Bio Exam 1 (unfinished)

List some parts of the membrane structure

fluid mosaic model, phospholipids, proteins, and carbohydrates

describe the bilayer formation

• forms spontaneously

• due to phospholipid shape and amphipathic nature

• held together by hydrophobic interaction (Van der Waals)

what do membrane proteins do

determine many membrane functions

can be transmembrane

some proteins attracted by fibers on each side

transmembrane

spans both sides of the membrane

has to be amphipathic

functions of the lipid bilayer

transport, enzymatic activity, signal transduction, cell-cell recognition, intercellular joining and attaching to cytoskeleton and the extracellular matrix

Describe carbohydrates

polysaccharides attached to a protein (glycoprotein) or lipid (glycolipid)

primarily for cell identification

Fluid mosaic model

flid = membrane components can move laterally within the membrane

mosaic = membrane has emergent properties based on components

Passive transport

does not require energy or apt

net movement down concentration gradient

results in dynamic equilibrium

includes simple diffusion, osmosis and facilitated diffusion

Diffusion

tendency of molecules of a substance to fill available space due to random motion

Dynamic Equilibrium

No net movement at equilibrium

Different substances diffuse independently

Diffusion of 2 solutes

net diffusion across both sides of the membrane as both substances diffuse independently of one another

What can diffuse

Small non polar and very small polar molecules (H2O, gasses and small hydrocarbons

NOT Protons, ions or charged molecules

Osmosis

diffusion of water across selectively permeable membrane

Solvent

A substance capable of dissolving other substances, the medium in which something is dissolved

Solute

A dissolved substance

How is the direction of osmosis determined

Low solute concentration to high solute concentration

Equalizes solute concentration 

Tonicity

Ability of a solution to cause a call to gain or lose water

Isotonic

[Solute] outside = [solute] inside cell

• No net H2O movement

hypertonic

[solute] outside call > [solute] inside cell

Cell loses H2O

Hypotonic

[Solute] outside cell < [solute] inside cell

cell gains H2O

What molecules cannot diffuse across a membrane

1. large molecules

2. Polar molecules even a little bigger than H2O

3. Ions and anything charges with - even H+

How are large molecules transferred across the lipid bilayer that cannot diffuse

Transported with proteins

Facilitated diffusion

Passable transport through a transport protein

Does not require ATP

Specific to substance being transported

2 types: Channel and carrier

Moves down concentration gradient

Active Transport

Requires ATP

Worked against concentration gradient

Transports through carrier protein

Bulk Transport

Transport many molecules at once with vesicles

Type of active transport

requires ATP

Enters/exits the cell without crossing the bilayer

Exocytosis

Vesicle containing waste or secretory products fuse with the plasma membrane

releases contents from cell

adds lipids to plasma membrane which causes it to grow

Endocytosis

Material taken into the cell by forming a vesicle by folding inwards

2 types: Phagocytosis, and Pinocytosis

Phagocytosis

Endocytosis that is cellular eating

large food valcuoles

Pinocytosis

Endocytosis cellular drinking

fluids and dissolved molecules

Metabolism

Sum of all chemical reactions and E transformation in an organism

Emergent property of life

Regulated to maintain homeostasis

Metabolic Pathway

Series of chemical reactions

Each step catalyzed by a specific enzyme

Anabolic Pathway

Synthetic - making new bonds, building bigger molecules - requires E

Simple to larger molecules

Dehydration reaction

Catabolic Pathways

Breaking bonds - large molecules broken into smaller - releases E

Big to small

Hydrolysis

Energy (E)

The capacity to do work (Or supply Heat)

Kinetic E

E of motion

Potential E

Stored E, the capacity to do work

1st Law of Thermodynamics

E can be neither created nor destroyed, only converted from on form to another Law of conservation of E

2nd Law of thermodynamics

Every E transfer increases entropy in the universe

E flow through ecosystems

Sun → stored as chemical E → converted to ATP → ultimately lost as heat

No conversion 100% efficient (2nd) 

Cells 40% efficient

Free Energy (G)

E available to do work

cant measure directly, can measure change

Delta Δ G

Change in free bonds

Building new bonds →

store E = +ΔG

Breaking Bons →

Release E =-ΔG

Exergonic reactions with ΔG

-ΔG release E, spontaneous

Endergonic reaction with ΔG

+ΔG, require E

E stored

ATP (adenosine triphosphate)

Primary “high E” molecule of the cell

Coupled reactions

Pair endergonic reactions (requires E) with exergonic reaction (releases E)

Exergonic reaction is often ATP hydrolysis

Catalyst

chemical that speeds a reaction without being used

Activation energy

Initial E needed to start a reaction

cause reaction to occur faster - cannot cause reaction that wouldn’t happen

Active sire

region that interacts with substrate

substrate

any substance acted upon by an enzyme

Induced Fit

enzyme changes shape slightly when bound to substrate

Causes slight change in substrate, facilitates breaking or forming bonds

Why Redox Reductions Matter

Make bonds → Store E; Break bonds → release E

What does Redox Reactions Require

e- transfer

Redox Reactions

Involves the movement/transfer of an e-

Always couples (reduction and oxidation)

Oxidation

Donating an e-

Reduction

accepting e-

Oxidizing agent

e- acceptor, becomes reduced

Reducing agent

e- donor, becomes oxidized

Is it easy to remove an e- from a covalent compound?

no

OILRIG

Oxidizing is losing, reduction is gaining (electrons)

Evolution

Unifying Idea of biology

All living organisms are modified decedents of a common ancestor

Emergent Properties

Results from arrangements and interactions of parts within a system

While is more than sum of parts

Method inquiry

Finding natural explanation for limited natural phenomena

Nonsense, quantifying, measurable structure or processes

Systematic

Not “haphazard”

Hypothesis

Testable proposed explanation for observations based on available fate; educated guess

Prediction

Expected outcome when test hypothesis

Theory

Broad explanation with significant support, leads to new hypothesis and accurate predictions

Law

Statement of what always occurs under certain circumstances. Observable patterns not explanatory - “what” not “why

EX: Thermodynamics

What are the basic elements of biology

Oxygen (O), Carbon (C), Hydrogen (H), and Nitrogen(N)

Electrons(-e)

Subatomic particles

1 charge; 1 unit negative charge

Moves rapidly around nucleus in a cloud

Potential Energy

Energy that a material processes due to location or structure

Can be used to to work - capacity to cause change

Once used, work has to be done to restore the energy

Where are e- located

distinct shells

What do each of the shell levels mean? Explain how energy moves in each of the levels.

Further from nucleus has a higher potential energy

Absorbs more E to move to higher shell

Releases E when falls to lower shell

Valence Shell

Outermost shell

Valance Electrons

occupy valiance shells

What is the charge of subatomic particles

-1

Molecule:

A compound of 2+ atoms held by chemical bonds

Explain chemical bonds movement of e-

“Want” full valence shell to be stable

Will donate or accept e- to achieve full valence shell or stability

Electronegativity

Measure of atoms affinity for e-

Atoms in molecules attract e- to varying degree

More electronegative = more strongly pulls e- towards self

Covalent Bonds

Sharing e- between atoms

Results in full valence shell

What is the strongest type of bond under biological conditions

Covalent Bonds

What is a Non Polar Covalent bond

same or similar electronegativity

What is a polar covalent bond

Unequal electronegativity

Ionic Bonds

Highly Unequal electronegativity

E- lost or gained

is an ion charged atom

Like charges repel

Opposites attract

What forms an ionic bond

attraction between anion and cation

Salts

Compound formed by ionic bonds - forms crystals

Dissolves in water

Ionic bonds break down in aqueous solution

Van der Waals Interactions

(relatively) short lived, (relatively) weak interactions due to electron position and motion

Area with partial + and - charges interact

Strong in large numbers

Include many different interactions

Hydrogen Bonds

Attractions between partial charges result when H binds to electronegative atom

δ (on H) tends to associate with δ- resulting interaction is H bond

Polar covalent bonds

Is constantly broken and reformed

Are hydrogen Bonds polar covalent bonds

yes

Cohesion

attraction between water molecules

Adhesion

attraction between water molecules and other substances

What is the universal solvent

water, H2O

Hydrophilic

Water loving

Hydrophobic

Water hating

What are organic compounds based on

Carbon

C bonded to H

the cell consists of __-__% water and the rest is __ based compounds

70-90%, Carbon (C)

How many bonds can carbon have?

4

Describe Hydrocarbons

1. Organic molecules of only C and H

2. Nonpolar, uncharged (nonionic)

   1. Hydrophobic

3. Can contain functional Groups

   1. Replace 1 or more H

Functional Groups

1. Key to molecular function

2. Replace H with something else

3. 6 Key groups