Biology Unit 2

• 1. Cells are the smallest working units of living things
• 2. All living things are made of cells
• 3. All cells come from pre-existing cells

• Prokaryotic
• small
• no membrane bound organelles
• no nucleus
• non specialized
• independant
• Eukaryotic
• larger cells
• membrane bound organelles
• true nucleus
• specialized
• dependant

• pro bacteria
• eukaryotic animals, humans, everything but bacteria

proteins they need amino acids which come from us eating proteins in order to make proteins for us

a semi\-permeable layer made up of two layers of phospholipids

• Receptor proteins sends messages or hormones between cells.
• marker proteins gives the cell and identity
• channel proteins allows molecules to pass through into the cell

jell like substance in cells made of cytsol and water contains the organelles

thin tubes and fillaments in the cell giving support and also used as a series of internal tracks

supplies the cell with energy makes ATP almost all is inherited from mother

contains the chromatin or instructions to making proteins

is DNA

condensed chromatin 46 of them in each cell

used to construct proteins

carries proteins out of the cell and makes phospholipids

prepares the proteins for shipment out of the cell

• break down large molecules
• repairs damaged cells
• destroys cell parts that are beyond repair (autophagy)
• if a cell dies it digests the entire cell (autolysis)

contains thylakoids which contain chlorophyll only in plant cells

store water, nutrients, and sometimes store toxins

• autophagy is when the lysosome eats just a disfunctional part
• autolysis is when the lysosome digests the entire cell if it dies

cell membrane is made up of phospholipids and it is semi-permeable. The cell wall is harder and sturdier

plant cells have a cell wall and a cell membrane animal cells just have membranes plant cells have chloroplasts and central vacuoles animal cells do not

the theory that mitochondria and chloroplasts once lived independantly and they eventually became part of our cells.

heterotrophics are cells that cannot make their own food becuase they do not have chlorophyll in them autotrophics can make their own food usually thru photosynthesis

the plant absorbs water and takes in carbon dioxide and then the chlorophyll traps the sunlight and the plant transforms it into glucose and oxygen gas

a solution is a solute dissolved into a solvent the solute is the thing getting dissolved the solvent does the dissolving

the amount of solute dissolved into solvent

diffusion is the movment of molecules from high to low concentration osmosis is exclusivly water moving high to low concentration

• hypotonic is an environment in which a cell will grow and swell up
• hypertonic it will shrink because of the amount of pure water in the cells and the amount of pure water around it
• isotonic will stay the same

the pressure that builds up in a cell due to a hypotonic environment turgor pressure is osmotic pressure in plants

it is when a plant cell shrinks very small and shrivels up this occurs in a hypertonic environment

diffusion is when molecules pass freely through the cell membrane facilitated diffusion is when the molecule is too large and it has to use a channel protein to get through

• endocytosis is the taking in large amounts of food by active transpot
• exocytosis is the forcing out contents by active transport

• active requires energy
• passive does not it is just a function that happens

• phagocytosis is a form of endocytosis it is when the cell takes in food
• pinocytosis is also endocytosis but it is when the cell takes in a liquid