Chapter 11.2: Chromosome Structure and Compaction

Question 1

What does the nucleosome accomplish?

Answer 1

Condenses naked DNA

Question 2

What does supercoiling accomplish?

Answer 2

Causes additional DNA compaction

Question 3

What does radial loop-scaffold accomplish?

Answer 3

Through progressive compaction, condenses DNA to rodlike mitotic chromosomes that are 10,000 times more compact than naked DNA

Question 4

What is linker DNA?

Answer 4

o Linker DNA connects one nucleosome with the next

Question 5

What are condensins?

Answer 5

 Protein complexes called condensins help condense interphase chromosomes into metaphase chromosomes

Question 6

What is G-banding?

Answer 6

o In G-banding, chromosomes are first gently heated and then exposed to Giemsa stain: this DNA dye preferentially darkens certain regions to produce alternating dark and light G bands

Question 7

What are idiograms?

Answer 7

o Diagrams of the banding patterns are called idiograms

Question 8

Define fluorescent in situ hybridization (FISH)

Answer 8

provides a convenient bridge betweeh the low resolution of a karyotype and the ultra-high resolution of a complete genomic sequence

Question 9

What provides a convenient bridge betweeh the low resolution of a karyotype and the ultra-high resolution of a complete genomic sequence?

Answer 9

fluorescent in situ hybridization (FISH)

Question 10

Compare the two FISH methods

Answer 10

 In one use the probe is a short, defined sequence such as a cDNA clone • The results are fluorescent spots showing the location of the corresponding gene in the genome  In spectral karyotyping (SKY), the probes are made from multiple DNAs that originated from positions scattered along the length of individual chromosomes • Each chromosome area is a different color

Question 11

Label the nucleosome

Answer 11