Chapter 3 - Nucleic Acids, Proteins, and Enzymes Flashcards

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1
Q

if you were given a diagram of a nucleotide what you expect to find as its components

A

phosphate, sugar, and a base

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2
Q

how is DNA different than RNA

A

it contains deoxyribose

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3
Q

the observations that DNA with a higher G + C content is more stable at high temperatures than DNA with a high A+ T content because of what?

A

because each G and C pair forms three hydrogen bonds between antiparallel strands, whereas each A and T pair forms just two

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4
Q

replication is the synthesis of ____ and transcription is the synthesis of _____

A

an identical copy of DNA; an RNA template based on the DNA template

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5
Q

Quaternary structure of proteins refers to ____?

A

the number and kind of protein subunits the protein has

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6
Q

the binding of a substrate to an enzyme

A

may involve hydrogen bonds and van der waals interactions

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7
Q

in a reaction catalyzed by an enzyme

A

the enzyme does not affect the equilibrium constant for the reaction

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8
Q

a competitive inhibitor of an enzyme-catalyzed reaction

A

is usually similar to the substrate

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9
Q

the rate of a reaction catalyzed by an enzyme that has a single polypeptide chain

A

may be increase or decreased by temperature

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10
Q

enzymes

A

may be subject to feedback inhibition

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11
Q

what are nucleic acids

A

palmers that store, transmit, and express hereditary information

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12
Q

two things proteins are essential for

A

metabolism and structure

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13
Q

pyrimidine

A

six membered single ring structure

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14
Q

purine

A

fused double-ring structure

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15
Q

DNA sugar groups

A

Adenine
Cytosine
Guanine
Thymine

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16
Q

RNA sugar groups

A

Adenine
Cytosine
Guanine
Uracil

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17
Q

what makes the DNA structure less flexible than that of RNA

A

lack of a hydroxyl group at the 2’ position of the deoxyribose sugar

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18
Q

complementary base pairing

A
In DNA 
A-T
C-G
In RNA
A-U
C-G
held together primarily by hydrogen bonds
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19
Q

RNA characteristics

A

single stranded
can fold back on itself to form a double stranded helix
this folding occurs by complementary base pairing

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20
Q

DNA characteristics

A

double stranded
consists of two polynucleotide strands of the same length
strands are antiparallel: 5’ ends are at opposite ends of the double-stranded molecule
remarkably uniform
sugar-phosphate groups form the sides of the ladder and the bases with their hydrogen bonds form the rungs on the inside

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21
Q

genome

A

complete set of DNA in a living organism

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22
Q

Enzymes

A

catalytic molecules that speed up biochemical reactions. most enzymes are proteins (some are RNA molecules)

23
Q

Defensive proteins

A

such as antibodies recognize and respond to substances or particles that invade the organism from the environment

24
Q

peptide bonds

A

in the “backbone” of a protein are formed as covalent “peptide bonds” between adjacent amino acids.

25
Q

hormonal and regulatory proteins

A

such as insulin control physiological processes

26
Q

receptor proteins

A

receive and respond to molecular signals from inside and outside the organism

27
Q

storage proteins

A

store chemical building blocks– amino acids – for later use.

28
Q

Structural proteins

A

such as collagen provide physical stability and enable movement

29
Q

transport proteins

A

such as hemoglobin carry substances within the organism

30
Q

Genetic regulatory proteins

A

regulate when, how, and to what extent a gene is expressed

31
Q

functions of proteins

A
enzymes
structure
defense
signaling
receptor
membrane transport
storage
bulk transport
gene regulation
32
Q

what are the building blocks of proteins

A

amino acids

33
Q

how can amino acids be classified

A

on the amino acids they posses

34
Q

labels amino acids can receive

A
polar charged (hydrophilic)
polar uncharged (hydrophilic) 
nonpolar (hydrophobic)
35
Q

what functional groups do amino acids contain?

A

nitrogen containing amin group and the (acidic) carboxyl group

36
Q

3 amino acids that are hydrophobic

A

glycine, proline, and cysteine

37
Q

primary structure of a protein

A

is established by covalent bonds

38
Q

____ of proteins are folded into 3D shapes

A

the polypeptide chains

39
Q

secondary structure of a protein

A

consists of regular, repeated, spatial patterns in different regions of a polypeptide chain.
alpha helix
beta pleated sheet

40
Q

tertiary structure of a protein

A

the polypeptide chain is bent at specific sites and then folded back and forth
results in the polypeptides definitive three-dimensional shape

41
Q

secondary and tertiary structures derive from ___

A

primary structure

42
Q

quaternary structure of a protein

A

results from ways in which these subunits bind together and interact. Hemoglobin is an example of a protein with multiple subunits

43
Q

catalyst

A

used to speed up a reaction without itself being permanently altered
proteins that are enzymes speed up biochemical reactions, acting as biological catalysts that are highly specific for their substrates

44
Q

substrate

A

name for reactants in a enzyme-catalyzed reaction

45
Q

an enzymes active site determines its ____

A

specificity

46
Q

active site

A

where the substrate molecule binds to the enzyme

47
Q

irreversible inhibition

A

if an inhibitor covalently binds to an amino acid side chain at the active site of an enzyme, the enzyme if permanently inactivated because it cannot interact with its substrate.
EX: DIPF (diisoprpyl phosphorofluoridate)

48
Q

reversible inhibition

A

an inhibitor is similar enough to a particular enzyme’s natural substrate that is can bind noncovalently to the active site, yet different enough that no chemical reaction occurs
analogus to a key that inserts into a lock but does not turn it

49
Q

competitive inhibitor

A

when a molecule competes with the natural substrate for the active site

50
Q

noncompetitive inhibitor

A

binds to an enzyme at a site distance from the active site. this binding causes a change in the shape of the enzyme, altering its activity.

51
Q

allosteric regulation

A

occurs when a non-substrate molecule binds or modifies a site other than the active site of an enzyme

52
Q

the activity of allosteric enzyme complexes results from what

A

the activity of both positive and negative regulators

53
Q

what effects enzyme activity

A

temperature and ph

54
Q

feedback inhibition

A

when the end product is present at a high concentration, some of it binds to a site on the commitment step enzyme, thereby causing it to become inactive