Chapter 2: Molecular Interactions Flashcards
1
Q
What are the four major groups of macromolecules?
A
carbohydrates
lipids
proteins
nucleotides
2
Q
what can macromolecules combine to form?
A
glycoproteins, glycolipids, lipoproteins
3
Q
*are biomolecules made mostly of carbon and hydrogen
*lipids have a backbone of
glycerol and 1–3 fatty acids
*are nonpolar and
therefore not very soluble in water
A
lipids
4
Q
what are the two categories of lipids?
A
fats
oils
5
Q
are long chains of carbon atoms bound to hydrogens, with a carboxyl (–COOH) or “acid” group at one end of the chain
A
fatty acids
6
Q
*have no double bonds between carbons, so they
are “saturated” with hydrogens
*solid at room temp
A
saturated fatty acids
7
Q
*have one double bond between two of
the carbons in the chain
*For each double bond, the molecule has two
fewer hydrogen atoms attached to the carbon chain
A
monounsaturated fatty acids
8
Q
have two or more double bonds
between carbons in the chain.
A
polyunsaturated fatty acid
9
Q
what are 3 types of lipid related molecules?
A
eicosanoids
steroids
phsopholipids
10
Q
modified 20-carbon fatty acids with a
complete or partial carbon ring at one
end and two long carbon chain “tails.”
A
eicosanoids
11
Q
lipid-related molecules whose structure
includes four linked carbon rings
A
steroids
12
Q
- *have 2 fatty acids and a phosphate group (–H2PO4)
* *important component of cell membrane
A
phospholipids
13
Q
- the most abundant biomolecule
* that for each carbon there are two hydrogens and one oxygen
A
carbohydrates
14
Q
what are the 3 categories of carbohydrates?
A
monosaccharides
disaccharides
polysaccharides
15
Q
- simple sugars
- building blocks of complex carbohydratess
- examples are ribose and glucose
A
monosaccharides
16
Q
- consist of glucose plus another monosaccharide
* examples are sucrose, maltose, lactose
A
disaccharides
17
Q
- glucose polymers
- glucose is stored in this form for energy
- animals (chitin & glycogen)
- plants (cellulose & starch)
- yeast/bacteria (dextran)
A
polysaccharide
18
Q
polymers of smaller building block molecules called amino acids
A
proteins
19
Q
- have a carboxyl group (–COOH), an amino group (–NH2), and a hydrogen attached to the same carbon
- The fourth bond of the carbon attaches to a variable “R” group
A
amino acids
20
Q
bond in which the amino group of one amino acid joins the carboxyl group of the other, with the loss of water.
A
peptide bond
21
Q
what are the different structures of proteins?
A
primary
secondary
tertiary
quaternary
22
Q
*The sequence of amino acids in a peptide chain
A
primary structure
23
Q
- Covalent bond angles between amino acids determine secondary structure
- alpha helix or beta pleated sheets
A
secondary structure
24
Q
- protein’s 3D shape
- fibrous proteins (collagen)
- globular proteins
A
tertiary structure
25
* Multiple subunits combine with noncovalent bonds
| * Hemoglobin molecules are made from four globular protein subunits
quaternary structure
26
*biomolecules that play an important role in energy and information transfer
*consists of (1) one or more phosphate
groups, (2) a 5-carbon sugar, and (3) a carbon-nitrogen ring structure called a
nitrogenous base
nucleotide
27
* nucleotide polymers
* RNA and DNA
* store and transmit genetic information
nucleic acids
28
include energy transferring compounds such as ATP, ADP, cyclic AMP
single nucleotides
29
* have a double ring structure
* nitrogenous base
* include adenine and guanine
purines
30
* have a single ring structure
* nitrogenous base
* includes cytosine, thymine, uracil
pyrimidines
31
what are the 2 functions of single nucleotides?
* capture and transfer energy in high energy electrons or phosphate bonds
* aid in cell-cell communication
32
what is the function of ATP, ADP, NAD, FAD?
energy capture and transfer
33
what is the function of cAMP?
cell-cell communication
34
* smallest particle of any element
* link by sharing electrons to form molecules
* consist of protons, neutrons, and electrons
atom
35
what are the three elements that make up 90% of our body mass?
oxygen
carbon
hydrogen
36
simplest type of matter
elements
37
determine the element (atomic #)
protons
38
determine the isotope
neutrons
39
* form covalent bonds
* create ions when gained or lost
* capture and store energy
* create free radicals
electrons
40
an atom that gains or loses neutrons becomes....
an isotope of the same element
41
an atom that gains or loses electrons becomes an.....
ion of the same elements
42
lipids + proteins
lipoproteins
43
proteins + carbohydrates
glycoproteins
44
carbohydrates + lipids
glycolipids
45
the units formed when two or more atoms link by sharing electrons
molecules
46
the links between atoms, which are formed by transferring/sharing of electrons
bonds
47
what are the main two types of bonds?
covalent bonds
| noncovalent bonds
48
* result when atoms share electrons
* these bonds require the most energy to make or break
* include nonpolar molecules and polar molecules
covalent bonds
49
* have an even distribution of electrons
| * molecules made of mostly carbon and hydrogen are usually this
nonpolar molecules
50
* have regions of partial charge
| * example is water
polar molecules
51
includes ionic bonds, hydrogen bonds, and Van der Waals Forces
noncovalent bonds
52
* electrostatic attractions between ions
| * example is NaCl
ionic bonds
53
* forms between a hydrogen atom and a nearby oxygen, nitrogen, or fluorine atom
* responsible for surface tensions
hydrogen bonds
54
weak, nonspecific attractions between atoms
Van der Waals Forces
55
```
*Molecules that have polar
regions or ionic bonds readily
interact with the polar regions
of water.
*This enables them to
dissolve easily in water
```
hydrophilic
56
* Water molecules interact with ions or other polar molecules to form hydration shells around the ions.
* This disrupts the hydrogen bonding between water molecules, thereby lowering the freezing temperature of water
hydrophilic interactions
57
have polar heads and nonpolar tails
phospholipid molecules
58
**Because they have an even distribution of electrons and no positive or negative poles, nonpolar molecules have no regions of partial charge, and therefore tend to repel water molecules
**Molecules like
these do not dissolve readily
in water
hydrophobic interactions
59
What are the categories of proteins?
1. enzymes
2. membrane transporters
3. signal molecules
4. receptors
5. binding proteins
6. immunoglobulins
7. regulatory proteins
60
biological catalysts
enzymes
61
found in the ECF and transport molecules within the body
binding proteins
62
* antibodies
| * help protect the body from foreign invaders
immunoglobulins
63
turn cell processes on and off or up and down
regulatory proteins
64
Any molecule or ion that binds to another molecule
ligand
65
how can proteins bind to other molecules?
noncovalent interactions on binding sites
66
model of protein binding where the binding site shape is not an exact match to the ligands' (L) shape
Induced fit model of protein-ligand binding
67
the degree to which a protein is attracted to a ligand
affinity
68
are protein binding reactions reversible
yes
69
* states that when a reaction is at equilibrium, the ratio of the products to the substrates is always the same
* binding reactions obey this law
law of mass action
70
what does a higher affinity for a ligand mean?
a larger Keq
71
equation of the equilibrium for a reaction
Keq= [PL]/[P][L]
72
reciprocal of the equilibrium equation
* is the dissociation constant
| * Kd= [P][L]/[PL]
73
what does a lower affinity for a ligand mean?
a larger Kd
74
what happens during a reaction at equilibrium?
rate of reaction in forward direction (r1) = the rate of reaction in the reverse direction (r2)
75
what is the ratio of bound to unbound at equilibrium?
it is always the same
76
* closely related proteins whose function is similar but whose affinity for ligand differs
* alters protein binding
isoforms
77
has increased affinity for oxygen
fetal isoform of hemoglobin
78
* alters protein binding
| * synthesized in an inactive form and must become activated
activation protein
79
how do the activation proteins become activated?
* enzymes remove portions of the protein
| * may require cofactors that must attach to the protein before the binding site becomes active
80
how are inactive forms of proteins identified?
prefix pro- or suffix -ogen added to the name of the active enzyme
81
* protein is inactive until peptide fragments are removed
| * essential for binding activity
proteolytic activation
82
* essential for binding activity
| * required for ligand binding at the binding site
cofactors
83
* alters protein binding
| * a factor that influences either protein binding or protein activity
modulation
84
what are the 2 mechanisms of modulation?
1. The modulator changes the proteins ability to bind the ligand
2. The modulator changes the proteins ability to create a response.
85
a modulator that binds to protein
| away from binding site and turns it on
allosteric activator
86
a modulator that binds to protein away
| from binding site and inactivates the binding site
allosteric inhibitor
87
blocks ligand binding at the binding site
competitive inhibitor
88
* alters proteins binding
| * the programmed production of new proteins (enzymes, receptors, membrane transport proteins)
up-regulation
89
* alters protein binding
| * the programmed removal of proteins
down-regulation
90
How do temperature and pH affect proteins?
* may disrupt protein structure and cause loss of function
| * can be irreversible if the protein becomes denatured
91
What happens if the protein concentration in the cell is constant?
the magnitude of the response is determined by the concentration of the ligand.
92
what does increased ligands result in?
increase in response
93
occurs when all the protein binding sites are occupied
saturation
