Chapter 4: DNA, Chromosomes and Genomes

Question 1

Genome

Answer 1

The totality of the genetic information carried in the DNA of a cell or an organism

Question 2

Double Helix

Answer 2

The 3D structure of DNA, in which two DNA chains are held together by hydrogen bonds between the bases are coiled around one another

Question 3

Gene

Answer 3

Information containing element that controls a discrete hereditary characteristic.

Question 4

Antiparallel

Answer 4

Describes the relative orientation of the two strands in a DNA helix the polarity of one strand is oriented in the opposite direction to that of the other

Question 5

Base pair

Answer 5

Two nucleotides in an RNA or DNA molecule that are held together by hydrogen bonds

Question 6

Complementary

Answer 6

Nucleic acid sequences that are capable of forming a perfect base paired duplex with one another

Question 7

Template

Answer 7

Single strand of DNA or RNA whose nucleotide sequence acts as a guide for synthesis of a complementary strand.

Question 8

Karyotype

Answer 8

Full set of chromosomes of a cell arranged with respect to size, shape and number

Question 9

Centromere

Answer 9

Constricted region of a mitotic chromosome that holds sister chromatids together

Question 10

Nucleosome

Answer 10

Any one of a group of small abundant proteins, rich in arginine and lysine that form the primary level of chromatic structure

Question 11

Cell Cycle

Answer 11

The orderly sequence by which a cell duplicates its contents and divides into two

Question 12

Chromatin

Answer 12

Complex of DNA, histones and nonhistone proteins in the nucleus of a eucaryotic cells

Question 13

Homologous Chromosome

Answer 13

One of the two copies of a particular chromosome in a diploid cell, each copy being derived from a different parent.

Question 14

Nucleosome

Answer 14

Beadlike structure in eucaryotic chromatin, composed of a short length of DNA wrapped around a core of histone proteins

Question 15

Exon

Answer 15

Segment of eucaryotic gene that consists of a sequence of nucleotides that will be represented in mRNA .

Question 16

Intron

Answer 16

Noncoding region of a eucaryotic gene that is transcribed into an RNA molecule but is then excised by RNA splicing

Question 17

H1

Answer 17

Linker histone protein that binds to DNA where it exits from a nucleosome and helps package nucleosomes in the 30nm chromatin fiber

Question 18

Replication origin

Answer 18

Location on a DNA molecule at which duplication of the DNA begins

Question 19

Telomere

Answer 19

End of a chromosome, associated with a characteristic DNA sequence that is replicated in a special way. Counteracts the tendency of the chromosome otherwise to shorten with each round of replication

Question 20

Histone Code

Answer 20

Combination of nucleosomal modification that determines how and when the DNA packaged in the nucleosome is accessed

Question 21

euchromatin

Answer 21

Less condensed region of interphase chromosome that stains diffusely

Question 22

Epigenetic Inheritance

Answer 22

Form of transmission of information from cell to cell, or from parent to progeny that is not encoded in DNA

Question 23

Position effect

Answer 23

Difference in gene expression that depends on the location of the gene on the chromosome.

Question 24

Nuclear lamina

Answer 24

Forms a thin sheetlike meshwork just beneath the inner nuclear membrane

Question 25

Regulatory DNA sequences

Answer 25

Responsible for ensuring that the gene is turned on or off at the proper time

Question 26

Kinetochore

Answer 26

Complex structure formed from proteins on a mitotic chromosome to which microtubules attach. Plays an active part in the movement of chromosomes to the poles

Question 27

What are the two types of protein that bind to the DNA to form eucaryotic chromosomes?

Answer 27

Histones and nonhistone chormosomal proteins

Question 28

linker DNA

Answer 28

Exposed DNA between the nucleosome core particles

Question 29

Histone octamer

Answer 29

Forms a protein core around which the double stranded DNA is wound. H2A, H2B, H3, H4 x2

Question 30

Chromatic remodeling complex

Answer 30

Loosens the DNA histone contacts. Can catalyze nucleosome sliding by sliding the DNA.

Can also catalyze the exchange of octameric subunits.

Question 31

Position effect varigation

Answer 31

Some cells express a gene while others do not

Question 32

HATs

Answer 32

Histone acetyl transferases - add an acetyl group to a histone. Adding an acetyl removes the negative charge of a lysine causing the chromatin to become more tightly wound.

Question 33

HDAC

Answer 33

Histone deacetylase complex - remove acetyl group

Question 34

Gene regulatory proteins

Answer 34

General name for any protein that binds to a specific DNA sequence to influence the transcription of a gene

Question 35

Code-reader complex

Answer 35

Recognizes specific histone modifications that recuit additional protein complexes.

Question 36

Barrier sequences

Answer 36

Specific DNA sequences that seperate one chromatin domain from another.

Question 37

Centric heterochromatin

Answer 37

A special stretch of DNa in which the centromere is embedded

Question 38

alpha satellite DNA

Answer 38

A region of repeated DNA sequences that build the centromere

Question 39

Lampbrush chromosome

Answer 39

Paired chromosomes in meiosis in immature amphibian eggs, in which the chromatin forms large stiff loops extending out from the linear axis of the chromosome

Question 40

Mitotic chromosome

Answer 40

Highly condensed duplicated chromosome with the two new chromosomes still held together at the centromere as sister chromatids

Question 41

Polytene chromosome

Answer 41

Giant chromosome in which the DNA has undergone repeated replication w/o separation into new chromosomes.

Question 42

Condensins

Answer 42

A class of proteins that uses ATP to help coil the two DNA molecules in an interphase chromosome.