Cell Reproduction Cell Cycle Mitosis Flashcards
A series of events from the time a cell forms until its cytoplasm divides
Cell cycle
Three phases of cell cycle
Interphase, mitosis, and cytoplasmic division
This is the interval between mitotic divisions when a cell grows, roughly doubles the number if it’s cytoplasmic components, and replicates it’s DNA
Interphase
1st interval (gap) of growth before DNA replication: the cell is metabolizing and growing in preparation for cell division
G1
Interval synthesis (DNA replication or when DNA is being synthesized).
S
2nd interval (gap) when the cell prepares to divide and produce a large amount of proteins needed for division.
G2
Controls regulate the cell cycle at different points.
Gene expression
Checkpoint genes whose products inhibit meiosis
Tumor suppressors
Plays a key role in the G1 checkpoint of cell division
P53 gene
The Gene’s product monitors the integrity of DNA
P53
What will happen if the p53 is mutated
Cancerous cells repeatedly divide
No stopping at the G1 checkpoint
Occurs when abnormally dividing cells disrupt body tissue, physically and metabolically
Malignant neoplasm (cancer)
Can break free and invade other tissues (metastasize)
Malignant neoplasms
A fertilized egg or zygote divides by
Mitosis
Cell division follows two basic processes of dividing the nuclear contents:
Mitosis and Meiosis
A conservative nuclear division that produces identical daughter nuclei
Mitosis
Is a reductive nuclear division that produces four unique cells with half of the original genetic material and is the basis for sexual reproduction
Meiosis
Chromosomes were first observed by the German Embryologist
Walther Flemming in 1882
Chromosomes exist in somatic cells as pairs:
Homologous chromosomes or homologues
About how many typical human chromosomes in the nucleotides in its DNA?
140 million
Replicated chromosomes consist of _ held together at the _.
Two sister chromatid; centromere
Four stages of mitosis:
Prophase, Metaphase, Anaphase, and Telophase
Chromosomes condense and spindle forms; nuclear envelope breaks up; spindle microtubules attach to chromosomes
Prophase
Dynamically assembles and disassembled array of microtubules that moves chromosomes during nuclear division
Spindle
Duplicated homologous chromosomes line up the spindle equator (halfway between spindle poles); Siste chromatids begin to move apart toward opposite spindle poles
Metaphase
Microtubules separate the sister chromatids or each chromosome and pull them toward opposite spindle poles; each DNA molecule is now separate chromosome
Anaphase
Two clusters of chromosomes arrive at the spindle poles and de-condense; new nuclei form
Telophase
The nuclear envelope reappears. The chromosomes de-condense. As telophase progresses, cytokinesis also occurs
Telophase
