Lesson 2 Flashcards
Robert Hooke
- made many improvements to compound microscopes
- first to see and name “cells”
- published first comprehensive book of microscopy (Micrographia)
Cell Theory
- cells are the building blocks of all plants and animals
- all cells come from the division of pre-existing cells
- cells are the smallest unit that perform all vital physiological functions
- each cell maintains homeostasis at the cellular level
why is cell size limited?
surface area to volume ratios
somatic cells
body cells, formed by mitosis
sex cells
germ cells, reproductive cells
ECF
extracellular fluid, includes any fluid outside the cells
- interstitial fluid, blood plasma, lymph, cerebrospinal fluid, etc.
cytoplasm
region between the plasma membrane and nucleus
cytosol
the clear gel/intercellular fluid within the cytoplasm
functions of the plasma membrane (4)
- physical barrier
- regulates entry/exit of material into/out of cells
- responses to changes in the ECF
- provides support to the cell
phospholipids
- 75% of membrane lipids
- amphipathic arrange in a bilayer
- drift laterally, keeping membrane fluid
cholesterol
holds phospholipids still and can stiffen membranes
glycolipids
phospholipids with short carbohydrate chains on extracellular face; contribute to glycocalyx
glycocalyx
carbohydrate component of glycoproteins and glycolipids located external to plasma membrane
- unique in everyone but identical twins
functions of the glycocalyx (7)
- protection
- immunity to infection
- defense against cancer
- transplant compatibility
- cell adhesion
- fertilization
- embryonic development
transmembrane proteins
pass completely through the membrane
most are glycoproteins
peripheral proteins
adhere to one face of the membrane
functions of membrane proteins
receptors, enzymes, channel proteins, carrier, cell-identity markers, cell-adhesion molecules (CAMs)