Genetics: Chapter 10

Front 1

contains the genetic material ; complexes of DNA and proteins?

Back 1

chromosomes

Front 2

main function of the genetic material?

Back 2

store information needed to produce and organism

Front 3

how is this accomplished?

Back 3

through the DNAs molecules base sequences

Front 4

most viruses can only infect specific cells in a specific host. this is called its ____ ____?

Back 4

host range

Front 5

viral genome can be SS or DS ; DNA or RNA; circular or linear.

Back 5

note

Front 6

complex viruses undergo ____ assembly while simple viruses (TMV) undergo self assembly?

Back 6

directed

Front 7

what is meant by directed assembly?

Back 7

virus assembly requires nonvirus parts

Front 8

give an example of a complex virus?

Back 8

bacteriophage, t2

Front 9

bacteria may have one to four identical copies of the same ____?

Back 9

chromosome

Front 10

bacterial chromosomal DNA is ussually ______?

Back 10

ciruclar

Front 11

account for majority of Bacterial DNA?

Back 11

structural gene sequences (encoding proteins)

Front 12

non transcribed DNA between adjacent genes?

Back 12

intergenic regions

Front 13

the bacterial origin or replication is only a few ___ nucleuotides in length?

Back 13

100

Front 14

repetitive sequenes, dispensed throughout the chromosome plays a role in ?

Back 14

folding, replication , and gene expression

Front 15

to fit inside the bacterial cell the chromosomal DNA must be compaced to about ____ folds?

Back 15

1000

Front 16

this compaction involves the formation of ?

Back 16

loop domains

Front 17

loop domains compact the structure about ___ fold?

Back 17

10

Front 18

a second way to compact the bacterial chromosome?

Back 18

DNA supercoiling

Front 19

chromosome ______ is influenced by supercoiling?

Back 19

function

Front 20

the chromosomal DNA in bacteria is ______ supercoiled?

Back 20

negatively

Front 21

two major effects of negative supercoils?

Back 21

compaction; and tensioin

Front 22

what is the purpose of "tension" produced by the negative supercoil:

Back 22

it enhances replication and transcription

Front 23

enzymes that control bacterial supercoiling?

Back 23

DNA gyrase (topoisomerase III) and topoisomerase I

Front 24

induced negative supercoils; and also relaxes positive supercoils when they occur?

Back 24

DNA gyrase

Front 25

relaxes negative supercoils?

Back 25

topoisomerase I

Front 26

what governs supercoiling in bacteria?

Back 26

the competing action of the DNA gyrase and topoisomerase I

Front 27

what is a way to prevent bacteria diseases?

Back 27

block the actions of DNA gyrase

Front 28

two main classes of drug that inhibit gyrase activity?

Back 28

quinolones; and coumarins

Front 29

do these inhibit eurkaryotic gyrases?

Back 29

no

Front 30

eukaryotic chromosomes are _____ while bacteria chromosomes are circular?

Back 30

linear

Front 31

the DNA-protein complex is termed ?

Back 31

chromatin

Front 32

when two species differ in size of their genomes its not becuase of the size of their genes its because of ?

Back 32

the accumulation of repetitive DNA sequences (no not encode protien)

Front 33

three types of DNA sequences needed for chromosomal replication and segregation?

Back 33

origins of replication; centromeres; telomeres

Front 34

genes are located between ____ and _____ regions along the entire chromosome?

Back 34

centromeric and telomeric

Front 35

which have more introns? yeast or mammal?

Back 35

mammals

Front 36

refers to the number of times a particular base sequence appears in the genome?

Back 36

sequnce complexity

Front 37

three main types of repetitive sequences?

Back 37

unique (non repetitive); moderately repetitive; and highly repetitive

Front 38

found once or a few times in a genome; includes structural genes as well and intergenic areas?

Back 38

unique sequences

Front 39

found a few hundred to a few thousand times; include genes for rRNA and histones; origin of replication; and transposable elements?

Back 39

moderately repetitive

Front 40

found tens of thousands to millions of times; each copy is relatively short; example "alu family " in humans?

Back 40

highly repetitive

Front 41

where are highly repetitive sequences localized?

Back 41

heterochromatic regions (centromeric and telomeric)

Front 42

note: tandem repetitive DNA has a base composition different from that of the rest of the chromasomal DNA

Back 42

note

Front 43

how can AT and GC paris be distinguished?

Back 43

by their densities

Front 44

which pair is less dense?

Back 44

AT pairs

Front 45

how can the repetitive DNA (dense) be seperated from the other DNA (not dense)?

Back 45

centrifugation

Front 46

the rate of renaturation of coplementary DNA strands provides a way to distinguish the three different types of _____ ______?

Back 46

repetitive sequences

Front 47

what does the renaturation rate of a particular DNA sequence depends on the...?

Back 47

concentration of its complementary partner

Front 48

highly repetitive DNA will be the _____ to renature?

Back 48

fastest

Front 49

unique sequences will be the ______ to renature?

Back 49

slowest

Front 50

what percent of human DNA is unique sequences?

Back 50

60-70 %

Front 51

the repeating structural unit within eukaryotic chromatin is the ______?

Back 51

nucleosome

Front 52

what is the nucleosome composed of?

Back 52

DS DNA wrapped in an octamer of histone proteins

Front 53

the nucleosome structure shortens the DNA length ___ fold

Back 53

seven fold

Front 54

histone proteins are basic; they contain many positive charged amino acids; these are..?

Back 54

lysine and arginine

Front 55

lysine and arginine bind with the _______ along the DNA backbone

Back 55

phosphates

Front 56

there are five types of histones; 4 are core histones that make up the _____?

Back 56

octamer (2 of each)

Front 57

and 1 is a _____ histone?

Back 57

linker

Front 58

revealed nucleosome structure?

Back 58

Kornberg

Front 59

play a role in the organization and compaction of the chromosomes. binds to linker DNA?

Back 59

Non Histone Proteins

Front 60

model of nucleosome structure was proposed by?

Back 60

Roger Kornberg

Front 61

who decided to test Kornberg theory?

Back 61

Markus Noll

Front 62

he did this via the following procedure?

Back 62

Digest DNA with the enzyme DNAase I; measure the molecular weight of the resulting DNA fragments;

Front 63

what was his rationale for this experiment?

Back 63

that linker DNA is more assessible than the "core DNA" to the DNAase I. thus, the cuts made by DNAase should occur in the linker region

Front 64

what was his hypothesis?

Back 64

test the beads on a string model of chromatin structure; if the model is correct, DNAase I should cut in the linker region. thereby producing DNA peices that are about 200 bp long

Front 65

Nucleosome Join to form a ____nm fiber

Back 65

30

Front 66

nucleosomes associate with each other to form a more compact structure termed the ________?

Back 66

30 nm fiber

Front 67

what plays a role in this compaction?

Back 67

histone H1

Front 68

at moderate salt concentrations, ___ is removed the result is the classic beads on a string morphology?

Back 68

H1

Front 69

at low salt concentrations, ___ is bound beads associate togther into a more compact morphology?

Back 69

H1

Front 70

shortens the total legnth of DNA another seven fold?

Back 70

30 nm fiber

Front 71

what is the correct model for the 30nm fiber?

Back 71

3D-zigzag model (not the solenoid model)

Front 72

less condense region; transcriptionally active; regions where 30nm fiber form radial loops domains?

Back 72

euchromatin

Front 73

tightly compacted region; transciptionally inactive; radial loop domains complacted even further?

Back 73

Heterochromatin

Front 74

there are two types of heterochromatin. what are they?

Back 74

constitutive and facultative heterochromatin

Front 75

example: bar body, region that can interconvert between euchromatin and heterochromatin?

Back 75

Facultative heterochromatin

Front 76

in metaphase chromosomes the radial loops are highly condensed and stay anchored to a _____?

Back 76

scaffold

Front 77

_____ are need for the compaction of radial loops?

Back 77

histones

Front 78

two multiprotein complexes help to form and organize metaphase chromosomes. which multiprotein plays a role in chromosome condensation?

Back 78

Condensin

Front 79

which are plays a role in sister chromatid alignment?

Back 79

Cohesin

Front 80

uses energy from ATP and catalyze changes in chromosome structure?

Back 80

SMC proteins (Structural matinainence of chromosomes)

Front 81

during interphase condensins are in the ______?

Back 81

cytoplasm

Front 82

when does condensins travel into the nucleus?

Back 82

start of M phase

Front 83

does condesins change the number of radial loops?

Back 83

no, the number of loops does not change only the size of the loops

Front 84

the two event previously discussed (nucleosome and 30 nm fiber) shortens the DNA ___ fold?

Back 84

50

Front 85

a third level of compaction involves interaction between 30 nm fiber and the ____ ____?

Back 85

nuclear matrix

Front 86

2 parts of the nuclear matrix?

Back 86

nuclear lamina; internal matrix protein

Front 87

the nuclear matrix involves the formation of ?

Back 87

radial loop domains