chromosome structure

Question 1

define genome

Answer 1

entire DNA sequence of an organism

Question 2

is the human genome the largest?

Answer 2

no

Question 3

mobile genetic elements make up 40% of DNA also known as fossils, not all are bad

Answer 3

transposons

Question 4

transposons are also known as

Answer 4

parasitic sequences, disrupting function or altering gene regulation “jumping genes”

Question 5

during what phase are chromosomes duplicated?

Answer 5

interphase

Question 6

when do chromosomes become highly condensed? and then what happens?

Answer 6

mitosis; then they are separated and distributed to two daughter nuclei

Question 7

what are the 3 major components of a chromosome?

Answer 7

replication origin, centromere, telomeres

Question 8

what is a replication origin? how many are there?

Answer 8

where DNA duplication begins; a lot

Question 9

what does a centromere do?

Answer 9

allows one copy of each duplicate to be pulled into each daughter cell

Question 10

what do telomeres do?

Answer 10

form the ends of a chromosome and protect the chromosome from being eaten away by DNA repair genes.

Question 11

what two sets of protein bind to DNA?

Answer 11

histones and non-histone proteins

Question 12

what is it called when DNA complexes with histone/ nonhistone proteins?

Answer 12

chromatin

Question 13

_________ make up the first level of organization and packing into the _______ which is the basic unit of chromatin structure.

Answer 13

Histones; nucleosome

Question 14

describe chromatin structure

Answer 14

fiber; if folded it looks like beads on a string. the string being DNA wound around the histone core

Question 15

the ability of a chromosome to fold and unfold into dense or loose chromatin makes it a what?

Answer 15

“fractal globule”

Question 16

proteins located at the base of the loops near the scaffold that play a role in attachment and further condensing

Answer 16

condensin

Question 17

crucial for development of eukaryotes by allowing changes in the accessibility and responsiveness of genes

Answer 17

packaging dna into nucleosomes

Question 18

aid in understanding chromatin organization

Answer 18

polytene chromosomes

Question 19

is chromatin inherited?

Answer 19

yes, through epigenetic inheritance (not through dna but in addition to it)

Question 20

what are the two types of chromatin in interphase?

Answer 20

heterochromatin and euchromatin

Question 21

what is heterochromatin?

Answer 21

highly condensed, contains very few genes or silenced genes

Question 22

what is euchromatin?

Answer 22

less condensed; can be packaged into heterochromatin

Question 23

where is heterochromatin found?

Answer 23

lies against the nuclear envelope in patches

Question 24

what separates the hetero and euchromatin?

Answer 24

barrier proteins