cellular processes. homeostasis the ability or tendency to maintain internal equilibrium....
TRANSCRIPT
Cellular Processes
Homeostasis
• The ability or tendency to maintain internal equilibrium.– Maintain – “keep”– Internal – “inside”– Equilibrium – “stable or balanced”
Why is maintaining homeostasis in our body important?
Why is it important for cells to maintain homeostasis?
Cell Membrane
• The “gateway” of the cell.• It regulates what goes in and what comes
out.• Thus is important in understanding how a
cell regulates homeostasis.
A Closer Look at the Cell Membrane
Phosphate head
Fatty Tails
2 layers
Phospholipid Bilayer
Why is the cell membrane also
called the phospholipid
bilayer?
How does the Phospholipid bilayer help maintain homeostasis?
• The membrane is selectively permeable.– “selects some substances to cross but not
others”
NO ENTRYENTER
How “things” get selected to come into and out of the cell…
DIFFUSION
OSMOSIS
ACTIVE TRANSPORT
DIFFUSION
• Movement of particles from an area of greater concentration to an area of lower concentration.
• Cell does not use energy to do this.• Diffusion stops when the two areas are equal.
(homeostasis)• FACILITATED Diffusion
– diffusion of large molecules through protein channels
OSMOSIS
• Diffusion of water• 3 types of solutions drive the force of
osmosis– Hypertonic solution (higher concentration of
solute that water)– Hypotonic solution ( lower concentration of
solute than water)– Isotonic solution (solute has same
concentration as water)
Osmosis
• 3 types of solutions drive the force of osmosis
Active Transport
• The movement of molecules against the concentration gradient. – Therefore it requires energy.– Energy is in the cell is called ATP
ATPRequiresEnergy
Types of Active Transport
• Endosytosis – “into the cell”– Phagosytosis – “cell eating”
• EX) White blood cells eat invading bacterial cells
– Pinocytosis – “cell drinking”
And how do cells let it out…
“Exit the cell”
Latin Roots• Phago – to eat• Pino – to drink• Exo – exit• Endo – enter• Iso – same/equal• Hyper – high• Hypo – low• Cyto – cell• Bi – two• Homeo - same