Chapter 2 Flashcards
Define matter
Matter – anything that takes up space and has mass (weight). It is composed of elements.
What are elements composed of?
Elements – composed of chemically identical atoms:
What are three types of elements?
• Bulk elements
* Trace elements
• Ultratrace elements
What is the smallest particle of an element?
an atom
How are bulk elements required in the body?
Bulk elements are required by the body in a large amount
What are examples of bulk elements?
Nitrogen, Oxygen, Carbon, and hydrogen
How are trace elements required in the body?
required by the body in small amounts
Bulk elements make up about 95% of what?
the body (body weight)
What are the characteristics of an atom?
smallest particle of an element that has the properties of that element
What are the characteristics of an electron?
extremely small particle with almost no weight; carries a negative electrical charge and is in constant motion around an atomic nucleus
What are the characteristics of a proton?
relatively large atomic particle; carries a positive electrical charge and is found within an atomic nucleus
What are the characteristics of a neutron?
particle with about the same weight as a proton; uncharged and thus electrically neutral; found within an atomic nucleus
What are the characteristics of an ion?
Particle that is electrically charged because it has gained or lost one or more electrons
What is a molecule?
particle formed by the chemical union of two or more atoms
What are atoms composed of?
subatomic particles such as; protons, neutrons, and electrons
What are characteristics or an atomic nucleus
• Central part of atom
• Electrons move around
*composed of protons and neutrons the nucleus
What defines an element?
the number of protons
What are examples of trace elements?
Cobalt, copper, fluorine, iodine, iron, maganeseum, zinc
What is the atomic number?
number of protons in the atoms of a particular element
What is the atomic weight of an atom?
The number of protons plus the number of neutrons
How do you know the number of neutrons an atom has?
Atomic number (protons) minus the atomic weight (protons and neutrons)
What are isotopes?
• Atoms with the same atomic number but different atomic weights
What isotopes are radioactive?
unstable isotopes meaning they may have unstable atomic nuclei that decompose, releasing energy or pieces of themselves until they reach a stable form.
Ex of elements with radioactive isotopes: O2, iodine, iron, phosphorus, and cobalt
What element often forms isotopes?
Oxygen (O16, O17, O18)
What is a molecule?
Molecule – particle formed when two or more atoms chemically combine
EX: H2, H2O
What is a compound?
Compound – particle formed when two or more atoms of different elements chemically combine
EX: H2O
What is a molecular formula?
Molecular formulas – depict the elements
present and the number of each atom present in the molecule
H2 C6H12O6 H2O
What are bonds?
links that are formed when atoms combine with other atoms
Where are electrons found?
• Electrons of an atom occupy regions of space called electron shells which circle the nucleus
• For atoms with atomic numbers of 18 or less, which rules apply?
- The first shell can hold up to 2 electrons
- The second shell can hold up to 8 electrons
- The third shell can hold up to 8 electrons
When is an atom stable?
When the outermost shell is full
What is the octet rule?
Except for the first shell, it takes eight electrons to fill the shells in most of the atoms important in living organisms
What does inert mean?
an atoms outermost electron shells are filled, meaning they already have a stable structure, so they are chemically inactive.
what is an ion?
•An electrically charged atom
* an atom that wants to gain or lose electrons to become stable
What is a cation?
- A positively charged ion
* Formed when an atom loses electrons
What is an anion?
- A negatively charged ion
* Formed when an atom gains electrons
What is an ionic bond?
an attraction between cations & anions
* formed when one atom gives 1 or more electrons completely to another
What is the most common bond in the body?
Covalent bond
How are covalent bonds formed?
formed when atoms share electrons
What bond is the strongest?
covalent bond
What do structural formulas show?
• Structural formulas show how atoms bond and are arranged in various molecules
How do polar molecules occur?
• Results when electrons are not shared equally in covalent bonds (if shared equally – nonpolar)
What is an important polar molecule?
water
What are the characteristics of a polar molecule?
- A weak attraction between the positive end of one polar molecule and the negative end of another polar molecule
- Formed between water molecules
- Important for protein and nucleic acid structure
What causes a chemical reaction?
Chemical reactions occur when chemical bonds form or break among atoms, ions, or molecules.
What are reactants?
Reactants are the starting materials of the reaction -the atoms, ions, or molecules
What are products?
Products are substances formed at the end of the chemical reaction
what is a synthesis reaction?
Synthesis Reaction – more complex chemical
structure is formed
What is a decomposition reaction?
Decomposition Reaction – chemical bonds are broken to form a simpler chemical structure
What is an exchange reaction?
Exchange Reaction – chemical bonds are broken and new bonds are formed
What is a reversible reaction?
Reversible Reaction – the products can change back to the reactants
What is an electrolyte?
Electrolytes – substances that release ions in water
What is an acid?
Acids – electrolytes that dissociate to release hydrogen ions in water
What is a base?
Bases – substances that release ions that can combine with hydrogen ions
What are salts?
Salts – electrolytes formed by the reaction between an acid and a base
What does a pH scale indicate?
the concentration of hydrogen ions in solution
What is a neutral pH?
Neutral – pH 7; indicates equal concentrations of H+ and OH
What is an acidic pH?
Acidic – pH less than 7; indicates a
greater concentration of H+
What is a basic/ alkaline pH?
Basic or alkaline – pH greater than 7; indicates a greater concentration of OH
What is a characteristic of an organic molecule?
• Usually larger than inorganic molecules
• Dissolve in water and organic liquids
*molecules contain carbon and hydrogen
Ex: proteins, carbs, lipids, fats, nucleic acids
What is a characteristic of an inorganic molecule?
• Usually smaller than organic molecules
• Usually dissociate in water, forming ions
* don’t contain carbon
* ex: water, oxygen, hydrogen, CO2, inorganic salts
What are the characteristics of water?
• Most abundant compound in living material
• Two-thirds of the weight of an adult human
• Major component of all body fluids
• Important role in transporting chemicals in the body
• Absorbs and transports heat
* medium for most metabolic reactions
What is the molecular formula for glucose?
C6 H12 O6+ O2
Why is oxygen used by organelles?
to release energy from nutrients in order to drive cell’s metabolic activities
*necessary for survival
What is carbon dioxide?
- waste produc released during metabolic reactions
* Must be removed from the body
What are Inorganic salts?
- Abundant in body fluids
* Sources of necessary ions
What are characteristics of carbohydrates?
- Supply materials to build cell structures
- Contain C, H, and O
- Ratio of H to O close to 2:1 (C6H12O6
- Monosaccharides – glucose, fructose
- Disaccharides – sucrose, lactose
- Polysaccharides – glycogen, cellulose
Characteristics of lipids?
• Soluble in organic solvents; insoluble in water
What are the characteristics of Fats (triglycerides)
- Used primarily for energy; most common lipid in the body
- Contain C, H, and O but less O than carbohydrates (C57H110O6
- Building blocks are 1 glycerol and 3 fatty acids per molecule
- Saturated and unsaturated
What are the characteristics of phospholipids?
- Building blocks are 1 glycerol, 2 fatty acids, and 1 phosphate per molecule
- Hydrophilic and hydrophobic
- Major component of cell membranes
what are the characteristics of staroids?
- Four connected rings of carbon
- Widely distributed in the body, various functions
- Component of cell membrane
- Used to synthesize hormones
What are characteristics of proteins?
- Structural material
- Hormones
- Receptors
- Enzymes
- Antibodies
- Protein building blocks are amino acids
- Amino acids held together with peptide bonds
What are examples of macronutrients?
carbs, lipids, protein
- these are consmed to provide energy
- water soluble
what is hydrophilic?
polar (water loving)
What is hydrophobic?
non polar ( doesn’t like water
