Alberts, Ch 4 - DNA, Chromosomes and Genomes Flashcards
Base pair
Two nucleotides in an RNA or DNA molecule that are held together by hydrogen bonds, G-C, A-T/U
Centrosome
Centrally located organelle of animal cells that is the primary microtubule-organizing center (MTOC) and acts as the spindle pole during mitosis, usually in pairs called centrioles
Chromatin
Complex of DNAm, histones and non-histone proteins found in the nucleus of a eukaryotic cell, material of which chromosomes are made
Chromosome
Structure composed of a very long DNA molecule and associated proteins that carries part of the hereditary information of an organism, especially evident in cells undergoing mitosis
Complementary
Capable of forming a perfect base-paired duplex with each other, having biochemical or structural features that marry up so that noncovalent bonding is facilitated
Copy number variations (CNV)
A difference between two individuals in the same population in the number of copies of a particular block of DNA sequence, variation arises from occasional duplicaions and deletions of these sequences
Deoxyribonucleis acid (DNA)
Polynucletide formed from covalently linked deoxyribonucleotide units, store of hereditary information within a cell and carrier of information from generation to generation
Double helix
Three-dimensional structure of DNA, in which two antiparallel DNA chains held together by hydrogen-bonding wound into a helix
Epigenetic inheritance
Inheritance of phenotypicchanges in a cell or organism that do not result from changes in the nucleotide sequence of DNA, can be due to positive feedback loops of transcription regulators or heritable modifications in chromatin such as DNA methylation or histon modifications
Euchromatin
Region of interphase chromose that stains diffusely, “normal” chromatin as opposed to condensed heterochromatin
Exon
Segment of eukaryotic gene that consists of a sequence of nucleotides that will be represented in mRNA or in a final transfer, ribosomal or other mature RNA molecule, in protein-coding genes encode the amino acids in the protein
Gene
Region of DNA that is transcribed as a single unit and carries information for a discrete hereditary characteristic, usually corresponding to single protein or single RNA
Genome
Totality of genetic information belonging to a cell or an organism, the DNA that carries the information
Heterochromatin
Chromatin that is highly condensed even in interphase, generally transcriptionally inactive
Histone
One of a group of small abundant proteins, rich in arginine and lysine, that combine to form nucleosome coresaround which DNA is wrapped
Histone H1
Linker histone protein that binds to DNA where it exits from a nucleosome and helps package nucleosomes ino the 30-nmchromatin fiber
Homolog
Oneof two or more genes that are similar in sequence as a result of derivation from the same ancestral gene, covers both orthologs and paralogs
Homologous
Genes, proteins, or body structures that are similar as a reult of a shared evolutionary evolution
Intron
Noncoding region of a eukaryotis gene that is transcribed into an RNA molecule but is then excised by RNA splicing during production of the mRNA or other functional RNA
Karyotype
Display of the full set of chromosome that are arranged with respect to size, shape and number
Lampbrush chromosome
Huge chromosome paired in preparation for meiosis, found in immature amphibian eggs
Mitotic chromosome
Highly condensed duplicated chromosome as seen at mitosis, consisting oftwo sister chromatids held together at the centromere
Nucleosome
Beadlike structure in eukaryotic chromatin, composed of a short length of DNA wrapped around an octameric core oh histone proteins, fundamental structure unit of chromatin
Position effect variegation
Alteration in gene expression resulting from change in the position of gene in relation to other chromosomal domains, especially heterochromatic domains, when an active gene is placed next to heterochromatin, inactivating influence of heterochromatin can spread to affect the gene to a variable degree
Pseudogene
Nucleotide sequence. Of DNAthat has accumulated multiple mutations thathave rendered an ancestral gene inactive and nonfuntional
Purifying selection
Natural selection operating in a population to slow genome changes and reduce divergence by eliminating individuals carrying deleterious mutations
Replication origin
Location on a DNA molecule at which duplication of DNA begins
Single-nucleotide polymorphism (SNP)
Variation between individuals in a population due to a relatively common difference in a specific nucleotide at a defined point in the DNA sequence
Telomere
End of a chromosome, associated with a characteristic DNA sequence that is replicated in a special way, counteracts tendency of chromosome otherwise to shorten with each round of replication
Template
Single strand of DNA or RNA whose nucleotide sequence acts as a guid for synthesis of a complementary strand
Antiparallel
Describesthe relative orientation of the two strands in a DNA double helix or two paired regions of a polypeptide chain, polarity of oone strand is opposite from the other
Centromere
Constricted region of a mitotic chromosome that holds sister chromatids together, also the site on DNA where kinetochore forms so as to capture microtubules from mitotic spindle
