FINAL Unit 1 Flashcards

Question

What is a permanent dipole-induced dipole bond?

Answer 1

dipole approaches nonpolar group, permanent dipole will create an induced dipole in nonpolar group

Answer 2

when ion goes near nonpolar group, it'll attract or repel electrons in nonpolar group - since electrons in bond are constantly moving, occasionally they become unevenly distributed around atoms in bond, creating a small temporary induced dipole

Answer 3

new induced dipole is electrostatically attracted to the ion

Answer 4

two induced dipoles | - are short-lived because induced dipoles are temporary

Answer 5

measure of atom's tendency to attract electrons to itself in covalent bonds (stronger tendency = larger electronegativity) higher lower O > N >> S = C = H = P

Answer 6

has regions of +/- charge, tend to interact with other polar molecules (ie. O-H, N-H, S-H, C-O, O-P)

Answer 7

does not have regions of +/- charge (ie. C-H)

Answer 8

anion: negative charge cation: positive charge

Answer 9

water-fearing, nonpolar molecules poorly able to undergo hydrogen bonding with water

Answer 10

water-loving, polar can undergo hydrogen bonding with water, readily dissolves in water

Answer 11

polar molecules excluded nonpolar molecules to drive biological processes such as protein folding and formation of cell membranes

Answer 12

has both hydrophobic and hydrophilic parts

Answer 13

1. complexity, with precise spatial organization on several scales 2. ability to change in response to environment 3. abilities to metabolize and to reproduce 4. capacity to evolve

Answer 14

energy cannot be created no destroyed and can only be transferred from one form to another - total energy of universe is constant but the form it takes changes - living organisms acquire energy from environment and transform to chemical form cells use - all organisms obtain energy from sun or chemical compounds: some energy for work, some energy dissipated as heat

Answer 15

degree of disorder in universe tends to increase - addition of energy increases order of system (decreases disorder) - entropy: amount of disorder - living organisms are highly organized, energy is needed to maintain this - cells is not an isolated system: take into account cell and environment - release of heat as organisms harness energy means total combination of cell + environment's entropy increases

Answer 16

- intramolecular bonds: covalent, ionic, hydrophobic - intermolecular bonds: non-covalent - interaction with surrounding water molecules

Answer 17

aqueous environment of the cell (outside of nucleus and organelles)

Answer 18

how macromolecules interact with polar water molecules

Answer 19

3D structure of macromolecules and their interactions with water (polarity is important)

Answer 20

one or more atoms that have particular chemical properties on their own - "add chemical character to carbon chains" - polar, therefore molecules that contain these groups become polar and soluble in aqueous environment, and they are reactive (joining simple molecules often takes place between functional groups)

Answer 21

- nonpolar | - functional group permits them to interact with water and link macromolecules

Answer 22

- function: cell's work (ie. enzymes, structural components) - monomer: amino acids (identity determined by R group) - covalent bond: peptide bond (carboxyl releases O2, amino group releases 2 hydrogens) - directionality: one end carboxyl and other amino, it affects function - some enzymes in our body only work on one end of the polypeptide and some digest both ways

Answer 23

- function: carry info in sequence of nucleotides - monomer: nucleotide - covalent bond: phosphodiester bond (phosphate group joins sugar, loss of H2O) - directionality: 3' (sugar) and 5" (phosphate), impacts how new DNA is put together during replication and affects function of RNA during translstion

Answer 24

- function: energy source, cell wall in bacteria/plants/algae - monomer: monosaccharide (simple sugar) - covalent bond: glycosidic bond (between 1' carbon of one monosaccharide, and hydroxyl group carried by carbon atom in different monosaccharide) - directionality: location of OH group and CH2OH group, diversity stems in part from monosaccharides that make up carbohydrates

Answer 25

- function: cell membrane, store energy, signalling molecules - monomer: 3 fatty acids and glycerol - covalent bond: Ester linkage - directionality: none

Answer 26

- hydrophobic - not defined by chemical structure - form oil droplets in cells

Answer 27

no C=C max. H atoms is attached to each carbon, chain is straight

Answer 28

have C=C fatty acid chains have kink at each double bond

Answer 29

- fatty acids differ in length of hydrocarbon chain (# carbons) - don't contain polar covalent bonds - electrons are distributed uniformly, therefore uncharged - BUT constant motion of electrons lead to slight +/- charges - affects neighbouring molecules - temporarily polarized molecules weakly bind to one another (van der Waals forces)

Answer 30

only come into play when atoms are close enough and are weaker than H bonds

Answer 31

amphipathic lipid bilayers and proteins

Answer 32

membranes are made up of phospholipids embedded with proteins - lipids provide permeability barrier and fluidity membrane lipids are important for cells because cells are dynamic and membranes must be able to form, reseal, bud, and fuse

Answer 33

bulkiness of head group relative to hydrophobic tails

Answer 34

lipids with bulky heads and single hydrophobic tail are wedge-shaped and pack into spheres

Answer 35

purified lipids with small heads and double tails - pH important because it ensures head groups are in their ionized form and hydrophilic - if phospholipids are added to a test tube of water at neutral pH, they spontaneously form spherical bilayer structures (liposomes) that surround a central space - as liposomes form, they may capture macromolecules present in solution

Answer 36

lipids with less bulky heads and 2 hydrophobic tails are roughly rectangular - form closed structures with an inner space because free edges would expose hydrophobic chains to aqueous environment

Answer 37

two layers of lipids in which hydrophilic heads are the outer surfaces and hydrophobic tails are sandwiched between and away from aqueous environment

Answer 38

- why bilayers are effective cell membranes - why membranes are self-healing: small tears in membrane are rapidly sealed by spontaneous arrangement of lipids surrounding damaged region because of the tendency of water to exclude nonpolar molecules

Answer 39

because of the extensive van der Waals forces between tails - weak bonds, therefore easily broken and reformed - lipids can move within plane of membrane

Answer 40

- in single layer of bilayer, van der Waals interactions between tails depends on length of fatty acid tails and presence of double bonds between neighbouring carbon atoms - saturated tails: no C=C, straight and tightly packed which reduced mobility - unsaturated tails: have C=C, kinks in tail which increases mobility - cholesterol helps maintain consistent fluidity by preventing big transitions from fluid to solid

Answer 41

- spontaneous - likely to happen in this direction - reaction moves from less stable to more stable

Answer 42

- not spontaneous - requires energy input to happen in this direction - reaction moves from more stable to less stable

Answer 43

measures how strongly bonded a system is

Answer 44

measures freedom to move of components of a system

Answer 45

important factors: chain length and degree of unsaturation - shorter tails are more fluid than longer tails - double bonds form kinks, therefore are more fluid than saturated lipids

Answer 46

small nonpolar molecules small uncharged polar molecules gases

Answer 47

large uncharged polar molecules ions (in aqueous solution, are surrounded by hydration shells) - prevented by hydrophobic interior of lipid bilayer

Answer 48

biological membranes control environment inside cells - plasma membrane encloses cell - internal membrane encloses an intracellular component

Answer 49

moves ions or other molecules across membrane

Answer 50

allows cell to receive signals from environment

Answer 51

catalyzes chemical reactions

Answer 52

attaches to other proteins and helps maintain the cell structure and shape

Answer 53

permanently associated with cell membrane and cannot be separated from membrane experimentally without destroying the membrane

Answer 54

temporarily associated with lipid bilayer or with integral membrane proteins through weak non-covalent interactions (easily separated from membrane) - interact with either polar heads or with integral membrane proteins - limit ability of transmembrane proteins to move within membrane

Answer 55

(type of integral membrane protein) - spans entire lipid bilayer - composed of 3 regions: 2 hydrophilic and 1 connecting hydrophobic - allows for separate functions and capabilities of each end of protein

Answer 56

provide an opening between inside and outside of cell through which certain molecules can pass, depending on their shape and charge - some are gated (open in response to a chemical or electrical signal)

Answer 57

binds to, then transports specific molecules - exist in two conformations: one open to one side of the cell, other open on other side - binding of transported molecules induces conformational change in membrane protein, allowing molecule to be transported across lipid bilayer

Answer 58

channel proteins that water molecules move through plasma membrane by - allows water to move much more readily across plasma membrane by facilitated diffusion than is possible for simple diffusion - water molecules are small enough to move polarity through bilayer by limited simple diffusion

Answer 59

goes down concentration gradient - simple diffusion: diffuses through lipid bilayer - facilitated diffusion: uses a protein channel in bilayer to diffuse across bilayer

Answer 60

goes against concentration gradient - requires energy - uses a protein transporter

Answer 61

- ATP is used as energy source to pump ions - sodium moving out of cell, potassium moving in - pumps are examples of membrane proteins that help with some type of active transport of molecules across the membrane

Answer 62

to establish an electrochemical gradient which is an energy source for secondary active transport

Answer 63

active transport that uses energy directly (ie. movement of ions take energy, which comes from energy stored in ATP)

Answer 64

driven by electrochemical gradient - because small ions cannot cross lipid bilayer, many cells use a transport protein to build up the concentration of a small ion on one side of the membrane - resulting [ ] gradient stores potential energy that can be harnessed to drive movement of other substances across membrane against their [ ] gradient - electrochemical gradient and co-transports one solute down its [ ] gradient as another solute is transported up its [ ] gradient MOVEMENT IS DRIVEN BY MOVEMENT OF PROTONS, NOT ATP DIRECTLY

Answer 65

1. protons are pumped across membrane by primary active transport 2. proton pump generated electrochemical gradient with higher [ ] of protons outside cell and lower [ ] of protons inside cell 3. antiporter uses gradient to move different molecule out of a cell against its [ ] gradient

Answer 66

``` regulation transport signalling structure force generation catalysis transcription and translation ```

Answer 67

sequence of amino acids in a protein joined by peptide bonds - determines how a protein folds (structure) - determines non-covalent interactions of a protein with itself and its environment

Answer 68

interactions between stretches of amino acids in a protein - result from hydrogen bonding in polypeptide between carbonyl and amide groups - forms alpha helix or beta pleated sheet

Answer 69

- H bonds along peptide backbone - backbone is twisted tightly, R groups projected outward (chemical properties of R groups determines where helix is positioned in folded protein and how it'll interact with other molecules) - spanning lipid bilayer: peptide backbone in helix is shielded from tails by hydrophobic R groups and secondary structure is stabilized by H bonds between amide and carbonyl groups

Answer 70

- H bonds between areas of the peptide backbone - polypeptide folds back and forth on itself, forming a pleated sheet - R groups project alternately above and below plane of sheet

Answer 71

longer-range interactions between secondary structures support 3D shape of a protein - determined by sum of all non-covalent interactions of R groups - final folded protein structure: stabilized by side-chain interactions (non-covalent interactions and disulfide bonds) as well as interactions between side chains and backbone atoms - determined by spatial distribution of hydrophilic and hydrophobic R groups - includes loops/turns in backbone that allow R groups to sit near each other and for bonds to form - determines function because its the 3D shape of the molecule that enables protein to serve as structural support, membrane channel enzyme, signalling molecule

Answer 72

polypeptide subunits can come together to form one functional unit - subunits can influence each other in subtle ways and influence their function - subunits can be identical or different

Answer 73

- proteins can lose their tertiary structure and unfold or denature due to disruption of non-covalent interactions - can happen by chemical treatment, high temperature that disrupts hydrogen and ionic bonds - proteins lose their functional activity ---> not all proteins can re-nature - mutant protein with amino acid that prevents proper folding are inactive/don't function - strong interactions between side chains = more difficult to denature - weak interactions between side chains = earlier to denature - stronger interactions = more stable protein

Answer 74

R group interactions the make-up of R groups in polypeptide chain determines structure and function

Answer 75

proteins with active sites in their tertiary structures - proteins fold to form active sites as enzymes, to bind substrates - form a complex with reactant and products - folds in a way such that amino acids important for binding substrate are in right position

Answer 76

1. binding of substrates in active site of enzymes trigger a shape change in enzyme 2. this helps the enzyme to make the transition state more stable 3. reaction is catalyzed, producing products 4. products are released

Answer 77

- protein folding brings specific amino acids close to each other to form the active site - amino acids that form active site are often far apart in linear sequence of unfolded enzyme

Answer 78

- proteins are denatured by heat - enzyme activity requires 3D tertiary structure of protein to bind substrate and catalyze enzymatic reaction - heating breaks up non-covalent interactions among R groups on side chains of amino acids which leads to loss of structure and function

Answer 79

by reducing activation energy of a chemical reaction - does not determine spontaneity - reducing activation energy stabilizes transition state - enzymes change path of reaction between reactants and products but not start or end points - less activation energy = faster reaction - enzymes not consumed in reaction - ΔG is the same with or without enzyme

Answer 80

required input of energy for the reaction to proceed

Answer 81

compound is formed when old bonds are breaking and new ones are forming - highly unstable - large amount of free energy

Answer 82

1. initiation: enzymes bind substrates in specific orientation in active sites, bringing the substrates close together 2. transition state stabilization: enzymes shape the "fit" at transition of products better than the substrate 3. termination: products released from active site

Answer 83

decrease activity of enzyme

Answer 84

increase activity of enzyme

Answer 85

usually form covalent bonds with enzymes and irreversibly inactivate them

Answer 86

form weak bonds with enzymes therefore dissociate easily from them

Answer 87

bind at active site and prevent substrate from binding (competes with substrate and reduce rate of reaction)

Answer 88

bind to a different site than the active site and affect substrate binding by changing shape of enzyme and reducing the rate of reaction at which enzyme converts substrate to product - often, but not always, happens at allosteric site

Answer 89

enzyme that is regulated by molecules that bind at sites other than active site - activity of enzymes can be influenced by both inhibitors and activators - play a key role in metabolic pathways - negative feedback: enzyme changes shape and alter activity of enzyme, final product inhibits first step of reaction

Answer 90

change in activity or affinity of a protein as the result of binding of a molecule to a site other than the active site

FINAL Unit 1 Flashcards

(115 cards)