Brainscape's Knowledge GenomeTM

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


See full index

B > protein structure and function > Flashcards

protein structure and function Flashcards

protein structure I protein structure II protein function and enzymology

1
Q

what are the 4 most important classes of large molecule

A
  1. carbohydrates
  2. lipids
  3. proteins
  4. nucleic acids
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what are the 3 main types of macromolecule

A
  1. carbohydrates
  2. proteins
  3. nucleic acids
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what is a polymer

A

a long molecules consisting of many similar or identical building blocks called monomers linked by covalent bonds

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

what facilitates the formation of polymers from monomers in cells

A

enzymes

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

what is a common reaction in the formation of polymers

A

dehydration reaction (condensation polymerisation) - monomers are covalently bound to each other with the loss of a water molecule

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

by what reaction do polymers disassemble into monomers

A

hydrolysis - the bonds between monomers in a polymer are broken by the addition of water molecules

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

are lipids polymers

A

no - but hydrolysis and condensation are still involved in their synthesis and breakdown

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

how many essential amino acids are there

A

20

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

what are carbohydrates

A

they include sugars and polymers of sugars

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

what are the simplest carbohydrates

A

monosaccharides - single sugars
followed by disaccharides - double sugars (2 monosaccharides)
followed by polysaccharides (carbohydrates - they are made of many sugars)

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

what is the most common monosaccharide

A

glucose

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

what are the 2 different types of sugar depending on the position of the carbonyl group

A

aldehyde sugar - aldose

ketone sugar - ketose

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

what are hexoses, trioses and pentoses

A

hexoses - sugars with 6 carbons
trioses - sugars with 3 carbons
pentoses - sugars with 5 carbons

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

although often drawn as linear structures what shape do sugars form in aqueous solution under physiological conditions

A

they form rings because it is the most stable form

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

what are 2 important roles of sugars

A

they are used for cellular work (respiration) and for synthesis of other types of small organic molecules (such as amino acids and fatty acids)

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

what kind of bond forms between two monosaccharides in a disaccharide

A

glycosidic linkage - a type of covalent bond

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

what are the monomers of maltose

A

2 glucose molecules (they are joined by a 1-4 glycosidic bond)

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

what are the monomers of sucrose

A

a glucose molecule and a fructose molecule

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

in what form do plants transport carbohydrate from leaves to roots and other non photosynthetic organs

A

in the form of sucrose

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

what are the monomers of lactose

A

a glucose molecule and a galactose molecule

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

disaccharides must be broke down into …………. for use as energy by organisms

A

monosaccharides

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

which enzyme breaks down lactose and explain how this relates to lactose intolerance

A

lactase
those intolerant to lactose lack lactase and the sugar is instead broken down by intestinal bacteria causing gas and cramping

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

where do plants store starch and what is it made of

A

they store it in plastids (plastids include chloroplasts)

it is made of glucose monomers

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

why does starch represent stored energy

A

because glucose is a major cellular fuel

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

what are the major sources of starch in the human diet

A

the fruits of wheat, maize, rice and other grasses

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

most glucose monomers are joined by what kind of linkages

A

1-4 linkages

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

what is the simplest form of starch

A

amylose (unbranched)

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

what is a more complex form of starch

A

amylopectin (branched) - it has 1-6 linkages at branch points

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

what is glycogen

A

a polymer of glucose that is more extensively branched than amylopectin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

where do vertebrates store glycogen

A

liver and muscle cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

what are the 2 classes of polypeptides

A

structural and storage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

give an example of a structural polypeptide

A

cellulose - a polymer of glucose with 1-4 glycosidic linkages

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

what is the difference between the glucose linkages in starch and cellulose

A

there are 2 slightly different ring structures for glucose - alpha (hydroxyl pointing down) and beta (hydroxyl pointing up)
cellulose has beta glucose whereas starch only has alpha

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

what is the shape of starch molecules

A

highly helical

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

what is the shape of cellulose

A

straight - never branched

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

in plant cell walls parallel cellulose molecules held together by hydrogen bonds are grouped into units called ……………..

A

microfibrils – cable like - very strong

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

enzymes that hydrolyse the alpha linkages of starch are able to/not able to hydrolyse the beta linkages of cellulose

A

not able to because the molecules are different shapes and enzymes are highly specific to shape

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

can we digest cellulose

A

no - but it aids digestion by stimulating mucus secretion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

which organisms can digest cellulose

A

cows - they have microbes (prokaryotes and protists) that break it down into sugars

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

what is chitin

A

a carbohydrate used by arthropods to build their exoskeletons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

what is an exoskeleton

A

a hard case that surrounds soft parts of an a animal
it is made up of chitin embedded in a layer of proteins I
it becomes hardened when proteins are linked together or encrusted with calcium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

what kind of linkages does chitin contain and how is it different to cellulose

A

beta linkages like cellulose but it has a nitrogen containing linkage whereas cellulose doesn’t

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

why are lipids not considered macromolecules

A

they are not big enough

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

what is the common trait of all lipids

A

they mix very poorly with water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

why are lipids non polar

A

even through they have some hydrophilic bonds they are mostly made up of long nonpolar hydrocarbon chains

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

what types of lipids are most important to biology

A

fats, phospholipids and steroids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

what are fats made from

A

glycerol and fatty acids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

what is glycerol

A

a triol - each of its 3 carbons has a hydroxyl group attached

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

what is a fatty acid

A

it has a long carbon skeleton

at one end of the skeleton is a carboxyl group giving it the acid name

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

how are fats made

A

3 fatty acid molecules join to glycerol by ester linkages

the resulting fat is often called a triglycerol/triglyceride

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

what is a saturated fatty acid

A

one with no double bonds in the carbon chain so the maximum number of hydrogens are able to bind

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

what is an unsaturated fatty acid

A

one with one or more double bonds in the carbon chain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

most double bonds in fatty acids are cis/trans

A

cis - this creates a kink in the hydrocarbon chain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

saturated/unsaturated fats can pack together closely

A

saturated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

unsaturated fats are usually ………… at room temperature

A

liquid (usually referred to as oils)

56
Q

saturated fats are usually ………… at room temperature

A

solid

57
Q

what are hydrogenated vegetable oils

A

found in marge - unsaturated fats have been synthetically saturated by addition of hydrogen, allowing them to solidify

58
Q

what types of fats can contribute to the development of atherosclerosis (a cardiovascular disease)

A

saturated fats

59
Q

trans fats contribute to ……….. disease

A

coronary

60
Q

what is the major function of fats

A

energy storage

61
Q

why are phospholipids essential for cells

A

because they are a major component in membranes

62
Q

what is the structure of a phospholipid

A

2 fatty acids attached to glycerol
the 3rd hydroxyl of glycerol is attached to a phosphate group - usually another small polar molecule is linked to this phosphate e.g. choline

63
Q

the phosphate head of a phospholipid is hydrophobic/hydrophilic while the tail is hydrophobic/hydrophilic

A

hydrophilic

hydrophobic

64
Q

when phospholipids are added to water they assemble into what

A

phospholipid bilayer - they are also arranged like this on the surface of a cell making up the membrane

65
Q

what are steroids

A

lipids characterized by a carbon skeleton consisting of 4 fused rings

66
Q

what is cholesterol

A

a type of steroid that is crucial in animals in their membranes and as precursors for other steroids
it is synthesised in the liver

67
Q

what are most enzymes made of

A

proteins

68
Q

how can enzymes regulate metabolism

A

by acting as catalysts

69
Q

what is the bond between amino acids in a polypeptide called

A

peptide bonds

70
Q

how many polypeptides make up proteins

A

one or more

71
Q

what is the alpha carbon of an amino acid

A

the carbon in the centre

72
Q

give different functions of proteins

A 
enzymes 
defence 
storage
transport 
hormones
receptors
contractile and motor proteins 
structural
73
Q

what are the 3 different types of sidechain

A

hydrophobic (nonpolar)
hydrophilic (polar)
electrically charged (polar)

74
Q

list the 9 hydrophobic amino acids

A 
gly - glycine
ala - alanine
val - valine 
leu - leucine 
ile - isoleucine 
met - methionine 
phe - phenylalanine 
trp - tryptophan
pro - proline
75
Q

list the 6 hydrophilic neutral amino acids

A 
ser - serine
thr - threonine 
cys - cysteine 
tyr - tyrosine 
asn - asparagine 
gln - glutamine
76
Q

list the 2 acidic amino acids

A

asp - aspartic acid

glu - glutamic acid

77
Q

list the 3 basic amino acids

A

lys - lysine
arg - arginine
his - histidine

78
Q

what is the polypeptide backbone

A

the repeated sequence of atoms

79
Q

what determines the chemical nature of a polypeptide

A

its shape which is ultimately determined by its sequence of amino acids - more specifically the sequence of side chains

80
Q

why type of proteins are spherical

A

globular

81
Q

what type of proteins are shaped like long fibres

A

fibrous proteins

82
Q

the function of a protein usually depends on its ability to ..…………. and bind to another molecule

A

recognise e.g. antibodies binding to antigens

83
Q

what molecules mimic endorphins which bind to the brain to relieve pain or give euphoria

A

morphine, heroin and other opiate drugs

84
Q

what are the 4 different structural levels in proteins

A

primary
secondary
tertiary
quaternary

85
Q

what is the primary structure of a protein

A

the sequence of its amino acids - this dictates the secondary and tertiary structures due to the chemical nature of the backbone and sidechains

86
Q

what is the secondary structure of a protein

A

regions stabilized by hydrogen bonds between atoms of the polypeptide backbone (not sidechains)
the 2 secondary structures are:
- alpha-helix - coil held together by H bonds between every 4th amino acid - dominate globular proteins - the side chains are on the outside of the helical rod
- beta-sheet - 2 or more segments of polypeptide chain lying side by side connected by H bonds - these dominate fibrous proteins - can be twisted into a cylinder - can be parallel or anntiparallel

87
Q

what is the tertiary structure of a protein

A

the 3D shape stabilized by interactions between side chains
interactions include:
- hydrophobic interactions (hydrophobic sidechains cluster in the centre and interact via van der waals)
- interactions between acid and base side chains (ionic)
- interactions between hydrophilic sidechains (hydrogen bonding)
- disulphide bridges (S-S) between cysteine monomers sulfhydryl groups (-SH)

88
Q

what is the quaternary structure of a protein

A

association of 2 or more polypeptides (only some proteins)

the polypeptides can be the same or different

89
Q

describe the structure of haemoglobin

A

2 alpha and 2 beta subunits that all consist primarily of alpha helices
each subunit has a non polypeptide component called heme which contains an iron atom that binds oxygen

90
Q

what causes sickle cell anaemia

A

the substitution of an amino acid in the primary structure of haemoglobin

91
Q

what is the shape of a normal red blood cell

A

disk shaped - biconcave

92
Q

what shape are blood cells in patients with sickle cell anaemia

A

sickle shape - abnormal haemoglobin molecules tend to aggregate into chains - these can clog vessels and impede flow

93
Q

apart from the different levels of protein structure what else can influence protein shape and function

A

the physical and chemical conditions in the proteins environment

94
Q

what is denaturation

A

when weak chemical interactions and bonds within a protein are destroyed causing the protein to unravel and lose its native shape
this can be due to many environmental factors including pH, salt conc, temperature etc

95
Q

name some diseases caused by accumulation of misfolded proteins

A

Alzheimer’s
Parkinson’s
mad cow disease

96
Q

what method is most commonly used to determine the 3D structure of a protein

A

x-ray crystallography which depends on diffraction of an x-ray beam by the atoms of a crystalized molecule
NMR can also be used to help find out the structure

97
Q

why is the structure of some proteins difficult to determine

A

some proteins don’t have a distinct 3D structure until they interact with a target protein or other molecule
these are called intrinsically disordered proteins

98
Q

what programmes an amino acid

A

a gene

99
Q

what do genes consist of

A

DNA

100
Q

what are the monomers of nucleic acids called

A

nucleotides

101
Q

what are the 2 types of nucleic acid

A

DNA and RNA

102
Q

what is gene expression

A

the process of DNA directing RNA synthesis and through RNA controlling protein synthesis

103
Q

what is the site of protein synthesis

A

ribosomes

104
Q

mRNA conveys genetic instructions for protein synthesis from the nucleus to the …………. in the cytoplasm

A

ribosome

105
Q

what is the general form of a nucleic acid

A

5 carbon sugar (pentose)
nitrogenous base (nitrogen containing)
1 to 3 phosphate groups (begins with 3 but 2 are lost in the polymerisation process)

106
Q

what is a nucleoside

A

the portion of a nucleotide that has no phosphate groups (base plus sugar)

107
Q

what is the structure of the nitrogenous base

A

has 1 or 2 rings that contain nitrogen atoms

the 2 families of nitrogenous bas are pyrimidines and purines

108
Q

describe the structure of a pyrimidine

A

1 six membered ring of carbon and nitrogen atoms

pyrimidine family members include thymine, cytosine and uracil

109
Q

describe the structure of purine

A

a larger 6 membered ring fused with a 5 membered ring

purine family members include guanine and adenine

110
Q

thymine is only found in DNA/RNA

uracil is only found in DNA/RNA

A

thymine - DNA

uracil - RNA

111
Q

what is the DNA sugar called

A

deoxyribose sugar - lacks an oxygen atom on the second carbon of the ring compared to ribose sugar

112
Q

what is the sugar called in RNA

A

ribose sugar

113
Q

what end of the nucleotide is the phosphate attached to

A

5’

114
Q

what kind of reaction links nucleotides together

A

dehydration

115
Q

adjacent nucleotides are linked by a ……………….. linkage which consists of a phosphate group that links the sugars of the 2 nucleotides

A

phosphodiester

116
Q

the repeating pattern of sugar and phosphate is called what

A

the sugar phosphate backbone

117
Q

what is attached the 3’ end of a polynucleotide

A

hydroxyl group

118
Q

in what direction is a polynucleotide built

A

5’ to 3’

119
Q

what describes the direction of polynucleotide strands in a double helix of DNA

A

they are antiparallel - one runs 5’ to 3’ and the other runs 3’ to 5’

120
Q

what type of bond forms between bases

A

hydrogen

121
Q

are RNA molecules single stranded or double stranded

A

single

122
Q

what does tRNA do

A

brings amino acids to the ribosome during polypeptide synthesis

123
Q

differences between DNA and RNA

A

DNA double helix but RNA has variable shape
DNA is double stranded whereas RNA is single stranded
RNA contains the base Uracil and DNA doesn’t
DNA contains the base Thymine whereas RNA doesn’t

124
Q

what is a genome

A

the full complement of an organisms DNA

125
Q

what is bioinformatics

A

the use of computer software and other computational tools to handle and analyses large data sets

126
Q

genomics

A

the comparison of different genomes or parts of them

127
Q

what is proteomics

A

analysis of large sets of proteins including their sequences

128
Q

what is Ehlers-Danloss syndrome caused by

A

defects in collagen synthesis

129
Q

all amino acids found in proteins are of which form D or L

A

L

130
Q

what do chaperones do

A

they help proteins fold up properly if they don’t fold spontaneously

131
Q

what is a domain

A

an independently stable part of a polypeptide, usually with a specific function(they often correspond to an exon)

132
Q

what is the structure of antibodies

A

contain 2 heavy and 2 light chains joined by disulphide bridges; both types of chain have variable and constant regions. Antigen specificity is conferred by the variable regions.

133
Q

what part of the antigen does the antibody recognise

A

the epitope

134
Q

at high altitude levels of …………. rises and enhances oxygen unloading from haemoglobin

A

BPG

135
Q

what is a globin

A

related proteins with very similar structures but different functions.

B (19 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions