Unit 11- Chromo Structure and Organelle DNA

Question 1

pos supercoiling

Answer 1

overroatated DNA (top coil going down right)

Question 2

*neg supercoiling

Answer 2

underrotated DNA

Question 3

topoisomerase

Answer 3

enzyme responsible for adding and removing turns in the coil

Question 4

euchromatin

Answer 4

• less condensed
• on chromo arms
• unique seq
• many genes
• replicated in S phase
• transcribes often
• crossing over is common

Question 5

heterochromatin

Answer 5

• more condensed
• at centromeres, telomeres, etc
• repeated seq
• few genes
• replicated late in S phase
• transcribes infrequently
• crossing over is uncommon

Question 6

linker DNA

Answer 6

DNA between chromososmes

Question 7

polytene chromos

Answer 7

created by repeating rounds of DNA replication w/ no cell division

Question 8

dnase I sensitivity

Answer 8

correlates w/ gene activity

Question 9

epigenetic changes

Answer 9

Stable alterations of chromatin structure that may be passed on
- methylation; capable of being reversed and altered due to environ factors

Question 10

centromere structure

Answer 10

constricted region where spindle fibers attatch

Question 11

telomere structure

Answer 11

ends of chromos

Question 12

c value

Answer 12

amount orgs differ in amount of DNA per cell

Question 13

gene family

Answer 13

similar but not identical copies of unique DNA seq that arose through duplication of an existing gene

Question 14

moderately repetitive DNA

Answer 14

150~300 bp long
- tatem
- interspersed
(short: SINEs: Alu ele
long: LINEs)

Question 15

highly repetitive DNA

Answer 15

less than 10 bp long
- microsatellite DNA

Question 16

endosymbiotic theory

Answer 16

mito and chloro were once free-livin bacteria

Question 17

human genome length

Answer 17

16,295 bp

Question 18

human mtDNA

Answer 18

circular; 16,569 bp; encodes 2 rRNA, 22 tRNA, and 13 proteins

Question 19

yeast mtDNA

Answer 19

5 times human; encodes 2 rRNA, 25 tRNAs, and 16 polypeptides

Question 20

flowering plant mtDNA

Answer 20

extensive size variation

Question 21

transposable elements

Answer 21

sequences that can move about in the genome

Question 22

genomic imprinting

Answer 22

an allele is expressed differently based on
whether it is inherited from the mom or dad
- caused by methylation

Question 23

hybridization

Answer 23

DNA from different sources will renature if they are complementary (don’t have to be all bases)

Question 24

replicative transposition

Answer 24

a new copy of the
transposable element is introduced at a new site while the
old copy remains behind at the original site

Question 25

nonreplicative transposition

Answer 25

the transposable ele-
ment excises from the old site and inserts at a new site with-
out any increase in the number of its copies.