Chromosomes Flashcards

1183907228	what are chromosomes composed of?	DNA and protein (histones)	0
1183907229	loci	location of a gene within a chromosome	1
1184566818	homologous chromosomes	genetically similar chromosomes (when talking about chromosomes obtained from mother and father side - one of each)	2
1184566819	How is DNA expressed in viruses?	RNA	3
1184566820	What other types of DNA exists?	nuclear and chloroplast DNA	4
1184566821	DNA + Proteins = ?	chromatin	5
1184566822	what are nucleosomes and their function	nucleosomes form from the unison of coiled DNA around histones.	6
1184566823	What are the different "types" in which chromosomes can be expressed? (ei: location of centromere)	Metacentric, Subcentric, Acrocentric, Telocentric, Acentric	7
1184566824	what are the steps in the cell cycle?	M phase - G1 phase - S phase - G2 phase	8
1184566825	what is M phase? (Mitosis)	shortest in the cell cycle. composed of prophase, metaphase, anaphase, and telophase (cytokenesis)	9
1184566826	what is G1 phase of the cell cycle?	during this phase the cell grows in preparation for S phase.	10
1184566827	what is S-phase of the cell cycle?	DNA replication step of cell cycle	11
1184566828	what is G2 phase of cell cycle?	post DNA synthesis. also serves as a checkpoint to ensure the 'quality' of DNA	12
1184566829	what is colchicine and its effects?	chemical that when applied to a cell undergoing mitosis it arrests it due to the fact that it interferes with the spindle formation	13
1185341346	what kind of division is meiosis I and what does it produce?	reductional division that produces 2 haploid cells from a single diploid cell	14
1186816337	what kind of division is meiosis II and what does it produce?	equational division and produces the separation of the sister chromatids into haploid cells	15
1186816338	what are the 5 stages in prophase?	leptotene, Zygotene, Pachytene, Diplotene, Diakenesis	16
1186816339	what goes on in leptotene stage?	called the thin thread stage, the long and thin chromosomes start to condense	17
1186816340	what goes on in Zygotene stage?	joined thread stage. Homologous chromosomes are held together by the synaptonemal complex. This is the beginning of synapsis	18
1186816341	what goes on in Pachytene stage?	thick thread stage. synapsis is complete. recombination nodules form. non sister chromatids of tetrads cross over, trading DNA strands and reuniting, resulting in exchange of genetic material. point of exchange is called chiasma	19
1186816342	what goes on in Diplotene stage?	double thread stage. the synaptonemal complex begins to disappear. chromosomes and chiasmata are visible	20
1186816343	what goes on in diakenesis?	double movement stage. Chromosomes reach most condensed form. Nucleoli and nuclear membrane disappear and spindle apparatus begins to form.	21
1186816344	interkenesis	period between 1st and 2nd meiotic divisions	22
1186816345	meiosis II	just as mitosis, but rather than replicating chromosomes in prophase, the end result is genetically different haploid cells (n+n+n+n)	23
1186816346	law of independent assortment	segregation or separation of a gene is independent of any other gene. this is true for unlinked genes on non homologous chromosomes	24
1186816347	law of segregation	one parent contains 2 unidentical copies of each gene. when mitosis occurs either of those 2 genes may be inherited	25
1186816348	gametogenesis	formation/creation of gametes	26
1186816349	spermatogenesis	male gametogenesis in the germinal epithelium of the seminiferous tubules	27
1186816350	oogenesis	epethilial germ line of the female ovaries is where the ovums originate from	28
1186930552	g1 phase	growth and preparation of the chromosomes for replication	29
1186930553	s phase	synthesis of DNA (DNA replication and duplication of the centrosome)	30
1186930554	g2 phase	preparation for mitosis	31
1186930555	m phase	mitosis and cytokenesis	32
1186930556	stages of mitosis	prophase, metaphase, anaphase, telophase, cytokenesis	33
1186930557	prophase	chromatin condenses into chromosomes. the nuclear envelope breakdown. centrioles begin to move towards opposite sides of the cell	34
1186930558	metaphase	spindles align the chromosomes at the center of the cell, forming metaphase plate	35
1186930559	anaphase	paired chromosomes (sister chromatids) separate at kinetochore and are pulled towards opposite sides of the cell	36
1186930560	telophase	chromatids arrive at opposite poles of the cell. new nuclei are formed, cell burrow initiates	37
1186930561	cytokenesis	in animal cells actin forms a ring around the cell and splits it in half. in plant cells a cell plate is formed in the middle	38
1186930562	meiosis I	reductional division	39
1186930563	prophase I	longest stage in meiosis. chromosomes coil. homologous chromosomes pair along their lengths, forming bivalent/tetrad structures (4 chromatids) . non sister chromatids break and rejoin during crossing over	40
1186930564	metaphase I	homologous chromosomes (bivalent/tetrad) allign in the equator forming metaphase plate. spindle is attached @ kinetochore.	41
1186930565	anaphase I	chromosomes start to move towards opposite poles. Disjunction occurs here, providing genetic variation. sister chromatids remain attached at centromere, moving towards same pole. 2 cells are begin to form 2n+2n	42
1186930566	telophase I and cytokenesis	2 new cells are formed, each with daughter cell having half the # of chromosomes but still consisting of 2 sister chromatids	43
1186930567	meiosis II	equational division	44
1186930568	prophase II	there s no chromosome replication. chromosomes condense , nuclear envelope disappears, centrioles replicate and move towards the poles	45
1186930569	metaphase II	centromeres contain 2 kinetochores that attach to spindle from the centrosomes. single chromosomes align @ metaphase plate.	46
1186930570	anaphase II	centromeres separate. chromosomes move towards opposite sides of the cell	47
1186930571	telophase II	nuclear envelopes form around each new set of haploid chromosomes	48
1186930572	cytokenesis II	takes place after telophase and 4 new haploid cells form. all genetically different	49
1187216767	Sister Chromatids	Sister chromatids are generated when a single chromosome is replicated into two copies of itself	50