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ch 2 3 and 4 bethel university
a helpful review
101
Biology
Graduate
01/27/2010

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Term
Matter
Definition
anything that has a mass and occupies space
Term
Element
Definition
the simplest form of matter, cannot be further broken down
Term
compound
Definition
combination of two or more atoms
Term
What are the three basic atoms making up organic matter?
Definition
C, H and O
Term
Atom Structures
Definition
atoms contain several different kinds of subatomic particles
Term
protons
Definition
positively charged particles located in the nucleus of an atom
Term
neutrons
Definition
neutral particles located in nucleus of an atom
Term
electrons
Definition
negatively charges particles located in the outer shells of the atom, circulating around the central nucleus
Term
Atomic Number
Definition
number of protons in the nucleus
identifies the element
Term
atomic weight
Definition
mass of a single atom.
number of protons and neutrons combined
Term
Energy levels
Definition
Total number of electrons in an atom equals the number of protons in the nucleus (in a stable atom)
Forms an electron cloud around the nucleus
Term
Bohr Model
Definition
a model resembling planets revolving around the sun; useful in visualizing the structure of atoms
Term
an atom is concidered inert when
Definition
An atom with eight electrons, or four pairs, in the outermost energy level is chemically inert
Term
atom that is active is
Definition
An atom without a full outermost energy level is chemically active
Term
Octet rule
Definition
atoms with fewer than eight or more than eight electrons in the outer energy level will attempt to lose, gain, or share electrons with other atoms to achieve stability
Term
isotopes
Definition
Isotopes of an element contain the same number of protons but different numbers of neutrons
Term
Isotopes have the same..... and therefore the same basic chemical properties as any other atom of the same element, but they have a different....
Definition
atomic number, atomic weight
Term
Radioactive isotope
Definition
an unstable isotope that undergoes nuclear breakdown and emits nuclear particles and radiation
Term
Chemical reaction
Definition
interaction between two or more atoms that occurs as a result of activity between electrons in their outermost energy levels
Term
Molecule
Definition
two or more atoms joined together
Term
Compound
Definition
consists of molecules formed by atoms of two or more elements
Term
Chemical bonds
Definition
bonds that are formed between two atoms or two molecules. A unity that occurs between two atoms.
Term
Ionic, or electrovalent
Definition
formed by transfer of electrons; strong electrostatic force that binds positively and negatively charged ions together.
Term
Covalent bond
Definition
formed by sharing electron pairs between atoms
Term
Hydrogen bond
Definition
Much weaker than ionic or covalent bonds
Results from unequal charge distribution on molecules
H20 is a classic example
Term
attractions between molecules
Definition
hydrogen bonds
Term
Chemical reactions
Definition
Involve the formation or breaking of chemical bonds
Term
three basic chemical reaction
Definition
synthesis, decomposition and exchange
Term
Metabolism
Definition
all the chemical reactions that occur in body cells
Term
Anabolism
Definition
Chemical reactions that join simple molecules together to form more complex molecules
Term
Chemical reaction responsible for anabolism is
Definition
dehydration synthesis
Term
Inorganic compounds
Definition
few have carbon atoms and none have C–C or C–H bonds
Term
Organic Compounds
Definition
Have at least one carbon atom and at least one C–C or C–H bond in each molecule
Often have functional groups attached to the carbon-containing core of the molecule
Term
Inorganic compounds: Water
Definition
The body’s most abundant and important compound
Term
Properties of water
Definition
-polar, high specific heat, and universal solvent and high heat of evaporation
Term
Oxygen and carbon dioxide
Definition
closely related to cellular respiration
Term
Oxygen
Definition
required to complete decomposition reactions necessary for the release of energy in the body
Term
Carbon dioxide
Definition
produced as a by product and works as a buffer in blood
Term
Electrolytes
Definition
Large group of inorganic compounds that includes acids, bases, and salts
Substances that dissociate in solution to form ions (resulting ions are sometimes called electrolytes
Term
Cations
Definition
positively charges ions
Term
Anions
Definition
negatively charged ions
Term
Acids and bases
Definition
common and important chemical substances that are chemical opposites
Term
acids
Definition
Any substance that releases a hydrogen ion (H+) when in solution; “proton donor”
Level of acidity depends on the number of H+ a particular acid will release
Term
Bases
Definition
Electrolytes that dissociate to yield hydroxide ions (OH) or other electrolytes that combine with H+
Described as “proton acceptors”
Term
pH scale
Definition
assigns a value to measures of acidity and alkalinity
Term
Buffers
Definition
Maintain the constancy of pH
Minimize changes in the concentrations of H+ and OH
Act as a “reservoir” for hydrogen ions
Term
Salts
Definition
Compound that results from chemical interaction of an acid and a base
Reaction between an acid and a base to form a salt and water is called a neutralization reaction
Term
Organic Compounds
Definition
organic compounds containing carbon, hydrogen, and oxygen; commonly called sugars and starches
Term
Monosaccharides
Definition
simple sugars with short carbon chains; those with six carbons are hexoses (e.g., glucose); those with five are pentoses (e.g., ribose, deoxyribose)
Term
Disaccharides and polysaccharides
Definition
two (di-) or more (poly-) simple sugars bonded together through a synthesis reaction (Figure 2-18)
Term
Lipids
Definition
Water-insoluble organic molecules that are critically important biological compounds
Term
what are the major roles of lipids?
Definition
Energy source
Structural role
Integral parts of cell membranes
Term
Triglycerides or fats
Definition
Most abundant lipids and most concentrated source of energy
Building blocks of triglycerides are glycerol (the same for each fat molecule) and fatty acids (different for each fat and determine the chemical nature)
Term
Triglycerides are formed by
Definition
dehydration synthesis
Term
saturated fatty acids
Definition
all available bonds are filled, solid at room temperature
Term
unsaturated fatty acids
Definition
fatty acids that have one or more double bonds between two carbons. liquid at room temperature. The best fatty acids for humans..
Term
Phospholipids..
Definition
Fat compounds similar to triglyceride
One end of the phospholipid is water soluble (hydrophilic); the other end is fat soluble (hydrophobic)
Phospholipids can join two different chemical environments
Phospholipids may form double layers called bilayers that make up cell membranes
Term
Steroids
Definition
Main component is steroid nucleus
Involved in many structural and functional roles
Term
Prostaglandins
Definition
Commonly called tissue hormones; produced by cell membranes throughout the body
Effects are many and varied; however, they are released in response to a specific stimulus and are then inactivated
Term
Proteins
Definition
Most abundant organic compounds
Chainlike polymers
Term
Amino acids
Definition
basic building blocks of proteins
Term
Essential amino acids
Definition
eight amino acids that cannot be produced by the human body
Term
Nonessential amino acids
Definition
12 amino acids that can be produced from molecules available in the human body
Term
Amino acids consist of
Definition
of a carbon atom, an amino group, a carboxyl group, a hydrogen atom, and a side chain
Term
levels of proteins
Definition
1. primary
2. secondary
3. tertiary
4. quaternary
Term
Importance of protein shape
Definition
shape of protein molecules determines their function
Term
native state
Definition
Final, functional shape of the protein molecule
Term
Denatured proteins have
Definition
have lost their shape and therefore their function
Term
Proteins can be denatured by
Definition
by changes in pH, temperature, radiation, and other chemicals
Term
DNA (deoxyribonucleic acid)composed of
Definition
Composed of deoxyribonucleotides: structural units consist of the pentose sugar (deoxyribose), phosphate group, and nitrogenous base (cytosine, thymine, guanine, or adenine)
Term
Alternating deoxyribose and phosphate units form
Definition
the backbone of the DNA
Term
The bases in DNA are held together by what kind of bonds
Definition
hydrogen bonds
Term
RNA (ribonucleic acid) composed of
Definition
Composed of the pentose sugar (ribose), phosphate group, and a nitrogenous base
Nitrogenous bases for RNA are adenine, uracil, guanine, or cytosine (uracil replaces thymine)
Term
Adenosine triphosphate, a nucleotide, is composed of
Definition
Adenosine
Ribose, a pentose sugar
Adenine, a nitrogen-containing molecule
Term
ATP, the three phosphates
Definition
High-energy bonds present between phosphate groups
Cleavage of high-energy bonds releases energy during catabolic reactions
Term
Adenosine triphosphate (ATP
Definition
Energy stored in ATP is used to do the body’s work
ATP often called the energy currency of cells
ATP is split into adenosine diphosphate (ADP) and an inorganic phosphate group by a special enzyme
If ATP is depleted during prolonged exercise, creatine phosphate or ADP can be used for energy
Term
Cell structures
Definition
Nucleus, Cytoplasm, Plasma Membrane
Term
Each cell contains a variety of membranes
what are they
Definition
plasma membrane and membraneous organelles
Term
Primary structure of a cell membrane is
Definition
a double layer of phospholipids.
Term
heads of phospholipids are..
Definition
hydrophilic
Term
the lipid tails are
Definition
hydrophobic
Term
........molecules are scattered among the phospholipids to allow the membrane to function properly at body temperature
Definition
Cholesterol
Term
Most of the bilayer is hydrophobic; therefore
Definition
water and water-soluble molecules do not pass through easily
Term
Cytoplasm
Definition
gel-like internal substance of cells that includes many organelles suspended in watery intracellular fluid called cytosol
Term
Two major groups of organelles
Definition
Membranous organelles and nonmembranous organells
Term
Endoplasmic reticulum
Definition
Made of membranous, walled canals and flat, curving sacs arranged in parallel rows throughout the cytoplasm; extend from the plasma membrane to the nucleus
Proteins move through the canals
Term
Two types of endoplasmic reticulum, name them
Definition
Smooth ER and Rough ER
Term
Rough endoplasmic reticulum
Definition
Ribosomes dot the outer surface of the membranous walls
Ribosomes synthesize proteins, which move toward the Golgi apparatus and then eventually leave the cell
Function in protein synthesis and intracellular transportation
Term
Smooth endoplasmic reticulum
Definition
No ribosomes border the membranous wall
Functions are less well established and probably more varied than those of the rough endoplasmic reticulum
Synthesizes certain lipids and carbohydrates and creates membranes for use throughout the cell
Removes and stores calcium ions from the cell’s interior
Term
Ribosomes
Definition
Each ribosome is a nonmembranous structure made of two pieces, a large subunit and a small subunit; each subunit is composed of rRNA and protein
Term
Golgi apparatus
Definition
Membranous organelle consisting of cisternae stacked on one another and located near the nucleus (Figure 3-7)
Processes protein molecules from the endoplasmic reticulum (Figure 3-8)
Processed proteins leave the final cisterna in a vesicle; contents may then be secreted to outside the cell
Term
Lysosomes
Definition
Made of microscopic membranous sacs that have “pinched off” from Golgi apparatus
The cell’s own digestive system; enzymes in lysosomes digest the protein structures of defective cell parts, including plasma membrane proteins, and particles that have become trapped in the cell
Term
Proteasomes
Definition
Hollow protein cylinders found throughout the cytoplasm
Break down abnormal or misfolded proteins and normal proteins no longer needed by the cell (and that may cause disease)
Break down protein molecules one at a time by tagging each one with a chain of ubiquitin molecules, unfolding the protein as it enters the proteasome, and then breaking apart peptide bonds
Term
Peroxisomes
Definition
Small membranous sacs containing enzymes that detoxify harmful substances that enter the cells
Often seen in kidney and liver cells
Term
Mitochondria
Definition
Composed of microscopic sacs; wall composed of inner and outer membranes separated by fluid; thousands of particles make up enzyme molecules attached to both membranes
The “power plants” of cells; mitochondrial enzymes catalyze series of oxidation reactions that provide most of a cell’s energy supply
Each mitochondrion has a DNA molecule, which allows it to produce its own enzymes and replicate copies of itself
Term
NUCLEUS
Definition
spherical body in center of cell enclosed by an envelope with many pores
Term
CYTOSKELETON
Definition
The cell’s internal supporting framework; made of rigid, rodlike pieces that provide support and allow movement and mechanisms that can move the cell or its parts
Term
Cell fibers
Definition
Intricately arranged fibers of varying length that form a three-dimensional, irregularly shaped lattice
Fibers appear to support the endoplasmic reticulum, mitochondria, and “free” ribosomes
Term
Microfilaments
Definition
smallest cell fibers
Serve as “cellular muscles”
Made of thin, twisted strands of protein molecules that lie parallel to the long axis of the cell
Can slide past each other and cause shortening of the cell
Term
Intermediate filaments
Definition
: twisted protein strands slightly thicker than microfilaments; form much of the supporting framework in many types of cells
Term
Microtubules
Definition
tiny, hollow tubes that are the thickest of the cell fibers
Made of protein subunits arranged in a spiral fashion
Function to move things around inside the cell
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