Chapter 11- Chromosomes Flashcards
The level of DNA structure that is the nucleotide sequence
Primary Structure
The level of DNA structure that is the double-stranded helix
Secondary structure
The level of DNA structure that is the high folding of DNA that takes place in cells
Tertiary structure
Additional winding/twisting of the double-helix DNA
Supercoiling
Clockwise supercoiling, overrotated
Positive supercoiling
Counterclockwise supercoiling, underrotated
Negative supercoiling
Proteins that add or remove rotations in DNA by breaking and then rejoining DNA strands
Topoisomerase
The type of topoisomerase that adds makes single strand breaks
Type I
The type of topoisomerase that makes double stranded breaks
Type II
The prokaryote version of a nucleus, where the DNA is
Nucleoid
The DNA and associated proteins of a chromosome in eukaryotes
Chromatin
Proteins in chromatin (eukaryotes) that play a structural role, roles in chromosome replication, chromosome segregation, and transcription
Non-histone Proteins
Small, positively charged, highly conserves proteins found in all eukaryotes, make up half the proteins in chromatin
Histones
The octamer of the four core histones H2A, H2B, H3, and H4
Nucleosome
One nucleosome is present ever how many base pairs
Around 200 bp (145-147 wrapped around the nucleosome, 20 bound to histone H1, and 30-40 bp of linker DNA)
The diameter of chromatin at the nucleosome level
11 nm
The diameter of chromatin when is is coiling in helical arrays, second level
30 nm
The diameter of chromatin in the third level, when it forms large loops
300 nm
The width of the fiber in the 4th level of chromatin organization, when there are fiber to fiber interactions
250 nm
The diameter of the chromatin during the fiber to fiber interactions (4th level)
700 nm
The diameter of the chromatin when it is condensed into a pair of sister chromatids
1400 nm
The chromatin structure that is usually transcriptionally active, relaxed
Euchromatin
The chromatin structure that is usually transcriptionally inactive, and tightly condensed
Constitutive Heterochromatin
The chromatin structure that is condensed or relaxed under specific conditions
Facultative heterochromatin
The portion of the nucleus that is occupied by the chromatin from each chromosome
Chromosome territory
Large regions of spatially interacting chromatin, and important aspect of transcriptional regulation
Topologically associating domain
Special DNA that is the attachment site for sister chromatids and spindle fibers during mitosis
Centromere
The ends of eukaryotic chromosome that contain tandem repeats and protect ehe ends of the chromosome
Telomere
A structure that occurs at the telomere in which the G-rich strand folds over and intermolecular H-bonds with the complementary strand
T-loop
A complex of six proteins that associates with telomeric DNA to mediate t-loop formation, protect the end sequences, and recruit and regulate telomerase
Shelterin
The amount of pg of DNA per haploid (1n) nucleus
C-value
An analysis used to determine the relative proportions of repetitive DNA and single-copy DNA in a genome
Cot Analysis
The type of DNA sequence in eukaryotes that had only one or few copies, variable length
Unique Sequence DNA
The type of DNA in eukaryotes that has 100s of repeats, 150-300 bp long, and can be tandem repeats or interspersed repeats
Moderately repetitive DNA
The type of DNA sequence in eukaryotes that is less that 10 bp long, in tandem repeats and clusters, 100,000s to millions of repeats, and found in centromeres and telomeres
Highly Repetitive DNA (satellite DNA)
The type of moderately repetitive DNA that appears in clusters
Tandem Repeat Sequences
The type of moderately repetitive DNA that is scattered throughout the genome
Interspersed repeat sequences
The type of interspersed repeat sequences that ate 100-300 bp in length
Short interspersed elements (SINEs)
The most common human SINEs
Alu sequences
The type of interspersed repeat sequences that are 6.5 to 8.5 kb in length, and makeup around 17% of the human genome
Long Interspersed elements (LINEs)
The most common human LINEs
L1 Sequences
Membrane bound structures inside eukaryotic cells that perform specialized functions
Organelles
An organelle present in all eukaryotes that is the site of electron transport and oxidative phosphorylation
Mitochondria (mt)
An organelle present in green plants and algae that are the sites of photosynthesis
Chloroplasts (cp)
The theory that mitochondria and chloroplast evolved from bacteria that were endocytosed and then developed into an endosymbiont
Endosymbiotic theory
