Chapter 11: Chromosome Structure And Transposable Elements

Front 1

Positive and Negative Supercoiling

Back 1

Coiled tertiary structure that forms when strain is placed on a DNA helix by overwinding or underwinding of the helix.

An overwound DNA exhibits positive supercoiling

An underwound DNA exhibits negative supercoiling.

Front 2

Transposable element

Back 2

DNA sequence capable of moving from one site to another within the genome through a mechanism that differs from that of homologous recombination.

Front 3

Nucleoid

Back 3

Bacterial DNA confined to a definite region of the cytoplasm.

Front 4

Chromatin

Back 4

Chromatin is a substance within a chromosome consisting of DNA and protein. The major proteins in chromatin are histones, which help package the DNA in a compact form that fits in the cell nucleus

Front 5

Euchromatin

Back 5

Chromatin that undergoes condensation and decondensation in the course of the cell cycle.

Front 6

Heterochromatin

Back 6

Chromatin that remains in a highly condensed state throughout the cell cycle; found at the centromeres and telomeres of most chromosomes.

Front 7

Nonhistone Chromosomal Proteins

Back 7

One of a heterogeneous assortment of nonhistone proteins in chromatin.

Front 8

Histone Proteins

Back 8

A histone is a protein that provides structural support to a chromosome. In order for very long DNA molecules to fit into the cell nucleus, they wrap around complexes of histone proteins

Front 9

Nucleosome

Back 9

Basic repeating unit of chromatin, consisting of a core of eight histone proteins (two each of H2A, H2B, H3, and H4) and about 146 bp of DNA that wraps around the core about two times.

Front 10

Centromere and Telomere

Back 10

Centromere: A constricted region of a chromosome that separates it into a short arm (p) and a long arm (q)

Telomere: Located at the end of a chromosome. They are made of repetitive sequences of non-coding DNA that protect the chromosome from damage.

Front 11

Epigenetic Changes

Back 11

Stable alteration of chromatin structure that may be passed on to other cells or to an individual organism.

Front 12

Repetitive DNA

Back 12

Sequences that exist in multiple copies in a genome.

Front 13

Short Interspersed Element (SINE)

Back 13

Short DNA sequence repeated many times and interspersed throughout the genome.

Front 14

Long Interspersed Element (LINE)

Back 14

Long DNA sequence repeated many times and interspersed throughout the genome.

Front 15

Terminal Inverted Repeats

Back 15

Sequences found at both ends of a transposable element that are inverted complements of one another.

Front 16

Flanking Direct Repeats

Back 16

Short, directly repeated sequence produced on either side of a transposable element when the element inserts into DNA.

Front 17

Retrotransposon

Back 17

Type of transposable element in eukaryotic cells that possesses some characteristics of retroviruses and transposes through an RNA intermediate.

Front 18

Melting temperature (Tm)

Back 18

Midpoint of the melting range of DNA.

Front 19

Renaturation

Back 19

The process by which two complementary single-stranded DNA molecules pair; also called reannealing.

Front 20

Hybridization

Back 20

Pairing of two partly or fully complementary single-stranded nucleotide chains.