Honors Bio Cellular Structure and Function Unit 4.5

endocytosis

when a cell takes in an external substance through the cell membrane by creating vesicles (sacks) to “hug” it in

exocytosis

to get rid of macromolecules that are too big for the cell, it releases macromolecules by fusing the vesicle with the plasma membrane

large cell size makes it…

hard to move nutrients into the cell

cells function best when

there is a larger surface area to volume ratio

small cell size makes it…

easy to absorb nutrients and excrete waste

unicellular organisms…

reproduce/clone asexually via cell division

multicellular organisms…

use cell division to grow and develop, and repair and renew cells once fully grown

interphase

when a cell grows and copies its DNA in prep for mitosis--90% of the cell cycle happens here

G1 phase “first gap”

cell growth and protein synthesis

S phase (synthesis)

dna replicated

G1/S Checkpoint

if cell does not pass, cycle stops completely, goes into senescence

G2 phase“second gap”

growth, protein synthesis, and organelle development

mitosis

division of nucleus, then division of cytoplasm (cytokinesis)

G2/M checkpoint

if cell does not pass, cycle stops to prepare DNA

G0 (senescence)

cell retirement home, waiting to die

apoptosis

cellular suicide…cell is damaged/gets signal proteins, shrinks, proteins help break down cell components, enzymes break down nucleus, cell parts removed from the body

in plant cells, vesicles form…

a cell plate

in plant cells, the cell plate…

forms a cell wall, causing the cell to split into two daughter cells

metastasis

the spread of cancer cells

in animals, cells are separated by…

the cleavage furrow drawing the plasma membrane towards the center, until the cell is eventually split into two daughter cells

the stages of mitosis in order are…

prophase, metaphase, anaphase, telophase, cytokinesis

prophase

chromatin condenses into chromosomes, and mitotic spindle starts forming

chromaTIN

substance from cell’s nucleus made of proteins and dna…

chromaTID

two sister chromatids make up a chromosome

chromosome

humans have 46, half from each parent chromatin condenses into chromosomes as the cell enters the mitotic phase

metaphase

nuclear membrane/envelope disintegrates, sis chromatids line up along metaphase plate with help from spindle fibers

metaphase plate:

invisible line that separates the two poles in a cell

anaphase

spindle fibers pull the sis chromatids apart, towards opposite poles. centromeres of the chromatids break apart

telophase

genetic material is completely separated, two new nuclear membranes/envelopes are formed around the chromosomes

cytokinesis

completion of mitosis, cytoplasm and cell organelles are separated

cancer cell abnormalities:

* too many dividing cells,
* large, dif shaped nuclei
* large nucleas to cytoplasm ratio
* dif shapes and sizes of cells
* loss of norm cell features
* disorganized, jumbled
* poorly defined tumor boundary

when mitosis and apoptosis are not in homeostasis…

tumor can form

prophase

anaphase

metaphase

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telophase/cytokinesis

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prophase

metaphase

anaphase

telophase/cytokinesis