Exam 1 Flashcards
Chromosome
A structure made of a long DNA molecules with many genes.
Chromatin
The combination of DNA and protein which makes up a chromosome.
Nucleolus
The region inside the nucleus which synthesizes rRNA and creates ribosomal subunits from it.
Nucleus
Houses genetic information in eukaryotes.
Mitotic Spindles
Microtubules which invade the nuclear area to move the chromosomes.
Centrosome
A region near the nucleus which contains two centrioles.
Centrioles
9x3 ring structures of microtubules. They help organize the mitotic spindles.
Microtubules
Part of the cytoskeleton; made of tubulin dimers. Involved in the disjunction of chromosomes during cell division.
Microfilaments
Thinnest part of cytoskeleton. Involved in the formation of a cleavage furrow during cytokinesis.
Nucleioid
The region in a prokaryote which contains the singular circular chromosome.
NOR
Nucleolus organizer region; DNA which encodes for rRNA. Prokaryotes don’t have a NOR.
Intergenic DNA
DNA which does not code for a protein end product
Sister Chromatids
The two chromatids of a singular replicated (X-shaped) chromosome.
Cohesin
The material which holds the sister chromatids together.
Non-sister Chromatids
The chromatids of two replicated (X-shaped) homologous chromosomes.
G1
Gap 1: a phase of interphase where no DNA is synthesized, and where cellular activity is focused on growth. It contains unreplicated chromosomes.
Checkpoint: checks if cell is healthy enough to divide; if no, enters G0
G2
Gap 2: a phase of interphase following the S phase and preceding the M phase. The volume of the cell doubles in preparation for division. It contains replicated chromosomes, and thus twice the amount of DNA.
Checkpoint: checks to ensure DNA properly replicated
S
A phase of interphase following G1 in which DNA is replicated. Chromosomes change from I shape to X shape. It contains replicated chromosomes, and thus twice the amount of DNA.
M
The phase in which mitosis happens: prophase, prometaphase, metaphase, anaphase, telophase.
Checkpoint: before anaphase, checks to see if chromosomes properly aligned on plate
Centromere
The location where sister chromatids join. Its position determines the chromosome’s appearance.
A single centromere is a requirement for accurate segregation of chromosomes.
Chromosomes are counted by functional centromere.
Metacentric
Centromere in the middle
Submetacentric
Centromere slightly above middle
Acrocentric
Centromere approaching end
Telocentric
Centromere at end