Gre Bio Chp 7 Eukaryotic Chromosome And Genome

Front 1

Nucleosome

Back 1

Spools of DNA wrapped around small histone proteins. Linked by a small protein strand and can be packed together up to 6 nucleosomes per turn.

Front 2

Chromosomes

Back 2

Nucleosomes packed into supercoiled loops

Front 3

Deletion

Back 3

A chromosomal fragment is lost as the chromosome replicates

Front 4

Duplication

Back 4

A fragment that detaches from a chromosome during a deletion reattaches to the homologous chromosome, leading to two sets of identical genes in a particular region. The original chromosome is shorter than normal where the deletion occured

Front 5

Inversion

Back 5

A deleted fragment attaches back to the chromosome it came from but in a reverse direction

Front 6

Translocation

Back 6

A fragment attaches to another chromosome, most commonly not a homologous chromosome. Sometimes reciprocal

Front 7

RNA Polymerase I and II

Back 7

Main enzymes responsible for making this transition between DNA codes and RNA codons

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Exons

Back 8

The coding sequences of a gene

Front 9

Introns

Back 9

The noncoding sequences of a gene

Front 10

5' capping

Back 10

Methylated guanines (G) are added to the 5' end of mRNA. Protects the 5' ed from degradation and damage as it travels around the cell and later initiates protein synthesis at the ribosome

Front 11

3' poly-A tail

Back 11

100-300 adenine nucleotides (A). Aids in stabilization and protection of mRNA transcript and translation at the ribosome

Front 12

snRNPs

Back 12

Short nuclear ribonucleoproteins. Similar to histones in DNA but for RNA

Front 13

Spliceosome

Back 13

Large ribonucleoprotein that forms during the excision of introns and the splicing together of introns

Front 14

Transposons

Back 14

Pieces of DNA that can move from place to place with an organism's genome. Involves the transposase enzyme the transposon produces and are always found between two inverted repeats

Front 15

Insertion Sequence

Back 15

A simple transposon composed of two inverted sequences surrounding a transposase gene.

Front 16

Complex Transposons

Back 16

Have not only inverted repeats and the transposase but also one of more genes that move as well

Front 17

Enhancers

Back 17

Noncoding regions of DNA that influence the activation of genes. Often located a considerable distance upstream from the gene that exert control over

Front 18

TATA Box

Back 18

A-T rich regions of DNA that are involved in positioning the start of transcription. A-T rich DNA tends to separate more easily due to only two hydrogen bonds instead of the three between C-G

Front 19

Transcription Factors

Back 19

Hundreds or thousands of proteins that exert transcriptional control over the genome. Some bind to enhancer sequences, other promoter.

Front 20

Methylation

Back 20

The attachment of methyl groups to nitrogenous bases. Methylated bases cannot be transcribed by RNA

Front 21

Unmethylated CG regions

Back 21

A promoter region used by scientists to find genes in an unknown genome.

Front 22

Gene Amplification

Back 22

A phenomenon in which certain genes are rapidly copied by the organism so that multiple copies of these genes exist within the genome. Most often during embryonic development