Brainscape's Knowledge GenomeTM

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


See full index

a level biology > module 2- biological molecules > Flashcards

module 2- biological molecules Flashcards

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

which 4 elements are the most important in living organisms ?

A
  • hydrogen
  • oxygen
  • carbon
  • nitrogen
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

which 2 elements are also really important for living organisms ?

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

what is bonding determined by ?

A
  • the number of unpaired electrons present in the outer orbitals of different elements
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

how many bonds to carbon atoms from with other atoms ?

A

4

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

how many bonds can nitrogen atoms form with other atoms ?

A

3

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

how many bonds can oxygen atoms form with other atoms ?

A

2

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

how many bonds can hydrogen atoms form with other atoms ?

A

1

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

what is a covalent bond ?

A

a strong bond where 2 atoms share a pair of electrons

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

what is an ionic bond ?

A

1 atom in a pair donates an electron and the other receives it forming 1 positive ion and 1 negative ion, held together by opposite charges

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

what is an ion ?

A

an atom/molecule where the total number of electrons isn’t equal to the total number of protons

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

what type of ion is positively charged and what type of atom is negatively charged ?

A

cation - positive
anion - negative

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

what are hydrogen bonds ?

A

a slightly negatively charged atom binds to a slightly positively charged hydrogen atom

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

what are molecules contained carbon described as ?

A

organic

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

which elements are in water ?

A

hydrogen
oxygen

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

what elements are in a carbohydrate ?

A

carbon
hydrogen
oxygen

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

what elements are in a lipid ?

A

carbon
hydrogen
oxygen

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

what elements are in a protein ?

A

carbon
nitrogen
hydrogen
sulfur
oxygen

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

what elements are in nucleic acid ?

A
  • carbon
  • nitrogen
  • oxygen
  • hydrogen
  • phosphorus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what happens when mineral ions are dissolved in solution ?

A

they are electrolytes

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

what are calcium ions used for ?

A

nerve impulse transmission
muscle contraction

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

what are sodium ions used for ?

A

nerve impulse transmission
kidney function

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

what are potassium ions used for ?

A

nerve impulse transmission
stomatal opening in leaves

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

what are hydrogen ions used for ?

A

catalyzing many reactions
ph regulation

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

what are ammonium ions used for ?

A

used by bacteria to make nitrate ions
used by plants to make up proteins

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

what are nitrate ions used for ?

A

the form plants take up nitrogen
used by plants to make proteins

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

what are hydrogen carbonate ions used for ?

A

to maintain blood plasma pH

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

what are chloride ions used for ?

A

to balance positive charges of sodium and potassium ions in cells

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

what are phosphate ions used for ?

A

cell membrane and formation
formation of nucleic acids
bone formation

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

what are hydroxide ions used for

A
  • catalyzing reactions
  • pH regulation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

what is an anabolic reaction ?

A

where smaller molecules join to form larger ones

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

what is a catabolic reaction ?

A

where larger molecules are broken down into smaller ones

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

what is a monomer ?

A

a small single molecule which joins together to make a polymer

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

what is a polymer (macromolecule )

A

a large molecule made up of monomers

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

what is a condensation reaction ?

A

when 2 molecules join together involving the removal of water

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

what is a hydrolysis reaction ?

A

when a molecule is split apart involving the addition of water

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

what is a hydrolysis reaction ?

A

when a molecule is split apart involving the addition of water

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

what is starch used for ?

A

an energy store for plants

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

how is starch formed ?

A

alpha glucose molecules joined by glycosidic bonds to form 2 different polysaccharides

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

what are the 2 types of starch ?

A

amylopectin
amylose

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

what substance in plants is stored by starch

A

glucose

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

how is amylose formed ?

A

by alpha glucose molecules joined together by 1-4 glycosidic bonds

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

give properties of amylose

A
  • helix shape ( formed by long chains of glucose which twist ) - these are stabalised by hydrogen bonds
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

how does the helix shape of amylose help with its function ?

A

it makes the polysaccharide more compact and less soluble than the glucose molecules used to make it

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

how is amylopectin formed ?

A

by 1-4 glycosidic bonds between alpha glucose molecules and glycosidic bonds between carbon 1-6 via condensation reaction

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

what type of shape / structure does amylopectin form ?

A

a branched structure

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

what is glycogen used for ?

A

in animals and fungi it is used as an energy storage molecule

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

glycogen forms more branches than amylopectin, how is this useful ?

A

it makes it more compact, needs less space to be stored

animals are more mobile so use more energy so need more energy storage space

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

how does branching help with glycogen ?

A

there are lots of free ends where glucose can be added or removed which speeds up the process
of storing or releasing glucose

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

what similar properties do amylopectin and glycogen have which makes them good for storage ?

A

insoluble branches and compact

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

why is starch a good energy store ?

A

it isn’t soluble so doesn’t affect the water potential of a cell

it is unreactive

it is compact and doesn’t take up much space to store

it releases energy quickly as there are lots of end points to release glucose from via hydrolysis using enzymes

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

why is glycogen a good energy store ?

A

it is insoluble
it has a branched structure = quick energy release

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

glucose is stored as starch or glycogen until it is needed for what process ?

A

respiration

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

to release glucose molecules from starch/glycogen, what reaction needs to occur ?

A

a hydrolysis reaction

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

what does a hydrolysis reaction do ?

A

addition of water molecules
this reverse the condensation reaction which forms the glycosidic bond

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

how is the hydrolysis reaction catalyzed ?

A

by enzymes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

how is the hydrolysis reaction catalyzed ?

A

by enzymes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

what is cellulose used for ?

A

in plant cell walls for structure and support

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

how is cellulose formed ?

A

by beta glucose which are joined together by every other molecule being flipped 180 degrees

in between each molecule a hydrogen bond links them

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

what type of chain molecule is formed in cellulose

A

a straight chain molecule

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

cellulose molecules are linked together by hydrogen bonds forming strong fibres
called what ?

A

microfibrils

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q

microfibrils join to form what in cellulose ?

A

macrofibrils

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
62
Q

what do macrofibrils join together to form what ?

A

fibres

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
63
Q

how are macrofibrils strong ?

A
  • they combine to produce forbes which are interwoven
  • they are embedded in a gel like structure called pectin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
64
Q

why is cellulose ideal for the structure of cell walls ?

A
  • microfibrils have high tensile strength due to glycosidic bonds betweeen individual glucose molecules and hydrogen bonds holding cellulose chains together
  • macrofibrils are criss crossed ( in different directions )
  • cellulose is embedded in pectin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
65
Q

why is cellulose hard to digest ?

A

most animals don’t contain enzyme cellulose

cellulose usually passes through digestive system and is used as a source of fibre

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
66
Q

what are polysaccharides

A

large polymers made by joining lots of monosaccharides together by condensation reactions making long chains

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
67
Q

how are monosaccharides joined (bonds)

A

glycosidic bonds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
68
Q

how do you test for simple sugars (all monosaccharides and most disaccharides )

A

benedict’s test

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
69
Q

how do you test for non reducing sugars (sucrose)

A

modified benedict’s test

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
70
Q

how do you test for starch ?

A

iodine test

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
71
Q

what are lipids ?

A

molecules containing hydrogen carbon and oxygen

generally fats/oils

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
72
Q

what state are fats at room temperature ?

A

solid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
73
Q

what state are oils at room temperature ?

A

liquid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
74
Q

what are the properties of lipids ?

A
  • they are soluble in organic solvents
  • they are NOT soluble in water
  • they are non polar molecules
  • hydrophobic
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
75
Q

what does non polar mean ?

A

the electrons of the molecule in outer orbitals are evenly distributed so there are no positive or negative areas so don’t form hydrogen bonds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
76
Q

what does hydrophobic mean ?

A

repels water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
77
Q

what are simple lipids known as ?

A

triglycerides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
78
Q

how many glycerol molecules to fatty acids are there in a triglyceride ?

A

1 glycerol molecule : 3
fatty acids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
79
Q

what chemical group is glycerol in ?

A

alcohols

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
80
Q

what chemical group are fatty acids in ?

A

carboxylic acids (-COOH)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
81
Q

what type of bonds form between glycerol and fatty acids ?

A

ester bonds

known as esterification

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
82
Q

forming a triglyceride is a condensation reaction, how are 3
water molecules formed ?

A

both glycerol and fatty acids have hydroxyl groups forming 3
water molecules and bonds between glycerol and fatty acids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
83
Q

what is needed for a triglyceride to break down ?

A

3 water molecules

then hydrolysis can take place

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
84
Q

what does a saturated lipid mean ?

A

there are no double bonds between carbon atoms in fatty acid chains

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
85
Q

what does an unsaturated lipid mean ?

A

there is 1 double bond between carbon atoms in a fatty acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
86
Q

what does a polyunsaturated lipid mean ?

A

there is more than 1 double bond between carbon atoms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
87
Q

how are double bonds less compact ? if

A

double bonds cause the molecule to kink

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
88
Q

why are unsaturated fats often liquid at room temp ?

A

there is a kink at double bonds which makes them less compact in arrangement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
89
Q

what can lead to obesity ?

A

excess fat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
90
Q

what are phospholipids ?

A

modified triglycerides which contain phosphorus carbon oxygen and hydrogen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
91
Q

where are phosphate ions (PO43-) found ?

A

cytoplasm of cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
92
Q

how are phosphate ions soluble in water ?

A

they have extra electrons which caused them to be negatively charged

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
93
Q

what is replaced with a phosphate group to form a phospholipid ?

A

1 fatty acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
94
Q

the phosphate end of the phospholipid is charged and can therefore dissolve in water, how could we describe this as ?

A

it is hydrophilic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
95
Q

the fatty acid end of a phospholipid is non polar and a long chain of hydrocarbons, what could we call this ?

A

the hydrophobic end

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
96
Q

the phospholipid had two ends, what are these 2 ends ?

A

the tail which is non polar, repelling water and called hydrophobic

the head which is charged, attracting water, and called hydrophilic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
97
Q

what does hydrophobic mean ?

A

repels water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
98
Q

what does hydrophilic mean ?

A

attracts water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
99
Q

how to phospholipids work with water ?

A

they form a layer on the surface of water

phosphate heads are in the water with the fatty acid tails sticking out

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
100
Q

what are surface active agents/surfactants ?

A

phospholipids in water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
101
Q

describe how phospholipids form a bilayer in water

A

phospholipids form a 2 layered sheet arrangement with the hydrophobic tails pointing inwards with the hydrophilic heads protecting them from water ?

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
102
Q

how does the bilayer phospholipids form help with cells ?

A
  • they help to form cell membranes
  • they are able to separate the aqueous environment in which cells usually exist from the aqueous cystol within cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
103
Q

how does the bilayer phospholipids form help with cells ?

A
  • they help to form cell membranes
  • they are able to separate the aqueous environment in which cells usually exist from the aqueous cystol within cells
104
Q

what are sterols ?

A

a type of lipid known as steroid alcohols

found in cells

105
Q

how are sterols structured ?

A
  • complex alcohol molecules based on a 4 ring carbon structure with a hydroxyl group at one end
  • have hydrophilic and hydrophobic characteristics
106
Q

how are sterols structured ?

A
  • complex alcohol molecules based on a 4 ring carbon structure with a hydroxyl group at one end
  • have hydrophilic and hydrophobic characteristics
107
Q

what part of sterols is hydrophobic and what part is hydrophilic ?

A

hydroxyl group = hydrophilic
rest of molecule = hydrophobic

108
Q

give an example of a sterol ?

A

cholesterol

109
Q

where is cholesterol made ?

A

liver
intestines

110
Q

what does cholesterol do ?

A

plays a role in the formation of cell membranes

111
Q

what does cholesterol do ?

A

plays a role in the formation of cell membranes

adds stability and regulates fluidity of cell membranes

112
Q

where is cholesterol positioned ?

A

between phospholipids with a hydroxyl group at the periphery of the cell membrane

113
Q

how does cholesterol regulate the fluidity of cell membranes !

A

it keeps them at low temperatures and stops them being too fluid at high temperatures

114
Q

give examples of what cholesterol manufactures

A

vitamin d
steroid hormones
bile

115
Q

give the roles of lipids ?

A
  • membrane formation and creation of hydrophobic barriers
  • hormone production
  • electrical insulation needed for impulse transmission
  • waterproofing
  • long term energy storage
116
Q

how are lipids used as a long term energy storage ?

A
  • for thermal insulation to reduce heat loss
  • cushioning to protect
    vital organs
  • adds buyancy for aquatic animals e.g whales
117
Q

how do you test for lipids ?

A

emulsion test

118
Q

describe how to carry out the emulsion test

A
  • mix sample with ethanol
  • mix solution with water
  • shake
  • if white emulsion forms at the top a lipid is present
119
Q

what is food synergy ?

A

where nutrients don’t work in isolation, they work as part of the combined effect of a whole range of nutrients

120
Q

which type of fat is healthier and why ?

A

unsaturated

121
Q

which type of fats do plants generally contain ?

A
  • unsaturated triglycerides, normally as oils
122
Q

what type of fats do animals generally contain ?

A

saturated triglycerides normally as solids

123
Q

why would people want to find a substitute for butter ?

A

it his high in saturation as it is made from cows milk

124
Q

how have scientists tried to make butte healthier in the past ?

A

using vegetable oils and using hydrogen to remove double bonds to make it a solid = MARGARINE

125
Q

why did the initial method of making margarine / healthier butter not work ?

A

when breaking the double bonds a by product called trans fat was produced

126
Q

what is an advantage of trans fat ?

A

it increases shelf life

127
Q

what is a disadvantage of trans fat ?

A

it is linked to corornary heart disease

128
Q

what do scientists now use when making a substitute for butter ?

A

they use mono/poly saturated plant oils

129
Q

what is an advantage of using mono/polysaturated plant oils in butter substitutes ?

A

it reduces high cholesterol levels which reduce the development of coronary heart disease

130
Q

what are carbohydrates ?

A

molecules which contain hydrogen carbon and oxygen

131
Q

what is the formula for carbohydrates ?

A

(CH2O)n

132
Q

what are carbohydrates also known as ?

A

saccharides/sugars

133
Q

what are carbohydrates also known as ?

A

saccharides/sugars

134
Q

what are monosaccharides ?

A

single, simple sugars

135
Q

give an example of monosaccharides ?

A

glucose

136
Q
A

i

137
Q

what are disaccharides ?

A

complex sugars, 2 monosaccharides joined together

138
Q

give an example of a disaccharide ?

A

maltose

139
Q

what is a polysaccharide ?

A

NOT a sugar

2+ monosaccharides joined together

140
Q

give an example of a polysaccharide

A

glycogen

141
Q

what is the formula of glucose ?

A

C6H12O6

142
Q

describe the structure of glucose ?

A

it is a monosaccharide composed of 6 carbons

143
Q

what is a hexose monosaccharide ?

A

a monosaccharide composed of 6 carbons

144
Q

what are the 2 variations of glucose ?

A

alpha
beta

145
Q

what are the 2 variations of glucose ?

A

alpha
beta

146
Q

what is the difference between alpha and beta glucose ?

A

the OH groups are switched

147
Q

what is the difference between alpha and beta glucose ?

A

the OH groups are switched

148
Q

glucose molecules are polar, what does this mean ?

A

they are soluble in water and have hydrogen bonds which from between the hydroxyl groups and water molecules

149
Q

how does glucose being polar a good thing ?

A

it allows glucose to be dissolved in the cytosal of a cell

150
Q

describe a condensation reaction between 2 glucose molecules ?

A

2 alpha molecules are side by side and the 2 hydroxyl groups react so the bonds are broken and new bonds are reformed in different places forming new molecules

151
Q

what type of bond is formed between the 2 OH molecules when glucose reacts in a condensation reaction ?

A

glycosidic bond

152
Q

why is the glycosidic bond in aloha glucose molecules known as a 1,4 glycosidic bond ?

A

the bond happens between carbon 1 and 4

153
Q

describe the formation of maltose ?

A

2 hydrogen and 1
oxygen atom are removed form the glucose monomers and join to form water

a bond forms between C1 & C4 forming maltose

154
Q

what is a product of a condensation reaction ?

A

water

155
Q

what do fructose + glucose make ?

A

sucrose

156
Q

what type of sugar is sucrose ?

A

a non reducing sugar

157
Q

what does galactose + glucose make ?

A

lactose

158
Q

what are pentose monosaccharides ?

A

sugars which contain 5 carbon atoms

159
Q

give 2 examples of a pentose monosaccharide ?

A

ribose
deoxyribose

160
Q

where is ribose present ?

A

RNA nucleotides

161
Q

where is deoxyribose found ?

A

DNA nucleotides

162
Q

water is a polar molecule, what does this mean ?

A

it has regions of positivity and negativity

163
Q

where are the regions of positivity in a water molecule ?

A

the hydrogen atoms with a + charge

164
Q

where are the regions of negativity in a water molecule ?

A

the oxygen atom

165
Q

why do polar molecules interact with each other ?

A

the positive and negative regions attract each other

166
Q

how to hydrogen bonds form between water molecules ?

A

the water molecules attract each other forming hydrogen bonds

167
Q

what are hydrogen bonds ?

A

bonds which form between molecules
they are weak but occur in high numbers

168
Q

why does water have a high boiling point and is liquid at room temperature ?

A
  • they move around so constantly make and break hydrogen bonds
  • it takes a lot of energy to increase the temperature and turn water to gas because of this
169
Q

why is water less dense when solid ?

A
  • it turns to ice when frozen
  • the polar nature of water molecules means water makes 4 hydrogen bonds to other molecules forming a spaced out lattice structure which is rigid and open
170
Q

why is water being less dense when solid a good thing ?

A

it creates a good habitat
it insulated water below

171
Q

what is cohesion ?

A

when molecules are attracted to each other

172
Q

how are water molecules cohesive ?

A

their polar nature

173
Q

how is water being cohesive a good thing ?

A
  • it makes it easy to flow
  • it helps plants draw water up their roots
  • helps when drinking up a straw
174
Q

how does water get a skin of surface tension ?

A
  • the molecules are more cohesive to each other than air
  • the surface of water molecules contract resisting the force
175
Q

what does adhesion mean ?

A

molecules are attracted to other materials

176
Q

water molecules are attracted to other materials, how is this helpful ?

A

water is attracted to the sides of xylem vessels

177
Q

water can act as a solvent, how is this helpful ?

A

many solutes in an organism can be dissolved, e.g proteins/amino acids

molecules in blood plasma can be dissolved

helps to transport dissolved compounds in and out of cells

178
Q

water is a solvent and a polar molecule, what does this mean ?

A

anything polar can dissolve in it

179
Q

anything polar can dissolve in water, why is this helpful ?

A

cellular reactions can take place in a solution

180
Q

how can water help dissolve things (biological ionic reactions) ?

A

it is polar so the slight + end attracts the - ion and the slight - end attracts the + ion so ions can fully dissolve in water

181
Q

water has a high specific heat capacity, what does this mean ?

A

it takes a lot of energy to raise 1 gram of it by 1 degree celsius

182
Q

how is water having a high specific heat capacity helpful ?

A
  • if doesn’t change state or temperature
  • it provides a stable environment and a good habitat
  • it acts as a coolant as it helps to buffer temperature changes during reactions in cells
  • it provides a stable temperature for enzyme controlled reactions
183
Q

water has a high latent heat of vaporization what does this mean ?

A

it takes a lot of energy to break all the hydrogen bonds between the molecules for it to go from a liquid to a gas (takes lots of energy)

184
Q

why is water having a high latent heat of vaporization helpful ?

A

it can be used as a cooling mechanism , e.g sweating

185
Q

why is water having a high latent heat of vaporization helpful ?

A

it can be used as a cooling mechanism , e.g sweating

186
Q

what are peptides

A

polymers made up of amino acid molecule s

187
Q

what are proteins

A

consist of one or more polypeptides arranged as macromolecules with specific biological functions

188
Q

what elements to proteins have ?

A

carbon
hydrogen
oxygen
nitrogen

189
Q

what are amino acids structure ?

A

basic structure - have an amine group
r group
carboxylic acid group

190
Q

how many amino acids are found in cells ?

A

20

191
Q

how many non essential amino acids are there ?

A

5

192
Q

how many essential amino acids are there ?

A

9

193
Q

how many conditionally essential amino acids are there ?

A

6

194
Q

what is the synthesis of peptides ?

A

amino acids join when amine and carboxylic acid groups connect to the central carbon atom

195
Q

what is the synthesis of peptides ?

A

amino acids join when amine and carboxylic acid groups connect to the central carbon atom

196
Q

how exactly are proteins synthesized

A

hydroxyl in carboxylic acid group of one amino acid reacts with a hydrogen in the amine group of another amino acid

197
Q

what bonds form between amino acids ?

A

peptide bonds

198
Q

what kind of reaction happens between amino acids ?

A

condensation reaction

199
Q

what is produced as a result of amino acids joining together ?

A

water

200
Q

what kind of compound is 2 amino acids joined together called ?

A

dipeptic compound

201
Q

what forms when many amino acids are joined together by peptide bonds ?

A

polypeptide

202
Q

how is the reaction of amino acid joining together (peptide bonds) catalysed ?

A

enzyme peptidyl transferase which is present in ribosomes

203
Q

how do different proteins differ from each other ?

A

different r groups of amino acids which make up a protein interact, forming different types of bonds which fold polypeptides into proteins

different sequence of amino acids = different structures = different shapes

204
Q

why are proteins specific shapes ?

A

they carry out specific functions in living organisms

205
Q

what are the different levels of protein. structures ?

A

primary
secondary
tertiary
quaternary

206
Q

what is the primary structure in proteins ?

A

it is the sequence in which amino acids are joined

only peptide bonds involved

directed by information carried in dna

particular amino acids in a sequence influences how the polypeptides told to give the protein it’s final shape = determines function

207
Q

what is the secondary protein structure ?

A

oxygen, hydrogen, nitrogen atoms of basic structure interact forming hydrogen bonds which pull the amino acid unto different shapes

208
Q

what 2 different shapes do the polypeptides make in secondary structure ?

A

alpha helix
beta pleated sheet

209
Q

what is the tertiary structure ?

A
  • folding of a protein into its final shape
  • coiling/folding of sections of proteins in their secondary structure brings r groups of different amino acids closer together to interact and fold more
210
Q

what interactions /bonds are involved in the tertiary structure ?

A
  • hydrophobic / hydrophilic interactions
  • hydrogen bonds
  • ionic bonds
  • disulfide bonds
211
Q

what is the quaternary protein structure ?

A
  • results from the association of 2 or more proteins called subunits
  • interactions between subunits are the same as the territory structure except they are between individual molecules
212
Q

give examples of proteins which are in the quaternary structure ?

A

hormones
enzymes

213
Q

how do hydrophobic and hydrophilic interactions in the quaternary structure occur ?

A
  • proteins are assembled in an aqueous environment
  • the way a protein fold depends on whether the r groups are hydrophilic or hydrophobic
  • hydrophilic groups are on the outside
  • hydrophobic groups are on the inside
214
Q

how are peptides broken down ?

A
  • protease enzymes reverse the reaction - turning peptides back into their amino acids
215
Q

what type of reaction breaks proteins down ?

A
  • hydrolysis reaction -
    water added
216
Q

what are globular proteins ?

A
  • compact, soluble in water usually spherical
217
Q

how do globular proteins form ?

A

when proteins fold into their tertiary structures
hydrophobic r groups are kept away from aqueous environment
hydrophilic r groups are on outside as they are soluble in water

218
Q

what are globular proteins used for ?

A

regulating processes needed for life such as chemical reactions

219
Q

give 3 examples of globular proteins ?

A
  • insulin
  • haemoglobin
  • protease
220
Q

what is the function of insulin ?

A

regulates blood concentration
hormone that fits into specific receptors in cell surface membrane

221
Q

what is the function of insulin ?

A

regulates blood concentration
hormone that fits into specific receptors in cell surface membrane

222
Q

what are features of insulin

A

soluble
precise shape

223
Q

what are conjugated proteins ?

A

globular proteins which constrain a non protein prosthetic group

224
Q

what are proteins without a prosthetic group known as ?

A

simple proteins

225
Q

give examples of a conjugated protein ?

A

haemoglobin
lipoprotein
glycoprotein

226
Q

lipid + protein

A

lipoprotein

227
Q

carbohydrate + protein

A

glycoprotein

228
Q

what is the structure of haemoglobin ?

A

quaternary protein made from 4 polypeptides - 2 alpha + 2 beta subunits
- each subunit has prosthetic haem group

229
Q

how is haemoglobin structured to help it carry oxygen around the body ?

A

the iron ion in the haem group can combine reversibly with oxygen

230
Q

what is the structure of catalase ?

A

quaternary protein containing 4 haem prosthetic groups

presence of iron II ions in prosthetic groups allow catalase to interact with hydrogen peroxide + speed up its breakdown

231
Q

what does catalase do in terms of hydrogen peroxide ?

A

hydrogen peroxide is damaging to cells and a common byproduct of metabolism - catalase helps to break this down to make sure cell damage doesn’t occur

232
Q

what is a fibrous protein ?

A

organized strong long molecules which aren’t folded into complex 3-D shapes

233
Q

how are fibrous proteins formed ?

A

from long insoluble molecules due to presence of high proportion of amino acids with hydrophobic r groups

234
Q

what is the structure of fibrous proteins like ?

A

contains limited range of amino acids with small r groups
amino acid sequence is in primary structure and repetitive

235
Q

give 3 examples of fibrous proteins ?

A

keratin
elastin
collagen

236
Q

where is keratin found ?

A

in nails skin and hair

237
Q

describe the structure of keratin ?

A

has a large proportion of sulfur containing amino acid cysteine - strong disulfide bones

238
Q

what determines keratins flexibility ?

A

the number of disulfide bonds present

239
Q

where is elastin found ?

A

elastic fibres present in :
blood vessels
alveoli in lungs

240
Q

what does elastin do ?

A

gives structures flexibility but so they can return to their normal size

241
Q

describe the structure of elastin ?

A
  • quaternary protein made from stretchy molecules called topoelastin
242
Q

what stretchy molecules are elastin made from ?

A

tropoelastin

243
Q

what is collagen ?

A

connective tissue found in skin tendons ligaments and the nervous system

244
Q

how is collagen formed ?

A

made up of 3 polypeptides wound together

245
Q

describe the structure of collagen !

A

rope like structure
flexible

246
Q

when is elastin formed ?

A

when multiple tropoelastin molecules aggregate via interactions between hydrophobic areas

247
Q

why can elastin stretch and recoil ?

A

tropoelastin molecules contain hydrophobic and lysine rich areas

248
Q

how is the structure of elastin stabilized ?

A

by cross linking covalent bonds involving lysine

249
Q

what shape does collagen make

A

triple helix

250
Q

what shape does collagen make

A

triple helix

251
Q

how does tropocollagen form ?

A

many hydrogen bonds form between polypeptide chains forming long quaternary proteins with staggered ends

these proteins join end to end

252
Q

how is collagen strong ?

A

tropocollagen cross links

253
Q

what elements are found in cholesterol ?

A

H, C, O, N

254
Q

what elements are found in ATP

A

H C O N P

255
Q

how is water a good solvent ?

A
  • medium for metabolic reactions
  • transport
  • organisms can take in nitrate ions to help them build proteins
256
Q

which processes involve ester bonds ?

A

synthesis of triglycerides and polynucleotides

a level biology (4 decks)

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