IB BIO Y1U4 - Cells

NUcleus

dna is stored in chromosomes

dna is transcribed into rna an carried to ribosomes

Ribosome

Protein Making machine

can be free floating in cytoplasm or fixed to ER

Rough Endoplasmic Reticulum

stedded with ribosomes

factory where proteins are assembled

Golgi

recieves proteins from the ER, modifies them by adding tags or signals, puts them in vesicles

vesicles

delivery truck

transfers proteins to cell membrane for excretion or to other organelles

Smooth ER

no protein synthesis

lipid synthesis

Harmful toxin detox

calcium storage

Lysosome

cell recycling center

full of powerful enzymes that break down molecules

plant vacuole

large and central

stores water and nutrients

does waste disposal

animal vacuole

waste disposal and nutrient storage

Mitocondria

site of cellular respiration

Glucose is converted into ATP

double membrane

Chloroplast

plant only

site of photosynth - captures light energy and converts to glucose

double membrane

nucleolus

produces ribosomes which are then moved to chloroplast

centrioles

cell division

organize microtubuals that pull chromosomes apart during miosis

cytoskeleton

network of criss crossing proteins against cytoplasm

structural support

phospholipid bilayer

amphipathic

hydrophobic tails pointing in

hydrophilic heads pointing out

selectively permiable - only select substances can cross without assistance

permiability ranking

impermiable → anything charged, needs help to get across (ex: ions)

mostly impermiable → large, polar, uncharged molecules (ex: glucose)

Mostly permiable → small, polar, uncharged molecules (ex: H2O)

Permiable →small nonpolar molecules (ex: steroids)

integral protein

protein embedded in cell membrane

amphipathic

Transmembrane → spans across the whole bilayer

peripheral protein

located on surface of bilayer on either side

hydrophillic

functions of membrane protein

transport - must be transmembrane, transports materials across bilayer

recognition - extracellular side, cell to cell recognition, id tags

receptors - recieve chemical signals

enzymes - catalyse reactions

adhesion - extracellular side, join cells together

Glycolipids and glycoproteins

• carbohydrate attatched to a lipid (glycolipid) or protein (glycoprotein)

• conjugated

• extracellular side

• used for cell recognition, adhesion, reception, and protection

cholesterol

amphipathic

prevents membrane from freezing at low temp (keeps phos lipids apart enough)

stabilizes membrane when temp to high

factors impacting membrane fluidity

temperature

cholesterol

saturated vs unsaturated fatty acid tails (cis unsaturated fats have bend and cant pack tightly → more fluid)

osmosis

diffusion of water across semipermiable membrane

aquaporin

channel protein that allows for more osmosis

facillitated diffusion

direction of water in osmosis

from HIGH concentration to LOW concentration

hypertonic

higher solute concentration in solution

water moves into solution from cell

hypotonic

higher solute concentration in cell

water moves into cell from solution

animal cell behavior in solutions

isotonic - normal

hypotonic - water moves into cell , cell lyses

hypertonic - water moves out of cell, cell shrinks or crenates

plant cell behavior in solutions

isotonic→plant is flascid and wilts, no net movement of water

hypotonic → plant is normal, water moves into cell, turgor pressure keeps plant upright

hypertonic solution →plant plazomlyzes, water moving out, cell membrane moves away from cell wall

active transport

requires energy

pump protein

integral transmem protein

moves substances across bilayer against concentration grad

REQUIRES ENERGY

Exocysotsis

materials excreted to outside the cell

vesicles fuse with membrane, and contents is expelled

ex: release of neurotransmitters

endocytosis

cell membrane caves in to bring contents into cell

cell membrane dips inward (Invagination) and creates vesicle inside cell containing contents

phagosytosis

cellular eating

ex: ingestion of pathogens by white blood cells

pinocytosis

cellular drinking

vesicle types

transport - move materials around cell

secretory - store and move materials for exocytosis

lysosomes - vesicles containing hydrolytic enzymes

peroxisomes- vesicles containing lipid and detoxification enzymes

clatherin coated pit

clatherin proteins come together on cell membrane to create clathrin coated pit, allowing cell membrane to invaginate for endocytosis

factors effecting diffusion rate

steeper conc grad → faster diffusion

shorter distance → faster diffusion

higher temp → faster diffusion

polar molecules diffuse slower

larger molecules diffuse slower

gated channels (facillitated diffusion)

ligand gated channels → channel opens when ligand binds to receptor

Voltage gated channels → channel opens and closes in response to changes in electrical charge along cell mem.

carrier protein

molecule binds to carrier protein

carrier protein undergoes confirmational change, opens to the inside and allows materials to pass through