ap bio (summer 2024)

Elements

A molecule composed of one kind of atom; cannot be broken into simpler units by chemical reactions.

Elements in Living Things

carbon, hydrogen, oxygen, nitrogen

trace elements

elements required by an organism in only minute quantities

Atom

the basic unit of a chemical element.

subatomic particles

protons, neutrons, electrons

Atomic nucleus

An atom's central core, containing protons and neutrons.

Isotopes

Atoms of the same element with different numbers of neutrons

Compound

A substance made up of atoms of two or more different elements joined by chemical bonds

chemical reaction

the process by which one or more substances change to produce one or more different substances

chemical bonds

the attractive forces that hold atoms together

ionic bond

A chemical bond resulting from the attraction between oppositely charged ions; formed when one or more electrons are transferred from one atom to another

covalent bonds

Bonds created by sharing electrons with other atoms.

hydrogen bonds

Very weak bonds; occurs when a hydrogen atom in one molecule is attracted to the electrostatic atom in another molecule

nonpolar covalent

electrons are shared equally

polar covalent

unequal sharing of electrons

polar

Molecule with partial charges. Mixes with water.

Cohesion

Attraction between molecules of the same substance --> property of water

Adhesion

An attraction between molecules of different substances --> property of water

surface tension

A measure of how difficult it is to stretch or break the surface of a liquid --> property of water

high heat capacity

absorbs and releases large amounts of heat before changing temperature --> property of water

expansion on freezing

when water freezes, the ice is less dense than the surrounding water and floats

capillary action

the combined force of attraction among water molecules and with the molecules of surrounding materials, allows water to rise up in a thin tube

adhesive

able to stick fast to a surface or object; sticky.

acidic

a pH below 7 is acidic; contains more H+ ions than hydroxide ions (OH-)

basic

pH above 7 is basic (alkaline); more OH- ions than H+ ions

neutral

a ph of 7

pH scale

scale with values from 0 to 14, used to measure the concentration of H+ ions in a solution

organic compounds

Compounds that contain carbon

inorganic compounds

Compounds that do not contain carbon

Polymers

large compound formed from combinations of many monomers

monomers

building blocks of polymers

Carbohydrates

Broken down to glucose to provide energy.

Monosaccharides

Single sugar molecules like glucose, fructose, galactose

Disaccharides

Carbohydrates that are made up of two monosaccharides like sucrose, lactose, maltose

Polysaccharides

Carbohydrates that are made up of more than two monosaccharides like starch, glycogen, cellulose

dehydration synthesis (condensation)

A chemical reaction in which two molecules covalently bond to each other with the removal of a water molecule.

glycosidic linkage

A covalent bond formed between two monosaccharides by a dehydration reaction.

Hydrolysis

Breaking down complex molecules by the chemical addition of water

amino acids

building blocks of proteins

amino acid groups

amino group, carboxyl group, R group (side chain)

Dipeptide

Two amino acids bonded together

peptide bond

covalent bond formed between amino acids

polypeptide

A polymer (chain) of many amino acids linked together by peptide bonds.

Protein

An organic compound that is made of one or more chains of amino acids and that is a principal component of all cells

primary structure

sequence of amino acids

secondary structure

Either an alpha helix or beta pleated sheet.

tertiary structure

Results from interactions between side chains of a protein

quaternary structure

Results from two or more polypeptide subunits.

chaperone proteins (chaperonins)

molecules that assist in folding other proteins

Lipids

Energy-rich organic compounds, such as fats, oils, and waxes, that are made of carbon, hydrogen, and oxygen.

types of lipids

triglycerides, phospholipids, sterols

glycerol

Combines with fatty acids to make lipids.

ester linkage

The linkage formed between the glycerol molecule and the fatty acids in a fat. This bond is formed through dehydration synthesis.

saturated lipids

fatty acids with all single bonds, solid at room temp. ex: butter, wax, blubber

unsaturated lipids

Fatty acids with one or more C=C double bonds

polyunsaturated fats

fatty acids with more than one double bond

Phospholipids

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

Hydrophobic

Having an aversion to water; will not absorb or dissolve in water (nonpolar)

Hydrophilic

Having an affinity for water; readily absorbing or dissolving in water (polar)

amphipathic molecules

molecules that have both hydrophilic and hydrophobic properties

Cholesterol

A lipid that forms an essential component of animal cell membranes and acts as a precursor molecule for the synthesis of other biologically important steroids.

nucleic acids

macromolecules containing hydrogen, oxygen, nitrogen, carbon, and phosphorus

nucleotides

Basic units of DNA molecule, composed of a sugar, a phosphate, and one of 4 DNA bases

deoxyribonucleic acid (DNA)

A double-stranded, helical nucleic acid molecule capable of replicating and determining the inherited structure of a cell's proteins. [deoxyribose sugar and nitrogenous bases adenine (A), cytosine (C), guanine (G), and thymine (T)]

ribonucleic acid (RNA)

A single stranded nucleic acid that functions in protein synthesis and as the genome of some viruses. [ribose sugar and nitrogenous bases adenine (A), cytosine (C), guanine (G), and uracil (U)]

Cell

The basic unit of structure and function in living things

The surface area-to-volume ratio of a cell

Accounts for the size limit of cells, allows for transport of molecules across the membrane

light microscopes

use light and glass lenses to magnify an image, used to study living cells

electron microscopes

use beams of electrons, rather than light, to produce images, used to study detailed structures of a cell that cannot be easily seen or observed by light microscopy.

prokaryotic cells

Small, simple, no nucleus, no membrane-bound organelles, single loop of DNA (nucleosome), no cellulose, cytoplasm, cell membrane, cell wall (made of carbs), sometimes have cilia or flagella (movement).

Eukaryotic cells

Larger, complex, with nucleus, membrane bound organelles, DNA tightly wrapped around histone proteins in chromosomes, cellulose in plant cell walls.

Cytoplasm

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

Nucleoid

A non-membrane-bounded region in a prokaryotic cell where the DNA is concentrated.

cell wall

A rigid layer of nonliving material that surrounds the cells of plants and some other organisms.

plasma membrane

A selectively-permeable phospholipid bilayer forming the boundary of the cells

Flagella

whiplike tails found in one-celled organisms to aid in movement

capsule

A sticky layer that surrounds the cell walls of some bacteria, protecting the cell surface and sometimes helping to glue the cell to surfaces.

organelles

Structures specialized to perform distinct processes within a cell.

phospholipid bilayer

Plasma membrane layers composed of phospholipid molecules arranged with polar heads facing the outside and nonpolar tails facing the inside.

peripheral proteins

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

integral proteins

proteins that penetrate the hydrophobic interior of the lipid bilayer (can be attached to one side or go through the membrane)

transmembrane proteins

Integral proteins that extend all the way through the membrane.

fluid mosaic model

The currently accepted model of cell membrane structure, which envisions the membrane as a mosaic of individually inserted protein molecules drifting laterally in a fluid bilayer of phospholipids.

adhesion proteins

membrane proteins that form junctions between adjacent cells.

receptor proteins

Proteins that transmit information in and out of cells. They allow communication between cells.

transport proteins

membrane proteins that use ATP to pump hydrophilic substances across a cell membrane

channel proteins

provide corridors that allow a specific molecule or ion to cross the membrane

cell surface markers

a membrane protein that identifies the cell type

Carbohydrate side chains

molecules on the outer surface of the plasma membrane that attach to the surface of some proteins

Cellular Nucleus

the membrane-bound organelle of eukaryotic cells that contains the cell's genetic material

Chromosomes

a threadlike structure of nucleic acids and protein found in the nucleus of most living cells, carrying genetic information in the form of genes.

Nucleolus

Found inside the nucleus and produces ribosomes

Ribosomes

site of protein synthesis

Endoplasmic Reticulum (ER)

An extensive membranous network in eukaryotic cells, continuous with the outer nuclear membrane and composed of ribosome-studded (rough) and ribosome-free (smooth) regions.

Rough ER

That portion of the endoplasmic reticulum studded with ribosomes that make membrane proteins and secretory proteins.

Smooth ER

That portion of the endoplasmic reticulum that is free of ribosomes; makes lipids

Golgi apparatus

A system of membranes that modifies and packages proteins for export by the cell

Vesicles

small membrane sacs that specialize in moving products into, out of, and within a cell

Mitochondria

This is the powerhouse of the cell, site of cellular respiration & production of ATP

Adenosine Triphosphate (ATP)

energy-carrying biological molecule, drives cellular activities, stores and releases energy