Bio - Cell Size and Organelles / Osmosis and Diffusion (Ch 4 and 5.6-)

lysosome

• in animal cells

• intracellular digestion

  • breaks down particles

• think cleaner —> destroys pathogens

centrosome/centriole

• anchors the cytoskeleton

• plays key role in cell division and organization

• in animal cells

gap junctions and tight/adhering junctions

• in animal cells (plasmodesmata alt)

• connects a cell directly to other cells or its environment

• tight = fastens plasma membrane of animal cells —> prevents fluid from leaking

• adhering = fastens cells to each other / basement membrane

• gap = closable channels connecting cytoplasm of calls —> when open it permits water/ions/molecs to pass through

• key importance is communication —> allows entire regions of cells to respond to stimuli

  • coordinate function

plasma membrane

• in plant and animal cell

• separates the contents from the external environment

• made of a lipid bilayer

• provide protection for the cell

nucleus

• in plant and animal cells

• hold all of the cells dna

  • keeps it safe from metabolic processes

• controls passage of certain molecs across its membrane - nuclear pores

rough ER

• in plant and animal cells

• folded into flattened sacs w/ thousands of ribosomes attached

• make polypeptides (proteins) that thread into the ER interior while assembled

  • synthesize proteins**

free ribosomes

• in plant and animal cells

• organelle of protein synthesis

  • on them proteins are made

• not attached to any membrane

smooth er

• in plant and animal cells

• no ribosomes

  • makes its own proteins

• synthesizes lipids

• can detoxify the liver

• stores/regulates calcium

• some proteins from rer make it here and become enzymes for various functions

golgi body

• in plant and animal cells

• modifies and sorts polypeptides and lipids

• finishing touches on the proteins/lipids

  • attaching sugars

• “packager” —> connects and sends

  • prevents build up

mitochondrion

• in animal and plant cells

• makes ATP by glucose breakdown

• energy

• powerhouse of the cell

peroxisome

• in animal and plant cells

• breaks down fatty acids, amino acids, toxins

  • metabolism?

• hydrogen peroxide was a by product —> gets broken down into H20 and 0

cytoskeleton

• in plant and animal cells

• contributes to cell shape

• internal organization and movement

• structural framework

  • acts as a pathway

large central vacuole

• in plant cells

• stores or breaks down waste/debris/toxins/food

• makes up most volume in cell

• keeps plant cells plump so stems stay firm

• stores water and molecs- 90% of cell

chloroplast

• in plant cells

• makes sugars

• plastids specializing in photosynthesis

• carry out photosynthesis

cell wall

• in plant cells

• is the rigid layer of secreted material that encloses the plasma membrane

• protects the cell and supports its shape

• prevents swelling = bursting

  • when vacuole swells with water keeps cell safe

plasmodesmata

• in plant cells (gap junction)

• open channels that connect the cytoplasm of adjoining cells

• allows substances to flow quick from cell to cell

  • sharing and communication

    • mvmt

• key importance is communication —> allows entire regions of cells to respond to stimuli

  • coordinate function

cillia / flagellum

• in plant and animal cells

• hair like - move in unison - coordinate

• used for motion + mobility

• rotates like a propeller

unified cell theory

1. every living organism is made of one or more cells

2. the cell is the basic structural/functional unit of life

3. all living cells come from pre-existing cells

4. cells contain hereditary material which they pass on to offspring

difference between prokaryotic and eukaryotic cells

prokaryotic have no nucleus or membrane bound organelles

• the eukaryotic cell does

endosymbiotic theory

explains how organelles in eukaryotic cells evolved from free living prokaryotes

• suggests that the nucleus/mitochondria/chloroplast were once separate cells that were either consumed by another bacteria or were parasites of it

• evidence: all three have a double membrane, DNA, ribosomes, same division method (binary fission)

endomembrane system

net work of membrane bound organelles responsible for the production, modification, packaging, and transport of proteins/lipids outside of the cell

1. nucleus - transcribe message on RNA that has the recipie for protein synthesis

2. SER/RER - synthesis proteins/lipids - RER folds proteins into complex shapes

3. vesicle - protects cell products and moves them —> envelope

4. golgi - final modifier and packager before export

5. vesicle - envelope

6. outside

animal and plant cell differences

• all living organisms have at least a plasma membrane, cytoplsm, DNA, and ribosomes

similarity between nucleus, mitochondrion, and chloroplast

all have a double membrane, DNA, ribosomes, and the same division method (binary fission)

cell size - key points on growth / mitosis

• cell efficiency is determined by SA / V

  • increase at different rates —> becomes less efficient as size grows

• want a high SA:V ratio

membrane structure

has a phospholipid bilayer

• hydrophilic head and hydrophobic tail

• fatty acid tails are permeable to non polar molecules

• because its non polar it doesnt let through polar molecules —> they are repelled

• will have a protein channel to let through large polar molecules

five common types of membrane proteins

1. transport - help molecules go through the membrane

2. recognition - unique identifiers for the cell

3. receptor - receives signals and transmits messages to the nucleuss

4. adhesion - helps cells stick together

5. enzyme - catalyze reaction without being altered

diffusion

particles (solute) moving from high to low concentration

• does not required a membrane

• movement of molecules

osmosis

water moving from high concentration water to low

• or low concentration solute to high

• wants to achieve equilibrium

factors that affect diffusion

1. temperature

2. pressure

3. cell size

4. concentration

hypertonic

the concentration of the solution is higher than the cell (or other object) placed inside

• the cell will shrink since water flows out of it

hypotonic

the concentration of the solution is lower than the cell placed inside

• the cell will grow since water flows into it

isotonic

the concentration of the solution and th ecell placed inside is the same

• the cell size does not change

active vs passive transport

active transport goes against the concentration gradient

• requires energy

passive transport goes with the gradient

• doesnt require energy

simple diffusion

doesn’t require a protein to cross the membrane

facilitated diffusion

requires a protein to move across the membrane

• carrier protein - lets charged ions through

• channel protein - lets polar molecules through

flaccid

the turgid pressure is at equillibrium

• low pressure

• isotonic

turgid

the plant cell is rigid and hard

• the vacuole has water

• hypotonic

plasmolyzed

the plant cell has very low water - weak and wilted

• hypertonic

role of cholestoral in cell membrane

is the goldilocks for the membrane —> keeps it just right

too cold: the membrane is too stiff and the phospholipids are compact so oxygen and CO2 arent permeable

too hot: membrane might kinetically break apart and be too permable

turgor pressure

pressure exerted against the plant cell wall

• animals cant handle a change in turgor pressure since it has no cell wall

  • IV and seawater

dynamic equilibrium

equally spaced molecules that are constantly moving

the process of water going through simple diffusion

go through aquaporins