Cell Structure and Function

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What do Prokaryotic Cells Only Have?

plasma membrane, cytoplasm, genetic material (chromosomes), and ribosomes

Only Types of Prokaryotic Cells

Archaea and Bacteria

Prokaryotic Parts (outside)

Capsule - a sticky outside layer that helps prokaryotes stick to surfaces and perhaps extra protection

Cell Wall - supports cell shape and protects cell

Plasma Membrane - phospholipid bilayer

Pili - hair like structures that help the prokaryote stick to surfaces or “reel in” other bacteria

Flagella - a tail thingy (like sperm) used for motion

Prokaryotic Parts (inside)

Ribosomes - free floating organelles, makes proteins

Plasmids - circular chunks of DNA

Nucleoid - one large circular chunk of DNA

Eukaryotic Cells

have internal membranes that:

• compartmentalize their functions (organelles)

• isolate specialized environments (pH, molecules)

• to increase internal surface area for reactions

• either autotrophic (plant-like) or heterotrophic (animal-like)

Endomembrane System

coordinates the sending of proteins from ribosomes to their destinations

Nucleus

• permamently stores DNA

• hosts DNA synthesis (replication)

• hosts RNA synthesis (transcription)

Nucleolus

compartment of nucleus that makes ribosomes

Ribosomes

where translation occurs for protein synthesis (protein assembly)

Free Ribosomes - make cytoplasmic proteins

Bound Ribosomes - stuck on the rough ER, make membrane and excretory proteins (only on eukaryotic cells)

Endoplasmic Reticulum (ER)

Rough ER: compartmentalizes the cell for protein synthesis (since it has bound ribosomes on its surface)

proteins go from rough ER to smooth ER then to golgi apparatus

Smooth ER: packages proteins into vesicles and send them to the golgi apparatus. some proteins stay in the smooth ER to become enzymes. smooth ER also makes phospholipids for cell membrane

Golgi Apparatus

“finishing” center of the cell

makes “final touches:” - adding phosphate groups, etc

sends finished proteins to the cell membrane to be excreted out of the cell or to lysosomes or perioxisomes

Vesicles

small membranous sacs that store materials or transport/secrete materials around/out of cells

Secretory Vesicles

fuse with the cell membrane to deliver membrane proteins or to release secretory proteins (exocytosis)

Vacuoles (type of vesicle)

larger vesicles that function as storage for food, water, or waste

Large Central Vacuoles

found in plant cells

stores water and exerts an outward force (turgor pressure) on the cell wall

this outside force provides rigidity and structure to plants (makes them upright and not wilted)

if plants are wilting, they need water to replenish their large central vacuole

Contractile Vacuole

contracts to dispel excess water, preventing the single-celled organism from absorbing too much water and dying (damn)

Lysosomes

produced by the golgi apparatus

digests old cell parts and large food molecules

in white blood cells, lysosomes destry engulfed pathogens

only in animal cells

Peroxisomes

formed by fusing vesicles from the mitochondria AND the Rough ER together

mostly found in our liver (in animals)

found in seeds (plants)

found in nearly ALL eukaryotes

Mitochondria

eukaryotic organelles that makes ATP (energy molecule) through aerobic respiration (with oxygen)

lots of folds in the inner membrane to increase surface area to maximize the amount of chemical reactions (to make teh most amount of ATP)

has its own DNA

Chloroplast

in plants

contains chlorophyll (the stuff that makes plants green), chlorophyll captures sun energy and carbon from CO2 to turn into glucose [energy])

thylakoids - flat green pancakes in chloroplasts.

stacks of them are called grana and increase surface area

also has their own DNA

Endosymbiotic Theory

explains why some organelles have their own DNA (mitochondria and chloroplast), where basically the mitochondria and chloroplast were prokaryotic cells that got absorbed by a eukaryotic cell so thats why theyre so complex

Cell Membrane

• not rigid, is flexible and can move to adapt to its surroundings

• can regenrate itself to a certain extent after damage has occured

• some organelles have their own membrane even thought the cell has its own membrane already

• channel proteins provide a passageway through the membrane

• there are small tunnels created between two animal cells (junctions) in order to quickly transport material between both cells

• some single celled bacteria reproduce by splitting into two bacterias (binary)