Cells and Organelles - OAT Bio

Nucleus

Contains cell’s DNA, coordinates cell functions (like protein synthesis and reproduction) “Control center”

Nucleolus

Site of rRNA synthesis

Cytoplasm

Fluid area where metabolic activities occur

Mitochondria

“Powerhouse”

Double layered, makes ATP, site of FA catabolism, has its own circular DNA and ribosomes

Ribosomes

Made of rRNA, makes proteins, found in eukaryotes and prokaryotes

Rough Endoplasmic Reticulum

Has ribosomes attached to mb, synthesizes/stores proteins that are secreted from the cell

Smooth endoplasmic reticulum

Synthesizes lipids, detoxifies drugs, stores calcium

Golgi

Modifies and packages proteins

Lysosomes

Made by golgi, responsible for apoptosis, breakdown of nutrients, bacteria, and debris

Peroxisomes

Common in liver and kidney, breaks down substances and converts H2O2 into H2O

Cytoskeleton function

Maintains cell shape and movement

What makes up the cytoskeleton?

Microtubules, Intermediate filaments, Microfilaments

Microtubules

Made of tubulin, supports cell and motility

Centrioles

Made of microtubules- develop spindle fibers for cell division

Cilia

Made of microtubules, short extensions for movement

Flagella

Made of microtubules, long extensions for movement

Intermediate filaments

Composed of keratin, maintains cell shape

Microfilaments

Composed of actin, used for cell shape/division

Vacuoles

membrane bound vesicles that move and store waste and metabolic products

Extracellular matrix

Provides mechanical support, helps connect adjacent cells

(mostly made of collagen)

Cell wall

protects and supports cell, controls water intake

only in plants

Plastids

Metabolic activities

(like chloroplasts for photosynthesis)

only in plants

Prokaryote traits

no nucleus

bacteria or archaea have sticky capsules on the cell wall

flagella from flagellin (not microtubules)

Phospholipid membrane permeability

Allows: Small, uncharged, hydrophobic

Denies: large, polar, or charged

Cholesterol function

Regulates fluidity of cell membrane

Channel proteins

allow passage of hydrophobic, polar, and charged substances

incudes Ion channels and porins

Ion channel

Voltage, ligand, or mechanically gated channels

Porins

“pore”, less specific, allows polar molecules

Carrier proteins

Specific molecules can pass after binding to protein and changing its shape

Transport proteins

Use ATP to transport materials across membrane, includes active transport and facilitated diffusion

Passive transport

No ATP

down the gradient

simple diffusion, osmosis, facilitated diffusion

Active transport

Uses ATP

against gradient

solutes like small ions, amino acids, and monosaccharides

Phagocytosis

plasma membrane engulfs undissolved material or bacteria

Pinocytosis

plasma membrane engulfs dissolved material (liquids)

Receptor-mediated Endocytosis

Form of pinocytosis, ligands bind to receptors

Hypertonic

More solute outside of the cell

Net water out of the cell

Hypotonic

Less solute outside of the cell

Net water flow inside

Isotonic

Equal solute concentration

no net water flow

Anchoring junctions

connects cells into sheets

e.g. Desmosomes

Tight junction

encircles each cell, makes seal that prevents passage of materials between cells

e.g. digestive tract lining

Gap junction

Narrow tunnels between animal cells, allows passage of ions and small molecules