Membrane-Bound Organelles

Membrane Bound Organelle

Covered by a membrane

Keeps each organelle separate from the rest of the cell

Only found in Eukaryotic Cells

Ribosomes & Centrioles are not membrane bound

Nucleus - Structure

Largest Organelle

Mostly Nucleoplasm (liquid within nucleus)

Nuclear Pores in nuclear envelope

Nucleolus

Nuclear Envelope - 2 layers of nuclear membrane

Nucleus - Function

Envelope -Separates contents of nucleus

Nuclear Pores - Allows passage of larger molecules through envelope

Nucleolus - Manufactures RNA & ribosomes

Chromatin - condenses DNA & proteins to form chromosomes

Contains genetic material & instructions to make proteins (controls protein production)

Mitochondria - Structure

Oval Shaped

Double Membrane - Inner Membrane folded into Cristae (large S.A.)

Fluid filled Matrix

Mitochondria - Function

Site where ATP is produced during aerobic respiration - Oxidises Glucose

Cristae - Increases energy capacity of cell

Matrix - Liquid containing proteins/lipids & traces of DNA to control production of proteins

Number of mitochondria depends on cell function

Golgi - Structure

Similar to SER, but more compact

Flattened stack of fluid-filled sacs

Membrane bound

Found near edges of cells (associated with vesicles)

Golgi - Function

Receives proteins from RER & lipids/carbs from SER

Modifies them (adds/removes components)

Labels them (to send to right destination)

Packages them (into vesicle)

Vesicles - Structure

Small, fluid-filled sac in cytoplasm

Membrane Bound

Vesicle - Function

Transports substances in/out of cell & between organelles, via plasma membrane

Some vesicles are Golgi or ER

SER (Smooth Endoplasmic Reticulum) - Structure

No Ribosomes

Continuous with outer Nuclear Envelope

Cisternae (flattened sacs) - enclosed by membrane

SER (Smooth Endoplasmic Reticulum) - Function

Making, Storing, Transporting Lipids

RER (Rough Endoplasmic Reticulum) - Structure

Ribosomes present

Continuous with outer Nuclear Envelope

Cisternae (flattened sacs) - enclosed by membrane

RER (Rough Endoplasmic Reticulum) - Function

Making, Storing, Transporting Proteins

Chloroplasts - Structure

Double Membrane

Contains Granum (stacks of thylakoid membrane)

Chlorophyll Molecules

Abundant in Pallisade Mesophyll

Chloroplasts - Function

Site of Photosynthesis (light energy used to derive C from CO2)

Lysosome - Structure

Vesicles - Surrounded by a single Membrane (from Golgi)

Contain Enzymes (up to 50 per vesicle)

Lysosomes - Function

Isolate potentially harmful enzymes in cell and release them outside cell

Break down materials ingested by phagocytic cells using digestive enzymes

Destroy material outside cell by releasing enzymes

Digest dead cells & Recycle worn out organelles

Ribosome - Structure

Free Ribosomes (NOT MEMBRANE BOUND) & RER Ribosomes

Very small

2 subunits with Ribosomal RNA

Made in Nucleus

Ribosome - Function

Site of protein synthesis

Free Ribosomes - make proteins used inside cell

RER Ribosomes - make proteins used outside cell

Centrioles - Structure

Small, Hollow cylinders - consist of bundles of micro tubules (made from tubulin protein) at 90º angles

NOT MEMBRANE BOUND

Centrioles - Function

From spindles fibres (separate chromosomes in cell division)

Involved in formation of cilia & undulipodia

Cilia & Undulipodia - Structure

Protrusions from cell

Surrounded by cell-surface membrane

Contain microtubules - Formed from centrioles

Cilia & Undulipodia - Function

Epithelial Cells have many cilia that move mucus

Some cells have a cilium used to detect signals from environment

Human undolipodia - Sperm cell

Flagella - Structure

Similar to cilia, but longer

Pretrude cell surface - surrounded by plasma membrane

9 pairs of microtubules in centre

Flagella - Function

Microtubules contract to move flagellum, propelling cell forward

Cytoskeleton - Structure

Network of Protein Structures inside cytoplasm

Made from microfilaments, intermediate filaments & microtubules

Cytoskeleton - Function

Microfilaments provide mechanical strength

Microtubules - provide strength; form track for motor proteins to transport substances/organelles throughout cell; form spindle fibres

Intermediate filaments anchor nucleus & extend to other cells, allowing signalling & communication