Intro to Bio 1124
Midterm Exam 1 Study Guide Vocabulary Key Concepts Other Important Things Vocab:
Element – a substance that cannot be changed to another substance by a chemical reaction
Atom – the smallest unit of an element that retains the properties of that element
Atomic number – an elements characteristic number of protons Mass number – the sum of the number of neutrons and protons
Electron shells – determine the reactive properties of elements and the structure of molecules
Covalent bonds - the sharing of electrons between atoms
**a trick to remembering this one is sharing is Caring; covalent starts with a C and is the sharing of electrons
Nonpolar covalent bond - a covalent bond in which the bond electrons are equally shared
Polar covalent bond - a covalent bond in which the electronegativity difference of the atoms creates a partly ionic bond; electrons are not equally shared
Electronegativity – a measure of how intensely an element pulls away from atoms in a covalent bond We also discuss several other topics like How does racism justify colonialism?
Ionic bond – a bond in which electrons are completely transferred from one atom to another
Ion – an atom with an electric charge due to losing or gaining electron(s) Cation – a positively charged ion
Anion – a negatively charged ion
Hydrogen bond – a weak bond between a hydrogen atom with a partial positive charge and an electronegative atom with a partial negative charge
Hydrophilic – attracted to water, likes water
Hydrophobic – repels water, does not like water Don't forget about the age old question of What is the hunger center?
Cohesion – attraction between like molecules
Adhesion – attraction between unlike molecules
Tetravalent – an atom with four valence electrons
Organic molecule – a molecule which contains carbon and is made by organisms
Hydrocarbons – molecules that contain only hydrogen and carbon
Isomers – molecules containing the same number of each element, but differing in structure (arrangement of atoms)
Structural isomers – molecules that differ in covalent partners, but have the same molecular formula
Cis trans isomers/geometric isomers – differ in arrangement around a double bond, but have the same molecular formula
Enantiomers – have the same molecular formula, but differ in arrangement around an asymmetric carbon
**enantiomers are mirror images of each other
Asymmetric carbon – a carbon bonded to four different atoms or groups of atoms
Monomer – a molecule that can bond to other molecules to form a polymer; like one "lego"
Polymer – made up of many monomers; like a lego creation
The Molecular Logic of Life – small molecules common to all organisms are ordered into many unique macromolecules to create an enormous diversity of forms We also discuss several other topics like In what phase does the centrosomes migrate to opposite sides of the cell?
Dehydration reaction – the formation of a polymer from monomers; produces H2O
Hydrolysis reaction – breaks apart polymers into monomers; uses H2O Carbohydrates - sugars and sugar polymers
**all have a carbonyl group, multiple hydroxyl groups, and a backbone of 3-7 carbons
Monosaccharide - the simplest form of a carbohydrate
Disaccharide - created by two sugar molecules joined together.
Glycosidic linkage – covalent bond between carbohydrate molecules by a dehydration reaction
Polysaccharides – polymers made up of tons of monosaccharides connected with glycosidic linkages; polymer
Lipids – hydrophobic fats, oils, vitamins, etc.
**lipids are diverse structurally; hydrophobic
Ester bond – hydroxyl plus a carboxyl group
Saturated fatty acid – fats; no double bond between the carbons and fatty acid chain; every carbon has the maximum amount of hydrogens bonded to it
Unsaturated fatty acid – oils; contains one or more double bonds and a fatty acid
Monounsaturated fatty acids – have only one double bond; healthy fats If you want to learn more check out What is it called to escape the cycle of reincarnation?
Polyunsaturated fatty acid – have more than one double bond; I.e. omega-3 fatty acid We also discuss several other topics like How did the gupta empire make money?
Proteins - polymers built of amino acid monomers that are diverse in structure and function
Polypeptide - a polymer of amino acids; a linear chain of amino acids We also discuss several other topics like Who should observe the person?
Primary structure (1°) - protein structure that is a sequence of amino acids in the protein
Secondary structure (2°) - protein structure that results from hydrogen bonding between hydrogen bonded to N and O bonded to C in the backbone; include helix and pleated sheet formations
Tertiary structure (3°) - the overall 3-D shape of the polypeptide of a protein caused by interactions between R-groups
Quaternary structure (4°) - the aggregation of 2 or more polypeptides to make a functional protein
Denaturation – a protein's loss of its 3-D structure and functionality due to various physical and/or chemical conditions
Rules regarding electron shells:
1. Atoms most often have an equal number of protons and electrons, but not always.
2. Electrons move around the nucleus in orbitals, or specific regions. 3. Each orbital can hold a maximum of two electrons.
An atom is most stable when its valence electron shell is full. Bond strength:
Covalent bonds are the strongest, hydrogen bonds are the weakest, ionic bonds fall somewhere in between.
Carbon is extremely versatile; can form a huge array of molecules because it is tetravalent
∙ Hydroxyl – OH
∙ Carbonyl – CO
∙ Carboxyl – CO2H or COOH
∙ Amino – NH2
∙ Phosphate – PO4-2
∙ Sulfhydryl – SH
∙ Methyl - CH3
Living things are built of four main classes of macromolecules:
4. Nucleic acids
Properties of polysaccharides are determined by:
1. Composition of monomers
2. The arrangement of bonds between monomers
Functions of polysaccharides:
Fats and oils are composed of glycerol and three fatty acid molecules; they are connected by ester bonds created in a dehydration reaction
Functions of proteins:
1. To facilitate chemical reactions (I.e. enzymes)
2. Structural support (I.e. collagen in the skin)
3. Transport molecules (I.e. hemoglobin)
4. Cell to cell communication (I.e. insulin)
Long polymers of amino acids, made up of amino groups, carboxyl, R groups(side chain, vary with amino acids) and an asymmetric carbon
Polypeptides form through a dehydration reaction
Things to Remember:
Oxygen is very electronegative.
Living things are made up mostly of water.
Water is the universal solvent.
Ions and molecules with polar covalent bonds are hydrophilic and dissolve in water.
Molecules made mostly of carbon and/or oxygen are hydrophobic and will not dissolve in water.
Humans are 70% water (by weight).
Plants can be up to 95% water (by weight).
Monosaccharides are usually a multiple of CH2O.
When the carbonyl is on the end of a monosaccharide, it is an aldose sugar.
When the carbonyl is on the interior carbon of a monosaccharide, it is a ketose sugar.
Sugars function as an immediate source of energy for organisms.
-ose refers to a carbohydrate.
Differences between starch and cellulose:
∙ Both are made of glucose monomers
∙ Both are used for energy storage in plants
∙ Glucose units are oriented in the same direction in starch molecules, but are rotated 180 degrees around the polymer chain in cellulose ∙ Starch is both edible and digestible, while cellulose is not ∙ Starch is weak as a material while cellulose is strong
∙ Starch is dissolvable in water, while cellulose is not
Fatty acids usually contain 16-18 carbons; the type of fatty acid is determined by its structure
Fats function in energy storage; excess energy is connected to fats and stored in adipose tissue
Phospholipids are the primary structure of the cell membrane Proteins are abundant and make up over half of the dry mass of most cells Proteins are made up of polypeptides, but not all polypeptides are proteins! There are four levels of protein structure
There are 20 different amino acids
Each is defined by its R-group
1. Are molecules with polar covalent bonds hydrophilic or hydrophobic? 2. What is the difference between cis-trans isomers and enantiomers? 3. Which end of a phospholipid is polar, and which is nonpolar? 4. Which element makes up the largest percent of human body weight? 5. What type of reaction breaks apart molecules?
6. What type of bonding creates polymers from monomers? 7. Which functional group do all carbohydrates have?
8. Define tetravalent.
9. What do starch and cellulose have in common?
10. Why are ionic bonds strong outside of water, but weak in water? 11.Which 6 elements make up a majority of human body weight? 12.What is the difference between a cation and an anion?
13.How many different amino acids are there?
14.What is the function of fat?
15.What is an R-group?
16.What causes the denaturation of proteins?
17.How many electrons can one orbital hold?
18. What is the difference between ionic and covalent bonding? 19.What is the significance of electronegativity?
20. What is the primary structure of the cell membrane?