03: Organelles and Cytoskeleton

ER function

Protein processing

Golgi apparatus function

Protein packaging

Mitochondria function

ATP synthesis

Lysosome function

Destruction

Peroxisome function

Destruction

Nucleus function

DNA storage

Nucleolus function

Ribosomal RNA synthesis

Cytoskeleton function

Structure

What organelle can be found on the outer nuclear membrane

Ribosomes

What membrane protein allows for communication between the nucleus and cytosol

Nuclear pore

Nuclear pore function

Allows passage of RNA out of the nucleus

Chromatin

Structure of DNA and binding proteins

Euchromatin

Loosely packed, transcriptionally active DNA

Heterochromatin

Densely packed, transcriptionally inactive DNA

Nucleoli function

Transcription for ribosomal RNA

Nuclear lamina

Protein network on the inner nuclear membrane

Key protein of the nuclear lamina

Lamins

Lamin function

Helps breakdown vesicles and reorganize membranes during cell division

Nuclear localization signal

Tag on a protein that sends it to the nucleus

Nuclear export signal

Tag on a protein that directs it out of the nucleus

RER location

Continuous with the outer nuclear membrane

RER function

Produces and immediately processes proteins

SER function

Lipid synthesis and cytochrome P450 storage

Golgi apparatus function

Post translational modification of proteins

Proteins that mediate the formation and fusion of vesicles

Clathrins and coatamers

Proteins that mediate endocytosis

Clathrins and caveolins

Mitochondria function

Site of oxidative phosphorylation

Structure of mitochondrial DNA

Small circular chromosome

Function of most mitochondrial proteins

ETC

Where does most of the mitochondrial DNA come from

The mother (oocyte has WAY more cytoplasm than sperm)

Other important functions of the mitochondria

Calcium storage and apoptosis

Class of enzyme contained in a lysosome

Hydrolases

Hydrolase function

Breaks down molecules to the building blocks

Examples of hydrolases

• Proteases

• Ribonucleases

• Lipases

• Phosphatases

Class of enzyme contained in a peroxisome

Oxidases

Oxidase function

Forms H₂O₂ to oxidize LCFA

Types of cytoskeletal filaments

• Intermediate filaments

• Microtubules

• Microfilaments

Intermediate filament

Fibrillar monomers that twist to form tetramers that are packed together to form filaments

Intermediate filament function

Filamentous structure

Example of intermediate filaments

Keratins

Intermediate filaments are present in what epithelial structures

Desmosomes and adhesion plaques

Microtubule function

Subcellular motility

Microtubule treadmilling

Dissociation at the minus end due to GTP hydrolysis and growth at the plus end due to the presence of GTP

Microtubule structure

alpha and beta tubulin associates into dimers, which make protofilaments, which associate to make microtubules

Role of microtubules in the cell cycle

Grabs chromosomes and pulls them apart

Motor proteins that move across microtubules

Dynein and kinesin

Cilia structure

Motile microtubules

Protein that provides cilia with motility

Dynein

Protein that coordinates the movement of ciliary subunits

Nexin

Anterograde movement

Movement from cell body → periphery

Retrograde movement

Movement from periphery → cell body

Motor protein that moves in an anterograde direction on microtubules

Kinesin

Motor protein that moves in an retrograde direction on microtubules

Dynein

Thin filament structure

Actin that associates into homodimers

G-actin

Actin that uses ATP to treadmill

Thick filament structure

Myosin that associates into homodimers

Myosin structure

Globular head and helical tail

How is myosin responsible for muscle movement

ATP hydrolysis moves the hinge of the head region

Microvilli structure

Actin draped in PM