Molecular Biology Chapter 4 By David Clark

Front 1

alle

Back 1

One particular version of a gene, or more broadly, a particular version of any locus on a molecule of DNA

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bp

Back 2

Abbreviation for base pair(s)

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locus (plural, loci)

Back 3

A place or location on a chromosome; it may be a genuine gene or just any site with variations in the DNA sequence that can be detected, like RFLPs or VNTRs

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Mbp

Back 4

Megabase pairs or million base pairs

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non-coding DNA

Back 5

DNA that does not code for proteins or functional RNA molecules

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exon

Back 6

Segment of a gene that codes for protein and is still present in the messenger RNA after processing is complete

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intergenic DNA

Back 7

Non-coding DNA that lies between genes

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intervening sequence

Back 8

An alternative name for an intron

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intron

Back 9

Segment of a gene that does not code for protein but is transcribed and forms part of the primary transcript

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primary transcript

Back 10

The original RNA molecule obtained by transcription from a DNA template, before any processing or modification has occured

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consensus sequence

Back 11

Idealized base sequence consisting of the bases most often found at each position

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pseudogene

Back 12

Defective copy of a genuine gene

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repeated sequences

Back 13

DNA sequences that exist in multiple copies

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repetitive sequences

Back 14

Same as repeated sequences

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highly repetitive DNA

Back 15

DNA sequences that exist in hundreds of thousands of copies

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LINE

Back 16

Long interspersed element

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long interspersed element (LINE)

Back 17

long sequence found in multiple copies that makes up much of the moderately repetitive DNA of mammals

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moderately repetitive sequence

Back 18

DNA sequences that exist in thousands of copies (but less than a hundred thousand)

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short interspersed element (SINE)

Back 19

Short sequence found in multiple copies that makes up much of the highly or moderately repetitive DNA of mammals.

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SINE

Back 20

Short interspersed element

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Alu element

Back 21

An example of a SINE, a particular short DNA sequence found in many copies on the chromosomes of humans and other primates

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B1 element

Back 22

An example of a SINE found in mice; the precursor sequence from which the human Alu element evolved

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satellite DNA

Back 23

Highly repetitive DNA of eukaryotic cells that is found as long clusters of tandem repeats and is permanently coiled tightly into heterochromatin

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tandem repeats

Back 24

Repeated sequences of DNA (or RNA) that lie next to each other.

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unequal crossing over

Back 25

Crossing over in which the two segments cross over are different lengths; often due to misalignment during pairing of DNA strands

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centromere

Back 26

Structure found on a chromosome and used to build and organize microtubules during mitosis

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centromere sequence (CEN)

Back 27

A recognition sequence found at the centromere and needed for attachment of the spindle fibers

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DNA fingerprint

Back 28

Individually unique pattern due to multiple bands of DNA produced using restriction enzymes, separated by electrophoresis

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heterochromatin

Back 29

Highly condensed form of chromatin that is genetically inert

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junk DNA

Back 30

Defective selfish DNA that is of no use to the host cell it inhabits and which can no longer move or express its genes

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mini-satallite

Back 31

Another term for VNTR (variable number tandem repeats)

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VNTR

Back 32

variable number tandem repeats

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variable number tandem repeats(VNTR)

Back 33

Cluster of tandemly repeated sequences in the DNA, whose number of repeats differs from on individual to another.

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selfish DNA

Back 34

A sequence of DNA that manages to replicate but which is of no use to the host cell it inhabits

Front 35

inverted repeat

Back 35

Sequence of DNA that is the same when read forwards as when read backwards, but on the other complementary strand. One type of palindrome

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mirrorlike palindrome

Back 36

Sequence of DNA that is the same when read forwards and backwards on the same strand. One type of palindrome

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palindrome

Back 37

A sequence that reads the same backwards as forwards

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hairpin

Back 38

A double stranded base-paired structure formed by folding a single strand of DNA or RNA back upon itself

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stem and loop

Back 39

Structure made by folding an inverted repeat sequence

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bent DNA

Back 40

Double helical DNA that is bent due to several runs of As

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negative supercoiling

Back 41

Supercoiling with a left handed or counterclockwise twist

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supercoiling

Back 42

Higher level coiling of DNA that is already a double helix

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covalently closed circular DNA (cccDNA)

Back 43

Circular DNA with no nicks in either strand

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linking number (L)

Back 44

The sum of the superhelical turns (the writhe, W) plus the double helical turns (the twist, T)

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open circle

Back 45

Circular DNA with one strand nicked and hence with no supercoiling

Front 46

twist, T

Back 46

The number of double helical turns in a molecule of DNA (or double stranded RNA)

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writhe

Back 47

Same as writhing number, W

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writhing number, W

Back 48

The number of supercoils in a molecule of DNA (or double-stranded RNA)

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ciprofloxacin

Back 49

A fluroquinolone antibiotic that inhibits DNA gyrase

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DNA gyrase

Back 50

An enzyme that introduces negative supercoils into DNA, a member of the type II topoisomerase family

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nalidixic acid

Back 51

a quinolone antibiotic that inhibits DNA gyrase

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norfloxacin

Back 52

a fluroquinolone antibiotic that inhibits DNA gyrase

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novobiocin

Back 53

An antibiotic that inhibits type II topoisomerases, espically DNA gyrase, by binding to the B-subunit

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quinolone antibiotics

Back 54

A family of antibiotics, including nalidixic acid, norfloxacin and ciprofloxacin, that inhibit DNA gyrase and other type II topoisomerase by binding to the A-subunit

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topoisomerase

Back 55

Enzyme that alters the level of supercoiling or catenation of DNA (i.e. changes the topological conformation)

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topoisomers

Back 56

Isomeric forms that differ in topology-i.e. their level of supercoiling or catenation

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type I topoisomerase

Back 57

Topoisomerase that cuts a single strand of DNA and therefore changes the linking number by one

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type II topoisomerase

Back 58

Topoisomerase that cuts both strands of DNA and therefore changes the linking number by two

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catenane

Back 59

Structure in which two or more circles of DNA are interlocked

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cruciform structure

Back 60

Cross shaped structure in double stranded DNA (or RNA) formed from an inverted repeat

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H-DNA

Back 61

A form of DNA consisting of a triple helix. Its formation is promoted by acid conditions and by runs of purine bases

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Z-DNA

Back 62

An alternative form of DNA double helix with left-handed turns and 12 base pairs per turn

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A-DNA

Back 63

A rare alternative form of double stranded helical DNA

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A-form

Back 64

An alternative form of double helix, with 11 base pairs per turn, often found for double stranded RNA, but rarely for DNA

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B-form or B-DNA

Back 65

The normal form of the DNA double helix, as originally described by Watson and Crick

Front 66

inosine

Back 66

A purine nucleoside, found most often in transfer RNA, that contains the unusual base hypoxanthine

Front 67

Z-form

Back 67

An alternative form of double helix with left-handed turns and 12 base pairs per turn. Both DNA and dsRNA may be found in the Z-from

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chromatin

Back 68

Complex of DNA plus protein which constitutes eukaryotic chromosomes

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histone

Back 69

Special positively charged protein that binds to DNA and helps to maintain the structure of chromosomes in eukaryotes

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Hoogsteen base pair

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A type of nonstandard base pair found in triplex DNA, in which a pyrimidine is bound sideways on to a purine

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nucleosome

Back 71

Subunit of a eukaryotic chromosome consisting of DNA coiled around histone proteins

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potential intrastrand triplex (PIT)

Back 72

Stretch of DNA that might be expected from its sequence to form H-type triplex DNA

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30 nanometer fiber

Back 73

Chain of nucleosomes that is arranges helically, approximately 30 nm in diameter

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euchromatin

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Normal chromatin, as opposed to heterochromatin

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heterochromatin

Back 75

A highly condensed form of chromatin that cannot be transcribed because it cannot be accessed by RNA polymerase

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chromatid

Back 76

Single double-helical DNA molecule making up whole of half of a chromosome. A chromatid also contains histones and other DNA associated proteins

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denaturation

Back 77

When used of proteins or other biological polymers, refers to the loss of correct 3-D structure

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melting

Back 78

When used of DNA, refers to its separation into two strands as a result of heating

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melting temperature (Tm)

Back 79

The temperature at which the two strands of a DNA molecule are half unpaired

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GC ratio

Back 80

The amount of G plus C relative to all four bases in a sample of DNA. The GC ratio is usually expressed as a percentage

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annealing

Back 81

The re-pairing of separated single strands of DNA to form a double helix

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hybrid DNA

Back 82

Artificial double stranded DNA molecule made by pairing two single strands from two different sources

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hybridization

Back 83

Pairing of single strands of DNA or RNA from two different (but related) sources to give a hybrid double helix

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renaturation

Back 84

Re-annealing of single-stranded DNA or refolding of a denatured protein to give the original natural 3-D structure