define and relate the terms electronegativity and polarity

Describe the structure of the plasma membrane and the different ways that proteins can be associated with the lipid bilayer (fluid mosaic model)

Fluid mosaic model: - Has a phospholipid bilayer: hydrophilic heads face towards the aqueous environment while hydrophobic tails face inwards away from the aqueous environment - has cholesterol (ampiphatic liquid) inserted into lipid bilayer in so its head group interacts with hydrophilic head of phospholipids, and the ring structure undergoes van Der Waals with fatty acid chains in the phospholipid - lipids can freely associate with each other and move around the plane of the membrane because there are van Der Waals forces between their fatty acid tails, and the forces are weak so they're easily broken - sometimes, lipids assemble into patches called lipid rafts in the membrane - proteins are embedded throughout the membrane >>> INTEGRAL: permanently associated with the membrane >>> PERIPHERAL: temporarily associated with the membrane through weak non covalent interactions, found either on the internal or external side of the membrane TRANSMEMBRANE: span the entire lipid bilayer

Compare and contrast the relative electronegativity of H, C, O, and N.

For bonding: O=N > C=H in electronegativity For sharing electrons in redox reactions: (O=N) > C > H in electronegativity

identify the number of covalent bonds formed by H, C, O, and N

H: 1 O: 2 N: 3 C: 4

Define the term diffusion

The random movement of molecules with net movement from an area of high concentration to one of low concentration.

Explain how the potential energy of two atoms changes as they form or break a bond

When a bond is broken, potential energy increases When a bond is formed, potential energy decreases. Breaking bonds absorb (require) energy, Forming bonds release energy.

Relate the potential energy change of an atomic interaction to its "strength"

as the potential energy of an atomic interaction increases, its strength increases because it would take more energy to break the atomic interaction if the interaction has a lower potential energy

Predict the structure of a phospholipid membrane in hydrophilic vs. hydrophobic environments

heads: hydrophilic tails: hydrophobic In hydrophilic environments, heads would face the aqueous environment and tails would face away from the aqueous environment In hydrophobic environments, tails would face the hydrophobic environment while heads would face away from it

define hydrophobic and hydrophilic

hydrophobic: non polar compounds that do not dissolve in aqueous solvents, cannot form H bonds with water hydrophilic: polar compounds that dissolve in aqueous solvents, can form H bonds with water

Predict the permeability of a molecule based on its chemical properties

membrane permeability from high to low: hydrophobic molecules > small polar molecules > large uncharged polar molecules > ions

Explain how polar and non polar covalent bonds are formed between atoms

non polar covalent bonds: electrons are shared equally between atoms b because they have similar electronegativites polar covalent bonds: electrons are shared unequally between atoms because they have different electronegativites (some attract more electrons than others)

Determine whether a molecule isa ble to participate in hydrogen bonding with itself or another molecule based on its chemical structure and relative electronegativity of its atoms

requirements for h bonding: - The donor molecule (the molecule that is donating the H atom) needs to be in a polar X-H bond in which the H has a partial positive charge The acceptor molecule (the molecule that is accepting the H atom) needs to have a partial negative charge so that the partial negative charge attracts the H with the partial positive charge and both the donor and acceptor molecules undergo H bonding

compare the relative strengths of bonds and electrostatic interactions and relate these strengths to the amount of energy required to break them

strongest to weakest: covalent bonds (intramolecular) > ionic bonds (intramolecular) > hydrogen bonds (intermolecular) > van Der waal forces (intermolecular) It takes more energy to break stronger bonds, so covalent bonds would have the lowest potential energy and hydrogen bonds would have the highest potential energy

Predict the net movement of water based on the relative tonicity of the two solutions

the net movement of water will be from the hypotonic solution to the hypertonic solution because water moves from areas of high to low solute concentration

Determine whether a molecule is likely to be hydrophilic or hydrophobic based on its ability to form hydrogen bonds with water

A hydrophilic molecule is able to form H bonds with water while a hydrophobic molecule is not able to form H bonds with water. This is because when H bonds are being formed with water, the donor molecule is water and the acceptor molecule is the other molecule forming the H bond with water. The H atom in water with the positive partial charge needs to be able to attract the areas of the other molecule with a partial negative charge. Molecules that have a partial negative charge are often polar (due to unequal sharing of electrons in polar molecules)- which is a type of hydrophilic molecule.

Describe the function of common eukaryotic organelles: mitochondrion, chloroplast, nucleus, endoplasmic reticulum, Golgi apparatus, lysosome, and vacuole

Mitochondrion: produces ATP ▪ Chloroplasts: Found in plant cells; Enable plant cells to harness energy from the sun to synthesize sugars through photosynthesis; location of photosynthesis ▪ Nucleus: Stores genetic information of the cell (DNA) and it is also the site of RNA synthesis ▪ Endoplasmic reticulum: Protein and lipid synthesis 2 Types: Rough ER and Smooth ER Rough ER: Synthesis of proteins Smooth ER: Synthesis of lipids ▪ Golgi Apparatus: Modifies and stories proteins and lipids ▪ Lysosome: Contain the enzymes that break down macromolecules ▪ Vacuole: "Contribute to the structural rigidity of plants by absorbing water and contributing to turgor pressure"

Predict the rate and direction of net movement of molecules based on their concentration gradients and the absence or presence of specific membrane transport proteins

Na+/K+ Pump (Primary Active Transport): - The sodium ions and potassium ions are pumped against their concentration gradients - for every 3 sodium ions pumped, 2 potassium ions are pumped in the opposite direction Na+ / Glucose Co-Transporter (Secondary Active Transport) : - Sodium ions are transported with its concentration gradient to provide energy for glucose to move against its concentration gradient. - Glucose moves from the lumen of the small intestine to inside the cells - Because glucose and sodium ions are being transported in the same direction, the Na+ / Glucose Co-Transporter is a symporter Glucose Carrier (Facilitated Diffusion) : - Glucose moves with its concentration gradient from the inside of the cell to the blood vessel

Describe each type of chemical bond and intermolecular force: nonpolar covalent bonds, polar covalent bonds, ionic bonds, hydrogen bonds, and van der Waals' forces

Nonpolar covalent: atoms with similar electronegativity share electrons, so the electrons are shared equally and charges are distributed equally Polar covalent: atoms with different levels of electronegativity share electrons, so the charges become separated because the electrons are not shared equally Ionic: electrons are transferred from one atom to another. A molecule with a positive charge (loses an electron) is attracted to a molecule with a negative charge (gains an electron). This type of bond is MORE polar than polar covalent bonds because they have a positive ion and a negative ion, so there is a clear separation of charges between the 2 particles. common with metals because metals have loosely held outer electron shells, so they are constantly losing electrons. (metal to nonmetal) Hydrogen: An interaction between a Hydrogen atom and an electronegative atom. Represented by a dotted line. - donor molecule (molecule that donates the partial positive H atom) needs to have a polar X-H bond - Acceptor molecule (molecule that accepts a partially positive H atom) needs to have a partial negative charge Van Der Waals: occur when electrons move around and temporarily pile up in one spot, causing molecules to be attracted to each other

Compare and contrast the different passive (simple diffusion, facilitated diffusion) and active (primary, secondary) transport mechanisms

PASSIVE: - Simple diffusion: molecules move from ares of high to low concentration without help from other substances (like membrane proteins) - Facilitated diffusion: molecules move down their concentration gradient with the help of membrane proteins BOTH: No input of energy *(ATP) required, solutes move from areas of high to low concentration with the concentration gradient ACTIVE: - Primary: energy (ATP) is used directly to transport molecules against their concentration gradient - Secondary: Energy (ATP) is indirectly used to form an electrochemical gradient that drives the transport of molecules from areas of high concentration to areas of low concentration; proteins are often used to help molecules move down their concentration gradient BOTH: require an input of energy (ATP)

Define the term diffusion Compare and contrast the different passive (simple diffusion, facilitated diffusion) and active (primary, secondary) transport mechanisms

Passive diffusion: from high concentration to low concentration - Simple diffusion: No energy or proteins required. Movement from areas of high concentration to low. - Facilitated diffusion: Uses a channel or a carrier. No energy required. Movement from areas of high to low concentration. Active diffusion: against concentration gradient, requires energy - Primary transport: - Secondary transport:

Determine whether a molecule is likely to be polar or non polar based on its chemical structure and relative electronegativity of its atoms

Polar molecules: differences in electronegativity among atoms that make up the molecule Non polar molecules: similarities in electronegativity among atoms that make up the molecule

o Differentiate between saturated and unsaturated fatty acids

Saturated: - Single C-C bond -No kinks -Intramolecular interaction -More rigid and packs more tightly Unsaturated: -Double C-C bonds -Has kinks -Intermolecular interaction -fluid, less rigid and more room for movement

Explain how the chemical properties of a phospholipid bilayer allow it to act as a semipermeable membrane

▪ A phospholipid bilayer is semipermeable because it enables some molecules to pass freely, others to pass under certain conditions and prevents some molecules from passing ▪ The bilayer has a phospholipid interior so ions and charged polar molecules cannot move across it. ▪ Certain molecules like proteins and polysaccharides are too large to cross the bilayer on their own. Gases like oxygen and carbon dioxide and nonpolar molecules like lipids are able to pass through the bilayer. ▪ Small uncharged polar molecules (like water) are able to pass through the bilayer to a limited extent. ▪ Membrane permeability (High to Low): Hydrophobic molecules > Small uncharged Polar molecules > Large uncharged polar molecules > Ions ▪ Proteins embedded in the membrane like transporters, channels and pumps can help certain molecules move across the membrane

Define the terms organelle, cytoplasm, and cytosol

▪ Organelle: A compartment in eukaryotes "that divide the cell contents into smaller spaces specialized for different functions" ▪ Cytoplasm: Contents of a cell other than the nucleus ▪ Cytosol: "The region of the cell inside the plasma membrane but outside the organelles; the jelly-like internal environment that surrounds the organelles

Define and relate the terms tonicity, osmosis, hypertonic, hypotonic, and isotonic

▪ Tonicity: "The state of a solution in respect of osmotic pressure" ▪ Osmosis: Net movement of water/solvent across a selectively permeable membrane ▪ Hypertonic: Higher solute concentration in one solution than another ▪ Hypotonic: Lower solute concentration in one solution than another ▪ Isotonic: Equal solute concentration in both solutions