Unit Two Bio

Cell M
NOT everything can enter or leave the cell.
↳ determined by the cell membrane.
Cell membrane - forms a barrier between the cytoplasm and the cell's environment
semipermeability- allows some things out; not all.
phospholipid bilayer - the two layers the phospholipids
hydrophilic ~ likes water
hydrophobic ~ hates water

phospholipids

• have a hydrophilic head
• has 2 hydrophobic tails-
• belongs to lipids
  -head-attracts to water
• tail- attracts hydrophobia’s
  stuff

what can pass
• Steroids/small lipids
• hydrophobic molecules

Membrane Proteins
• contain primarily our lipids
↳ especially chlorestorol
It helps keep shape

Integral membrane proteins
. are permanently embed ed in membrane

help w/ transport cell receptors; some are responsible for adhesion.

transmembrane → entire cell membrane
monotopic → attached on one side.

Peripheal Membrane Proteins-temporarily on one side; can be easily removed can attach to imp or can stick into small portion-of lipid bilayer; most are hydrophilic.

o Nucleus center of cell; in charge of activities; holds DNA
o Golgi - makes lysosomes e packages/transports proteins
o Mitochondria - powers cell; converts ATP into useable energy.

Endoplasmic reticulum- makes ribosomes ↳ Smooth-> no ribosomes

Rough has ribosomes

• cell membrane - controls what goes in/out, support; outside of cell.
lysosomes- breakdown dead cells; digests new materials brought in.
centrioles - help divide cell during cellular division
cytoplasm-jelly-like substance that holds everything in place

• vacuole ~ storage area for materials/water.
• cytoskeleton - holds everything together

o central vacuole-major place for water

Chloroplast- make sunlight into energy during photosynthesis; contains chlorophyll, giving green color

Cell wall-outside cell membrane; structural support/ gives square shape

Cell Theory

1. All cells come from other cells
2. Cells are the smallest unit of life

All living things are made up of cells.

Prokaroytic
Older
No membrane bound organelles
Contain only cell wall, cell membrane, and cytoplasm
DNA is free floating
Ex: bacteria and archaea bacteria

Eukaryotic
younger
membrane bound organelles
DNA
Ex: plant and animal cells

Passive Transport
• does not require ATP
energy
examples include:
-diffusion; facilitated diffusion; osmosis
moves from high-low
concentration

Active Transport
Requires ATP energy
-examples include:
Endocytosis

• exocytosis

moves from low-high concentratioN

diffusion- the movement of molecules across the membrane in
a high-> low concentration gradient; happens easily w small molecules

facilitated diffusion when a protein transport helps large molecules get through the phospholipid bilayer
common examples glucose into GLUT protein channel

Endocytosis-The taking in of things into all
pinocytosis- taking in of water
phagocytosis- taking in of larger molecules
receptor-mediated
water going in solid particles already deposit formed,
closes to form vesicle
exocytosis- letting things out.

Osmosis the movement of water across a cell

hypertonic lots of solute- cell shrives-water moves out of cell

isotonic equal- cell remains the same

hypotonic- lots of solvent- cell swells- water moves into cell

Homeostasis- the body's ideal equalness

Negative Feedback

tries to counteract whatever is breaking homeostasis ex: sweating when hot; shivering When cold.

Positive Feedback

Amplifying whatever is breaking homeostasis ex: contractions; ripening in fruit