Campbell Biology Chapter 16 Terms Flashcards

7677978725	Transformation	change in genotype and phenotype due to the assimilation of external DNA by a cell. Griffith discovered that killing pathogenic Streptococcus pneumoniae and mixing the remains with non-pathogenic bacteria caused this	0
7684034734	Avery, MacLeod, McCarty	discovered that DNA was the transforming agent, not RNA or protein	1
7677978726	Bacteriophages (phages)	viruses that infect bacteria	2
7684310426	virus	dna in a protective coat, often protein	3
7684310427	Hershey and Chase	discovered that DNA is the genetic material of T2 phage. showed that only dna entered the e coli cell, protein stayed behind. radioactive sulfur tagged the protein and radioactive phosphorus tagged the dna	4
7684310428	T2 Phage	phage of e coli used in hershey chase experiment	5
7684310429	Erwin Chargaff	Determined that the levels of A and T, and C and G are always equal in normal DNA. "chargaff's rules" base composition and a-t c-g	6
7684310430	"handedness" of dna	right-handed	7
7684310431	word describing the directional behavior of the two backbones of dna	antiparallel	8
7684310432	purines	Adenine and Guanine 2 rings	9
7684310433	Pyrimidines	thymine and cytosine and uracil 1 ring like the base of a pyramid	10
7684310434	Adenine-thymine h bonds	2 between A and T	11
7684310435	cytosine-guanine h bonds	3 between c and g	12
7685048106	semiconservative	describes replication in which one strand is newly synthesized and one represents part of the original strand	13
7685048107	Meselson and Stahl	proved semiconservative replication pretty much	14
7685048108	origins of replication	short stretches of DNA having a specific sequence of nucleotides at which replication of the dna molecule begins	15
7685048109	replication fork	A Y-shaped region on a replicating DNA molecule where parental strands of dna are being unwound	16
7685048110	helicases	unwind DNA strands at replication forks by breaking hydrogen bonds	17
7685048111	single-strand binding proteins	while helicase is doing its thing, these bind to the unpaired DNA strands, keeping them from re-pairing	18
7685048112	Topoisomerase	an enzyme that alters the supercoiled form of a DNA molecule. relieves strain due to dna unwinding by breaking, swiveling, and rejoining dna strands	19
7685048113	primer	a short segment of DNA that acts as the starting point for a new strand. initial nucleotide chain during dna synthesis. synthesized by enzyme called primase. generally 5-10 rna nucleotides long	20
7685048114	primase	An enzyme that joins RNA nucleotides to make the primer. starts a complementary rna chain from a single rna nucleotide, adding more rna nucleotides 1 at a time	21
7685048115	where does replication begin after the synthesis of the primer	at the 3' end of the rna primer	22
7685048116	DNA polymerase	catalyze the synthesis of new dna by adding nucleotides to existing chain. dna pol 3 and 1 are the most important ones in e coli, but eukaryotes have like 11	23
7685048117	direction of dna polymerase strand elongation	5' -> 3' direction, can only attach to 3' end	24
7685048118	Leading strand synthesis	dna polymerase remains in the replication fork and continuously adds nucleotides as the fork progresses	25
7685048119	lagging strand synthesis	dna pol works along the other template strand in the direction away from the fork. synthesized discontinuously, in a series of segments, called Okazaki fragments	26
7685048120	Okazaki fragments	discontinuous segments of the lagging strand	27
7685048121	dna pol 1 role in lagging strand synthesis	replaces the primers of the leading strand with DNA. these new strands are then joined to existing ones by ligase	28
7685048122	primase as a molecular break	coordinates placement of lagging primers and rates of replication on leading and lagging strands	29
7685048123	error rate in new completed dna molecule	1 in 10 billion or 10^10 nucleotides	30
7685048124	initial pairing errors between incoming nucleotidss and those in template strand	1 in 10^5 nucleotides	31
7685369997	mismatch repair	repair enzymes correct errors in base pairing from replication errors not caught by the dna polymerase	32
7685369998	nuclease	DNA cutting enzyme	33
7685369999	nucleotide excision repair	enzymes cut out incorrect bases and fill in correct bases. consists of nuclease, polymerase, and ligase action	34
7685370000	thymine dimers	caused by UV radiation - adjacent thymine molecules in a dna strand becomes covalently bonded	35
7685370001	Xeroderma pigmentosum	inherited defect in nucleotide excision repair enzyme. mutations in skin cells go uncorrected.	36
7685370002	human telomere sequence	TTAGGG	37
7685370003	telomerase	catalyzes the lengthening of telomeres in germ cells. not usually active in somatic cells	38
7685370004	Nucleoid	area in a prokaryotic cell that contains a large, circular chromosome. dense dna, coiled and supercoiled. no membrane	39
7685370005	Chromatin	complex of DNA and proteins that forms chromosomes within the nucleus of eukaryotic cells	40
7685370006	heterochromatin	hetero is more compacted, similar to a metaphase chromosome. visible as irregular clumps under light microscope. largely inaccessible to cellular machinery due to compaction	41
7685370007	euchromatin	The less condensed form of eukaryotic chromatin that is available for transcription. more dispersed.	42
7685523499	histone	~100 amino acid proteins. more than a fifth of histone amino acids are positively charged lysine or arginine, bind well to negatively charged dna.	43
7685523500	nucleosome	repeating subunit of chromatin fibers, consisting of DNA coiled around histones - beads on a string. the string between the beads is called linker DNA. consists of dna wound around a protein core of 8 histones, 2 of each of the 4 main histone types. n-terminus histone tail extends out from the nucleosome.	44
7685523501	levels of dna packing	the double helix, 10-nm fibers, 30-nm fibers, looped domaons (300-nm fibers), metaphase chromosome	45
7685523502	30-nm fiber	linker dna and histone tails interact. this level contains the 5th type of histone	46
7685523503	looped domains	300nm fibers. 30nm fibers wrap around a protein scaffold. the scaffold is rich in one type of topoisomerase	47
7685523504	metaphase chromosome	one chromatid is 700nm wide. genes always end up in the same place at this level btw.	48
7685523505	10-nm fiber	nucleosome beads on a string	49