Tags & Description
Centric fragment
A piece of chromosome containing a centromere
Acentric fragment
A chromosomal piece without a centromere
dicentric chromosome
A chromosome with two centromeres
Inversion
The replacement of a section of a chromosome in the opposite orientation
deletion
the loss or absence of one or more nucleotides from a chromosome
Translocation
a part of the translation process in which the mRNA is shifted one codon in relation to the ribosome.
reciprocal translocation
A chromosomal configuration in which the ends of two nonhomologous are broken off and become attached to the non-homologs
deletion loop
See image
pseudodominance
the phenomenon in which a recessive allele confers the phenotype when only one copy of the allele is present, as in hemizygous alleles or in deletion heterozygotes
Deletion mapping
a technique used to find out the mutation sites within a gene
genetic imbalance
unnatural ratio of gene expression
Haploinsufficiency
lethal phenotype due to expression of only a single wild type allele
pericentric inversion
A chromosomal inversion that includes the centromere within the inverted region
paracentric inversion
A chromosomal inversion that does not include the centromere in the inverted region
Suppression (of recombination)
The phenomenon where a mutation (suppressor) restores the wild-type phenotype to a different mutation. the suppressor mutation may be in the same gene as the original mutation (intragenic suppression) or may be in a different gene (intergenic suppression)
variegation
Patchiness; a type of position effect that results when particular loci are contiguous with heterochromatin
duplication
extra copies of a chromosomal region are formed
aneuploidy
the condition of a cell or of an organism that has addition or deletions of whole chromosomes
euploidy
the condition of a cell or organism that has one or more complete sets of chromosomes
polyploid
anything above diploid
tetraploid
organism with four homologous sets of chromosomes
triploidy
organism containing three homologous sets of chromosomes
monosomy
absence of one member of a chromosomal pair
disomy
normal state of chromosomes in a eukaryote cell
trisomy
chrosomal abnormality in which there is one more than the normal number of chromosomes in a cell
nullisomic
A diploid cell missing both copies wof the same chromosome
Down syndrome
Trisomy 21 (three chromosomes on chromosome 21)
nondisjunction
the failure of a pair of homologous chromosomes to separate properly during meiosis
mosaic
Individuals made up of two or more cell lines with different genotypes that originated in the same zygote
heterochromatin
Chromatin that remains tightly coiled ( and darkly staining) throughout the cell cycle (transcriptionally inactive)
Chromatin
The DNA-protein complex that composes the eukaryotic chromosome
ribose
a pentose sugar important as a component of ribonucleic acid
deoxyribose
a sugar that is a constituent of nucleic acids
phosphate
a salt of phosphoric acid
nitrogenous base
A molecule that contains nitrogen and has the chemical properties of a base
pentose sugar
5 carbon sugar
nucleotide
Basic structure of DNA and RNA that consists of a nitrogenous base, a sugar, and one or more phosphates
nucleoside
A sugar-base compound that is a nucleotide precursor. A 5-carbon sugar with a nitrogenous base attached
Purine
Double C and N rings, has Adenine and Guanine
Pyrimidine
Single C and N rings, has Thymine, and Cytosine, and Uracil
DNA base pairs
Adenine, guanine, cytosine, thymine
RNA base pairs
Adenine, guanine, cytosine, uracil
DNA
Deoxyribonucleic acid, heritable molecule
RNA
Ribonucleic Acid, single helix, shorter than DNA
dsDNA
double-stranded DNA
ssDNA
single strand DNA
sugar-phosphate backbone
Forms the structural framework of nucleic acids, including DNA and RNA, joins together nucleotides in a DNA sequence
phosphodiester bond
a chemical bond of the kind joining successive sugar molecules in a polynucleotide
Chargaff's ratios
Amount of A = T, amount of G=C
double helix
the normal structure of DNA consisting of two helices rotating about the same axis
antiparallele
parallel but orientated oppositely
complementarity
the correspondence of DNA bases in the double helix so that adenine in one strand is opposite thymine in the other strand and cytosine in one strand is opposite guanine in the other. relationship explains Chargaff's rule
histones
Arginine- and lysine- rich basic proteins making up a substantial portion of eukaryotic nucleoprotein
nucleosome
the basic structure of eukaryotic chromatin that is composed of approximately 165 base pairs of DNA wrapped around a histone structure that consists of two molecules each of H2a, H2b, H3, and H4
solenoid
contains six nucleosome per turn
2nm fiber
short region of DNA double helix
11nm fiber
1st level packaging (nucleosome) "beads- on- a- string" form of chromatin
30nm fiber
2nd level (solenoid)
240nm fiber
3rd level (chromosome scaffold)
700nm fiber
4th level condensed scaffold
1400nm fiber
metaphase chromosome
chromosome banding
Characteristic banding pattern in chemically stained chromosomes
euchromatin
Eukaryotic chromosomal regions that are diffuse during interphase and presumably are the regions that are actively transcribed. (transcriptionally active)
Facultative heterochromatin
can shift between transcriptionally active and inactive states
centromeres
constrictions in eukaryotic chromosomes on which the kinetochore lies. Also, the DNA sequence within the constriction that is responsible for binding the kinetochore
telomere
the ends of linear eukaryotic chromosomes
C-value
genome size
C-value paradox
Genome size does not correlate with complexity of organism
transposon
repetitive DNA sequences that have the capability to move (transpose) from one location to another in genome
junk DNA
Eukaryotic DNA that lacks genes and has no known purpose
semiconservative replication
the mode by which DNA replicates, where each strands acts as a template for a new double helix.
theta structure
an intermediate structure formed during the replication of a circular DNA molecule
replication fork
The point at which the two strands of DNA are separated to allow replication of each strand
replication bubble
an unwound open region of the DNA helix from where the replication of DNA occurs
origin of replication
a sequence of DNA at which replication is initiated on a chromosome, plasmid or virus
DNA polymerase 1
removes RNA primers and replaces with DNA
DNA polymerase 3
Builds leading strand and Okazaki fragments
Primer
In DNA replication, a length of DNA or RNA, which is base paired to a single- stranded DNA template, that provides a 3' end for the addition of another nucleotide
leading strand
Strand of DNA being replicated continuously towards the replication fork
lagging strand
The DNA strand that is replicated discontinuously away from the replication fork
continuous replication
uninterrupted DNA replication in the 5' to 3' direction that is moving in the same directions the replication fork
discontinuous replication
DNA replication in short 5' to 3' segments that are moving away from the replication fork
Okazaki Fragments
Segments of newly replicated DNA produced during discontinous DNA replication on the lagging strand a
RNA Primase
A RNA polymerase that creates the short RNA primer for initiation of okazaki fragment synthesis during DNA replication. (places RNA primers)