EXAM 4 terms

Biological Sciences 2200 with Birchler at University of Missouri- Columbia

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By: Alex Taylor
Created: 2010-11-11
Size: 71 flashcards
Views: 52

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DNA Ligase

an enzyme that will join together DNA fragments generated by digestion with restriction endonucleases

plasmid

used as a vector for cloning. Plasmids are useful for cloning up to about 10kb. Beyond that, plasmids are unstable.

isoschizomers

Enzymes that cleave the SAME DNA sequence (not necessarily the same cut); i.e. the recognition sequence is the same.

3' vs 5' overhang

generated from staggered cleavage via restriction endonucleases. In a 5' overhang, the 5' end of the DNA made by the cut hangs over the 3' end.

electrophoresis

Gel electrophoresis separates cleaved fragments of DNA on the basis of their size. Smaller fragments travel faster (therefore: farther) because they are less hindered by the agarose.

ethidium bromide

Gel is stained with ethidium bromide prior to electrophoresis. Ethidium bromide intercalates between bases in DNA in electrophoresis, and gives off visible light when in the presence of UV light (you can see bands using photography in a UV light box).

restriction fragment

fragments of DNA digested by restriction endonucleases (used in restriction mapping and cloning).

restriction map

order and location of restriction recognition sites on a piece of DNA
1) linear or circular?
2) fragments that don't change in double digest are on ends
3) add up pieces that are cleaved by only one enzyme to fit pieces together in a consistent manner.

gene library

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yeast artificial chromosome

YACs can clone up to 200-500 kb

transposon tag

a screen is conducted to recognize a transposition of a previously cloned transposable element (TE) into a gene to make a mutation. The TE is used as a radioactive probe onto lamba library of mutant DNA to retrieve the flanking sequences.

chromosome walk

using probes to find overlapping sequences from a region of the chromosome. The analysis of these overlaps can "walk" to the sequence in question from a known gene.

dideoxynucleotide

Dideoxynucleotides have no OH group on the 3' carbon (precluding the formation of a new phosphodiester bond), and thus stop DNA extension. Used in sequencing. Smallest fragments at 5' end.

restriction fragment length polymorphism (RFLP)

multiple forms of the length of restriction fragments caused by 1) Nucleotide changes that create/destroy sites 2) deletion of sequences between sites 3) insertion or transposition of sequences between sites. Used as markers to map genes.

Southern Blot

1) genomic DNA is digested with RE
2) Fragments are resolved via electrophoresis
3) DNA denatured by NaOH and transfered to nitrocellulose filter
4) filter probed with DNA/RNA homologous to gene of interest
5) detect location of radioactivity

Polymerase Chain Reaction (PCR)

can be used with v. small amounts of DNA. Uses synthetic oligionucleotides as primers to flank and replicate a given fragment of DNA. Microsatellites/STR (short tandem repeats) can be analyzed as a "genetic fingerprint."

nucleosomes

subunits of chromatin (the combination of DNA and protein in the nucleus) and histones (chromosomal proteins). Each nucleosome has two subunits of histone, H2A, H2B, H3, H4 =octamer.

histones

chromosomal proteins. Each nucleosome has two subunits of histone, H2A, H2B, H3, H4 =octamer.

scaffold

Loops of DNA/protein attach to the scaffold.
nucleosomes coil into solenoid
solenoid loops attach to scaffold
scaffold and loops form supercoils.

scaffold attachment regions

SARs hold the loops to the scaffold.

heterochromatin

"heavily staining"
densely packed, few active genes, near centromere

euchromatin

"light staining"
less densely packed, most active genes, near ends of chromosomes.

centromere

cites of attachment of spindle fiber to chromosome. Yeast centromere =125 nucleotides. Human centromeres= 2 to 3 million base pairs.

telomere

ends of chromosomes to resolve problem with DNA replication. They form hairpin loops at the end of chromosomes, which act as a primer for replication. TTAGGG repeats and can be added with telomerase.

variable number tandem repeats

Type of repetitive DNA. 15-100 nucleotide repeated for 1.5 kb. Can be used for DNA figerprinting.

SINEs

retroposons are RNA that is converted to DNA and inserts into a new location- Alu is a retroposon that comprises 5% of human DNA. Short interspersed elements (SINES).

LINEs

Long interspersed elements- related to retroviruses. There are 20000 to 40000 copies per human genome.

telocentric

chromosomes with centromere near the end (mice)

acrocentric

centromere off center (closer to end than middle, though) (some human chromosomes)

metacentric

centromere near middle (some human chromosomes)

acentric

chromosome without a centromere

holocentric

chromosomes with "diffuse centromeres" that have spindle attachments at many sites. (scorpions, wood rushes).

deletion

usualy lethal when homozygous, no recom. in region spanning deletion, cannot revert. cri du chat syndrom (deletion of short arm of chromosome 5), cancer, transmitted in gametes, seldom in plants.

duplication

change with an extra copy of some chromosomal region

inversion

chromosomal segment rotates 180 degrees. paracentric, where inverted area does not include centromere, or pericentric, where the inverted segment includes the centromere.

translocation

exchange between nonhomologous chromosomes "reciprocal translocation"

asymmetric pairing

duplications can change copy number by asymmetric pairing followed by recombination -> can lead to hemoglobin defects.

inversion loop

null

paracentric inversion

inversion that does not include the centromere

pericentric inversion

inversion that includes the centromere.

dicentric bridge

generated by recombination of a paracentric inversion loop. Bridge breaks, fragment is lost.

acentric fragment

generated by recombination of a paracentric inversion loop. Bridge breaks, fragment is lost.

alternate segrgation

null

adjacent 1 segregation

If adjacent centromeres go together (AB vs A'B'). Usually causes duplications and defieciencies that are inviable.

adjacent 2 segregation

null

Aneuploid

an addition or subtraction of chromosomes relative to the normal number, may have affects on phenotype.

Euploid

the normal number of chromosomes characteristic of a species or exact multiple of that number.

Monosomic

(2n-1) one member of a pair of homologues is missing. lethal in animals

trisomic

three copies of a chromosome. NOT triploid (three entire sets of chromosomes). Often lethal in animals, can result in less vigorous plants.

double trisomic

null

nondisjunction

null

Down syndrome

the most common human aneuploidy (TRISOMY 21). Characterized by mental retardation, epicanthic fold on eyes, short stature, hands creased all the way across, large tounge, infertile males, short life span.

monoploid

1 set of chromosomes: male bees, wasps, and ants. The monoploid number, x, is the number of chromosomes in a basic set, not the number of sets of choromosomes, which can be denoted 2x (diploid), 3x, etc.

polyploid

More than two sets of chromosomes.

haploid

the number of chromosomes (n) in the gametes.

colchicine

interferes with the spindle, which doubles the chromosome number. New homozygous lines can be created this way.

autopolyploid

multiple sets of chromosomes from the same species

allopolyploid

multiple sets of chromosomes from DIFFERENT species.

homoeologous

the related chromosomes from different species (only partially homologous) in allopolyploids.

triploidy

can come to being from the acceptance of two sperm by an egg, gametes that result from failed meiosis, and the cross of a tetraploid and a diploid.

quadrivalent

all four chromosomes in autotetraploids are associated.

trivalent

three associated chromosomes in an autotetraploid

univalent

a nonassociated chromosome in an autotetraploid

bivalent

If the four chromosomes of a autotetraploid are paired in twos.

nullisomic

the situation in which an organism can tolerate the loss of a pair of homologues, usually because of multiple genomes.

extranuclear genes

null

cytoplasmic genes

null

mitochondria

null

plastids

null

cytoplasmic segregations

null

maternal effect

null

About this deck

By: Alex Taylor
Created: 2010-11-11
Size: 71 flashcards
Views: 52

About StudyBlue

“Simply amazing. The flash cards are smooth, there are many different types of studying tools, and there is a great search engine. I praise you on the awesomeness.”
Dennis