APBio Unit 1-4

Macromolecules

Molecules composed of thousands of atoms: the four main classes being carbohydrates, lipids, prteins, and nucleic acids

Active transport

Movement of molecules against a gradient from a region of low concentration to high concentration; requires energy (ATP)

(e.g., Na+/K+ pumps)

Polymer

Chainlike molecules, consisting of many similar or identical building blocks linked by covalent bonds.

Carrier Protein

An integral membrane protein that undergoes a conformational change to move a molecule from one side of the membrane to another.

Monomer

Make up polymers: connected by covalent bonds.

Cell wall

Found in plant cells and not animal cells, an additional layer of protection and rigidity

Dehydration Synthesis

(Condensation Reaction): Covalent bonds which connect monomers have distinct functions: One monomer provides a hydroxyle group and the other provides a hydrogen, creating water (as a biproduct) and a bond between the monomers.

Central Vacuoles

Found in plant cells, for large storage of food and water

Hydrolysis

Adding water to reverse dehydration synthesis, so the polymer recieves a hydrogen atom and a hydroxyl group

Channel Protein

type of cell membrane protein used in passive transport (specifically facilitated diffusion)

Carbohydrates

A macromolecule made up of C, H and O, with a 2:1 ratio between the hydrogen and oxygen.

Chloroplast

Site of photosynthesis

Monosaccharides

Simple sugars with 1 ring: Provides immediate energy, classified by the amount of carbons

Cilia

Appendage that protrude from eukaryotic cells for movement

Disaccharides

Double sugars with 2 rings

Concentration Gradient

difference in concentration of a substance on two sides of a membrane

Contractile Vacuole

Found in freshwater organisms, pump out excess water that diffuses inward because organisms in a hypotonic environment

Polysaccharides

Polymers, with many rings, joined by glucosidic linkages. Acts as an energy storage macromolecule, building materials for cells or whole organisms

Maltose

A disaccharide formed by joining the two glucose molecules: found in malt sugar

Prokaryotes

Cells with no nuclear or internal membranes

Sucrose

A disaccharide formed by joining glucose and fructose, major form of sugars in plants: found in table sugar

Eukaryotes

Cells with internal membranes (e.g., nucleus, organelles)

Lactose

A disaccharide formed by joining glucose and galactose. People who lack the enzyme to digest this sugar are "intolerant"

Theory of Endosymbiosis

Chloroplasts and mitochondria were formerly tiny prokaryotes that took up residence inside larger cells and formed a permanent symbiotic relationship; eukaryotes evolved from engulfing prokaryotes

Nucleus

Contains chromosomes; surrounded by selectively permeable membrane that contains nuclear pores for the passage of molecules like mRNA

Glucosidic Linkages

the bond that bonds polysaccharides

Starch

During photosynthesis: glucose is a biproduct that is stored in plastids and chloroplasts

Nucleolus

Where ribosome components are synthesized and assembled

Cellulose

Made up cell walls of plants, using beta rings

Ribosomes

Site of protein synthesis

Found free in the cytoplasm or attached to the rough endoplasmic reticulum

Glycogen

An animal polysaccharide. Human produces excess sugar, highly branched. Humans and vertebrates store this in the liver and muscles

Endoplasmic Reticulum

Membranous system of channels and flattened sacs that transverses the cytoplasm

Rough - site of protein synthesis

Smooth - synthesizes steroid hormones and other lipids; connects rough to Golgi

Chitin

Makes up the exoskeleton of pill bugs; extremely strong, contains nitrogen-containing appendage on each glucose. Structural support for the cell walls of many fungi.

Golgi Apparatus

Packages and secretes substances produced in the ER; lies near nucleus; consists of flattened membranous sacs

Lysosomes

Sacs of hydrolytic enzymes that digest macromolecules; Also carries of apoptosis

Absent from plant cells

Found in large numbers in white blood cells

Lipids

Literally no affinity for water (hydrophobic), nonpolar molecules. Have C, H and O, but not in a 2:1 ratio.

Triacylglycerols

(Fats): Store large amounts of energy, made up of 1 glycerol + 3 fatty acids -> 1 fat + 3 water molecules. Functions as energy storage, to cushion vital organs, and insulation.

Mitochondria

Site of aerobic cellular respiration, the process that generates ATP

(Tied to theory of endosymbiosis)

Ester Linkage

Joins 3 fatty acids to a glycerol, creating a triacylglycerol

Cytoskeleton

Complex network of protein filaments that extends through cytoplasm and gives cell its shape and ability to moves (e.g., microtubules, microfilaments)

Saturated fatty acids

Fatty acids with single bonds, hydrogen at every possible position, a straight shape, from an animal source. Solid at room temperature.

Plasma membrane

Selectively permeable outer layer of cells; made of a phospholipid bilayer with proteins dispersed throughout

Fluid mosaic model

Model for plasma membrane that includes

-glycolipids: cell-to-cell recognition

-phospholipids: hydrophobic tails, hydrophilic heads

-cholesterol: for stability

-transmembrane proteins (e.g., pumps, enzymes, channels): for movement of large polar molecules and active transport

Unsaturated fatty acids

Fatty acids with double and single bonds, without hydrogens at every possible position, a kinked/bent shape, from a plant source. Liquid at room temperature.

Phospholipid

2 fatty acids attached to a glycerol, with a phosphate group in the 3rd position. Have both hydrophobic and hydrophilic bonds

Passive transport

Movement of molecules down a gradient from a region of high concentration to a region of low concentration; no energy required

Steroid

A type of phospholipid: A carbon skeleton with 4 fused carbon rings, which are closely interlocked. ex., cholesterol

Facilitated diffusion

Diffusion that requires membrane channels; larger, polar molecules

Proteins

Built up of 20 types of amino acids, which can unravel or denature in response to changes in pH, salt concentration, and temperature because they disrupt the bonds between parts of the protein

Osmosis

Type of diffusion where water diffuses across a membrane

Primary Structure

The unique sequence of amino acids, determined by DNA. Changing this affects a protein's conformation and ability to function.

Hypertonic

Cell shrinks because water flows from higher water potential to lower water potential out of the cell; solution has higher concentration of solute

Secondary Structure

Results from hydrogen bonds at regular intervals doing the polypeptide backbone, typically developed as an alpha helix or a beta pleated sheet.

Hypotonic

Cell swells or bursts because water moves from higher water potential to lower water potential into the cell; solution has lower concentration of solute

(Plant cells do not burst, they become turgid)

Tertiary Structure

The protein has folded up upon itself, held together by hydrogen bonds, ionic bonds, Van der Waals reactions, or disulfide bridges

Isotonic

Nothing happens to the cell because the concentrations of the solutions outside and inside the cell are equal

Quarternary structure

Union of 2+ polypeptide subunits

Diffusion

Movement of molecules from an area of higher concentration to an area of lower concentration.

Enzymes

Speeds up the rate of reactions, but are not consumed by the reaction. Lowers the activation energy of a reaction, and makes it easier to perform these reactions.

Endocytosis

A cell engulfs material from the environment by folding its plasma membrane inward

Exocytosis

a process by which the contents of a cell vacuole are released to the exterior through fusion of the vacuole membrane with the cell membrane.

Substrate

A reactant that binds to an enzyme

Active Site

A pocket/groove on the surface of a protein on the surface of the protein into which the substrate fits. The substrate is held to this area through weak interactions, such as hydrogen bonds or Van der Waals.

Phagocytosis

A type of endocytosis in which a cell engulfs large particles or whole cells

Induced Fit Hypothesis

As the substrate binds, the enzyme changes shape leading to a tighter induced fit, bringing chemical groups into position to catalyze the reaction.

Pinocytosis

A type of endocytosis in which the cell ingests extracellular fluid and its dissolved solutes.

Cofactors

Non-protein factors, helping the enzyme fit substrates. ex: zinc, iron, copper

Receptor Mediated endocytosis

The movement of specific molecules into a cell by the inward budding of membranous vesicles containing proteins with receptor sites specific to the molecules being taken in; enables a cell to acquire bulk quantities of specific substances.

Competitive Inhibitors

Blocks the active site from having a substrate meet. Acts as a feedback mechanism

Selective Permeability

A property of a plasma membrane that allows some substances to cross more easily than others.

Noncompetitive inhibitors

Blocks the substrates at a place away from the active site.

transport protein

A membrane protein that is responsible for moving hydrophilic substances from one side to the other.

Allosteric Enzymes

Enzymes that can change their shape: one shape is active (reaction occurs) and one is inactive (reaction doesn't occur)

Cells

Smallest functional unit of life

Nucleic Acids

An organic compound made up of a pentose sugar, phosphate, and nitrogen base. The three types are DNA, RNA and ATP

Organelles

A membrane-enclosed structure with a specialized function within a cell.

Ribonucleic acid (RNA)

Many types of instructional nucleic acid, which is directed by DNA and contributes to protein production

Cell Theory

This says that all living things are made of cells, that cells are the basic unit of structure and function and that cells only come from other cells.

Cytoplasm

A jellylike fluid inside the cell in which the organelles are suspended

Deoxyribonucleic acid (DNA)

Provides the genetic coding for organisms and directs RNA synthesis: synthesized through dehydration synthesis, connecting the sugar of one nucleotide to another with a strong phosphodiester.

Nucleotide

The building blocks of nucleic acids

Hydrophilic

water loving

Pentose sugar

Deoxyribose and ribose; a building block of nucleic acids

Hydrophobic

water fearing

Phosphate

Makes DNA and RNA charged; a building block of nucleic acids

Phospholipid

A molecule that is a constituent of the inner bilayer of biological membranes, having a polar, hydrophilic head and a nonpolar, hydrophobic tail.

Nitrogen base

Adenosine, Thymine, Guanine, Cytosine, Uracil (RNA); building blocks of DNA. A+T are always together, and G+C are always together based on their properties. U is only found in RNA.

Receptor Protein

proteins in the plasma membrane that are sensitive to the presence of specific extracellular molecules called ligands

Purines

Adenosine, Guanine; have a double ring,

Aquaporin

A membrane protein, specifically a transport protein, that facilitates the passage of water through channel proteins.

Pyrimidines

Thymine, Cytosine, Uracil; Single ring

Cotransport

The coupling of the "downhill" diffusion of one substance to the "uphill" transport of another against its own concentration gradient.

Phosphodiester Link

The bond between a sugar and a phosphate.

integral protein

Transmembrane proteins with hydrophobic regions that completely span the hydrophobic interior of the membrane.

Element

a substance that cannot be broken down to other substances by chemical reactions

Peripheral Protein

Protein appendages loosely bound to the surface of the membrane and not embedded in the lipid bilayer.

Pressure Potential

This measurement has a minimum value of 0 (when the solution is open to the environment); it increases as pressure increases.

Atom

smallest unit of matter that still retains the properties of an element

Atomic number

number of protons, which is unique to that element

Simple Diffusion

Net movement of dissolved particles from higher concentration to a region of lower concentration