BIO 152 Module 1 Section 5

Eukaryotic cell

A cell with a membrane-bound nucleus andd other membrane-bond compartments

Organelle

A specialized cellular structure that performes a particular function

Cytoplasm

The contents inside the plasma membrane but outside the nucleus including cytosol and organelles

Cytosol

The fluid portion of the cytoplasm

Cytoskeleton

A network of protein filaments that supports cell structure and helps organize and move cellular components

Endomembrane system

A group of membranes and compartments that work together to make, modify, sort, and transport proteins and lipids

Vesicle

A small membrane-bound compoartent used for transport or storage

Endocytosis

Uptake of material when the plasmamembrane folds inward and forms a vesicle

Exocytosis

Release of material when an internal vesicle fuses with the plasma membrane

Genome

The complete collection of an organism’s genetic material

Nucleus

Houses most of the cell’s dna; site of transcription

Large compartment with a double membrane

Nuclear envelope

Separates the nucleus from the cytoplasm; pores regulate exchange

two membranes surrounding the nucleus

Nucleolus

Produces rRNA and assembles ribosomal subunits

Dense region inside nucleus

Ribosomes

Build proteins by translating mRNA

Tiny dots, free in teh cytosol and attached to rough ER

Rough ER, Endoplasmic Reticulum

Helps produce, fold, and process proteins entering the secetory pathway

Membrane network covered with ribosomes

Smooth ER

Lipid synthesis; also detoxification and calcium storage in appropriate cells

Membrane network without ribosomes

Golgi apparatus

Modifies, sorts, and packages proteins and lipids

Stack of flattened membrane sacs

Lysosome

Digests and recycles macromolecules and cellular material

Small membrane-bound comportment

Peroxisome

Performs oxidation reactions including some fatty acid breakdown

Small membrane bound compartment

Mitochondrion

Produces much of a cell’s ATP through Cellular respiration

Double membrane with a highly folded inner membrane

Chloroplast

Photosynthesis in photosynthetic plant cells

Double membrane with internal stacks of membrane discs

Central vacuole

Storage breakdown of materials and support through turgor pressure

Large compartment occupying much of a plant cell

Plasma membrane

Selectively regulated movement between cell and surroundings

Thin boundary around the cell

Cell Wall

Support and resistance to excessive swelling

Rigid layer outside the plant plasma membrane

Plasmodesmata

Chanells connecting plant cells, Connections passing through cell walls

Differences between plant and animal cells

Animal cells have no cell wall, hcloroplast, large central vacuole, or plasmaodesmata

The endomembrane system

conecects the production, processing, and delivery of cellular materials

Main components: Nuclear envelope, ER’s, Golgi apparatus, Transport vesicles, Endosomes and lysosomes, Vacuoles, and plasma membrane

Route for protein from production to secretion

Nucleus to nuclear pore to ribosome to rough ER, to Transport vesicle, to golgi apparatus, to secetory vesicle, to exocytocies

Endocytosis

Folds inward and pinces off. Brings extracellular material into a vesicle

Exocytosis

Fuses with an internal vesicle

Releases cargo outside and adds vesicle membrane to plasma membrane

Three types of cytoskeleton

Microfilaments

Microtubiles

Intermideate filaments

Microfilaments

Made of actin they are thin filiments composed of two strands intertwined, they support cell shape, help change cell shape, and assist endo/excoytocis

Microtubules

Made of tublin they are hollow cylinders.

They are tracks for transport, chromosome movement, and are support in cilian and flagella

Intermediate Filaments

Made from various proteins

Tough rope like fibers

Their main function is mechanical strenght, stabilize cell structure, and help anchor organells

G actin

Individual globular actin subunits

F actin

Filiments assembles from those subunits

Motor protein associate with actin

myosin

Microtubule motor protein

Kinesin and dynein

How do the endomembrane system and cytoskeleton work together to secrete proteins?

The rough ER and Golgi process and package proteins into vesicles. Motor proteins move vesicles along microtubules, while actin helps with events near the cell surface. Vesicles fuse with the plasma membrane, releasing proteins by exocytosis.

Why have membrane bound compartments useful

to maintain different ph vals, ion concentrations, conentrate enzyems and their substrates, seperate processes that would interfere with each other, isolate potentially damaging reactinons, maintian gradients