BIO 202 Study Guide - Midterm Guide: Electron Configuration, Carboxylic Acid, Relative Atomic Mass
16 Jun 2018
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Sp16 BIO 202.02 Midterm 1 Learning Objectives:
Chapter 2 The Chemical Context of Life
1. Define atom, element, molecule, compound.
-Atom: The smallest unit of matter that retains properties of an element
-Element: Substance that cannot be broken down into another substance through chemical reactions.
-Molecule: Two or more atoms held together by covalent bonds.
-Compound: Substance consisting of two or more elements in a fixed ratio
2. Identify the four major elements of living things
-Hydrogen, carbon, oxygen, nitrogen.
3. Distinguish between the following pairs of terms: neutron and proton, atomic number and atomic weight (mass
number).
-Neutron vs Proton: a neutron is neutrally charged whereas a proton is positively charged.
-Atomic number vs atomic weight: Atomic number is equal to the amount of protons in an element it also
deteies a eleet’s plae o the peiodi tale. Atoi eight is ho uh a ato of the eleet eighs
in amu, usually weight of protons and neutrons summed up.
4. Describe the structure of an atom. Know what orbitals and shells are, and understand the connection between
electron configuration and reactivity.
The less filled the outer shell of the electron configuration, the more
reactive the element.
5. Distinguish between and discuss the biological importance of the following: non-polar covalent bonds, polar
covalent bonds, ionic bonds, hydrogen bonds, and van der Waals interactions
-non-polar bonds: Equal sharing of electrons.
-polar covalent bonds: Unequal sharing of electrons. Electrons centered around more electronegative particle.
-ionic bonds: When a cation metal and anion nonmetal bond.
-hydrogen bonds: Noncovalent attraction between hydrogen and electronegative atom.
-van der Waals interactions: Weak attractions between any molecule due to everchanging charge of all atoms
Chapter 3 Water and Life
1. Describe why H2O is polar.
H side is slightly positive, O is very negative, making it polar.
2. Describe why solid H2O is less dense than liquid H2O.
“olid HO’s oleules ae futhe apat upo feezig, akig it less dese tha liuid HO.
3. List and explain the four properties of water that emerge as a result of its ability to form hydrogen bonds
-Adhesion: Ability for H2O to be attracted to other substances as a result of its polarity. (it is sticky!)
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-Cohesion: Ability for water molecules to stick together.
-Surface Tension: The attraction of hydrogen bonds in water molecules minimizes the surface area of water.
4. Distinguish between the following sets of terms: hydrophobic and hydrophilic substances, a solute, a solvent,
and a solution.
-Hydrophobic: water repelling
-Hydrophilic: water loving
5.Define molecular weight (mass), mole, and molarity. Know how these concepts are used to describe a solution.
Be able to describe how to prepare a solution of a given molarity and volume
-Molecular weight: weight of molecule
-Mole: a unit of measure to measure atoms and molecules
-Molarity: concentration of moles/liter in a solution
6. Define acid, base, and pH. Know the concentration of H+ and OH- at a given pH.
-Acid: low pH value, more H+ ions. H+ donator
-Base: high pH value, more OH- ions in solution. H+ acceptor
-If it’s a stog aid, oetatio of aid is = oetatio of H+ eause fo ee oleule aid, thee is
molecule H+ dissociated. If weak acid, determine contration from equilibrium.
-If concentration of H+ known, pH + pOH=14 in water solutions.
7. Explain how buffers work.
Buffers are composed of acid and conjugate base. It opposes the change of pH by pushing the equilibrium and
therefore resisting pH change in a solution
Ex: Carbonic acid buffering system
Chapter 4 Carbon and the Molecular Diversity of Life
. Eplai ho ao’s eleto ofiguatio eplais its ailit to fo lage, ople, diese ogai
molecules
-Cao’s eleto ofiguatio has upaied electrons in its outer orbital. This tetravalence allows 4 branches
of covalent bonds off each carbon atom and allows infinite possible structures.
2. Describe how carbon skeletons may vary and explain how this variation contributes to the diversity and
complexity of organic molecules
-Carbon skeletons can be linear, branched or be in ring shapes. They also can have double or triple bonds. This
allows many different types of organic molecules
3. Distinguish among the three types of isomers: structural, geometric (cis-trans), and enantiomer
-Structural: Have different covalent arrangement of atoms, same molecular formula.
-Geometric (cis-trans): Have same covalent arrangements but differ in spatial arrangement.
-Entaniomer: Isomers that are mirror images.
4. Name the major functional groups found in organic molecules, describe the basic structure of each functional
group, and outline the chemical properties of the organic molecules in which they occur
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GROUP NAME
STRUCTURE
COMPOUND NAME
PROPERTIES
HYDROXYL
-OH
Alcohol, compound name
ends in -ol
-Polar because electrons are near oxygen
atom
-Forms hydrogen bonds with water
molecules, dissolves organic compounds
ie sugar.
AMINO
/H
-N
\H
Amines
-Acts as base, can pick up H+ from
surrounding solutions.
-Found in cells in ionized form with charge
1+
CARBONYL
-C=O
\ x
Ketone when within carbon
skeleton
Aldehyde when at the end of
carbon skeleton
-Found in sugars creating either ketose or
aldose.
CARBOXYL
-C=O
\OH
Carboxylic acid, inorganic
acids
-Donates H+ because of polar covalent
bond between O2 and H
-Found in cells in ionized form with charge
of 1-
SULFHYDRYL
-SH
Thiols
-Two sulfhydryl groups react to form a
covalent bond. This stabilizes protein
structure.
PHOSPHATE
O
||
-O--P--O-
|
O-
Organic Phosphate
-Contributes negative charge to molecule
2- @ end, 1- if internally in the chain.
-Have potential to react with water to
release energy
METHYL
-CH3
Methylated compound
-Affects gene expression.
-Affects shape and function of sex
hormones
5. Summarize the Miller-Urey experiment
and explain its significance
-The atmosphere bulb was filled with a
mixture of gases and water vapor and had
electrical currents running through to
siulate eal eath’s atosphee.
-The condenser had cold water flowing
through it ad tued the gas ito ai
-Heat would cause evaporation in the
oceanic bulb.
-At the ed foud that oea ate
contained simple and complex organic
molecules like formaldehyde, HCN,
hydrocarbons, and amino acids.
Chapter 5 The Structure and Function of
Large Biological Molecules
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Document Summary
Chapter 2 the chemical context of life: define atom, element, molecule, compound. Atom: the smallest unit of matter that retains properties of an element. Element: substance that cannot be broken down into another substance through chemical reactions. Molecule: two or more atoms held together by covalent bonds. Compound: substance consisting of two or more elements in a fixed ratio: identify the four major elements of living things. Hydrogen, carbon, oxygen, nitrogen: distinguish between the following pairs of terms: neutron and proton, atomic number and atomic weight (mass number). Neutron vs proton: a neutron is neutrally charged whereas a proton is positively charged. Atomic number vs atomic weight: atomic number is equal to the amount of protons in an element it also dete(cid:396)(cid:373)i(cid:374)es a(cid:374) ele(cid:373)e(cid:374)t"s pla(cid:272)e o(cid:374) the pe(cid:396)iodi(cid:272) ta(cid:271)le. Ato(cid:373)i(cid:272) (cid:449)eight is ho(cid:449) (cid:373)u(cid:272)h a(cid:374) ato(cid:373) of the ele(cid:373)e(cid:374)t (cid:449)eighs in amu, usually weight of protons and neutrons summed up: describe the structure of an atom.
