Definition: A rapid increase in the number of cells.
How? When cells divide quickly and not many are dying.
Why? For growth, cell replacement, and tissue repair in multicellular organisms.
The hero behind the scenes? Mitosis! Keeps the genome consistent during cell proliferation.
Growth - From Baby Yoda to Master Yoda 🌱🪐
Animals
Stages: Embryonic → Juvenile → Adult (no more growth, congrats you're Yoda!).
Baby Phase: Cell proliferation everywhere in the embryo.
Kiddo Phase: Some body parts, like growth plates near bone ends, have active cell proliferation leading to that sudden height boost during teenage years!
Plants
Growth HQ: Meristems (kind of like plant growth factories).
Apical Meristems: Tips of stems and roots. Think of it like the top of an ice cream cone!
Some cells: "I'll stay here and divide more!"
Others: "I'm out! Let's get bigger and find a job!" (Like root lengthening or making leaves/flowers).
Cell Replacement - Out with the Old, In with the New! 🔄
Old cells on the skin's surface? They've done their job and are kicked out.
New cells? Produced in the basal layer of the epidermis, these guys move upwards, making lots of keratin (a tough protein) on the way. By the time they reach the top, they're flat and dead. Thanks to friction, we wave them goodbye as they've made us waterproof and safe!
Debate Time! 🤔: Is cell replacement real cell proliferation? It's tricky because while cells are dividing in one skin layer, they're dying in another.
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Definition: A rapid increase in the number of cells.
How? When cells divide quickly and not many are dying.
Why? For growth, cell replacement, and tissue repair in multicellular organisms.
The hero behind the scenes? Mitosis! Keeps the genome consistent during cell proliferation.
Growth - From Baby Yoda to Master Yoda 🌱🪐
Animals
Stages: Embryonic → Juvenile → Adult (no more growth, congrats you're Yoda!).
Baby Phase: Cell proliferation everywhere in the embryo.
Kiddo Phase: Some body parts, like growth plates near bone ends, have active cell proliferation leading to that sudden height boost during teenage years!
Plants
Growth HQ: Meristems (kind of like plant growth factories).
Apical Meristems: Tips of stems and roots. Think of it like the top of an ice cream cone!
Some cells: "I'll stay here and divide more!"
Others: "I'm out! Let's get bigger and find a job!" (Like root lengthening or making leaves/flowers).
Cell Replacement - Out with the Old, In with the New! 🔄
Old cells on the skin's surface? They've done their job and are kicked out.
New cells? Produced in the basal layer of the epidermis, these guys move upwards, making lots of keratin (a tough protein) on the way. By the time they reach the top, they're flat and dead. Thanks to friction, we wave them goodbye as they've made us waterproof and safe!
Debate Time! 🤔: Is cell replacement real cell proliferation? It's tricky because while cells are dividing in one skin layer, they're dying in another.
Unlock the Full Content!
Dive deeper and gain exclusive access to premium files of Biology HL. Subscribe now and get closer to that 45 🌟