Honors Biology, Cell Growth and Division

Unit 4

cyclin

controls progression of cells, starts mitosis

internal regulators

initiates mitosis

external regulators

speed up and slow down mitosis

growth factors

the “go” signal

apoptosis

the programmed cell death for unnecessary cells

chalones

prevent cells from entering mitosis

contact inhibition

normal cells stop dividing and migrating once they touch more cells

metastasis

cancerous cells breaking away and traveling through the bloodstream too form more tumors

tumor

caused by uncontrolled cell growth due to DNA mutations

proto-oncogene

the gas pedal for mitosis. When this becomes stuck, cells will grow uncontrollably.

p53

the break pedal for mitosis, prevents cancer. Elephants have 20 copies; humans have 1.

tumor suppressant genes

normal genes that slow cell division and repair DNA

endostatin

a form of cancer treatment that stops tumors from forming blood vessels.

embryo

the early stages of development

zygote

fertilized egg

morula

comes after zygote stage, is a cluster of cells from cell division

blastula

comes after morula stage, is a hollow ball of cells

gastrula

comes after blastula stage, has three cell layers

totipotent

stem cells become the whole organism

pluripotent

stem cells become any organ

multipotent

stem cells become different tissues

morula

This stage of embryonic development is totipotent

blastula

This stage of embryonic development is pluripotent

gastrula

This stage of embryonic development is multipotent.

blastocyst

a blastula where its cells have become specialized

adult stem cells

these are multipotent, found in all people

mesenchymal stem cells

these are mutlipotent, found in all people

binary fission

this is the process that prokaryotes divide in

a limited amount of DNA, and a decreasing surface area to volume ratio

why cells must divide