Cell Biology Chapter 2 Flashcards
What are the 5 Principles Important to Cell Biology?
Characteristic of carbon Characteristics of water Selectively Permeable Membranes Synthesis by Polymerization of Small Molecules Self-Assembly
What is the Characteristics of Carbon?
Carbon has unique properties that make it suitable as the backbone of biologically important molecules. The carbon atom is the most important atom in biological molecules
What is the Characteristics of Water?
The water molecule has several unique properties that make it suitable as the universal solvent of living systems
What are Selectively permeable membranes?
Membranes define cellular compartments and control the movements of molecules and ions into and out of cells and organelles
What is Synthesis by Polymerization of small Molecules?
Most biological macromolecules are polymers formed by linking many similar or identical small molecules known as monomers
What is Self-Assembly?
Biological macromolecules are often capable of self-assembly into higher levels of structural organization because the information needed to specify the spatial configuration of the molecule is contained in the polymer
What do molecules of importance to the cell biologist have?
A backbone, or skeleton, of carbon atoms linked together convalently in chains or rings
Which is the most important atom in biological molecules?
The Carbon atom
What is the total number of covalent bond per atom and in what conditions?
Bonds per carbon atom is 4 whether carbon atoms form single, double, or triple bonds with other atoms
Carbon atoms are most likely to form covalent bonds with what ?
Other carbon atoms, oxygen, hydrogen, nitrogen, and sulfur
Carbon-containing molecules are what? How is it expressed. Explain the visible portion of sunlight.
Carbon-containing molecules are stable. Stability is expressed as bond energy- the amount of energy required to break 1 mole (6*10^23) of such bonds. The visible portion of sunlight is lower in energy than C-C bonds
What can visible light can’t do what? What is more hazardous and why?
Visible light can’t break the bonds of organic molecules; Higher-energy ultraviolet light is more hazardous; Ultra violet light has an energy that is enough to break carbon-carbon bonds spontaneously
What does the ozone layer do?
The ozone layer filters out much of the much ultraviolet radiation that would otherwise reach Earth’s surface and disrupt the covalent bonds that hold biological molecules together
What are Hydrocarbons? What role do they play?
Hydrocarbons are chains or rings composed only of carbon and hydrogen; play an important role in the structure of biological membranes
What does the interior of every biological membrane look like? What does it project into? What does the feature have?
It is a nonaqueous environment consisteng of the long hydrocarbon “tails” of phospholipid molecules; Projects into the interior of the membrane from either surface; feature of membranes has important implications for their tole as permeability barries
What do Biological Compounds usually contain? What are they a part of?
Contain carbon, hydrogen, and one or more atoms of oxygen, nitrogen, phosphorus, or sulfur; part of functional groups
What are functional groups and what are some important functional groups?
are common arrangements of atoms that confer specific chemical properties on a molecule; Carboxyl and phosphate groups - negatively charged, amino groups - positively charged, hydroxyl, sulfhydroxyl, carbonyl, and aldehyde - uncharged, but polar
What is a covalent bond?
Strong chemical bond in which 2 atoms share 2 or more electrons
What is a polar bond? How do they result and what do polar bonds have?
Electrons are not shared equally between 2 atoms; they result from a high electronegativity of oxygen and sulfur compared to carbon and hydrogen; they have high water solubility compared to C-C or C-H bonds in which electrons are shared equally
Why does water have an indispensable role for life?
It is the universal solvent in biological systems
Water’s most critical attribute and what does it account for?
It’s polarity; accounts for water’s cohesiveness, temperature-stabilizing capacity, and solvent properties
What gives water its polarity? What is it called when the oxygen atom is at one end ? What does it result in?
Unequal distribution of electrons; Is highly electronegative drawing the electrons toward it; results in partial negative charge at this end of the molecule and a partial positive charge around the hydrogen atoms
What does their polarity do? Which molecules are associated with each other? What are those associations called? What does the added effect account for?
makes water molecules attracted to each other; electronegative oxygen of one molecule is associated with the electropositive hydrogens of nearby molecules; called hydrogen bonds, 1/10 strong as covalent bonds, accounts for water’s characteristics
What is water characterized by? What is the combined effect of many hydrogen bonds?
By an extensive network of hydrogen-bonded molecules which make it cohesive; accounts for water’s high: surface tension, boiling point, specific heat, and heat of vaporization
What is the surface tension of water?
The result of the collective strength of vast numbers of hydrogen bonds
What is specific heat? What does it give, what is it much higher than, what is used to break? How does water change temperature?
The amount of heat a substance must absorb to raise its temperature 1C; high specific heat gives water its temperature-stabilizing capacity; the specific heat of water is much higher than most liquids; Heat is first used to break numerous hydrogen bonds in water; water changes temperature relatively slowly, protecting living systems from extreme temperature changes