AP Bio Unit 1 & 2

Cohesion

bonding between like molecules, causes surface tension

Surface Tension

measure of how difficult it is to break or stretch surface of liquid

Adhesion

bonding between unlike molecules

Transpiration

movement of H2O up plants

Thermal energy (heat)

total amount of KE in system

Temperature

measure intensity of heat due to average KE of molecules

Water has a ____ specific heat

high

Evaporative Cooling

Process where the surface of an organism or object cools as water evaporates; molecules with the highest kinetic energy leave first, lowering the average temperature of the remaining liquid.

Insulation by ice

less dense, floating ice insulates liquid H₂O below

Solution

liquid, homogeneous mixture of 2+ substances

Solvent

dissolving agent (liquid)

Solute

dissolved substance

Water = ______ solvent

versatile

Acid

increases H+ concentration (HCl)

Base

reduces H⁺ concentration (NaOH)

Buffers

minimize changes in concentration of H+ and OH- in a solution (weak acids and bases), keeps blood at a stable pH

Carbonic Acid – Bicarbonate System

important buffers in blood plasma

Major elements of life

CHONPS

Isotopes

number of neutrons varies, but same number of protons, radioactive isotopes used as tracers

Van der Waals Interactions

slight, fleeting attractions between atoms and molecules close together, weakest

Organic chemistry

branch of chemistry that specializes in study of carbon compounds

Organic compounds

contain Carbon (& H)

Carbon has __ valence electrons

4

Carbon can form up to ___ covalent bonds

4, can be single, double, or triple

Isomers

same molecular formula, but differ in atom arrangement, different structures —> different properties/functions

Water is _____ dense than ice

more

Capillary action

the ability of water to flow in narrow spaces against gravity due to adhesion and cohesion

What makes water polar

polar covalent bonds, contributes to hydrogen bonding

Solvent of life

water is a versatile solvent, polar so can dissolve polar molecules & ions

Four emergent properties of water

cohesive behavior, moderation of temperature, expansion upon freezing, solvent of life

Water can form _____ bonds because it is polar

hydrogen

elements in carbohydrates

Carbon, Hydrogen, Oxygen

elements in lipids

Carbon, Hydrogen, Oxygen, sometimes Phosphorus

elements in proteins

Carbon, Hydrogen, Oxygen, Nitrogen

elements in nucleic acid

Carbon, Hydrogen, Oxygen, Nitrogen, Phosphorus

monomer

chemical subunits that create polymers

polymer

macromolecule made of many monomers

dehydration synthesis

a chemical reaction where water is removed to bond monomers together, forming polymers

hydrolysis reaction

the process that breaks down polymers into monomers by adding water.

Ribosomes

Small non-membrane-bound organelles composed of rRNA and proteins; synthesize proteins by translating mRNA into amino acid sequences.

mRNA

Messenger RNA; carries genetic information from DNA to ribosomes for protein synthesis.

Endoplasmic reticulum (ER)

Network of membranes involved in protein and lipid synthesis; connects to the nuclear envelope.

Smooth endoplasmic reticulum

Lacks ribosomes; synthesizes lipids, detoxifies drugs, and stores calcium ions.

Rough endoplasmic reticulum

Studded with ribosomes; synthesizes and modifies proteins for secretion or membrane insertion.

Golgi complex

Stack of flattened membranes that modifies, sorts, and packages proteins and lipids into vesicles for transport.

Mitochondria

Double-membrane organelle that produces ATP through cellular respiration.

Matrix

The innermost compartment of mitochondria containing enzymes for the Krebs cycle.

Intermembrane space

Space between inner and outer mitochondrial membranes; site of proton accumulation for ATP production and the electron transport chain.

Cristae

Folds of the inner mitochondrial membrane that increase surface area for ATP synthesis.

Lysosomes

Membrane-bound organelles containing hydrolytic enzymes for digestion and recycling of cellular waste.

Hydrolytic enzymes

Enzymes that break down biomolecules using water in hydrolysis reactions.

Vacuoles

Membrane-bound sacs for storage of water, nutrients, or waste; large central vacuole maintains turgor in plant cells.

Photosynthesis

Process by which plants convert light energy, water, and CO₂ into glucose and oxygen.

Chloroplasts

Double-membrane organelles in plant cells that perform photosynthesis.

Thylakoid

Membranous sac inside chloroplasts; contains chlorophyll and light-dependent reaction machinery.

Grana

Stacks of thylakoids that increase surface area for light absorption.

Stroma

Fluid surrounding thylakoids where the Calvin cycle (light-independent reactions) occurs.

Plasma membrane

Phospholipid bilayer that encloses the cell, controls what enters/exits, and maintains homeostasis.

Phospholipid

Molecule with hydrophilic phosphate head and hydrophobic fatty acid tails; forms the bilayer structure of membranes.

Amphipathic

Having both hydrophilic and hydrophobic regions (like phospholipids).

Peripheral proteins

Loosely attached to membrane surface; involved in signaling or maintaining cell shape.

Integral proteins

Embedded in the lipid bilayer; often function as transporters or receptors.

Fluid mosaic model

Describes membrane as fluid with various proteins floating in or on the lipid bilayer.

Cholesterol

Lipid molecule within the bilayer that stabilizes membrane fluidity, preventing it from becoming too rigid or too fluid.

Glycoproteins

Proteins with carbohydrate chains attached; involved in cell recognition and signaling.

Glycolipid

Lipid with carbohydrate attached; helps in cell recognition and stability.

Selectively permeable

Allows certain molecules to cross the membrane while restricting others.

Channel proteins

Form pores in the membrane for passive movement of ions or small molecules.

Carrier proteins

Bind and change shape to transport specific molecules across the membrane.

Cell wall

Rigid structure outside plasma membrane; provides support and protection. Made of cellulose (plants), chitin (fungi), or peptidoglycan (bacteria).

Concentration gradient

Difference in solute concentration across a membrane.

Passive transport

Movement of molecules down their concentration gradient without energy input.

Diffusion

Movement of molecules from high to low concentration until equilibrium is reached.

Facilitated diffusion

Passive transport using membrane proteins for molecules that can’t diffuse directly through the lipid bilayer.

Active transport

Movement of molecules against their concentration gradient using energy (ATP).

ATP

Adenosine triphosphate; main energy currency of the cell.

Endocytosis

Process of taking materials into the cell by engulfing them in vesicles.

Phagocytosis

“Cell eating”; endocytosis of large particles or cells.

Pinocytosis

“Cell drinking”; endocytosis of fluids and small molecules.

Receptor-mediated endocytosis

Specific uptake of molecules via receptor-ligand binding.

Exocytosis

Vesicles fuse with plasma membrane to release materials outside the cell.

Cotransport

Coupled transport of two substances across a membrane using one gradient to drive another.

Symport

Both substances move in the same direction across the membrane.

Antiport

Substances move in opposite directions across the membrane.

Electrochemical gradient

Combined force of electrical charge difference and concentration difference across a membrane.

Membrane potential

Voltage difference across a membrane due to ion distribution.

Na⁺/K⁺ ATPase (Na⁺/K⁺ pump)

Active transport protein that pumps 3 Na⁺ out and 2 K⁺ in using ATP to maintain membrane potential.

Osmosis

Diffusion of water through a selectively permeable membrane.

Aquaporins

Channel proteins that facilitate rapid water movement across membranes.

Osmolarity

Total solute concentration of a solution.

Tonicity

Effect of a solution on cell water balance (based on solute concentration).

Hypotonic

Solution with lower solute concentration than the cell; water moves into cell.

Hypertonic

Solution with higher solute concentration than the cell; water moves out of cell.

Isotonic

Solution with equal solute concentration; no net water movement.