Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

MCAT-BIOLOGY > Biologically Important Molecules > Flashcards

Biologically Important Molecules Flashcards

You may prefer our related Brainscape-certified flashcards:
MCAT flashcards AP® Biology flashcards Biology 101 flashcards
1
Q

what are the four biologically important classes of molecules?

A

protein, carbohydrate, fat, nucleic acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what makes the polypeptide chain unique and functional?

A

the sequence and composition of amino acids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what does the structure of an amino acid consist of?

A

variable R group, carboxyl group (COOH), tetrahedral alpha carbon (central carbon), amino group (NH2)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

side chain (variable R group)

A

the unique feature of each amino acid that provides distinct physical and chemical properties

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

peptide bond

A

covalent bond that links amino acids together into polypeptide chains

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

disulfide bridges

A

covalent bond between cysteine R groups

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

how are peptide bonds formed?

A

reaction between carboxyl group of one amino acid with amino group of another amino acid, loss of water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

backbone of amino acid

A

NCCNCC

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what is the beginning functional group in a polypeptide chain?

A

amino group

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what is the terminal functional group in a polypeptide chain?

A

the carboxyl group

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

residue

A

an individual amino acid that is part of a polypeptide chain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

proteolysis/proteolytic cleavage

A

hydrolysis of a protein by another protein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

proteolytic cleavage is a specific means of:

A

cleaving specific peptide bonds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

proteolytic enzyme/protease

A

the enzyme that does the cutting in proteolysis/proteolytic cleavage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what is the R group in the amino acid cysteine?

A

a thiol group (SH) - can form disulfide bond

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

a cysteine residue in a disulfide bond is called:

A

cystine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

denatured

A

improperly folded proteins, generally nonfunctional

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

denaturation

A

the disruption of a protein’s shape without breaking peptide bonds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

how can proteins be denatured?

A

urea (disrupts hydrogen bonding interactions), extreme pH, extreme temperatures, changes in salt concentration (tonicity)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what is the primary structure of amino acids?

A

the order of amino acids bonded to each other in the polypeptide chain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

primary structure of proteins is the same thing as:

A

the sequence

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what is the bond that determines primary structure?

A

peptide bond (this is the bond that links one amino acid to the next in the polypeptide)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

what is the secondary structure of amino acids?

A

the initial folding of a polypeptide chain into shapes stabilized by noncovalent interactions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

what is the bond that determines secondary structure?

A

hydrogen bonds between the backbone (also disulfide bonds)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

what are the two most common secondary structures?

A

alpha helix and beta sheets

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

parallel beta-pleated sheets

A

adjacent polypeptide strands run in the same direction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

antiparallel beta-pleated sheets

A

adjacent polypeptide strands run in the opposite direction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

what is the tertiary structure of amino acids?

A

the interactions between amino acid residues located more distantly from each other in the polypeptide chain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

what are the bonds/interactions that determines tertiary structure?

A

interactions of R groups with each other and the solvent (water), determined by hydrophobicity/hydrophilicity of R group: non-covalent interactions, van der Waals forces, hydrogen bonds, disulfide bonds, and electrostatic interactions (between distant amino acids on the SAME polypeptide chain)

30
Q

what distinguishes tertiary and quaternary disulfide bonds?

A

tertiary disulfide bonds and bonds between residues located far apart on the SAME polypeptide chain, quaternary disulfide bonds are between different polypeptide chains

31
Q

what is the quaternary structure of amino acids?

A

interactions between polypeptide subunits

32
Q

subunit

A

a single polypeptide chain that is part of a large complex containing many subunits

33
Q

multisubunit complex

A

a large complex containing many subunits

34
Q

what is the bonds that determine quaternary structure?

A

non-covalent interactions, van der Waals forces, hydrogen bonds, disulfide bonds, electrostatic interactions (between DIFFERENT polypeptide chains)

35
Q

oxidation

A

also known as combustion, the process of breaking down carbohydrates to form carbon dioxide, releases large amounts of energy

36
Q

monosaccharide

A

a single carbohydrate molecule, also known as a simple sugar

37
Q

glycosidic linkage

A

the covalent bond between two sugar molecules

38
Q

how is the glycosidic bond formed?

A

by a dehydration reaction that requires enzymatic catalysis

39
Q

what are the tree physiological roles played by lipids?

A

1) in adipose cells, triglycerides store energy
2) in cellular membranes, phospholipids form the barrier between intracellular and extracellular environments
3) cholesterol serves as a building block for steroid hormones

40
Q

hydrophobicity

A

degree of “water fearing”

41
Q

what is the cardinal characteristic of lipids?

A

ALL WATER FEARING/HYDROPHOBIC

42
Q

hydrophilic

A

water loving

43
Q

what is another term for hydrophobic

A

lipophilic

44
Q

what is another term for hydrophilic

A

lipophobic

45
Q

saturated

A

a fatty acid with no carbon-carbon bond

46
Q

unsaturated

A

fatty acid with one or more Z/cis double bonds that form kinks in the structure

47
Q

describe the structure of a fatty acid

A

consists of a hydrophilic head (COO-) and hydrophobic tail, chain has an even number of carbons

48
Q

in aqueous solution, free fatty acids automatically form:

A

a micelle structure

49
Q

hydrophobic interaction

A

the force that drives the tails into the centre of the micelle (hydrophobicity)

50
Q

triacylglycerol/triglyceride

A

the storage form of fatty acids as fat

51
Q

what is triglyceride composed of?

A

three fatty acids esterified to a glycerol molecule

52
Q

lipases

A

enzymes that hydrolyze fats

53
Q

why are fats more efficient energy storage molecules than carbohydrates?

A

1) packing-hydrobicity allows for closer packing while carbohydrates are generally solvated
2) energy content-fact molecules store more energy than carbohydrates

54
Q

phospholipids

A

membrane lipids derived from diacylglycerol phosphate (DG-P)

55
Q

how do phospholipids minimalize their interactions with water?

A

by forming a lipid bilayer

56
Q

what interactions drives the formation of the lipid bilayer?

A

hydrophobic interactions

57
Q

what interactions stabilize the lipid bilayer once formed?

A

van der Waals forces between the long hydrophobic tails

58
Q

double bonds (unsaturation) in phospholipid fatty acids result in:

A

increased membrane fluidity by prevent orderly packing of hydrophobid lipid tails

59
Q

what is another way of increasing fluidity of fatty acid?

A

by decreasing the length of fatty acid tails (reduced van der Waals interactions)

60
Q

how does cholesterol act as a modulator of membrane fluidity?

A

at low temperatures, it increases fluidity; at high temperatures, it decreases fluidity; constantly maintains fluidity at an optimum level

61
Q

what are the three structural determinants of membrane fluidity?

A

degree of saturation, tail length, and amount of cholesterol

62
Q

how are steroids similar to fats?

A

hydrophobic

63
Q

how are steroids unique from fats?

A

have basic tetracyclic ring system (similar to cholesterol) but otherwise distinct

64
Q

lipoproteins

A

structure formed when steroid cholesterol is carried in the blood in a package with fats and proteins

65
Q

what is the state of phosphoric acid as it exists in the human body?

A

in anionic form due to its potential to donate three hydrogens

66
Q

phosphate is also known as:

A

orthophosphate

67
Q

anhydride linkage

A

the bond between two orthophosphates to form pyrophosphate

68
Q

the bond in pyrophosphate is:

A

POP

69
Q

is the pyrophosphate bond high or low energy:

A

it is a HIGH-ENERGY PHOSPHATE BOND because: the negative charges repel each other, more favourable than linked phosphates due to resonance forms and favourable interactions with water

70
Q

what is the universal short-term energy storage molecule

A

ATP (a nucleic acid)

71
Q

what are nucleotides composed of?

A

a phosphate group, nitrogenous base, a deoxyribose or ribose sugar group

MCAT-BIOLOGY (17 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions