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89 Cards in this Set

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Aneuploidy
gain or loss of one or more chromosomes form normal (2n) diploid set
Nullisomy
(2n-2) always lethal and so unkown among live births, because both copies of a particular chromosome types are lost, so all genes on that particular chromosome are completely absent
Monosomy
(2n-1)usually lehtal in animals unless chromosome involved is a: 1)very small autosome 2)sex chromosome [XO, but YO lethal]
Tetrasomy
(2n+2) usually lethal in animals unless chromosome involved is a sex chromosome (such as XXXX or XXXY)
Trisomy
(2n+1) usually lethal in animals unless chromosome involved is a: 1)sex chromosome 2)very small autosome
Down Syndrome
[trisomy 21 John L. Down] origin of third copy of chromo#21, non-disjunction of this chromosome type during meiosis in either male or female parents (usually female)
Results of Down Syndrome
reduction of IQ, general health and life expectancy. Poor motor control, cheerful personality, broad flat face, fold corner of eyes
Monosomy 21
[presence of only 1 copy of this chromosome type] is non-existnet even though the diagrams of primary and secondary non-disjunction show that meiotic non-disjunction always produces equal numbers of n+1 and n-1 gametes [maternal age effect= higher age: higher chance]
Origin of Aneuploidy
chromosomal nondisjunction (meiotic accidents: failure of chromosmoes to seperate normally)
Polyploidy
more than 2 multiples of haploid (n) chromosome set present
a)Polyploidy in animals and plants
rare in animals, common in plants (and important for agriculture)
diploid-2n
triploid-3n(sterile)
tetraploid-4n
pentaploid-5n(sterile)
hexaploid-6n
b)Polylpoidy origin of extra sets
1)autopolyploid
2)allopolyploidy
1)Autopolyploid
2)Allopolyploidy
1)ALL SETS FROM SAME SPECIES double fertilization [polyspermy] producing triploid offspring
2)MULTIPULE SETS FROM AT LEAST 2 SPECIES interspecific hybrization, as in commercial bread wheat, which is an allohexaploid (AABBDD)
Variation in Chromosome structure
a)Defective chromosome
b)Chromosome heterozygote
c)Balanced and Unbalanced
d)Chromosomes defects arise
Chromosome Heterozygote
is defined to be one normal and one defective
Defective Chromosomes
are heritable-often passed unchanged to offspring
a)Balanced Chromosomal Mutation
b)Unbalanced Chromosmal Mutation
a)no genetic information has been lost but location of certain genes has been altered
b)there is a gain or loss of genetic information compared to the normal situation
Chromosome Defects
arise as a spontaneous double-stranded break or a pair of breaks (broken ends are 'sticky' but don't always re-join properly
Potential Consequences of a break
a)loss of terminal piece(very bad)-unbalanced
b)abnormal reattachment(bad)-balanced
c)normal reattachment of broken pieces (best)-balanced
Terminal Deletion
(normal) ABCDEFoGHI and QRSTUoVWXYZ
(alter) BCDEFoGHI and QRSTUoVWXYZ
Intercalary Deletion
(normal) ABCDEFoGHI and QRSTUoVWXYZ
(alter) ABDEFoGHI and QRSTUoVWXYZ
Tandem Direct Duplication
(normal) ABCDEFoGHI and QRSTUoVWXYZ
(alter) ABABCDEFoGHI and QRSTUoVWXYZ
Tandem Inverted Duplication
(normal) ABCDEFoGHI and QRSTUoVWXYZ
(alter) ABBACDEFoGHI and QRSTUoVWXYZ
Tandem Direct Duplication
(normal)ABCDEFoGHI and QRSTUoVWXYZ
(altered)ABABCDEFoGHI and QRSTUoVWXYZ
Tandem Indirect Duplication
(normal)ABCDEFoGHIand QRSTUoVWXYZ
(altered)ABBACDEFoGHI and QRSTUoVWXYZ
Dispersed Direct Duplication
(normal)ABCDEFoGHI and QRSTUoVWXYZ
(altered)ABCDEFoGABHI and QRSTUoVWXYZ
Dispersed Indirect Duplication
(normal)ABCDEFoGHI and QRSTUoVWXYZ
(altered)ABCDEFoGBAHI and QRSTUoVWXYZ
Paracentric Inversion
(normal)ABCDEFoGHI and QRSTUoVWXYZ
(altered)AEDCBFoGHI and QRSTUoVWXYZ
Pericentric Inversion
(normal)ABCDEFoGHI and QRSTUoVWXYZ
(altered)ABHGoFEDCI and QRSTUoVWXYZ
Reciprocal Translocation
(normal)ABCDEFoGHI and QRSTUoVWXYZ
(altered)QRSTCDEFoGHI and ABUoVWYZ
Non-reciprocal Traslocation
(normal)ABCDEFoGHI and QRSTUoVWXYZ
(altered)QRABCDEFoGHI and STUoVWYZ or ABCDEFoGHI and STUoVWXYZQR
(SPECIAL) pericentric inversion AND paracentric inversion
a)change chromosome shape [para=parallel]
b)don't involve the centromere, will leave a submetacetric chromosome as submetacentric [peri=around]
(classically) gene
1)unit of heredity controls a particular trait
2)unit of transmission b/w generations
3)unit of pheno expression w/in an individual
Particulate
transmission b/w generations doesn't chnage the nature of the gene (EXCEPT GENE MUTATIONS)
(Molecular) gene
made of DNA but NOT ALL DNA is part of a gene [98% of human genome doesn't code for RNA transcript]
Non-coded DNA
1)structure element of chromosome [centromere and telomeres]
EUKARYOTES chromosomes- special protiens
histones [structural elements without carrying genetic information]
DNA
deoxyribonueleic acid
RNA
ribonucleic acid
Construction of gene mapping
small pieces to overall big piece [cuts down on chance of undetected double crosses]
Non-coding DNA
can't be called alleles because they do segregate during meiosis DON'T produce pheno differences
1 map unit or 1% recombination
approx equal to 1,000,000 bp of DNA
haploid gneome contains
3 Gb of DNA
diploid genome contains
6 Gb of DNA
4 secrets of DNA sucess
a)DNA can be copied for transmission thru a process= replication (during S period interphase)
4 secrets of DNA sucess
b)DNA carries genetic info and can store in a non-expressed form [a)barr bodies b)sperm cell nuclei c)gene dig enzymes
4 secrets of DNA sucess
c)Genetic info can change through process of mutatio= alteration, loss or gain of genetic info
4 secrets of DNA sucess
d)Expression of genetic info
[most genes control production of particular proteins through mRNA intermediate but some genes make tRNA or rRNA rather than mRNA
3 stop codons
UAA, UGA or UAG
[always written 5'-nnn-3']
n
any nucleotide (A,C,U,G)
y
either pyrimidine (C,U)
r
either purine (A,G)
Overview of genetic code (9)
1)code linear= read left to right (5'--3')
Overview of genetic code (9)
2)each 'word' in mRNA is 3 bases long ONE CODON (3 CONSECUTIVE BASES) SPECIFIES ONE AMINO ACID IN RESULTING POLYPEPTIDE)
Overview of genetic code (9)
3)with triplet code, there are 4x4x4=46 possible codons, each one with a)specific unambiguous meaning b)meaning maybe context-dependent
Overview of genetic code (9)
4)some amino acids(18 of 20 codons) are specified by more than one codon (degeneracy or redundancy)
Overview of genetic code (9)
5)NOT EVERY naturally occurring amino acid has a place in the genetic code [some BECAUSE OF POSTTRANSLATION MODIFICATION OF PROLINE)
Overview of genetic code (9)
6)NO PUNCTUATION between adjacent codons EVERY DNA OR RNA sequence can be translated according to any of three theoretical reading frames TRANSLATION MACHINERY recognizes the correct reading frame
Overview of genetic code (9)
7)certain codons specify beginnig (start) and end(stop) of message
Overview of genetic code (9)
8)codons read in non-overlapping fashion *single base subsitution mutation might alter more than one consecutive amino acid in the plypeptide (DOESN'T HAPPEN)
Overview of genetic code (9)
9)genetic code is universal SINGLE CODING DICTIONARY used by most a)prokaryotic b)eukaryotic
Consequences of synonymy (redundancy) of genetic code (2)
1)many third position base subsitutions (mutations) don't alter the amino acid sequence
2)cell doesn't need 61 different tRNAs, each serving a different mRNA codon
Synonymous (silent) substitution
a mutation in the DNA that results in an altered mRNA swquence but NO CHANGE in the polypeptide sequence
mRNA
tRNA
rRNA
=messenger RNA
=transfer RNA
=reibosomal RNA
mRNA gene
tRNA gene
rRNA gene
=gene coding for messenger RNA
=gene coding for transfer RNA
=gene coding for ribosmal RNA
ssDNA
ssRNA
dsRNA
=single strand DNA
=single strand RNA
=double strand DNA
Information flow (focus on protien-coding genes)
dsDNA-(transc)-ss mRNA-(transl)-polypeptide
dsDNA-(transc)-ss rRNA (never translated)
dsDNA-(transc)-ss tRNA (never tranlated)
Nucleic acids (DNA or RNA)
long molecules(polymers) made of building blocks(nucleotides) that are themselves composed of three subunits
DNA
breaks into monomers-- breaks into--nucleotides--breaks into--deoxyribose (5 carbon sugar), phosphate (PO4) and nitrogenous base: C T A G
RNA
breaks into monomers-- breaks into--nucleotides--breaks into--ribose (5 carbon sugar), phosphate (PO4) and nitrogenous base: C U A G
Nitrogen Bases: Pyrimdines
Cytosine, Uracil and Thymine (single ring)
Nitrogen Bases: Purines
Adenine and Guanine (double ring)
Sugar: Ribose (RNA)
5 carbon sugar (has OH attached to 2,3 carbons)
Sugar: (Deoxyribose)
5 carbon sugar (has OH attached 3 and H attached 2 carbon)
Nucleotide (3)
nitrogenous base + sugar + phosphate group--(2 neg charges)
Watson-Crick double helix model of DNA (source)
Chargaff's rules, X-ray diffraction data (relative numbers= molar amounts of each base present in DNA from various species)
Chargaff's Rule
[A]=[T] or [A]/[T]=1
[C]=[G] or [C]/[G]=1
[A+G]=[C+T] or [purines]=[pyrimdines]
[A]=[T]=[C]=[G]=1/4
Other possible ratios, like %GC
%GC = {[G + C]/[G + C + A + T]} X 100
(OR ASYMMETRY RATIO)
[A + T]/[C + G]
X-ray diffraction data
suggesting that the DNA molecule is:
a)helical
b)long and narrow
c)has a repeating structure
d)is composed of >1 polynucleotide chain
Details about DNA
a)two chains have anti-parallel orientation
b)pairs of bases project from opposite sugar-phosphate strands meet in center of molecule (HYDROGEN BONDS]
Two types of basepairs (bp) can form
a) A=T (LESS DENSE)
b) C=G (MORE DENSE/SMALLER/ THERMOSTABILITY)
Number of (bp) for every 360 degree twist of the molecule
10 bp distance
DNA molecule
right-handed nature of DNA/ alternating major and minor grooves run along the right- hand fashion
DNA Grooves
sites for DNA-binding proteins
Width of double helix
2 nm (including phosphate backbone)
Hydrogen bonds and hydrophobicity
stability of genetic material (dissolve in water due to the neg charge of the phosphate groups on the outside of the molecule, whater cannot cause the two strands to seperate [NEED TO COLD, DRYNESS, HIGHT SALT]
Conservative DNA replication
new strands
Semi-conservative DNA replication
parental acts as a template with a new strand
Dispersive DNA replication
segmented replication in new strands