AP Bio Unit 2: Cell Organelles and Membrane Functions, Chapter 6 - 7

Biochemistry

Study of chemical processes in cells

Prokaryotic Cells vs Eukaryotic Cells

Prokaryotic
- Bacteria and archea
- Membrane free nucleiod and structures

Eukaryotic
- Fungi, animals and plants
- Membrane bound nucleus and organelles

Organelle

Membrane enclosed structure in a cell

Cytosol

Fluid present in interior of the cell

Cell Membrane

Phospholipid bilayer with various protiens, enzymes, carbohydrates and lipids that encase a cell and organelles

Nucleus

Location of DNA and directs protien synthesis

Nuclear Envelope

Double layered membrane sorrounding nucleus

Nuclear Lamina

Net-like layer of protiens that supports the shape of nucleur envelope from the inside

Chromosomes

Big coils of DNA wrapped around the protein histone

Nucleolus

Inner region of nucleos where RNA is transcribed

Nuclear structure

Ribosomes

Non membrane bound structure, made of rna and protiens, carries out protien synthesis

Free Ribsomes vs Bound Ribosomes

Free Ribosomes
- Cytoplasm
- Make protiens that function in cytosol

Bound Ribosomes
- Held in membranes
- Make protiens that function in membranes

Endomembrane System

Nucleus, ribosomes, endoplasmic reticulm, golgi apparatus, lysosomes, vesicles, vacuoles and plasma membrane.

Carries out protien synthesis, protien transport, metabolism and movement of lipids, and detoxing poisons

Vesicles

Sacks made of mebrane that transport protiens

Endoplasmic Reticulum

Folded membranes that sorround the nuclear envelope

Smooth ER

ER without ribosomes in membrane
- Synthesis of lipids
- Detoxing poisons
- Metabolizing carbohydrates
- Storing calcium ions

Rough ER

ER with ribosomes in the membrane
- Creates glycoproteins in lumen(inner area)
- Glycoproteins: Protein with carbohydrate attached

Transitional ER

Area of the ER used to transport proteins through transport vesicles

Golgi Apparatus

Processes, stores, and ships out products/protiens from ER. Made of many membrane sacks called cisternae. Finishes proteins from ER and creates non-protien products.

Cis face (Golgi Apparatus)

Recieves and absorbs product of the ER

Trans face (Golgi Apparatus)

Ships finished products out

Lysosome

Organelle containing hydrolytic enzymes to digest/hydrolyze macromolecules. Acidic interior. Made by ER and Golgi App

Phagocytosis

Unicellular protists eat by engulfing particles, forms food particle

Autophasy

Recycling products/materials in a cell

Vacuole

Large vesicle that serves as storage, different internal pH than cytosol. Carries out enzymatic hydrolysis in plants and fungi.

Contractile Vacuole

Pumps water from a cell

Central Vacuole

Large vacuole in mature plant cells, contains "cell sap" and inorganic ions. Grows and allows the cell to grow without new cytoplasm

Mitochondria

Carries out cellular respiration. Found in almost all eukaryotic cells.

Mitochondria Structure

Contains its own ribosomes and DNA. Contains a folded inner membrane, folds called cristae

Chloroplasts

Cite of photosynthesis. Found only in plant cells. It is a plastid, a series of closely realted plant organelles including amyloplast and chromoplast.

Chloroplast Structure

Stroma is the inner liquid, like cytosol. It contains ribosomes and DNA. Thylacoids are stacked to form granules.

Peroxisomes

Single membrane bound metabolic compartment. Removes hydrogen atoms to create H2O2, then creates H2O. Breaks down fatty acids, detoxifys alcohol, etc

Glyoxysome

Peroxixomes found in fat storing tissue of plant seeds, used to make fatty acids into sugars

Cytoskeleton

The network of microtubules, centrosomes, centrioles, cilia, flagella, and microfilaments in a cell. Provides structure and anchors organelles.

Cell Motility

Movement of a cell and its organelles

Motor protiens

Guide organelles along microtubules of the cytoskeleton to transport them

Microtubules

Compression resisting hollow rods made of the protien tubulins. Shape and support the cell, provide tracks for organelles to move.

Tubulins in microtubules

Tubulin dimers(joined alpha and beta), make up structure. The plus end of the structure is able to gain and lose tubulin more quickly than the other end.

Centriole

9 sets of triplet microtubules in a ring shape.

Centrisome

Area near nucleous where most microtubules originate. Contains two centrioles(sometimes)

Basal body

Area at the base of microtubules that exit extracellular space. Structure of microtubules are covered by membrane and anchored to cell.

Dyneins

Protiens that cause the movement of cilia and flagella.

Flagella

Long, tail like structure that aids in movement of the cell

Cilia

Hair like structures that aid in movement of the cell

Primary cilia

Nonmotile, recieve signals for the cell

Internal structure of cilia and flagella

9+2 pattern, 9 doublets of microtubules wrapped around 2 single microtubules

Microfilament

Thin, solid rods made from actin(protien) twisted double chain. Thinner than microtubules. Tension bearing.

Cortical microfiliments

Just inside membranes, provide support to structure

Intermediate filaments

Bigger than microfiliments and smaller than microtubules. Found in some animal cells, diverse group made of keratin protiens. More permanent and structually supportive, make up nuclear lamina.

Microfilament v Microtubules

Microfilament
- Actin double helix
- Flexible but strong

Microtubules
- Alpha and beta tubulin tubes
- Stiff

Cortex

Outer cytoplasmic layer of cell

Myosin

Protien that interacts with microfiliments to contract muscle cells

Psuedopodia

Used by some cells for movement, myosin reliant

Cytoplasmic Streaming

Circular motion of cytoplasm in plant cells, allowing recources to be distributed. Reliant on microfiliments

Cell wall

Structure found in plant cells. Microfibrils made of cellulose join with other polysaccharides and protiens

Process of creating a cell wall

- Primary, weak wall is made
- Cell either strengthens original wall or creates second cell wall with a durable matrix

Middle lamella

Area between two cell walls of different cells. Contains pencin, which holds the walls together

Plant v animal cell

Extracellular matrix

Structures outside a cell that coordinate it's behavior. Constructed of glycoprotiens and carbohydrate containing molecules

Collagen

Protien found in extracellular matrix. 40% of protien in the human body

Proteoglycan

Protien core with carbohydrate chain

Fibronectin

Glycoprotien that bonds to integrins(receptor protiens)

Plasmodesmata

Channels that connect seperate plant cells

Tight junctions

Animal cells bond closely together, preventing anything from separating them

Desmosomes

Intermediate filaments pull to hold cells together, occurs with animal cells

Gap junctions

Protiens from the membranes extend to create tunnels, occurs with animal cells

Amphipathic molecule

A molecule with a hydrophobic and hydrophillic end

Fluid mosiac model (membrane)

The modern theory that the cell membrane is full of constantly moving and fluid parts

What are some ways the membrane is fluid?

- Held together by hydrophobic interactions
- Lipids can fully flip around
- Protiens can shift over time or be moved by cytoskeleton

Temperature's effect on membrane fluidity in animal and plant cells

Unsaturated(Plant)
- Fluid, kinks are harder to compact
- Less cholesterol
Saturated(Animal)
- Solid, no kinks are easier to compact
- More cholestorol

Cholestorol in membranes

Acts as fluidity buffer, restrains movement but also makes it harder to pack

Interegal/transmembrane protiens

Protiens that extend the entire length of the membrane. Usually contain hydrophyllic passages

Peripheral protiens

Loosely bound to one side of the membrane. Could be attatched by cytoskeleton

Glycolipids

Carbohydrates bonded to lipids found in the membrane

Glysoprotiens

Carbohydrates attatched to protiens found in the membrane

Membrane carbohydrate function

Act as markers and communicators to other cells

Selective permiability

Membrane's ability to control what comes in and out. Hydrophobic molecules pass easily. Polar pass slowly and ionic have a harder time

Transport protiens

Allow hydrophillic and ionic molecules to pass through membranes easier.

Kinds of transport protiens

Channel - Create channel for hydrophillic molecules
Aquaporins - Transfer water
Carrier protiens - Forms around compounds and brings them through membrane

Passive transport

Diffusion of a molecule to create an equalibrium

Osmosis

Movement of free water to balance solution concentrations

Tonicity

Ability of sorrounding solution to affect a cell's water concentration

Isotonic

Equal solution inside and outside of cell, equal movement of water back and forth

Hypertonic

More solute and less free water outside cell, cell loses water

Hypotonic

Less solute and more free water outside cell, cell gains water

Osmosis reactions with cell wall

Isotonic - Flacid: Cell is flimsy and wilty
Hypertonic - Plasmolyosis: Membrane shrivels away from cell wall, withers and dies
Hypotonic - Turgid: Cell swells, stressing cell wall and creating stiffness

Osmosis reactions without cell wall

Isotonic - Normal
Hypertonic - Shiveled
Hypotonic - Lysed: Cell swells and bursts

Facilitated diffusion

Diffusion of polar and ionic molecules through transport protiens, form of passive diffusion

Active transport

Cell needs to expend energy because it moves against the concentration gradient. Powered by ATP hydrolysis

Membrane potential

Voltage across membrane, negative on cytoplamic side compared to extracellular side

Electrochemical gradient

The chemical and electrical forces acting on ions

Electrogenic pump

Transport protien that generates voltage

Proton pump

Electrogenic pump used in plants, pumps out H+

Cotransport

A transport protien uses the energy from brining in a molecule to push out another molecule

How large molecules leave the cell

vesicles

Exocytosis

The process by which large molecules are secreted from the membrane after being transported by vesicles

Endocytosis

The process by which large molecules are brought into the cell and transported by vesicles

Phagocytosis

Cell ingulfs a particle and metabolizes it

Pinocytosis

Cell takes in drops of extracellular fluid