BI220 - Cell Structure and Function

organelles

• membrane bound structure w/ specialized function

• structure = function

non-endomembrane organelles

• Vacuole

• Peroxisome

• Mitochondria

• Chloroplasts

endomembrane organelles

• series of interconnected membrane bound compartments

  • Nuclear Envelope

  • Endoplasmic Reticulum (ER)

  • Golgi Apparatus

  • Plasma Membrane (PM)

  • Lysosomes

  • Vesicles

route of endomembrane pathway

secreted → endocytosis → inserted into membrane

nucleus function

container of genome and RNA synthesis

nuclear envelope

double membrane that surrounds nucleus

nuclear pore

multiprotein complex that selectively allows passage in/out nucleus

nucleoplasm

gel-like material holding chromosome, etc, inside nucleus

chromosome territories

assigned seats

nuclear lamina

• protein meshwork on inner membrane of nuclear envelope that provides structure

  • lamins and intermediate filaments

nuclear matrix

meshwork of protein filaments found throughout nucleus

nucleolus

region involved in production and storage of ribosomes

endoplasmic reticulum structure

• single membrane w/ distinct domains

  • continuous with outer nuclear membrane

lumen

internal space between membrane

2 domains of ER

• rough ER

• smooth ER

rough ER function

• protein synthesis, folding, initial processing

  • synthesizes proteins to be secreted, attached to membrane, or remain in endomembrane system

glycosylation

addition of carb modifications

smooth ER function

fatty acid, lipid biosynthesis, detoxification

Golgi apparatus structure

• cisternae

  • stacks polarized and connected via vesicle movement

cisternae

• 5-7 interconnected flattened stacks

  • each stack has unique function

cis-golgi network

collects vesicles from ER

trans-golgi network

site of protein and lipids export from Golgi → plasma membrane/other organelles

Golgi apparatus function in animal cells

• protein glycosylation

  • further process carbs that were added to ER

  • “labels” to sort glycoproteins

• synthesis of glycolipids and lipid metabolism

  • further processes phospholipids destined for ER

• sorts proteins and lipids to next destination via vesicles

Golgi apparatus function in plant cells

site where cell wall complex sugars are made

lysosome structure

membrane-enclosed organelles containing over 50 diff. digestive enzymes

• shape and size dependent on up-taken materials

where do enzymes originate from in lysosome

Golgi

internal pH of lysosome

< 5

lysosome function

• breakdown all biomolecules, invading viruses and bacteria, and damage organelles

• aide in cell breakdown during apoptosis

• broken down molecules can be recycled

3 vesicles

• between ER and Golgi

• between Golgi and plasma membrane

• between Golgi and lysosome

vesicle structure

small membrane bound bundles

vesicle function

transporters of cell

• moves material throughout cell

plasma membrane structure

phospholipid bilayer → cell border

plasma membrane function

keep inside in and outside out

vacuole structure

membrane bound and fluid filled organelle

do vacuoles have cytoplasm

no

vacuole function in animal cells

• storage of nutrients, waste, and water

  • have many, small vacuoles

vacuole function in plant/yeast cells

• site of digestion

  • usually 1 large vacuole

peroxisome structure

• contains 50 diff. enzymes

  • from cytosol

• H202 crystalized within organelle

what do peroxisomes process

hydrogen peroxide (H2O2)

peroxisome function

• site of oxidation reactions

  • creates H2O2

• breaks down fatty acid → acetyl CoA

  • key for Krebs cycle

mitochondria structure

• two membranes

  • outer, inner

• cristae

• intermembrane space

• matrix

cristae

inner membrane folds

• increase SA → increase ATP production

intermembrane space

space between membranes

mitochondria matrix

space between inner membrane

mitochondria function

• cellular respiration

  • use O2 to breakdown carbs and fats → ATP

chloroplast structure

• 3 membranes

• thylakoids

  • where light-dependent reactions of photosynthesis happen

• lumen

  • inside thylakoid

• granum

  • stack of thylakoid

3 membrane names in chloroplast

• outer

• inner

• thylakoid

3 space names in chloroplast

• inter membrane space

• stroma

• thylakoid lumen

what two organelles are semi-autonomous

• mitochondria

• chloroplast

semi-autonomous

• contain own DNA and ribosomes

• make some of own proteins

chloroplast function

• photosynthesis

  • use sunlight to synthesize simple sugar

• chlorophyll and light harvesting machinery in thylakoid membrane

• CO2 → sugar in stroma