________	covalently linked to tRNAs	32
1633876142	Each of the 20 aminoacyl-tRNA synthetases recognizes a single amino acid and ______________________________________.	covalently links it to a cognate tRNA	33
1633876143	Genetic code is degenerate...	more than one codon can code for a specific amino acid	34
1633876144	Wobble rule:	only first 2 nucleotides have to be complementary	35
1633876145	Ribosomes are...	protein-synthesizing machines	36
1633876146	Ribosomes are large __________________________________.	ribonucleoprotein complexes and consist of a small and large subunits	37
1633876147	Methionyl-tRNAiMet recognizes the __________________________	AUG start codon	38
1633876148	Eukaryotic translation initiation usually occurs at _______________________________________	the first AUG closest to the 5' end of an mRNA.	39
1633876149	Each stage of translation - initiation, elongation and termination - requires ______________________________	specific protein factors including GTP-binding proteins that hydrolyze GTP.	40
1633876150	During chain elongation each incoming aminoacyl-tRNA moves through three ribosomal sites:	A-site, P-site, E-site	41
1633876151	Each strand in a parental duplex DNA acts as a template for _________________________________	synthesis of a daughter strand and remains base-paired to the new strand (semiconservative mechanism).	42
1633876152	DNA polymerases require __________________________________	a primer to initiate replication	43
1633876153	Duplex DNA is unwound, and daughter strands are formed at the...	DNA replication fork.	44
1633876154	At a replication fork, one daughter strand (leading) is elongated ____________. The other (lagging) is formed as a ___________________________________.	continuously, series of discontinuous (Okazaki) fragments from primers synthesized every few hundreds nucleotides	45
1633876155	DNA replication occurs ___________________ from each origin	bidirectionally	46
1633876156	DNA polymerases introduce copying ______________________________________	errors and also correct them.	47
1633876157	Chemical and radiation damage to DNA can lead to...	mutations	48
1633876158	High-fidelity DNA excision repair systems...	recognize and repair damage	49
1633876159	Eukaryotic cells have three excision-repair systems for correcting DNA damage:	Base excision, Mismatch excision, Nucleotide excision	50
1633876160	Two systems utilize recombination to repair double-strand breaks in DNA:	-Non-homologous end-joining can link DNA segments from different chromosomes. -Homologous recombination can repair DNA damage and generate genetic diversity.	51
1633876161	Deamination leads to...	point mutations	52
1633876162	Holliday structure	an intermediate in DNA recombination with four DNA strands	53
1633876163	Alternative resolution of a Holliday structure:	1) Cutting the bonds and ligating the ends regenerates the original chromosomes. 2) Cutting the bonds and ligating the ends generates recombinant chromosomes.	54
1637305237	Synthesis of all nucleic acids go from...	5' to 3'	55
1637306170	Adenine and Thymine have ____ hydrogen bonds	2	56
1637306171	Cytosine and Guanine have ____ hydrogen bonds	3	57
1637308227	DNA does not have a __________ group	hydroxyl	58
1637311590	In eukaryotes transcription occurs only in the...	nucleus	59
1637311591	Transcription starts at	+1	60
1637311592	Everything before +1 is considered	upstream	61
1637311593	Everything after +1 is considered	downstream	62
1637318652	Mature RNA excludes all	Introns	63
1637337503	What does tRNA do?	brings amino acids to the site of protein synthesis	64
1637337504	rRNA is responsible for...	formation of peptide bonds	65
1637337505	mRNA provides...	the message for what protein should be present	66
1637337506	Small subunit of ribosomes is responsible for...	initiation of translation	67
1637337507	Large subunit of ribosomes is responsible for...	elongation and termination	68
1637337508	"A site" of ribosome is known as...	acceptor site	69
1637337509	"P site" of ribosome is known as...	peptide bonding	70
1637337510	"E site" of ribosome is known as...	exit site	71
1642786712	Which structures are protein building machines?	Ribosomes	72
1642786713	Base excision	repairs T-G mismatches and damaged bases	73
1642786714	Mismatch excision	repairs other mismatches and small insertions and deletions	74
1642786715	Nucleotide excision	repairs chemical adducts that distort normal DNA shape	75
1642786716	Which DNA breaks are the most harmful in terms of cell life?	double-strand breaks	76
1642786717	Viruses	small parasites that can replicate only in host cells. Viral genomes may be either DNA (DNA viruses) or RNA (RNA viruses) and either single- or double- stranded.	77
1642786718	Most viral host ranges are...	narrow	78
1642786719	Viral capsids are...	regular arrays of one or a few types of protein	79
1642786720	Some viruses have an outer...	envelope, which is similar to the plasma membrane but contains viral transmembrane proteins.	80
1642786721	Lytic viral growth cycles lead to...	death of host cells	81
1642786722	Lytic viral infection entails...	absorption, penetration, synthesis of viral proteins and progeny genomes, assembly of progeny virions, and release of thousands of virions, leading to the death of host cell	82
1642786723	Viral DNA is...	integrated into the host-cell genome in some non-lytic viral growth cycles.	83
1642786724	Non-lytic viral infection generally does not lead to	cell death	84