Biology 2.1.2 Flashcards
1
Q
What does higher electronegativity mean
A
greater affinity for electrons(oxygen higher than hydrogen)
2
Q
hydrogen bonds is an electrostatic attraction that forms between a hydrogen atom that is covalently bonded
A
to a more electronegative atom/group and the electronegative atom of a polar molecule
3
Q
What is a polar molecule
A
Molécules where electrons spend more time closer to one atom(will be delta -) than the other(delta+)
4
Q
Hydrogen bonds form between
A
polar molecules
5
Q
Why does water have a high boiling point?
A
Hydrogen bonds are weak but in high numbers
6
Q
Why is ice less dense than water
A
Below 4 degrees celsius,
hydrogen bonds fix positions of polar molecules further than their average distance in liquid
7
Q
What is cohésion in water
A
Water moves as one mass because of hydrogen bonds
8
Q
Name a function of cohesion in water
A
plants can draw water up from their roots
9
Q
Is water a solvent
A
Yes because it’s a polar molecule
10
Q
Why water good as a solvent for humans
A
Cytosol mainly water-water can transport dissolved compounds in/out cells
11
Q
What is capillary action and how can it occur?
A
Water can rise up narrow tube against gravity
Because of
Cohesion(water molecules stick)
Adhesion(between water molecules and other polar or surfaces)
12
Q
Why is it beneficial that water takes a lot of energy to raise temperature and evaporate?
A
Our body temperature doesn’t increase and when it does the water inside us won’t evaporate
13
Q
Why is water good as a coolant
A
Takes alot of energy to overcome hydrogen bonds so when chemical reactions occur in our cells temp is maintained
14
Q
Why is ice floating good
A
Provides an insulating layer to aquatic life
15
Q
Why is there surface tension on water and who does this benefit
A
water molecules are more cohesive with eachother than with the air
16
Q
What does a carbohydrate contain
A
carbon hydrogen and oxygen
17
Q
What is the general formula of carbohydrates
A
Cx(H2O)y
18
Q
A single sugar unit is known as a monosaccharide, give examples
A
glucose fructose and ribose
19
Q
Two monosaccharides linked forms disaccharide, examples include
A
lactose and sucrose
20
Q
Two or more monosaccharides linked forms polysaccharide, examples include
A
glycogen cellulose and starch
21
Q
because glucose has 6 carbons, it is a
A
he ose monosaccharide
22
Q
what are the two structural variations of the glucose molecule and what is the structural difference
A
alpha and beta. OH group on carbon 1 in opposite positions
23
Q
Polymers are long chain
A
molecules made up by the linking of multiple individual molecules in a repeating pattern
24
Q
a hydrogen bond is an electrostatic
A
attraction that forms between a hydrogen atom that is covalently bonded to a lore electronegative atom or group and the electronegative atom of a polar molecule
25
what is the monomer of carbohydrates
monosaccharides
26
proteins made up of
carbon hydrogen oxygen nitrogen sulfur
27
polymer of proteins are
polypeptides
28
nucleic acids made up of carbon hydrogen oxygen and
nitrogen and phosphorus
29
what is the monomer of nucleic acids
nucleotides
30
2 glucose after condensation reaction form
maltose
31
hydrolysis is the chemical reaction where
the chemical bond between monomers is broken by adding a water molecule
32
which binds form between amino acids
peptide bonds
33
what bond between monosaccharides
glycosidic
34
what bond between nucleotides
phosphodiester
35
a condensation reaction is a chemical reaction forming
a chemical bond between monomers releasing a molecule of water
36
Polymer RNA is broken down into what when which reaction breaks the phosphodiester bonds between the monomers
into nucleotides
when hydrolysis
37
Which Polymer is broken down into monosaccharides when hydrolysis breaks which bonds between monomers
glycogen
glycosidic
38
What is the monomer of insulin
amino acids
39
glucose and fructose undergo condensation reaction to form
sucrose and water
40
carboxylic acid and alcohol undergo condensation
and form ester link and water
41
2 amino acids undergo condensation reaction make
dipeptide and water
42
glucose is what type monosaccharide
hexose monosaccharide which means it has six carbon atoms
43
what type of bond is a glycosidic
covalent
44
Carbons are numbered in molecular structure diagrams
clockwise
45
Name three hexose monosaccharides
fructose
glucose
galactose
46
what do galactose and glucose form
lactose
47
name two pentose monosaccharides
ribose
deoxyribose
48
what is the general formula for carbohydrates
CH2O
49
How does benedict’s test work when reducing sugars present
reagent is blue copper(2) sulfate ions
when reducing sugars present they donate electrons
making copper(1) which is brick red
50
Why if sucrose is boiled with dilute HCl before benedict’s test will result be positive even though sucrose is non reducing
it is hydrolysed by HCl and made into fructose and glucose which are reducing therefore positive test
51
What is the advantage with reagent strips
can show concentration of reducing sugars because of colour coded chart
52
if starch is present what colour will solution of sample and potassium iodide be
purple black
and if it’s not
yellow brown
53
if starch is present what colour will solution of sample and potassium iodide be
purple black
and if it’s not
yellow brown
54
why is the glucose molecule adapted to its function in living organisms
it is soluble so transported easily because it is dissolved in the cytosol of the cell
It is quickly broken down to release energy(lots energy stored in bonds)
55
isomerism is where each
isomer has the same chemical formula but a different structural formula (like alpha and beta glucose)
56
define disaccharide
formed from 2 monosaccharides joined by glycosidic bond during condensation reaction
57
Maltose is two
glucose molecules joined by an alpha 1-4 glycosidic bond
58
sucrose is glucose and
fructose joined by an alpha 1-4 glycosidic bond
59
Lactose is formed from glucose and
galactose joined by a beta 1-4 glycosidic bond
60
name three polysaccharides
starch
cellulose
glycogen
61
what are the three groups of functions of carbohydrates
structural units and stores or sources of energy
62
which polysaccharide acts as an energy store and source in animal cells
glycogen
63
which polysaccharide acts as an energy store and source in animal cells
glycogen
64
which polysaccharide acts as a structural unit in plant cells
cellulose
65
what polysaccharide is used as an energy store and source in plant cells
starch
66
Why do plants store glucose as starch(a polymer of alpha glucose)
it is insoluble in water so won’t affect osmosis
67
Name the two polysaccharides in starch
amylose and amylopectin
68
all monosaccharides and some disaccharides are
reducing sugars
69
how can make Benedict’s non reducing sugar test fully quantitive
filter brick red precipitate leaving just blue solution
white light red filter
colorimeter measures absorbency of red by the solution
more absorbency of red means more blue present
and therefore less reducing sugar
you can plot a calibration curve and use to predict glucose concentration
70
name a common non reducing sugar
sucrose
71
how would sucrose react if heated with benedict’s reagent
negative result
will remain blue
72
how to test for non reducing sugars
do reducing sugars test first
will stay blue
boil with HCl to hydrolyse(separate monomers)
then do reducing sugars test again and will be positive result(brick red)
73
test for starch?
mix potassium iodide solution with sample
positive if changes from yellow-brown to purple-black
74
amylopectin is a mix of
1,4 and 1,6 alpha glycosidic bonds
75
amylopectin is a long branched chain which means
glucose released quickly as branches make it easier
for enzymes to get to glycosidic bonds and hydrolyse them
76
where do animals store glucose as glycogen
in liver and muscle cells
77
glycogen has lots of
and is
branches
compact (good for storage)
78
amylose has only
1.4 alpha glycosidic bonds
79
amylose is an
unbranched chain of alpha glucose
80
what allows amylose to coil
angles of glycosidic bonds between alpha glucoses make it coil
81
cellulose is a polymer of
beta 1,4 glucose molecules
82
alternating structure of cellulose stops it
coiling up keeps chain straight
83
cellulose is
unbranched
84
what forms between cellulose chains forming microfibrils
hydrogen bonds
85
the space between microfibrils allow
water and mineral ions to pass through
sometimes these areas can be blocked
86
OH is what group
hydroxyl
87
why is water acting as a solvent important for survival of organisms
it can dilute toxic substances
can act as a medium for metabolic reactions
88
why are waters properties relating to density important for survival of organisms
oxygen/nutrients/resources can circulate in sea etc
89
cohesion holds water molecules together which means
chain of water can form brought up the xylem
90
what properties of water are involved in the transport role of water in a stem
adhesion
cohesion
solvent
91
glycogen is compact and
energy dense which means a lot of energy for little amount
92
why does glycogen being branched mean fast release glucose
greater SA for enzyme activity and glucose can be removed
93
properties of cellulose which make it suitable for being basis of plant walls
can form hydrogen bonds with neighbouring chains
high tensile strength
insoluble
unreactive
94
structural differences between glucose and starch
starch is a polymer glucose a monomer
polysaccharide glucose is a monosaccaride
starch has glycosidic bonds glucose doesn’t
starch has a lower ratio of carbon to hydrogen and oxygen than glucose
95
a triglyceride is made by combining
one glycerol molecule and three fatty acid chains
96
fatty acids belong to what group
carboxylic acid
carboxyl group and hydrocarbon chain
97
glycerol and fatty acid what groups interact to form eater bonds and three water molecules
this process is called
hydroxyl
estérification
98
a triglyceride being broken down is a what reaction
hydrolysis
99
fatty acid chains with no double bones are
saturated
100
monounsaturated is
one double bond between carbon atoms
101
two or more double bonds is
polyunsaturated
102
double bonds causes molecule
to kink
103
why are oils liquid lipids at room temperature
presence of double bonds
bends mean don’t pack closely
104
plants contain what triglycerides
unsaturated
normally occur as oils
more healthy for humans
105
phospholipids contains what as-well as the usual carbon hydrogen oxygen
phosphorus
106
how does phospholipids look
one fatty acid chain replaced by phosphate group
107
phosphate ions are what in water
soluble
108
fatty acid tails are
non polar hydrophobic
repelled by water
109
phosphate head of phospholipid is charged and
hydrophilic
110
what is a surfactant
phospholipids can form a layer on the surface of water with heads in water tails sticking out
111
phospholipids can form
bilayer
membrane (seperate aqueous environment cells in and aqueous cytosol)
112
sterols are
a type of lipids found in cells
113
sterols structure
four carbon ring with hydroxyl group at one end
hydroxyl is polar and the rest hydrophobic
114
cholesterol is a sterol
where does the body manufacture it
liver and intestine
115
what does cholesterol do
adds stability and regulates cell membrane fluidity
keeps membrane fluid at low temps
stops becoming too fluid at high temps
116
what is manufactured by cholesterol
vitaminD
steroid hormones
bile
117
roles of lipids
(non polar)
membrane formation and hydrophobic barriers
hormone production
electrical insulation for impulse transmission
waterproofing
118
lipids roles in long term energy storage
thermal insulation to reduce heat loss
cushioning to protect vital organs
buoyancy for aquatic animals
119
process in which triglycerides are synthesised is called
estérification (type of condensation réaction)
120
process in which triglycerides are synthesised is called
estérification (type of condensation réaction)
121
triglycerides are
broken down in respiration to release energy and generate ATP
122
how can triglycerides be used as an energy store
insoluble in water
so doesn’t affect water potential
form insoluble droplets because tails point inwards
123
in water phospholipids form
micelles
and monolayer
124
cholesterol has shape
small flattened shape
125
triglycerides made up of
one glycerol molecule with three fatty acids
126
how are triglycerides synthesised
by formation of an ester bond between each fatty acid and the glycerol molecule
127
what groups do glycerol and fatty acids belong to
alcohol
carboxylic acid
128
estérification is a
condensation reaction
129
what is needed to hydrolyse triglycerides
three water molecules
130
if there are two or more double carbon bonds on a fatty acid
is polyunsaturated
131
why are unsaturated fatty acids liquid at room temperature
double bonds causes kinks so cannot pack so closely
132
which fats are healthier in human diet
unsaturated
in plants
present as oils rather than solid fats
133
how go from triglyceride to phospholipid
replace one fatty acid with phosphate group
134
what are surfactants
short for surface active agents
(phospholipids form later on water)
135
sterol structure
complex alcohol molecules
four carbon ring structure
hydroxyl group at one end
hydroxyl is polar hydrophilic
rest is hydrophobic
136
where is cholesterol manufactured
liver and intestines
137
what do lipids (triglycerides particularly) provide under skin and around vital organs
thermal insulation reduce heat loss
cushioning to protect vital organs
buoyancy for aquatic animals
138
due to non polar, lipids roles
membrane formation hydrophobic barriers
hormone production
electrical insulation impulse transmission
waterproofing(plants leaves)
139
what is the emulsion test to identify lipids
sample mixed with ethanol
then with water and shaken
emulsion it’s positive
140
what makes a different amino acid in terms of structure
a different R group
141
What’s the difference between essential and non essential amino acids
essential fan only be obtained from what we eat
142
how do amino acids join
through peptide bonds a condensation reaction
amine and carboxylic acid groups connect
OH of carboxylic acid and H of amine group
143
what enzyme catalyses formation of polypeptides
peptidyl transferase
present in ribosomes(site protein synthesis)
144
bonds between R groups allow for
polypeptides folding into complex structures (proteins)
145
primary structure of proteins is the
sequence in which the amino acids are joined
the sequence influences how the polypeptide folds and specific shape(determines function)
146
the bonds involved in primary structure are
peptide bonds
147
secondary structure is where
the oxygen hydrogen and nitrogen atoms of the amino acids interact
148
if hydrogen bonds form within the amino acid chain cause
alpha helix (coil shape)
149
if polypeptide chains lie parallel and join with hydrogen bonds
beta pleated sheet
150
tertiary structure is the folding
of a protein into its final shape
secondary structures brings R groups closer
these interact
151
name four interactions that happen between R groups
hydrophobic and hydrophilic interactions
hydrogen bonds
ionic bonds
disulphide bonds(covalent and between R groups with sulfur atoms)
152
quaternary structure results from interactions between
subunits between different protein molecules
153
protein subunits of quaternary structure can be
identical or different
154
proteins are assembled in the aqueous cytoplasm so
hydrophilic R groups on outside
155
what enzyme catalyses hydrolysis of peptides
protease
156
why does biuret test go purple
peptide bonds form violet coloured complexes with copper ions in alkaline solutions
157
biuret reagent consists of
copper sulphate solution and alkali
158
why are globular proteins soluble in water
hydrophilic R groups on outside
159
what type of protein is insulin
globular
160
why does insulin being a globular protein good for its function as a hormone regulating blood glucose concentration
hormones are transported from the bloodstream need to be soluble
have to fit specific receptors on cell surface membrane so have to have specific shape
161
conjugated proteins are globular proteins that
contain a non protein component (prosthetic group)
proteins without are simple
162
give examples of prosthetic groups
lipids or carbohydrates
lipoproteins and glycoproteins
163
how many polypeptides make up haemoglobin
4 so it’s a quaternary protein
164
haemoglobin has two alpha
and two beta subunits each with a prosthetic haem group(iron 2 ion)
165
how can haemoglobin carry oxygen around body
iron 2 ions can combine reversibly with an oxygen molecule
166
how does catalase catalyse breakdown of hydrogen peroxide
iron 2 ions in its four prosthetic haem groups
can interact with hydrogen peroxide
167
why is catalase important
makes sure hydrogen peroxide which is a bioproduct of metabolism doesn’t accumulate as it is dangerous to cells if it does
168
fibrous proteins are
strong long molecules which aren’t folded into 3D shapes and are insoluble
169
fibrous proteins have a
high proportion of amino acids with hydrophobic R groups
limited range of amino acids so sequence repetitive
170
why is hair more flexible than nails of both contain keratin
keratin contains lots of cysteine(contains sulfur)
so lots of disulphide bridges
the amount of these bonds determines flexibility
171
why is keratin strong inflexible and insoluble
strong disulphide bridges
172
why is elastic fibres present in alveoli and walls of blood vessels
flexibility to expand and return to normal shape
elastin is the fibrous protein present in elastic fibres
173
elastin is what level protein
quaternary and made from tropoelastin
174
where is collagen found
in skin tendons nervous system and ligaments
175
collagen is made up of
three polypeptides wound together rope like structure
has flexibility
176
name three fibrous proteins
keratin, elastin, collagen
177
collagen is made up of three
polypeptides wound in long and strong rope like structure
178
two types of nucleic acid
DNA and RNA
179
what elements do nucleic acids contain
carbon hydrogen oxygen nitrogen phosphorus
180
what is a nucleotide made up of
pentose monosaccharides
a phosphate group
nitrogenous base
181
nucleotides linked together by condensation forming
polynucleotide
