basic chemical units that cannot be broken apart by chemical process.
How many naturally occuring elements are there?
How many elements are required by living things?
What elements is 96% of the human body composed of?
Oxygen, Hydrogen, Carbon, and Nitrogen
critical elements found in the body in very small amounts.
What is an e xample of a trace element?
Each element consists of how many atoms?
The smallest particle of an element that has the characteristics of that element.
center of the atom
surround the nucleus at different energy levels
positive charge- in nucleus
0 charge (nuetral) – in nucleus
Negative charge- orbits nucleus
What kinds of charges attract?
positive and negative
What is the greatest number of electrons in the first shell?
Atoms of the same element that have different numbers of neutrons.
Unstable isotopes are what?
What can happen to the nucleus of an unstabble isotope?
It can decay spontaneously
What can happen to the particles and energy of an unstable isotope?
They can be given off.
2 o r more elements in a fixed ratio that are chemically combined.
Occur w hen 2 atoms share one or more pairs of electrons forming molecules.
a group of atoms held together by covalent bonds having no overall charge.
Attracting force between 2 ions of opposite charges
An atom that has gained or lost an electron
The resulting compound of an ion is what?
Starting materials i n chemical reactions
MAtter is not created or destroyed but ___.
mixture of 2 or more substances, consisting of a solvent and a solute.
Chemical that causes another substance to dissolve in a solution.
The substance in a solution that is dissolved
Any substance that forms hydrogen ions in water
Any substance that forms hydroxide ions in water.
OH combines with H+ to form what?
Describes the acidity of solutions
0 on pH scale
14 on pH scale
pH of 7 is ___.
An atom’s attraction for shared electrons
In water, ____ is electronegative
The oxygen in H2O forms what?
Polar covalent bonds
Polar covalent bonds
Shared electrons are pulled closer to the more electronegative atom.
The oxygen in H2O has a slightly what and 2 slightly what?
Negagative pole, positive poles
Hydrogen bonds in H2O are _____ chemical bonds.
Hydrogen bonds in H2O cause ______.
making water molecules stick together
Hydrogen bonds in H2O gives water a high_____.
High surface tension
A measure of the d ifficulty to stretch or break the surface of a liquid.
Hydrogen bonds in H2O also cause _____.
An attraction between molecules of different substances
Water resists temperature changes and acts as an ____ that helps maintain a steady environment.
Water ____ when it freezes.
Ice floats where?
Water also helps to form _______.
movement of molecules from an area of higher concentration to an area of lower concentration.
All moving objects have _____.
molecules are in motion
The random motion of molecules
True/False: Diffusion requires energy.
What 3 things is diffusion affected by?
Concentration, Temperature, and pressure.
Diffusion of water molecules
Temperature can do what to molecules?
Slow them down or speed them up.
Compounds made by cells that contain carbon.
Carbon completes it’s outer shell by doing what?
Compounds composed of only hydrogen and carbon
Chain of carbon atoms in organic molecules
Carbon skeletons can vary in ____.
True/false: Carbon skeletons can be branched and unbranched.
Carbon skeletons can have ______ bonds, varying in locations.
Carbon skeletons may be arranged in _____.
Smaller units of macromolecules:
Larger units of macromolecules
Chains of monomers
Macromolecules are formed by ______.
Macromolecules are broken by:______.
A method by which polymers can be broken apart.
How is each element identified?
By a symbol
How many electrons can the second energy level hold?
How many electrons can the third energy level hold?
True/false: atoms contain different amounts of protons and electrons.
All of the chemical reactions that occur within an organism
Substances that undergo chemical reactions.
Substances formed by chemical reactions
Chemical equations must always be written so that they are _____.
When elements combine to form compounds, do the elements take on new characteristics, or do they keep the original characteristics?
They no longer have their original properties.
A combination of substances in which the individual components retain their own properties.
What percent range does water make up of organisms?
70 to 95 percent
When atoms in a covalent bond do not share electrons equally, they form what?
a polar molecule
a molecule with an uneual distribution of charge
Continuous movement but no overall concentration change
How many electrons does Carbon have in its outer energy level?
How is a double bond of Carbon formed?
Each atom shares 2 electrons.
Compounds with the same simple formula but different three dimensional structures.
Whats an example of 2 isomers?
Glucose and fructose
What are the 4 classes of Macromolecules?
Carbohyrdates, lipids, proteins, and Nucleic acids.
Carbohydrates range from______.
Small sugar molecules to large polysaccharides.
What are the monomers of Carbohydrates?
What is the function of Carbohydrates?
They are the main source of energy
What 3 elements make up Carbohydrates?
Carbon, hydrogen, oxygen.
What are the 2 polymers of Carbohydrates?
Polysaccharides and Disacharrides
What are 5 examples of Carbs?
Glucose, Starch, Cellulose, Glycogen, Sucrose
A double sugar formed from 2 monosaccharides by dehydration synthesis.
Long chains of sugar units linked together by dehydration synthesis.
Polysaccharides can also be _____that cells break down to obtain sugar.
Long term storage in plant roots and other tissues.
2 examples of starches?
Potatoes and grains
Long term energy storage in animals.
Where is glycogen stored in animals?
In the liver and muscle cells.
forms cable like fibrils in the tough walls that enclose plant cells.
Cellulose is a major component of what 2 things?
Wood and paper
What 2 elements do lipids mainly consist of?
Carbon and Hydrogen atoms linked by nonpolar covalent bonds
True/false: Lipids are hydrophobic.
What are the 2 main functions of lipids?
Energy storage and cell membranes
What is the most common type of lipid?
Glycerol + 3 fatty acids
A 3 carbon molecule that serves as a backbone for the lipid molecule.
fats that have double bonds; do not solidify at room temperature
What kind of fats are unsaturated?
fats with the maximum number of hydrogen; solid at room temperature
What kindsof fats are saturated?
Major component of cell membranes
What are the 3 monomers of Lipids?
Fat, Phospholipid, Chlesterol/steroids
What are 4 examples of lipids?
Unsaturated fats, Saturated fats, Estrogen, Testosterone
Essential to the structures and activities of life.
What is the monomer of Protein?
Amino acids (20 of them)
What elements make up proteins?
Carbon, hydrogen, oxygen, nitrogen, and usually sulfur.
What is the function of proteins?
Energy, Transport, structure
What are amino acids?
Have a central Carbon covalently bonded to 1 hydrogen, 1 amino group, 1 carboxyl group, and 1 chemical group.
How are amino acids linked together?
Covalent linkage of amino acids form what?
A polypeptide bond
What is the polymer of proteins?
What breaks apart polypeptides?
a protein that can change the rate of a reaction. (chemical catalyst)
Enzymes change the _____ of chemical reactions without chemically changing itself.
What are 4 examples of proteins?
Enzymes, Hemoglobin-blood, Actin, Nyosin-muscle
a complex macromolecule that stores celluslar information in the form of a code.
What 5 elements make up nucleic acids?
Carbon, hydrogen, oxygen, nitrogen, phosphorus
What is the function of nucleic acids?
They store genetic information
What are the 2 types of nucleic acids?
DNA and RNA
genetic material inherited from parents
What are the monomers of nucleic acids?
Nucleotides (5 of them)
What are the 3 parts of a nucleotide?
5 Carbon sugar, phosphate group, nitrogenous base
What are the 5 different nucleotides?
Adenine, Guanine, Thymine, Cytosin, and Uracil (only in RNA)
DNA is what shape?
A double helix
What is t he polymer of Nucleic acid?
What are 2 examples of nucleic acids?
DNA and RNA