The Chemistry of Biology Flashcards
What is electronegativity?
The ability to atoms to attract other atoms
What is responsible for an atoms electronegativity?
- ) The number of protons in its nucleus
2. ) The distance between the nucleus and the valence shells
Home come electronegativity decreases as one moves down the columns?
As you move down the periodic table the valence electrons get further and further away from the nucleus. One of two factors in determining electronegativity is closeness to Proton. The closer to the proton, the more electronegative.
What is the most electronegative atom commonly found in organisms?
oxygen
What type of bond to C and H form?
They have approximately equal electronegativity, so they form a non-polar covalent bond.
What happens when electrons are shared non-symetically?
a polar covalent bond
Where do electrons in polar covalent bonds hang out?
The electrons spend the majority of their time near the nucleus of the more electronegative atom.
How are partial charges on atoms produced?
Polar bond produce them. The more electronegative atom attracts a disproportionate number of electrons to hang out near its nucleus. This makes the less electronegative atom somewhat positive.
How are ionic bonds formed?
The transfer of electrons
Name two common highly electronegative atoms?
Oxygen and Nitrogen
Are ionic bonds common in biological molecules?
No
Is structure based on function or vice versa?
Function is based on structure
Why is water so essential to life?
It is an excellent solvent. It can turn many substances into a solution
How are water molecules bonded together?
The negative oxygen attaches to the positive hydrogen.
What makes is possible for almost any charged polar molecule to dissolve in water?
Hydrogen bonding.
What happens to substances that are uncharged and non-polar when they are dissolved in water?
They can’t from bonds with the hydrogen and thus do not dissolve.
What does hydrophilic mean?
Substances that are capable of forming hydrogen bonds and thus become solutes when water is added.
What does hydrophobic mean?
Molecules that are uncharged and cannot from hydrogen bonds. For hydrophobic substances water is not a solvent.
What is cohesion?
Attraction between molecules
Why is water cohesive?
Because of the hydrogen bonds that form in between molecules.
What is adhesion?
This attraction between unlike molecules
In what situations is water adhesive?
When water adheres to a solid surface that has any amount to polarity
What are the forces that case a meniscus in a glass tube?
- ) The adhesion of the water molecules to the surface of the glass
- ) Water molecules adhere with other water molecules creating a lattice of bonds that resist the upward pressure of adhesion
What causes surface tension?
Water molecules at the surface have no water molecules above them with which to create a hydrogen bond. As a result they want to cohere with the nearest neighboring surface molecules. This tension created minimized the total surface area as the water is “attracted” to itself.
What are the important consequences of surface tension?
Water resists forces that want to increase its surface ears, this resistance means that water functions like an elastic membrane.
Why does heating water cause it to become less dense?
Heating water break apart the crystal lattice that has lots of space between its structures.
How many hydrogen bonds does each water molecule participate in its solid state?
4
What are proteins made of?
Polymers of amino acids
How are the amino acids of proteins linked?
The amino acids of a protein are linked by peptide bonds
What does the suffix -ose mean?
Sugar
How do monosaccharides differ?
Monosaccharides can be classified according to the spatial arrangement of their atoms.
Where is Peptidoglycan found?
It support the cell walls of bacteria.
What is specific heat?
The amount of energy required to raise the temperature of 1 gram of substance by 1 degree centigrade.
What happens to specific heat as molecules increase in polarity?
The higher the polarity, the more energy required to change temperature.
Does water have a high specific heat?
Yes! it take a lot more energy to vaporize water than it does most other liquid at room temperature
Why does sweating or dousing ourselves with water work to cool us down?
In order for water molecules to evaporate a great deal of heat must be absorbed from one’s body.
What does endothermic mean?
A process that absorbs or requires heat.
What does exothermic mean?
A process that releases heat
What are the two forms of energy?
Potential and actual
Where is there the most potential energy in an electron?
In the outer shells, further away from the proton
What is energy called when it is stored in chemical bonds?
Chemical energy
What is the energy of motion called?
Kinetic energy
What is thermal energy?
the kinetic energy of molecular motion
What is temperature a measure of?
The amount of thermal energy molecules possess. Hot is more. Cold is less
What is heat?
The transfer of thermal energy between objects
What happens after hydrogen and oxygen become H2O?
Their potential energy drops
What happens to the excess energy when H and O become H2O
It is released as heat and light
What is the first law of thermodynamics?
Energy is conserved it cannot be created or destroyed
What is entropy?
The level of disorder in a system
What is the second law of thermodynamics?
Entropy always increases in an isolated system
What are the two factors that determine if a reaction will proceed spontaneously? (As in doesn’t need energy added to the system)
- ) When the product is less ordered than the reactants
2. ) When the product has lower potential energy than the reactants
What is a functional group?
A group of atoms that have a predictable chemical behavior.
How many covalent bonds can carbon form?
4
What is nucleic acid is made of?
Nucleotides
What ar the three components of a nucleotide?
- ) Phosphate group
- ) Five carbon sugar
- ) Nitrogenous base
What is the order of the three components of a nucleotide?
The phosphate group is attached to the 5 carbon sugar, which is attached to the nitrogen base.
What are the monomers of ribonucleic acid (RNA)?
ribonucleotides
What are the monomers of deoxyribonucleic acid (DNA)?
deoxyribonucleotides
What the is the difference between DNA and RNA?
The 5-carbon sugar. In ribonucleotides the sugar is ribose. Ribose has an -OH in both functional group. In deoxyrobonucleic acid the sugar is deoxyribose. Deoxyribose is lacking an O in one of its functional groups.
What does deoxy mean?
Lacking oxygen.
Besides differing the type of sugar they have what are other ways that nucleotides can differ?
They can have different nitrogenous bases.
What are the two potential groups that nucleotides’ nitrogenous bases can belong to?
Purines and Pyrimidines
What are the purines?
Guanine and Adenine
What are the pyrimidines?
Cytosine, Uracil, Thymine
What is a larger molecule, purines or pyrimidines?
purines
Where do the shape of molecules come from?
Carbon atoms furnish molecules with their overall shape
What determines the behavior of a compound (the types of chemical reactions in which it participates)?
This is determined by how H, N, O, P or S atoms are bonded to carbon.
Do amino functional groups function as acid or bases?
Bases
Do carboxyl functional groups function as acids or bases?
Acids
What functional groups do amino acid contain?
aminos and carboxyls
What steps should I take when I encounter a new molecule?
- ) Examine the size and shape of the carbon framework
- ) Examine the types of covalent bonds present based on the electronegativity of the atom. This will tell me two things a.) the polarity of the molecule b.) the amount of energy stored
- ) Locate functional group and note the properties these groups give the molecules
What are four groups that are bonded to the central carbon atom?
- ) A hydrogen atom
- ) An amino functional group (NH2 or NH3)
- ) A carboxyl group (COOH)
- ) A distinctive R group or side chain
What happens to amino acid at a pH of 7?
They act as a base and donate one of their hydrogens. So that the formula of the amino group becomes H2N
What happens to molecules that are uncharged?
They cannot form hydrogen bonds. This mean they can’t bond with water and are therefore hydorphobic.
What is stronger covalent bonds or polar bonds?
covalent bonds.
What bonds can sulfhydryl (SH) form?
S-S bonds. These S-S bond link different parts of large proteins
What are S-S bond formed by sulfhydryl good for?
They link different part of large proteins
What needs to happen before an enzymeattic reaction can take place?
- ) Enzymes need to collide in a precise orientation
- ) They need to have enough kinetic energy to overcome the repulsion between electrons that come into contact as a bonds form.
List the components of a prokaryotic cell?
Ribosome, plasmid, cell wall, plasma membrane, chromosome and cytoplasm
What is the most prominent structure inside a prokaryotic cell?
the chromosome