Honors Biology Chapter 2

H2O

2 covalent bonds

A single covalent carbon atom can form a maximum of how many single covalent bonds?

4

second energy level

8 electrons

third energy level

8 electrons

carbon

a component of almost all biological molecules, 4 electrons in its outermost layer, can form 4 covalent bonds

chemical reaction

a process that changes, or transforms, one set of chemicals into another

element

a pure substance that consists entirely of one type of atom

activation site

a site where reactants can be brought together to react

chemical compound

a substance formed by the chemical combination of 2 or more elements in definite proportions

solvent

a substance in which another substance is dissolved

catalyst

a substance that speeds up the rate of a chemical reaction, lowers a reaction's activation energy, cells make catalysts

hydrogen bond

a weak interaction involving a hygrogen atom and a flourine, oxygen, or nitrogen atom

nucleus

at center of atom formed when protons and neutrons bind together

unsaturated

atleast one double bond, less hydrogen, share 4 electrons

isotopes

atoms of the same element that differ in the number of neutrons they contain

atom

basic unit of matter

exothermic

chemical reaction that releases energy in the form of heat or sometimes light and sound

endothermic

chemical reactions that absorb energy

nucleic acid

complex macromolecules that store and transmit genetic information

nucleotides

composed of carbon, nitrogen, oxygen, phosphorus, and hydrogen atoms (CHONP)

proteins

compounds made of small carbon compounds, store energy

valence electrons

electrons available to form bonds

products

elements or compounds produced by a chemical reaction

reactants

elements or compounds that enter into a chemical reaction

activation energy

energy that is needed to get a reaction started

dissacharide

formed by 2 monosaccharides

ionic bonds

formed when one or more electrons are transferred form one atom to another; donating and accepting

vertical rows

group

polar molecules

have an unequal distribution of charges

Van der Waals force

intermolecular forces of attraction

macromolecules

large molecules formed by joining smaller organic molecules together

oil

liquid at room temperature

polysaccharides

longer carbohydrate molecules

lipids

made mostly of carbon and hydrogen (CH)

solution

mixture of water and non dissolved material

homogenous mixture

mixture that has a uniform composition throughout

buffers

mixtures that can react with acids or bases to keep the pH within a particular range

adhesive

molecules from different compounds are attracted to each other due to H bonds

polymers

molecules made from repeating units of identical or nearly identical compounds linked together by a series of covalent bonds

cohesive

molecules of the same type of compounds are attracted to each other due to H bonds

covalent bonds

moving electrons actually travel about the nuclei of both atoms; atoms share at least 2 electrons

electrons

negative charge, outside of nucleus

neutrons

no charge

atomic mass

number of protons and neutrons in an element

atomic number

number of protons in an element

first energy level

only 2 electrons

base solutions have__

pH values higher than 7

acid solutions have__

pH values lower than 7

horizontal rows

period

protons

positive charge

ion

positively and negatively charged atoms

polarity

property of having two opposite poles

enzymes

proteins that act as a biological catalyst (within a living thing), speed up chemical reactions that take place in cells, lowers activation energy

substance

reactants of enzymes catalyzed reactions

amino acids

small carbon compounds made of carbon, nitrogen, oxygen, hydrogen, and sometimes sulfur (CHONS)

monomers

smaller units that make up polymers

molecule

smallest unit of most compounds

fat

solid at room temperature

law of conservation of mass

states matter cannot be created or destroyed

carbohydrates

store enrgy and serve as a major source of energy, compounds composed of carbon, hydrogen, and oxygen in a ratio of one oxygen and two hydrogen (CH20)

chemistry

study of matter

acids

substances that release Hydrogen ions (H+) when dissolved in water

bases

substances that release hydroxide ions (OH-) when dissolved in water

colloide

super mixed heterogeneous mixture

saturated

tail chains with only single bonds between the carbon atoms, share 2 electrons

heterogeneous

the components remain distinct and non dissolved in the solvent

pH

the measure of concentration of H+ in a solution

solution

the mixture where all components are evenly distributed throughout

solute

the substance that is dissolved in the solvent

mass number

total number of protons and neutrons in the nucleus of an atom

simple sugars, monosaccharides

values of n ranging from 3 to 7

atomic mass

weighted average of the masses of an element's isotopes

radioactive isotopes

when a nucleus breaks apart, it gives off radiation that can be detected and used for many applications

How does a single covalent bond form?

when they share two electrons