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Chpt 2-Cell Biology

Chapter 2: Chemistry of the Cell-USDFall2018-Dr. Karen Koster

What are the two ways in which carbon is involved in importnat molecules of biology? Major component of the backbone/skeleton Linked covalently in chains or rings
What is biological chemistry? chemistry of living systems
What is the valence of carbon? 4
What does a valence of 4 mean for carbon? it will form four chemical bonds
What is the octet rule? Most atoms want their outer valence shell to have 8 electrons
What does a valence of 4 do for carbon? Gives it structural variation
What is mostly likely to form covalent bonds with carbon? Carbon(4), Oxygen (2), sulfur, hydrogen(1), and nitrogen(3)
What is a single bond? sharing of 1 pair of electrons
What is a double bond? sharing of 2 pairs of electrons
What is a triple bond? sharing of 3 pairs of electrons
How is stability expressed? bond energy
What is bond energy? amount of energy required to break 1 mole (6x10^23) of such bonds
How is bond energy expressed? in calories
What is a calorie? amount of energy needed to rais 1 gram of H20 1 degree
What is a hydrocarbon? molecule containing only hydrogen and carbon
Hydrocarbons are essentially ________ in water. insoluble
Hydrocarbons play an importnat role in the structure of what? biological membranes
The interior of every biological membrane is a ________ environment. nonaqueous
what usually projects into the interior of membranes? hydrocarbon "tails" of phospholipids
What gives important implications to permeabilitity barriers of biological membranes? location of the hydrocarbon "tails" of phospholipids (interior) and the polar heads (exterior)
What is a functional group? specific arrangements of atoms that confer characteristic chemical properties on the molecule they're attached to
What bond has the highest bond energy? C-C triple bond
What bond has the second highest energy? C-C double bond
What has the third highest bond energy? H-C bond
What has the fourth highest bond energy? C-C single bond
What has the fifth highest bond energy? C-N bond
What has the lowest bond energy? (as a single bond) hydrogen bonds
What functional groups are negative (acidic) and biological pH? carboxyl and phosphate
What functional groups are positive (basic) at biological pH? amino
What functional groups are neutral at biological pH? hydroxyl, sulfhydryl, carbonyl, aldehyde
What is a carboxyl functional group? carbon double bonded to O and single bonded to OH
What is a phosphate functional group? phosphate double bonded to O and 3 single bonds to OH
What is an amino functional group? carbon bonded to NH2 (NH3+ at biological pH)
What is a hydroxyl functional group? carbon bonded to OH
What is a sulfhydryl functional group? carbon bonded to SH
What is a carbonyl functional group? carbon double bonded to O (and usually 2 other carbon)
What is an aldehyde functional group? carbon double bonded to O and bonded to an H
What is an ion? atom/molecule that are charged because they have gained/lost a proton
What is a polar bond? unequal sharing of electrons
What often makes up a polar bond? (biologically) Oxygen, sulfur, or nitrogen bound to a carbon or a hydrogen
Why do O,S,N cause polar bonds? Oxygen and sulfur have increased electronegativity
What is electronegativity? affinity for electrons
Polar bonds have a ______ water solubility and ______ chemical reactivity. higher water solubility and higher chemical reactivity
What is oxidization? when carbon containing compounds lose an electron to ather molecules such a smolecular o2
Is oxidization a release of energy or absorption of energy? release of energy
What is reduction? when carbon containing compounds gain an electron
Is reduction a release of energy or absorption of energy? requires energy
What structural characteristic gives carbon containing molecules great diversity? tetrahedral structure
Why does the tetrahedral structure of carbon containing molecules matter? it gives carbon the opportunity for 4 different atoms or groups to be bonded to it in a tetrahedral configuration which leads to 2 possible spatial configurations
What are stereoisomers? mirror images as shown by a plane of symetry
What is an asymmetric carbon? carbon atom with four different substituents
How many stereoisomers are possible for each asymetric carbon in a molecule? 2
What is the equation for determining number of stereoisomers in a compound? 2^n (n is number of asymmetric carbons?
Water is a ________ solvent. universal
What is the most abundant component of cells and organisms? water
What weight of cells and organisms is made of water? 75-85%
What is polarity? unequal distribution of eletrons within a molecule
What angle results from polarity? 104.5 degree (in water)
in water oxygen has a _________ charge. partial negative
in water hydrogen has a ________ charge. partial positive
What allows molecules to be attracted to eachother? polarity
What is a hydrogen bond? partial positive attraction of hydrogen with a highly electronegative atom
Each water molecule is hydrogen bonded to ___ other water molecules. three
What gives water its high cohesiveness? tendency to hydrogen bond
What characteristics of water are caused by its tendency to hydrogen bond? (4) high surface tenison, high boiling point, high specific heat, high heat of vaporization
What is specific heat? amount of heat a substance must absorb per gram to increase the temperature 1 degree Celcius
What is the specific heat of water? 1 calorie per gram
What buffers water against large changes in temperature? energy that goes into water is used to break the hydrogen bonds which acts as a buffer from a large increase in temperature
What is heat of vaporization? amount of energy required to convert 1 gram of a liquid into a vapor
Water has a _____ heat of vaporization. high
Water is an excellent general solvent due to its _____. Polarity
What is a solvent? fluid in which another substance is dissolved
What is a solute? the substance being dissolved in a solvent
Many molecules in cells are also ______ and hydrogen bond with water polar
What does hydrophilic mean? have an affinity for water and readily dissolve
Are most small organic molecules hydrophobic or hydrophilic? hydrophilic
What does hydrophobic mean? low affinity for water and unlikely to dissolve
Are lipids hydrophobic or hydrophilic? hydrophobic
Are proteins hydrophobic or hydrophilic? hydrophobic
Are nonpolar molecules generally hydrophobic of hydrophilic? hydrophobic
Are hydrocarbons hydrophobic of hydrophilic? hydrophobic
What are cellular membranes? essentially a hydrophobic permeability barrier
Where are phospholipids found? cellular membranes
Where are glycolipids found? cellular membranes
Where are membrane proteins often found? cellular membranes
What is often found in cellular membranes except those of bacteria? sterols
What is the sterol in animals? Cholesterol
What is the sterol in fungi? Ergosterol
What is the sterol in plants? Phytosterol
What does amphipathic mean? A molecule/compound has both a hydrophilic and hydrophobic region
What two compounds are often amphipathic and where are they found? lipids and proteins in cell membranes
How are phospholipids organized? often into two layers
Where does the polar head of phospholipids face? outward towards the aqueous environment
Where do the hydrophobic tails of phospholipids face? inward and interacting with eachother to minimalize their interactions with the aqueous environment
What membranes have lipid bilayers? every known biological membranes
What causes membran bilayers? the amphipathic tendency of proteins and lipids, most specifically phosphlipids with their hydrophobic tails facing inwards and their hydrophilic heads facing outwards
Lipid Bilayers are _______ permeable. selectively
What does the hydrophobic interior of membranes allow? (3) Permeability to nopolar molecules Quite impermeable to most polar molecules Highly impermeable to ions
On a scale from 1-4 for permeability (1=none, and 4+all) how permeable are ions? 1
On a scale from 1-4 for permeability (1=none, and 4+all) how permeable are uncharged polar molecules? 2
On a scale from 1-4 for permeability (1=none, and 4+all) how permeable are small, uncharged polar molecules? 3
On a scale from 1-4 for permeability (1=none, and 4+all) how permeable are ions? 4
Compounds with MW of _____ readilty diffuse across membranes regardless of polarity? 100
What are transport proteins? specialized transmembrane proteins
What is a hydrophilic channel? channel through an otherwise hydrophobic membrane
What is a carrier? binds a specific solute on one side of the membrane then undergoes a cnformational change to move the soute across the membrane
What are macromolecules? ordered array of linear or branched polymers
What does a biological hierarchy? denotes how biological molecules and structures can be organized into a series of levels with each level building on the preceding
Most cellular strctures are composed of small, _____ organic molecules. watersoluble/hydrophilic
What is level one of the hierarchy system? small organic molecules
What is level two of the hierarchy system? macromolecules
What is level three of the hierarchy system? Supramolecules
What is level four of the hierarchy system? Organelle
What is level five of the hierarchy system? The cell
what are some examples of the first level of the hierarchy system? amino acids, glucose, nucleotides
What are some examples of the second level of the hierarchy system? proteins, cellulose, DNA
What are some examples of the third level of the hierarchy system? membrane, cell wall, chromosome
What are some examples of the 4th level of the hierarchy system? choloroplast/mitochondria, nucleus
Will the fifth level of the hierarchy system always be the cell? yes
How are most macromolecules generated? by the polymerization of small organic molecules into longer chains
What is the monomer of polysacchrides? glucose and other monosaccharides
What is the monomer of lipids? glycerol, fatty acids, or steroids
What is the monomer of proteins? amino acids
What is the monomer of nucleic acids? nucleotide
Monomers can be transported across most ______ membranes. Biological
What are the three major kinds of macromolecular polymers in cells? proteins, nucleic acids, and polysaccharides
What are nucleic acids? informational macromolecules
In nucleic acids, the order of the nucleotide monomers is _____. nonrandom
Do amino acids transmit info? nope
what do amino acid monomers do? they determine the 3D structure of the protein
How many different amino acids are there in proteins? 20
What are some roles of proteins? structure, defense, transport, signalling, catalysis
What are polysaccharides? usually consist of a single repeating subunit or two subunits in strict alternation
What is a storag polysacharide used for? energy storage
What are some examples of storage polysaccharides? starch and glycogen
What are some examples of structural polysaccharides? starch and chitin
What is the first basic principle of the polymerization of macromolecules? they are always synthesized in a stepwise polymerization of similar or identical small molecules called monomers
What is the second basic principle of the polymerization of macromolecules? The additon of each monomer occurs with the removal of a water molecule in a condensation reaction
What reaction occurs during polymerization? condensation reaction
What is the third basic principle of the polymerization of macromolecules? In order for the monomers to be joined they must become activated monomers
What is the fourth basic principle of the polymerization of macromolecules? activation of monomers usually occurs with carrier molecules
What is the fifth basic principle of the polymerization of macromolecules? energy required to couple monomers and carriers is ATP
What is the sixth basic principle of the polymerization of macromolecules? macromolecules have directionality
What does directionality mean in terms of macromolecules? the two ends of the polmer chain are chemically different from one another
What does self-assembly mean? The information required to specify the spontaneous folding and coiling of macromolecules to form more complex structures is inherent in the polmer themselves
Once a macromolecule is syntehsized, assembly into compex structures will occur _______ without furthur ______. spontaneously, energy
What is the function of Molecular chaperones? they assist in protein folding to prevent incorrect molecular interactions
Every protein or other macromolecule in the cell is held together by _______ bonds Covalent
What are hydrogen bonds important for? maintaining 3D structure of proteins and holding together the two strands of DNA
What are ionic bonds important for? they are usually found in fuctional groups and maintain protein structures
What are Van der Walls forces? weak interaction between two atoms that only occur if the atoms are close to eachother
What are hydrophobic interactions? tendency for nonpolar g roups to associate with eachother as they minimize their contact with water
What is a polypeptide? immediate produce of amino acid polymerizaton
How does a polypeptide become a protein? must fold, coil, and go through a conformational change
What id denaturation? unfolding of a polypeptide
How do you denature a protein? apply high temp, high acidity, alkaline conditions, chemical agents or general disruption of the native environment
What is renaturation? return of a polypeptide to its correct structure
How do you renature a protein? return it to conditions in which the native conformation is stable
Does self-assembly also apply to more complex structures? yes
What more complex structure go thourhg self-assembly? ribosomes
Created by: kenzigustafson