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BIo 1201 Exam 2
Summer 2012, Crousillac, LSU
92
Biology
Undergraduate 1
06/14/2012

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Term
Polymer
Definition
A large molecule consisting of many identical or similar subunits connected together
Term
Monomer
Definition
A subunit (or building block) of a polymer
Term
Polymerization
Definition
The bonding of many small subunits (monomers) to form long molecules (polymers)
Term
Condensation Reactions
Definition
A polymerization reaction in which the covalent linkage of the monomers is accompanied by the removal of a water molecule, which creates a chemical bond (requiring energy)
Term
Hydrolysis
Definition
The breaking of the covalent bond between two monomers by the addition of water (produces energy)
Term
Carbohydrates
Definition
Used as fuels and building material; organic molecules made of sugars and their polymers; three types (Monosaccharide, Disaccharide, Polysaccharide)
Term
What do carbohydrates contain?
Definition
Carbon, hydrogen, and oxygen, which occur in the ratio 1-2-1
Term
Glycosidic Linkage
Definition
a covalent bond formed by a dehydration synthesis between two sugar monomers
Term
Polysaccharides
Definition
Macromolecules that are polymers of a few hundred or thousand monosaccharides; for energy storage and structural support
Term
Starch
Definition
A glucose polymer that is used as a storage polysaccharide in plants
Term
Glycogen
Definition
A glucose polymer that is used as a storage polysaccharide in animals; stored in the muscle and liver of vertebrates
Term
Carb-Loading
Definition
A process by which athletes are able to double or triple the amount of glycogen stored in their muscles; used to delay the onset of muscle fatigue
Term
Water Weight
Definition
Every ounce of glycogen in the body can have as much as four ounces of water bound to it; losing glycogen causes this extra water to be lost as well
Term
Cellulose
Definition
A linear un-branched polymer of glucose; a structural polysaccharide; most abundant organic molecule on the planet; reinforces plant cell walls because hydrogen bonds hold the strands together
Term
Chitin
Definition
Structural polysaccharide that is a polymer of an amino sugar; forms the exoskeleton of arthropods; found in the cell walls of some fungi
Term
Lipids
Definition
Mostly hydrophobic molecules with diverse functions; made up of fatty acids; a diverse group of organic molecules that are insoluble in water, but will dissolve in nonpolar solvents
Term
Fats & Oils
Definition
for energy storage
Term
Why do we crave fats?
Definition
Fats store enormous amounts of energy, so humans have evolved an extremely strong taste preference for foods that are high in fats
Term
Olestra
Definition
"Fake fat" designed to be similar to fats in taste and texture; cannot be digested by humans; has 8 fatty acids attached to a molecule of sucrose, rather than being a triglyceride with 3 fatty acids linked to a glycerol; because the molecule is so complex in shape, your body's digestive chemicals can't grab onto it and break it down, so it passes through your digestive system without being digested
Term
Fats
Definition
stored in adipose tissue cells; insulates the body and protects vital organs
Term
Saturated Fats
Definition
Have as many hydrogens attached to them as possible; solid at room temperature; ex.: butter, lard
Term
Unsaturated Fats
Definition
Have at least 1 carbon-carbon double bond; liquid at room temperature; ex.: olive oil
Term
Phospholipids
Definition
Have 2 ends that behave differently in water (hydrophilic heads and hydrophobic tails); in water, they self-assemble into a bi-layer that shields their hydrophobic portion from the water
Term
Steroids
Definition
Class of lipids that includes many hormones; characterized by a carbon skeleton consisting of 4 fused rings with various functional groups attached; includes cholesterol
Term
Cholesterol
Definition
A component of animal cell membranes; used as a molecular precursor for many steroids
Term
Nucleic Acids
Definition
Class of lipids that store and transmit information; made up of nucleotides; made up of a 5-carbon sugar, nitrogenous base, and a phosphate group; G,A,T,C; sugars (ribose, deoxyribose)
Term
How many hydrogen bonds are in DNA?
Definition
3
Term
How many hydrogen bonds are in RNA?
Definition
2
Term
Proteins
Definition
Poly-amino acids that are held together by peptide bonds; have amino acids as monomers
Term
Amino Acids
Definition
Monomers of proteins; Nonpolar, Polar, or Charged
Term
Nonpolar Amino Acids
Definition
C-H bond
Term
Polar Amino Acids
Definition
OH bond
Term
Charged Amino acids
Definition
Acidic & Basic
Term
Primary Protein Structure
Definition
the specific sequence of amino acids in a particular protein; any changes in this structure result in changes in all the remaining levels of structure
Term
Secondary Protein Structure
Definition
Repeated polypeptide segments that are coiled or folded into patterns; the result of hydrogen bonding between the components of the amino acid backbone
Term
Tertiary Protein Structure
Definition
The overall 3-dimensional shape of a polypeptide that results from interactions between the side-chains of the various amino acids; can also involve hydrophobic interactions at the core of the polypeptide; the hydrophobic effect is responsible for protein folding
Term
Hydrophobic residues
Definition
Tend to cluster together in the inside of a folded protein, away from water
Term
Quarternary Structure
Definition
Some proteins consist of two or more polypeptide subunits; The aggregation pattern of these subunits
Term
Why does compartmental organization exist within a cell?
Definition
To isolate reactions so that they may occur without interference from incompatible metabolic processes elsewhere in the cell
Term
What is DNA?
Definition
Organized chromosomes
Term
What are chromosomes composed of?
Definition
Chromatin
Term
What does chromatin consist of?
Definition
DNA and proteins
Term
Ribosomes
Definition
Composed of rRNA and protein; main function is protein synthesis
Term
Free ribosomes
Definition
Ribosomes suspended in the cytosol
Term
Bound Ribosomes
Definition
Ribosomes that are attached to the outside of the endoplasmic reticulum or the nuclear envelope
Term
Endoplasmic Reticulum
Definition
Extensive network of membranes in eukaryotic cells that is continuous with the nuclear envelope
Term
Rough E.R.
Definition
contains ribosomes on the outer surface; site of secretory protein synthesis
Term
Golgi apparatus
Definition
Stores and modifies products of the E.R. before sending them to their appropriate destination in the cell
Term
Glycoprotein
Definition
A polypeptide chain that is assembled to a ribosome bound to the rough E.R. and inserts itself into the rough E.R. through a pore; it is folded into its native shape inside the rough E.R. and in most cases, a carbohydrate is covalently bonded to it
Term
Smooth E.R.
Definition
outer surface that lacks ribosomes; synthesis of lipids, metabolism of carbohydrates, and detoxification of drugs and poisons; important for steroid production; important in liver cells for detoxification; adds (OH) group to toxins, making them water soluble, easier to flush from the body
Term
the Cis face of the Golgi apparatus
Definition
Receives vesicles from the E.R.
Term
the Trans face of the Golgi Apparatus
Definition
Ships vesicles to the appropriate destination
Term
Lysosomes
Definition
Organelles consisting of hydrolytic enzymes used to digest large molecules; very acidic environment; used to digest food and recycle cellular materials
Term
Vacuoles
Definition
Used as a disposal site for metabolic byproducts; prevents accumulation of dangerous molecules
Term
Mitochondria
Definition
Site of cellular respiration, where ATP is generated from sugars, fats, and proteins with the help of oxygen
Term
Chloroplasts
Definition
Site of photosynthesis; only found in plants and algae; convert solar energy to chemical energy by manufacturing sugars from CO2 and water
Term
Chloroplasts
Definition
Contain chlorophyll, as well as enzymes that catalyze the reactions that occur during photosynthesis; found in leaves, and other green parts of plants
Term
Thylakoids
Definition
Groups of flattened, stacked, interconnected sacs
Term
Stroma
Definition
fluid within the chloroplast; contains DNA, enzymes, and ribosomes
Term
Peroxisomes
Definition
Contain enzymes that transfer hydrogen from various substrates to oxygen, producing hydrogen peroxide as a byproduct; often used to break down fatty acids into smaller molecules to be used as fuel for mitochondria during cellular respiration; help remove toxins and break down fatty acids
Term
Cytoskeleton
Definition
Composed of microtubules, microfilaments, and intermediate filaments; determines cell motility
Term
S.J. Singer & G. Nicolson
Definition
proposed that membrane proteins are dispersed, individually inserted into the phospholipid bilayer with their hydrophilic regions protruding; Fluid Mosaic Model
Term
Integral Proteins
Definition
penetrate the hydrophobic core of the phospholipid bilayer; many are transmembrane proteins
Term
Transmembrane Proteins
Definition
Span the entire membrane; others are just embedded into the core
Term
Transport proteins
Definition
Provide a hydrophilic channel that is selective for a particular solute; or undergo conformational changes to shuttle a substance from one side of the membrane to the other
Term
Facilitated Diffusion
Definition
Diffusion across a membrane with the help of transport proteins
Term
Aquaporins
Definition
Water channel proteins that facilitate the movement of water across biological membranes; very common in kidney cells
Term
Gated Channels
Definition
Open or close in response to a stimulus
Term
Ligand Gates
Definition
Activated by chemical messengers such as hormones or neurotransmitters
Term
Voltage Gates
Definition
Activated by changes in electrical membrane potential
Term
Selective Permeability
Definition
The property of biological membranes which allows some substances to cross more easily than others
Term
Diffusion
Definition
The process in which a substance moves from an area of greater concentration to an area of lesser concentration; a process of spreading molecules out evenly into the available space
Term
Hypertonic
Definition
Solution with greater concentration of solute compared to another solution
Term
Hypotonic
Definition
Solution with lower concentration of solute compared to another solution
Term
Isotonic
Definition
Solution with an equal concentration of solute compared to another solution
Term
Osmosis
Definition
The diffusion of water across a selectively permeable membrane from a region of low solute concentration to a region of high solute concentration, diluting it, until there is equal concentration of solute on both sides of the membrane
Term
Hypotonic Solution
Definition
Water rushes inward until it causes the cell to burst
Term
Hypertonic Solution
Definition
Water rushes out of the cell and it shrinks
Term
Isotonic Solution
Definition
Ideal for animal cells; Water moves equally in both directions
Term
Amphipathic
Definition
a condition where a single molecule has both hydrophilic and hydrophobic regions
Term
Dayson & Danielli
Definition
Said that the difference between the two sides of a phospholipid bilayer could be accounted for if the membrane were coated on both sides with hydrophilic proteins
Term
Enzymatic Proteins
Definition
May have its active site exposed to a substrate in either the cytosol, or the extracellular fluid; several of these can be situated next to each other within the membrane so as to accomplish a central task
Term
Signal Transduction Proteins
Definition
Usually a receptor with a binding site for a chemical messenger called a ligand; the ligand can, in some cases, initiate a conformational change that relays, or transduces, the signal to the inside of the cell
Term
Cell-Cell Recognition Proteins
Definition
Certain glycoproteins that serve as "i.d. tags" and docking sites for proteins on other cells
Term
Osmoregulation
Definition
An adaptation to control the water balance in organisms living in hypertonic, hypotonic, or terrestrial environments
Term
Sodium-Potassium Pump
Definition
in animals; is an electrogenic pump that translocates 3 Na+ ions out of the cell, for every 2 K+ ions into the cell
Term
Electrogenic pump
Definition
a transport protein that generates voltage across a membrane; uses active transport to create a membrane potential
Term
Exocytosis
Definition
Secretion of macromolecules
Term
Endocytosis
Definition
The process by which cells take in material
Term
Phagocytosis
Definition
Endocytosis of solid particles
Term
Pinocytosis
Definition
The endocytosis of fluid droplets
Term
Receptor-Mediated Endocytosis
Definition
common occurrence in brain; antidepressants
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