Alberts, Ch 4 - DNA, Chromosomes and Genomes

Question 1

Base pair

Answer 1

Two nucleotides in an RNA or DNA molecule that are held together by hydrogen bonds, G-C, A-T/U

Question 2

Centrosome

Answer 2

Centrally located organelle of animal cells that is the primary microtubule-organizing center (MTOC) and acts as the spindle pole during mitosis, usually in pairs called centrioles

Question 3

Chromatin

Answer 3

Complex of DNAm, histones and non-histone proteins found in the nucleus of a eukaryotic cell, material of which chromosomes are made

Question 4

Chromosome

Answer 4

Structure composed of a very long DNA molecule and associated proteins that carries part of the hereditary information of an organism, especially evident in cells undergoing mitosis

Question 5

Complementary

Answer 5

Capable of forming a perfect base-paired duplex with each other, having biochemical or structural features that marry up so that noncovalent bonding is facilitated

Question 6

Copy number variations (CNV)

Answer 6

A difference between two individuals in the same population in the number of copies of a particular block of DNA sequence, variation arises from occasional duplicaions and deletions of these sequences

Question 7

Deoxyribonucleis acid (DNA)

Answer 7

Polynucletide formed from covalently linked deoxyribonucleotide units, store of hereditary information within a cell and carrier of information from generation to generation

Question 8

Double helix

Answer 8

Three-dimensional structure of DNA, in which two antiparallel DNA chains held together by hydrogen-bonding wound into a helix

Question 9

Epigenetic inheritance

Answer 9

Inheritance of phenotypicchanges in a cell or organism that do not result from changes in the nucleotide sequence of DNA, can be due to positive feedback loops of transcription regulators or heritable modifications in chromatin such as DNA methylation or histon modifications

Question 10

Euchromatin

Answer 10

Region of interphase chromose that stains diffusely, “normal” chromatin as opposed to condensed heterochromatin

Question 11

Exon

Answer 11

Segment of eukaryotic gene that consists of a sequence of nucleotides that will be represented in mRNA or in a final transfer, ribosomal or other mature RNA molecule, in protein-coding genes encode the amino acids in the protein

Question 12

Gene

Answer 12

Region of DNA that is transcribed as a single unit and carries information for a discrete hereditary characteristic, usually corresponding to single protein or single RNA

Question 13

Genome

Answer 13

Totality of genetic information belonging to a cell or an organism, the DNA that carries the information

Question 14

Heterochromatin

Answer 14

Chromatin that is highly condensed even in interphase, generally transcriptionally inactive

Question 15

Histone

Answer 15

One of a group of small abundant proteins, rich in arginine and lysine, that combine to form nucleosome coresaround which DNA is wrapped

Question 16

Histone H1

Answer 16

Linker histone protein that binds to DNA where it exits from a nucleosome and helps package nucleosomes ino the 30-nmchromatin fiber

Question 17

Homolog

Answer 17

Oneof two or more genes that are similar in sequence as a result of derivation from the same ancestral gene, covers both orthologs and paralogs

Question 18

Homologous

Answer 18

Genes, proteins, or body structures that are similar as a reult of a shared evolutionary evolution

Question 19

Intron

Answer 19

Noncoding region of a eukaryotis gene that is transcribed into an RNA molecule but is then excised by RNA splicing during production of the mRNA or other functional RNA

Question 20

Karyotype

Answer 20

Display of the full set of chromosome that are arranged with respect to size, shape and number

Question 21

Lampbrush chromosome

Answer 21

Huge chromosome paired in preparation for meiosis, found in immature amphibian eggs

Question 22

Mitotic chromosome

Answer 22

Highly condensed duplicated chromosome as seen at mitosis, consisting oftwo sister chromatids held together at the centromere

Question 23

Nucleosome

Answer 23

Beadlike structure in eukaryotic chromatin, composed of a short length of DNA wrapped around an octameric core oh histone proteins, fundamental structure unit of chromatin

Question 24

Position effect variegation

Answer 24

Alteration in gene expression resulting from change in the position of gene in relation to other chromosomal domains, especially heterochromatic domains, when an active gene is placed next to heterochromatin, inactivating influence of heterochromatin can spread to affect the gene to a variable degree

Question 25

Pseudogene

Answer 25

Nucleotide sequence. Of DNAthat has accumulated multiple mutations thathave rendered an ancestral gene inactive and nonfuntional

Question 26

Purifying selection

Answer 26

Natural selection operating in a population to slow genome changes and reduce divergence by eliminating individuals carrying deleterious mutations

Question 27

Replication origin

Answer 27

Location on a DNA molecule at which duplication of DNA begins

Question 28

Single-nucleotide polymorphism (SNP)

Answer 28

Variation between individuals in a population due to a relatively common difference in a specific nucleotide at a defined point in the DNA sequence

Question 29

Telomere

Answer 29

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

Question 30

Template

Answer 30

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

Question 31

Antiparallel

Answer 31

Describesthe relative orientation of the two strands in a DNA double helix or two paired regions of a polypeptide chain, polarity of oone strand is opposite from the other

Question 32

Centromere

Answer 32

Constricted region of a mitotic chromosome that holds sister chromatids together, also the site on DNA where kinetochore forms so as to capture microtubules from mitotic spindle