Asexual Reproduction
A reproductive process that involves only one parent and produces offspring that are identical to the parent.
Cell cycle (G0, G1, S, G2, M)
The process in which eukaryotic cells divide
G0
where most of our cells are located. cells here leave G1 and are NOT dividing (but can re-enter the cycle)
G1
Cell grows and organelles are duplicated
S Phase
DNA and centrosome replication
G2
final growth and preparation for mitosis
Mitosis
part of eukaryotic cell division during which the cell nucleus divides
Interphase
Cell grows, performs its normal functions, and prepares for division; consists of G1, S, and G2 phases
M Phase
The phase of the cell cycle that includes mitosis and cytokinesis.
Restriction point
A point of no return in G1 of the cell cycle; once this point passes, a cell is committed to a full round of the cell cycle
Nuclear division
the division of a cell's nucleus, as in mitosis
Cytokinesis
division of the cytoplasm to form two separate daughter cells
Cleavage Furrow
The area of the cell membrane that pinches in and eventually separates the dividing cell
Cell Plate
A double membrane across the midline of a dividing plant cell, between which the new cell wall forms during cytokinesis.
DNA synthesis (replication)
S phase, during which a cell's DNA is duplicated prior to cell division
Replication origins
specific sequence of DNA where DNA synthesis begins
Daughter Cell
the two new cells that result from mitosis and cytokinesis
Semi-conservative
Each half of an original DNA molecule serves as a template for a new strand
Chromosome
a threadlike structure of DNA (nucleic acids and protein) found in the nucleus of cells
Replicated Chromosome
A chromosome that has been copied; consists of two identical chromatids
Sister chromatids
joined identical copies of the original chromosome
Homologous Pair
a pair of chromosomes, one from each parent, that have relatively similar structures and gene values
Centromere
Area where the chromatids of a chromosome are attached
Leading Strand
The new continuous complementary DNA strand (5' to 3' direction)
Lagging Strand
The strand that is synthesized in fragments using individual sections called Okazaki fragments
Okazaki Fragment
short segment of DNA synthesized discontinuously in small segments (3' to 5' direction)
Histone
a protein that DNA wraps around to condense
Anti-parallel
Separate strands that run in a different direction (3' to 5' and 5' to 3')
Ligase
An enzyme that connects two (okazaki) fragments of DNA to make a single fragment
Nucleosome
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Mutation
A change in a gene or chromosome.
Mutagenic
Pertaining to producing a mutation.
Excision repair
locates and repairs incorrect sequence by removing a segment of the DNA and then adding the correct nucleotides
Chromosome segregation
separation of the sister chromatids during mitosis in which each new nucleus receives one copy of each chromosome
Mitotic spindle
A football-shaped structure formed of microtubules and proteins that is involved in the movement of chromosomes during mitosis and meiosis.
Spindle poles
Sites around the centriole where microtubules attach to
Kinetochore
A specialized region on the centromere that links each sister chromatid to the mitotic spindle.
Prophase
1st phase of mitosis: Chromosomes condense (and become visible), nuclear envelope dissolves, spindle forms
Metaphase
2nd phase of mitosis: Chromosomes line up in the middle of the cell
Anaphase
3rd phase of mitosis: Chromosomes separate and move to opposite ends of the cell
Telophase
Nuclear membrane reforms, chromosomes move to opposite poles and unwind into chromatin.
Checkpoints
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Apoptosis
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Helicase
an enzyme that "unzips" DNA, starting at the replication origin and bubbling to break the hydrogen bonds holding the strand together
Primer
A short segment of RNA that acts as the starting point for replication. It tells the DNA Polymerase where to start.
DNA Polymerase
attaches complementary nucleotides to the exposed bases on the original strand
Endonuclease
finds and removes a mistake in DNA
Ligase
an enzyme that connects two (okazaki) fragments of DNA to make a single fragment
Purine
Adenine and Guanine, made of two nitrogenous bases
Pyrimidine
Cytosine, Thymine, and Uracil made of one nitrogenous base (CUT the PY)