Exam 3 and Quiz Study Guide Bio 189

Fluid Mosaic model

the membrane is considered to be a fluid combination of phospholipids, proteins, and other molecules

Plasma membrane

• Membrane barrier surrounding cell

• Selectively permeable → allows certain items to pass from one side of the barrier to the next

Selective permeable

Allow certain items to pass from one side of the bilayer to the other.

Parts of a Phospolipid

1. Complex phosphate group → Hydrophilic

2. Glycerol backbone → 3 - carbon sugar

3. Two fatty acid chains → Hydrophobic, C + H chains

Inside and Outside membrane → composed of -P (negatively charged phosphate → hydrophilic)

Total Part of a Plasma membrane

Proteins, Cholesterol, Glycoproteins, Glycolipids

What molecules can easily pass through the membrane without help?

Small, neutral (non-polar) molecules Ex: CO2, O2

What molecules struggle to pass through the membrane and need help?

Large, polar molecules Ex: glucose

• Requires transport proteins inside the membrane to move to the other side

Embedded

Inside membrane

Attached

Outside membrane

Whats inside the plasma membrane?

• Cholesterol (steroid)

• phospholipids (they are the bilayer)

• integral proteins

Whats outside the plasma membrane

• Cytoskeleton filaments

• Peripheral proteins

• Carbohydrates

Membrane fluidity is regulated by____

Cell membrane fluidity

Type of phospholipid → SAT or UNSATURATED fatty acids

Cholesterol amount → temperature buffer

• Regulates fluidity at low and high temps

Membrane is hot

• More Saturated fatty acids in phospholipid

• Cells want more rigid/viscous membrane (less fluid)

Membrane is cold

• More Unsaturated fatty acids in phospholipids

• Cell wants more fluidity

Peripheral Proteins

• Attached to surface of membrane

• Hydrophilic

Intergral Proteins

• Inside the bilayer - among fatty acids

• (Hydrophobic + Hydrophilic) → Amphipathic

Membrane protein functions

1. Transport 2. Enzyme Activity 3. Signal Transduction 4. Cell to Cell

Diffusion

Molecules → [HIGH] to → [low]

What effects the rate of Diffusion?

1. Temperature

2. Concentration gradient

3. starting diameter of solute

High temp → Faster Diffusion

Greater the difference from [High] to [Low] → Faster Diffusion

Smaller starting diameter → Faster Diffusion

(Greater concentration gradient)

Molecules are in a constant motion? True or False

True

Bowinian Motion

Molecules → constantly moving and bumping into one another, heading into unique directions

Ex: billiard balls

• molecules get evenly spread

Gradient

Difference in concentration across region

Osmosis (Passive)

• Movement of water (or solvent) across a selectively permeable membrane

• Diffusion of water → [High] to [low]

Water moves towards → MORE SOLUTE

Water likes more stuff

Solute Concentration

[High Solute] on one side → less room for water → Low water concentration

[Low Solute] on one side → more room on low concentration side

3 Types

Isotonic [Equal Solute] = [Equal Solute] on both sides

Hypotonic [More Solute inside] ←[Less Solute]

Hypertonic [Low Solute inside] ← [More Solute]

Isotonic

Equal solute concentration on both sides of the plasma membrane

[Inside] = [Outside]

[Solute] = [Solute]

Equal [Solute] → Equal water concentration

Water molecules move in and out at EQUAL RATE. No Net movement of water across membrane

Hypertonic

Higher solute concentration → OUTSIDE cell

Low solute concentration → INSIDE cell

Water concentration HIGHER in side the cell and at a LOWER concentration outside the cell.

Random Molecular motion → Diffusion [High] to [Low]

Water leaves the cell going outside the membrane

Cell → Shrivels and shrinks in size

Hypotonic

Low Solute concentration → OUTSIDE

High Solute concentration → INSIDE

[Low Solute] → water concentration higher

[High solute] → water concentration lower

Low water concentration INSIDE and high water concentration OUTSIDE

Remember Diffusion → [High] to [Low]

Cell → Swell, no cell wall protection leads to burst of cell

What happens to Animal and Plant cells during a Hypertonic, Isotonic, and Hypotonic solution

Isotonic → Equal [solute] going in and out

• Animal cell normal

• Plant cell → Flaccid

• (limp or soft because water is no longer pushing the plasma membrane into the cell wall, no structure) loss of tugor

Hypertonic → Higher [solute] outside | Lower [solute] inside

• Animal cell → Shriveled (water leaves the cell, remember diffusion [High] to [Low]

• Plant Cell → Plasmolyse (water leaves the cell, no pressure to keep structure up → shrinking, wilting)

Remember: [Low Solute] = High water concentration (Diffusion [High] to [Low]

Hypotonic → Low [solute] outside | higher [solute] inside

[High water] | [Low water] = Water rushes inside the cell leading to burst

• Animal Cell → Lysed (to burst)

• Plant Cell → Turgid (Swollen , puffed up, normal state)

Solute concentration displaces the water concentration

High Solute → low water concentration

(solute takes up space)

Low Solute → high water concentration

(water takes up space)

Hypo

Animal cell lyses, BURSTS. Plant cell is ok (cell wall prevents burst)

Hyper

Animal cell SHRINKS. Plant cell Plasmolyze (Shrinks because of loss of water)

Osmoregulation

Process of controlling solute concentration and water balance within the cell (organism)

Ex: homeostasis

Passive Cell Transport

[High] → [Low]

DOWN the gradient

• NO energy input required for molecules → cross membrane

• NO energy needed to cross membrane

Simple Diffusion

Facilitated Diffusion

• Ex: diffusion, osmosis

Gradient - difference in concentration across region

Active Cell Transport

[Low] → [High]

UP the gradient

• Requires energy (ATP)

• Ex: Co transport, Bulk Transport (like endocytosis)

Simple Diffusion

Molecules move down the gradient

DIRECTLY through the membrane

PASS through membrane with NO HELP

Molecules

• Small (2 - 3 atoms)

• Non-polar (Hydrophobic

Ex: O2, CO2, fatty acids

H2O can pass through the membrane BUT

• very slowly

• abundant

• small

Facilitated Diffusion (helped progress)

Molecules move down gradient via

PROTEIN TRANSPORTERS (not directly by themselves)

Molecules TOO LARGE, they NEED HELP

Molecules

• Large

• Polar, and/or CHARGED (Hydrophilic)

Ex: Ion’s, Macromolecules, H2O

Channel Protein (Diffusion)

Diffusion → Continuous (CONSTANT) transport of molecules across bilayer (NO STOPPING)

• Specific for the molecule (like an ion)

ONLY used for Passive Transport Diffusion

• Channel never changes shape

Aquaporus

Channel proteins that move WATER (H2O)

• water holes

• Specifically made for only water

Carrier Protein (1 molecule at a time)

Discontinuous transport of molecules across bilayer

• Spe

Enzymes role in biochemical reactions

Biological catalyst to speed up chemical reactions by lowering activation energy

Active site

Were the hydrolysis occurs, were the enzyme meets with the substrate.

• The site on the enzyme were the substrate binds

Substrate (Starch)

(Were all the catalysis occurs) Reactants starting molecules

• Substrate = Reactant

Products

Simple Sugars (Gluecose)

• Ending molecule of a reaction

Enzyme (Amylase)

“ase” → Enzyme

Enzymes are Catalysts → to increase the rate of chemical reactions to rates that are biologically useful.

Function of this amylase (enzyme)

Break down starch into simple sugars

All the chemical reactions that occur in the cell

Metabolism

Specific Function of Enzymes

Catalyze (accelerate) reactions → Lowering activation energy needed for the reaction to occur

• Speeds up reaction time to make substrates into products

To activate, an enzyme needs to bind to a ____ to form an enzyme - substrate complex

substrate

Activation Energy

Energy needed to transform the substrate into products(s)

1. Enzyme lowers amount of activation energy needed to transform the substrate into products

LESS ENERGY to make SUBSTRATES → PRODUCTS

Enzyme Function → Catalyze substrate into product diagram

1. Substrate attaches to Enzyme at the Active Site

2. Enzyme changes shape → when substrate enters active site (making the fit more snug)

3. Enzyme Complex

4. Enzyme + Products leaving active site

Enzymes choose specific substrates to bind with. One chemical reaction with one type of substrate.

• Enzyme (Key) only has 1 lock (substrate) to turn.

True

Factors effecting Enzyme Speed

Most Enzymes are → Proteins (can be altered by…)

1. PH 1-13

2. Temperature

3. Salt Concentration

Result of PH, Temperature, and Salt Concentration on Enzyme

Changes the shape of enzymes active site → preventing substrate binding

three - dimensional shape of enzyme is disrupted.

Factors on Enzyme Activity

Enzyme Concentration:

High enzyme concentration → High enzyme activity

Time:

Enzyme has more time to catalyze reaction → High enzyme activity, High Asorbance

Temperature:

IDEAL / Optimal Temp (37 degrees C) → High enzyme activity

pH:

IDEAL / Otimpal pH (ex: 9pH) → High Enzyme Activity

High Absorbance meaning

Solution Color: Dark Blue

Amount of Starch: A lot

Enzyme Activity: Low

Low Absorbance

Solution Color: Light Blue

Amount of Starch: Not a lot

Enzyme Activity: High

How to tell if something is a enzyme

Ends in “ase”

Ex: Amalyase → Enzyme (ends in “ase”)

How do enzymes catalyze a reaction?

Lower Activation Energy

How do enzymes lower activation energy?

1. Position/Orient substrate in specific way

2. Weaken covalent bonds by bonding substrate

Aerobic Cellular Respiration

Metabolism of glucose (C6 H12 O6) Using O2 to generate lots of ATP

• Catabolism of gluecose using Oxygen (O2) to generate lots of ATP

Aerobic Cellular Respiration Formula

C6 H12 O12 + 6O2 → 6CO2 + 6H20 + ATP (Energy)

Gluecose is Oxidized

Glycolysis

1. First Step

2. Located → Cytoplasm (outside mitocondria)

3. O2 NOT NEEDED

IN : Gluecose, NAD+

OUT : Pyruvates, NADH, ATP

NAD + → NADH (More e- / energy)

Pyruvate Oxidation (Transition Stage)

Located → Mitocondrial Matrix

Needs O2 (Oxygen)

IN: Pyruvates, NAD +, COA

OUT: Acetyl COA, NADH, CO2

Citric Acid Cycle (Krebs Cycle)

Located → Matrix

• Requires O2 (Not directly)

IN: Acetyl COA, NAD+, FAD

OUT: CO2, NADH, FADH2, ATP

Oxidative Phosphorylation (Electron Transport)

Located → Inner mitochonidrial membrane

• Requires and uses O2 (oxygen) → final electron acceptor

IN: NADH, FADH2, O2

OUT: NAD+, FAD, H2O, A lots of ATP, Drop

Two Types of Fermentation

Lactic Acid Fermentation and Alcohol Fermentation

Lactic Acid Fermentation