Biol 1441: Chapter 12
42 Cards in this Set
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Meisosis
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sex cells (gametes)
Produce nonidentical daughter cells
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Gametes
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egg, sperm (23 chromosomes)
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Mitosis
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somatic cells
Body cells (46 chromosomes)
Every single cell in your body (except sex cells!)
Produces identical daughter cells
Division for growth and repair
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Chromosomes
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supercoiled DNA
Only present when cell is getting ready to divide
(after the DNA is replicated)
Visible with a light microscope
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All other times DNA is...
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Chromatin
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Gametes
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23 total chromosomes
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Somatic Cells
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46 total chromosomes
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Sister Chromatids
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Identical DNA molecules
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Sister chromatids attached at...
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Centromere
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One chromosome that duplicates into...
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TWO sister chromatids
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Two main phases of the cell cycle
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1. Mitotic (M) Phase
2. Interphase
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Mitotic (M) phase
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mitosis and cytokinesis
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Mitosis
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the division of the nucleus
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Cytokinesis
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the division of the cytoplasm
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Interphase
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cell growth & copying of DNA
~90% of the cell cycle
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Sub-phases of Interphase
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G1 phase
S phase
G2 phase
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G1
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Cell growth and work
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S1 (DNA Synthesis)
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Copy DNA
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G2
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Preparing for mitosis, organelle replication
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5 Phases of Mitosis
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Prophase
Prometaphase
Metaphase
Anaphase
Telophase
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Prophase
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Chromatin condenses into chromosomes (now visible)
Mitotic spindle begins to form
Centrosomes begin to move apart
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Mitotic Spindle
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Controls movement of chromosomes using microtubules
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Kinetochores
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protein associated with the centromere (each sister chromatid has one)
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Cytokinesis
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formation of cleavage furrow
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Cleavage Furrow
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groove in the cell surface near the metaphase plate
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Binary Fission
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"Division in half"
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Specific checkpoints
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where cell cycle stops until a go-ahead signal is received
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3 Major Checkpoints
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G1 Checkpoint
G2 Checkpoint
M Checkpoint
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G1 Checkpoint
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cell is large enough to divide, enough nutrients are available to support the resulting daughter cells
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G2 Checkpoint
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DNA replication in S phase has been completed successfully
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M Checkpoint
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all of the chromosomes
are attached to the mitotic spindle by a kinetochore
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Cyclins
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Regulatory proteins involved in cell cycle control-concentration varies (cyclically)
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Cyclin-dependent kinases (Cdks)
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Regulatory proteins involved in cell cycle control- concentration constant
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Oncogenes
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Mutated or amplified genes involved in cell growth and differentiation
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Proto-oncogene
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normal non-mutated oncogene
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Tumor Suppressors
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Function to inhibit cell growth- cell cycle check points, DNA damage repair
Recessive - Loss of function
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Internal Signal
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kinetochores not attached to spindle microtubules, send a molecular signal that delays anaphase
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External Signal
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growth factors, proteins released by certain cells that stimulate other cells to divide
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{External Signals}
Density-dependent inhibition
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crowded cells stop dividing
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{External Signals}
Anchorage dependence
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cells must be attached to a substratum in order to divide
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Benign Tumor
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If abnormal cells remain at the original site
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Malignant Tumor
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invade surrounding tissues & metastasize
Moves to other parts of the body
May form secondary tumors
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Biol 1441: Chapter 12