Cell Structure and Organelles

Nucleus

determines which proteins ribosomes synthesize

Nucleolus

where ribosomes are formed

Nucleus

✅ stores instructions

Nucleus

blueprint

Ribosomes

✅ builds proteins

Ribosomes

assembles amino acids into protein chains

Ribosomes

producers

Rough ER & Golgi Apparatus

processors

Rough ER

✅ protein packaging/transport

Rough ER

✅ folds and shapes raw protein chains

Golgi

✅ modification/packaging/shipping

Golgi Apparatus

✅ modifies, packs, and ships proteins; it tags the protein so it knows where to go

Mitochondria

✅ ATP production

Chloroplast

✅ produces glucose using light (❌ does replace the mitochondria)

Chloroplasts

energy producing organelle that is present in strictly plants and algae

Mitochondria

energy producing organelle that is present in both plants and animals

Cell membrane

✅ regulates transport (❌ but doesn't block everything harmful)

Vacuole

✅ storage/regulates water balance

True or False: Plant cells do not need mitochondria because they have chloroplasts."

False. Plants make food with chloroplasts, but they still need mitochondria to turn that food into ATP.

If the question mentions: Enzymes/Insulin/Antibodies

Ribosome to Rough ER to Golgi (because these are all functional proteins that must be produced, processed, and secreted)

If the question mentions: Lipids/Steroids/Detoxification

Smooth ER (the smooth er handles lipids and detoxifies toxins. they are highly concentrated in liver cells)

If the question mentions: Active Transport/Pumping Ions

Mitochondria (ATP Count) (cus moving things along the concentration gradient requires high energy, meaning cells need tons of ATP)

Lysosomes

acidic recycling centers

Lysosomes

contain hydrolytic enzymes to break down polymers (proteins, lipids, old organelles) into reusable parts

white blood cell engulfing a bacteria

lysosome does the heavy lifting

highly involved in apoptosis(programmed cell death)

lysosomes

peroxisome

chemical detoxing

peroxisome

contains oxidative enzymes that strip hydrogen from toxic molecules, temporarily creating hydrogen peroxide (H2O2), before breaking it down into water (H2O + O2)

peroxisome

specifically target fatty acids and toxins like alcohol (abundant in human liver and kidney cells)

the three that provide the structural framework and internal "highway system" of the cell

cytoplasm, cytoskeleton, centrosomes

cytoskeleton

an incredibly fluid and dynamic network of protein filaments (microfilaments, intermediate filaments, and microfilaments)

cytoskeleton

gives the cell its shape, anchors organelles, and acts as a track for internal transport aka "highway"

centrosomes

main microtubule organizing center

centrosomes

present in both animal and plant cells but plant cells do not have centrioles

centrioles

tiny barrel shaped structures inside the centrosome

centrioles

during mitosis, they migrate to opposite ends of the cell and pull chromosomes apart

cytosol vs cytoplasm

cytosol is only the fluid (water, ions, soluble proteins), cytoplasm the entire region between the nucleus and the plasma membrane, including cytosol and suspended organelles

phospholipid bilayer

literal foundation of the cell MEMBRANE

phospholipid bilayer

its structure dictates homeostasis inside the cell

phospholipid bilayer

amphipathic (dual natured)

phosphate heads

part of the plasma membrane that is polar and hydrophilic (water loving)

phosphate heads

part of the plasma membrane that face the watery outside and inside of the cell

fatty acid tails

part of the plasma membrane that is nonpolar and hydrophobic

fatty acid tails

hide in the middle of the two layers, away from the water

Highly Permeable (Free Pass) – Small, non

polar molecules (O2, CO2), steroid hormones) that easily dissolve into and slip through the hydrophobic fatty acid tails.

Slightly Permeable (The Sneak-Through)

Small, uncharged polar molecules (H2O, ethanol) that are technically repelled by the oily core but are small enough to occasionally slip through temporary gaps between phospholipids.

Impermeable (Blocked Bulky)

Large, uncharged polar molecules (Glucose) that are too large to squeeze through membrane gaps and too hydrophilic to interact with the hydrophobic core.

Completely Impermeable (Hard Lock)

Charged ions (Na+, K+, Cl-) that can never pass through the bilayer on their own because they are trapped in heavy hydration shells and totally rejected by the non-polar tails.

Hydration Shell

A heavy, bulky "cage" of water molecules that tightly surrounds a charged ion due to electrostatic attraction, drastically increasing the ion's effective size and locking it out of the membrane.

Electrostatic Rejection

The process by which the oily, nonpolar interior of the lipid bilayer refuses to interact with charged ions or large polar molecules, pushing them back because it cannot break their bonds with water.