2.1.2 Biological Molecules Flashcards
1
Q
why are polysaccharides less soluble in water
A
- because of compact size
- because regions that could hydrogen-bond with water are hidden away inside the molecule due to the coiled structure
2
Q
nutrients ingested are broken down by …
A
digestion
3
Q
what are catabolic reactions
A
- breaking down monomers so you can absorb them
(energy is released)
4
Q
what are anabolic reactions
A
- building up molecules
> products of digestion are absorbed into the blood stream and used to build larger molecules
(energy is used)
5
Q
what are metabolic reactions
A
balance between your catabolic and anabolic reactions
6
Q
define metabolism
A
the sum total of all the chemical reactions that take place in the organism (releases heat)
7
Q
define excretion
A
the removal of metabolic waste materials (sweat, urea, CO2)
8
Q
name all the required ‘nutrients’ + their roles in the human body
A
- Carbohydrates
- Proteins
- Lipids
- Vitamins and Minerals
- Nucleic Acids
- Water
9
Q
what is the role of carbohydrates in the body
A
- insulin
- keeps you full / primary source of energy
- glucose = quick release
- glycogen = long term storage
- structure in some organisms
10
Q
what is the role of proteins in the body
A
- cell growth
- enzymes
- muscles (movement)
- membranes
- antibodies
- most hormones made
11
Q
what is the role of lipids in the body
A
- protect your cells
- insulation (thermal + electrical - myelin sheath)
- energy
- some hormones
- protective layer
12
Q
what is the role of vitamins and minerals in the body
A
- iron - haemoglobin
- take part in metabolic reactions
- form parts of larger molecules
13
Q
what is the function of water in the body
A
- keeps cells hydrated
- important for cooling + excretion
- blood + body + brain is mostly water
- solvent for most metabolic reactions
14
Q
how many bonds do each of the following make:
C
N
O
H
A
C = 4
N = 3
O = 2
H = 1
15
Q
what molecules are carbohydrates made up of
A
C, H, O
16
Q
what molecules are lipids made up of
A
C, H, O (P)
17
Q
what molecules are proteins made up of
A
C, H, O, N (S)
18
Q
what molecules are nucleic acids made up of
A
C, H, O, N, P
19
Q
what are monosaccharides
A
- Cn (H2O)n
- monosaccharides are the simple sugar monomer units of carbohydrates
20
Q
what are the variations in monosaccharides
A
- triose (3)
- pentose (5)
- hexose (6)
> the different monosaccharides have different number of carbon atoms each (corresponding to their name/number)
21
Q
name the properties of all monosaccharides
A
- they are sugars so taste sweet
- soluble in water
- insoluble in non-polar solvents
- form crystals
- they are all reducing sugars which means they will test positive for Benedicts solution and turn from blue to brick red
22
Q
what type of monosaccharide is glucose
A
a hexose monosaccharide (6 carbon atoms)
23
Q
what do glucose molecules contain plenty of
A
- many bonds that can be broken down during respiration to release energy
- energy used to make ATP
24
Q
what are isomers
A
- molecules with the same formula, but whose atoms are arranged differently in space
25
what are the 2 types of glucose
- alpha or Beta
26
what determines if a molecule is an alpha or beta glucose
- the orientation of the OH (hydroxyl group) on Carbon 1
27
how can you tell if a glucose molecule is alpha
- hydroxyl (OH) found below C1
- Alpha Below
28
how can you tell if a glucose molecule is beta
- hydroxyl (OH) found above C1
- Beta Above
29
what is the acronym for differentiating between alpha and beta glucose
- ABBA
- Alpha Below
- Beta Above
30
what is the significance of a and B glucose
- slight structural difference can lead to very different molecular properties
- animals + plants have enzymes that break down a glucose only because of the shape
- B glucose can therefore not be respires + used for energy
31
why are glucose molecules polar + soluble in water
- because of the hydrogen bonds that form between hydroxyl groups and water molecules
32
why is the solubility of glucose important
- so it can be dissolved in the cytosol of the cell
33
what is cytosol
- fluid contained in cytoplasm
34
what is is the test for reducing sugars + how does it work
- Benedicts reagent
- the reducing sugar reduces the Cu2+ ions in the blue copper sulphate to Cu+ forming a brick red precipitate
35
why is the test for reducing sugars semi quantitative
- because the colour of the solution can tell you the quantities of reducing sugar
- green, yellow, orange, brick red
36
in polymerisation (condensation reactions) what happens to monomer / polymers
- monomers are joined together to form a polymer
- water molecule is eliminated
37
is polymerisation anabolic or catabolic
anabolic
38
what happens during condensation reactions
- a water molecule is released
- a covalent bond is formed
39
in hydrolysis what happens to monomers / polymers
- polymers are split into monomers
- water molecule is formed
40
is hydrolysis anabolic or catabolic
catabolic
41
what happens during hydrolysis
- a water molecule is formed
- a covalent bond is broken
42
what happens when monosaccharides join together + what is produced
- a new covalent bond is formed called a glycosidic bond + water is produced
43
what are disaccharides
- a sugar formed when two monosaccharides are joined by glycosidic linkage
44
what does the water provide in a hydrolysis reaction
- the water provides the hydroxyl group (OH-) and hydrogen (H+) which help the glycosidic bond to break
45
a glucose + a fructose =
sucrose
46
a glucose + a glucose =
maltose
47
b galactose + a glucose =
lactose
48
which main disaccharide is not a reducing sugar
sucrose
49
state the molecular formula + type of sugar + role in body of: a Glucose
- C6H12O6
- hexose
- energy source, component of starch + glycogen which acts as energy stores
50
state the molecular formula + type of sugar + role in body of: b Glucose
- C6H12O6
- hexose
- energy source, component of cellulose which provides structural support in plant cell walls
51
state the molecular formula + type of sugar + role in body of: Deoxyribose
- C5H10O5
- pentose
- component of deoxyribonucleic acid (DNA)
52
state the molecular formula + type of sugar + role in body of: Ribose
- C5H10O5
- pentose
- component of ribonucleic acid (RNA), ATP and NAD
53
how can non reducing sugars test positive for benedicts
- first must be hydrolysed with acid into its consistent monosaccharides which are reducing sugars so then will test positive
54
describe the structure of water
- water is made up of 2 hydrogen bonds which are covalently bonded to one oxygen atom
55
why is water described as a polar molecule
- there's an unequal sharing of electrons causing oxygen to become slightly negative and hydrogen atoms become slightly positive
- water is polar molecule due to the unevenly distributed charge
56
how do polar molecules interact with each other and what do they form
- they interact as the positive and negative regions of the molecules attract each other and form bonds called hydrogen bonds
57
describe qualities of hydrogen bonds
- hydrogen bonds are relatively weak so they break and reform easily giving water its characteristic
> but collectively hydrogen bonds provide strength and structure
58
name some properties of water
- being liquid
- density
- acts as a solvent
- acts as a transport medium
- coolant
- provides habitat
- high specific heat capacity + high latent heat of vaporisation
59
what helps water to flow
- water molecules constantly move around and as they do the hydrogen bonds are continuously being broken and built up allowing water to flow
60
water has a ... viscosity meaning it can ...
- low viscosity, meaning it can flow easily
61
due to water being liquid at room temp what can it do
- provide habitats for living things (rivers, seas, lakes)
- form large part of tissues in living organisms
- provide reaction medium for chemical reactions
- provide a transport medium
62
what's an advantage of water being dense
- aquatic organisms can float easily
63
what's advantages of ice being denser than water + floating on it
- creates an insulating layer so aquatic organisms can survive in body of water
> layer also reduces rate of heat loss from body of water
> aquatic organisms have stable environment in which to live in the water
64
why is water a great solvent
- water is great solvent as polar (hydrophilic) molecules dissolve easily in water since they are polar
- the positive and negative parts of water molecules are attracted to oppositely charged parts of the solute
65
because water is a great solvent what can happen
- molecules and ions can be transported around living things when dissolved in water
- many reactions happen in cytoplasm of cell which is over 70% water
66
what is cohesion
- water molecules 'sticking' together as hydrogen bonds between molecules pull them together
> this means when water is transported, molecules stick together
67
what is adhesion
- adhesion occurs between water molecules and other polar molecules and surfaces
68
what is capillary action
- the effects of adhesion and cohesion result is water carrying out capillary action
- capillary action is the process of when water rises up narrow tube against force of gravity
> cohesion allows water molecules to stick together and adhesion allows the water molecules to adhere to the surface
69
why does water have a high specific heat capacity and why is it a good feature
- high specific heat capacity due to energy needed to break the hydrogen bonds
> means water doesn't heat up or cool easily
- good property as water acts as a buffer against rapid temperature changes
> maintaining constant temperatures is important as living organisms need stable temperatures for enzyme controlled reactions + to live
70
why does water have a high latent heat of vaporisation and why is it a good feature
- high latent heat of vaporisation as large amounts of energy needed for water molecules to evaporate
- good as living things an cool down and keep their temperature stable
> e.g. when mammals sweat they become cool as heat is lost through water vapour
71
what features of water makes it a good habitat
- water buffering temperature provides stable environment for aquatic organisms
- ice being less dense than water provides surface habitat for animals + keeps water body temp stable
- has surface tension allowing smaller invertebrates + animals to live on surface
72
how is surface tension formed on surface of water
- water molecules on surface are hydrogen bonded to molecules beneath and so more attracted
> this causes surface of water to contract and gives surface of water ability to resist force applied to it
73
how are polysaccharides formed
- joining 2 molecules of glucose forms disaccharide maltose
- addition of further glucose molecules produces polysaccharide amylase
- each new bond is between C1 of one glucose and C4 of the next glucose
> called a 1-4 glycosidic bond
74
how are polysaccharides fromed
- by the condensation of many monosaccharides
75
what is the difference between homopolysaccharides + heteropolysaccharides
- homopolysaccharides = polysaccharides made solely of one kind of monosaccharide
- heteropolysaccharide = polysaccharides made of more than one monomer
76
where do plants store energy + as what
- store energy as starch in chloroplasts + membrane bound starch grains
77
where do humans store energy + as what
- store energy as glycogen in cells of muscles + liver
78
what are the main polysaccharides
- starch
- glycogen
- cellulose
79
describe starch
- energy storage in plants
- a glucose forming mixture of straight amylose chains and branched amylopectin
- starch is a homopolysaccharide as its made of 2 polysaccharides of amylose + amylopectin
80
describe amylose + how it's formed + its structure
- main component of starch found in plants
- formed by a glucose molecules joined by 1-4 glycosidic bonds
- as chain increases, structure begins to coil up
- there are hydrogen bonds within the coil holding it together (stabalises)
> now amylose is slightly soluble
81
why is amylose slightly soluble
- because the OH groups on outside of cell form H bonds with water
82
describe amylopectin + its structure
- found in starch + made from glucose molecules
- it's branched as it contains 1-4 and 1-6 glycosidic bonds
> the more there are glycosidic bonds the more branched it is
83
what is the enzyme responsible for hydrolysing 1-6 glycosidic linkages
glucosidase
84
describe how the iodine test works
- in potassium iodine solution the iodine molecules become trapped in 'coils' of amylose and form amylose-iodine complex
> the formation of this complex changes the colour of iodine from brown to blue/black
85
describe glycogen + its structure
- found in animals
- made from glucose monomers but has many more branches than starch (has 1- 4 and 1-6 bonds)
- compact
- large molecule so doesn't leave the cell
- doesn't change the osmotic potential of cell as it's largely insoluble
86
why does glycogen have so many branches + usefulness
- this is so there are more ends so it's easier to hydrolyse glucose units off for energy
> the enzymes hydrolyse to release glucose
87
key properties of amylopectin + glycogen
- insoluble
- branched
- compact
88
list key features of why polysaccharides are good energy stores
- compact
- hold glucose molecules in chains
- branched chains
- less soluble
89
explain why polysaccharides being compact is good
- they don't occupy large amount of space + occur in dense granules within cell
90
explain why polysaccharides having glucose molecules in chains is good
- so the glucose molecules can be easily snipped off from end of chain by hydrolysis when needed for respiration
> hydrolysis reactions are always catalysed by enzymes
91
explain why polysaccharides having branched chains is good
- tend to be more compact
- allows lots of glucose to be snipped off at same time by hydrolysis when lots of energy is required quickly
92
what is the enzyme responsible for hydrolysing 1-4 glycosidic linkages
amylase
93
describe cellulose + its structure
- found in plant cell walls
- made from b glucose monomers, with 1-4 glycosidic bonds
- H bonds between chains hold structure together
+ give plants structural rigidity
- every alternate b glucose rotates 180 so it can create a long straight chain
- strong linear chains form microfibrils
- structural support + rigidity for plant
94
why are alternate beta glucose molecules turned upside down
- because b glucose molecules can't join in the same way as a glucose molecules due to the hydroxyl groups being too far from each other to react
- they rotate so the hydroxyl groups are close to from chains
> now it's unable to coil or form branches
95
why is cellulose insoluble
- no free OH groups available to from H bonds with
> because all the OH are used within to make hydrogen bonds
96
how are microfibrils formed
- cellulose molecules make hydrogen bonds with each other to form microfibrils
97
how are fibres produced + what do they make
- microfibrils join together forming macrofibrils which then combine to produce fibres
- these strong, insoluble fibres then make cell wall
98
why do microfibrils + macrofibrils have very high tensile strength + why it's useful
- because of the strength of the glycosidic bonds
- because of hydrogen bonds between chains
- useful as it prevents plants cells from bursting when turgid + helps support the plant + protects delicate cell membrane
99
how does macrofibrils contribute to extra strength in cellulose
- macrofibrils run in all direction + criss-cross the wall to create extra support
100
why is it difficult to digest cellulose
- because the glycosidic bonds between glucose molecules are difficult to break
- most animals don't even have an enzyme to catalyse the reaction
101
what makes cell wall fully permeable
- there is space between macrofibrils for water + mineral ion uptake
102
what's the difference between cellulose + chitin
- chitin has acetylamino group (NH.OCCH3) rather than hydroxyl group on C2
- forms cross-links between long parallel chains of acetylglucosamine
103
what are the basic monomer unit of proteins
- amino acids
104
how is a dipeptide formed
- condensation reactions link amino acids together into a dipeptide by forming a covalent peptide bond and releasing water
- hydroxyl in carboxylic acid group of one amino acid reacts with a hydrogen in the amine group of another acid
105
how is polypeptide formed
- addition of further amino acids in dipeptide creates polypeptide
106
what are amino acids sometimes known as
- amphoteric because they have both acidic and basic properties
107
describe the structure of amino acid
- carboxyl group (-COOH)
- variable group - R
- Hydrogen
- amine group (-NH2)
- all amino acids have same basic structure only R group differs
108
what is used to test for proteins + how does it work
- The Biuret test
- biuret reagent contains copper sulphate + alkaline potassium hydroxide
> blue ring will first appear if protein is present which when gently shaken will gradually turn the solution a mauve / purple colour
- test detects presence of peptide bonds
- relies on reduction of Cu2+ ions to Cu+
> Cu+ forms a complex with nitrogen component of peptide bond in alkaline solution
109
what does the biuret reagent contain
- copper sulphate + alkaline potassium hydroxide
110
how can plants manufacture all of their amino acids
- using nitrate from the soil + organic molecules made by photosynthesis
111
can animals make all of their amino acids
- they can make some amino acids (non-essential amino acids)
- the rest they acquire from their diet (essential amino acids)
112
why can't animals store excess amino acids
- because the amino group makes them toxic
113
what happens to excess amino acids in animals
- they get transported to the liver where the amino group is removed (deamination) and converted to urea and excreted in urine via the kidney
114
what is deamination
process in which excess amino groups are removed
115
what is left of the amino acid after deamination
- a keto acid (contains carboxyl group + variable group)
> you can respire the keto acid
116
what is the role of enzymes in protein breakdown
- formation + breakage of peptide bonds in organisms is controlled by enzymes
- covalent peptide bonds are strong and must be broken down by protease enzymes
117
describe the primary structure in proteins
- primary structure is the sequence of amino acids in a polypeptide
- it determines the structure and function of the protein
- the sequence is coded for in the DNA in the nucleus
- peptide bonds (which are covalent bonds) present
> structure held by peptide bonds not easily broken down
118
describe the secondary structure in proteins
- chain of amino acids then takes on either of 2 secondary structures:
> a helix
> b pleated sheet
- held by hydrogen bonds easily broken as hydrogen bonds are weak individually
119
describe the tertiary structure in proteins
- secondary structure further coils / folds to form tertiary structure
- this is held in place by different types of bonds and interactions
- it determines the 3D shape of the protein and hence its function
120
name the bonds responsible for maintaining tertiary structure
- disulfide bonds
- ionic bonds
- hydrogen bonds
- hydrophobic + hydrophilic interactions
121
describe the disulfide bonds used in tertiary structure of proteins
- aka disulfide bridges
- covalent bonds
- strongest of the bonds
- only form between R-groups containing sulfur atoms
122
describe the ionic bonds used in tertiary structure of proteins
- form between oppositely charged R-groups
- form between carboxyl and amino groups that are part of R groups
> ionise into NH3+ and COO- groups
- positive and negative groups like this are strongly attracted to each other forming ionic bond
- stronger than hydrogen bonds
123
describe the hydrogen bonds used in tertiary structure of proteins
- form between hydrogen atoms with slight positive charge + other atoms with slight negative charge
- in amino acids they form in hydroxyl, carboxyl and amino groups
- weakest of bonds formed
124
describe the hydrophilic + hydrophobic interactions used in tertiary structure of proteins
- weak interactions between polar and non-polar R groups
- causes twisting of amino acid chain, which changes shape of protein
125
describe the quaternary structure in proteins
- how many polypeptide chains are arranged to make the complete protein molecule
- results from association of several protein chains / subunits
- interactions can be between different protein molecules
- protein subunits can be identical or different
126
describe why haemoglobin protein contains quaternary structure
- made up of 4 subunits
- 2 alpha chain
- 2 beta chain
127
how are peptides broken down
- protease enzymes catalyse the reaction of turning peptides into their constituent amino acids
- hydrolysis reaction takes place which requires using water molecule to break peptide bond
> reforms the amine and carboxylic acid groups
128
what are the 2 main categories of the tertiary + quaternary structure of proteins
- fibrous
- globular
129
describe the structure + features of globular proteins
- compact, water soluble + roughly spherical in shape
- formed when hydrophobic R groups on amino acid are turned inward when folded + hydrophilic groups on outside
- soluble
130
why are globular proteins soluble + why is it important
- hydrophilic groups on outside protein make it soluble in water as water molecules can easily cluster around + bind to them
- water solubility important for regulating many processes necessary to life e.g. chemical reactions, immunity, muscle contraction
131
describe the structure + features of fibrous proteins
- formed from long, insoluble molecules
- have regular, repetitive sequences of amino acids with hydrophobic R groups
> features enable them to form fibres, which have structural function
- they are strong + long
- NOT folded into complex 3D shapes like globular
132
give examples of some globular proteins
- conjugated proteins - haemoglobin
- insulin
- enzyme - pepsin
133
describe the structure/properties/functions of conjugated proteins
- globular proteins containing a non-protein component called a prosthetic group
> proteins without prosthetic = simple protein
- haem groups are example of prosthetic group + contain iron II
134
describe the structure/properties/functions of haemoglobin
- red, oxygen carrying pigment founds in red blood cells
- quaternary protein made from 4 polypeptides (2 alpha + 2 beta pleated sheets)
- each polypeptide contains haem group
135
what polypeptide chains are haemoglobin made of + bonds
- 4 polypeptide chain
- 2 alpha + 2 beta pleated sheet
136
how can haemoglobin transport oxygen around body
- each of the 4 polypeptide contains haem group which can combine reversibly with oxygen molecule, allowing haemoglobin to transport oxygen
- oxygen molecule binds to iron in each haem group turning haemoglobin from purple red to bright red colour
137
describe the structure/properties/functions of insulin
- hormone made of 2 polypeptide chains (a helix + b pleated sheet)
- chains fold into tertiary structure joined by disulfide links
- soluble as amino acids with hydrophilic R groups on outside of molecule
- hormone involved in regulation of blood glucose concentration
138
what polypeptide chains is insulin made of + bonds
- 2 polypeptide chains
- alpha helix + beta pleated sheet
- disulfide links
139
how does insulin regulate blood glucose concentration
- when glucose levels are too high, insulin binds to glycoprotein receptors on outside of muscle + fat cells to increase their uptake + rate of glucose from blood
140
describe the structure/properties/functions of pepsin
- enzyme that digests protein in stomach
- made of single polypeptide chain of 327 amino acids
- but folds into symmetrical tertiary structure held by hydrogen bonds + 2 disulfide bridges
141
why is pepsin so stable in the acidic environment of the stomach
- pepsin has 4 amino acids with basic R groups + 43 amino acids with acidic R groups
- it's stable in stomach's acidic environment as there are fewer basic groups to accept H+ ions, and therefore there's little effect on enzyme's structure
142
what polypeptide chains is pepsin made of + bonds
- single polypeptide chain of 327 amino acids
- hydrogen bonds + 2 disulfide bonds
143
give examples of some fibrous protein
- collagen
- keratin
- elastin
144
describe the structure + properties of collagen
- collagen is a connective tissue found in skin, tendons, ligaments, and nervous system
- many different forms but all made up of 3 polypeptides wound together in a long + strong rope like structure
- has flexibility
145
describe some functions of collagen to provide mechanical strength
- in artery walls: layer of collagen prevents artery bursting when withstanding high pressure from blood pumped by heart
- tendons made of collagen + connect muscle to bones, allowing them to pull on bones
- bones made from collage + reinforced with calcium phosphate, which makes them hard
- cartilage + connective tissue made from collagen
146
describe the structure + properties of keratin
- keratin has large proportion of the sulfur containing amino acid, cysteine
> results in many disulfide bridges between its polypeptide chains + alongside hydrogen bonding, the molecule becomes very strong, inflexible and insoluble
- the degree of disulfide bonds determines the flexibility
> hair contains fewer bonds making it more flexible than nails which contain more bonds
147
describe some functions of keratin
- found in finger nails, hair, claws etc
- provides mechanical protection
- an impermeable barrier to infection + being waterproof
> prevents entry of water-borne pollutants
148
describe the structure + properties of elastin
- elastin found in elastic fibres
- elastin is quaternary protein made from many stretchy molecules called tropoelastin
- cross-linking and coiling make structure of elastin strong + extensible
149
describe some functions of elastin
- found in living things where they need to stretch or adapt to their shape as part of life processes
> skin can stretch around bones + muscles due to elastin and when pinched/pulled can go back to normal
> elastin in lungs allows them to inflate + deflate
> in bladder helps expand to hold urine
> like collagen, elastin helps blood vessels to stretch + recoil as blood is pumped through them, helping maintain pressure wave of blood as it passes
150
what are lipids
- large complex molecules known as macromolecules, not polymers as they're made up of different components bonded together
151
what elements do lipids contain
- carbon, hydrogen, and oxygen
152
describe some features of lipids
- non-polar so insoluble
- make up 5% of organic matter or cell
153
what are the 3 most important lipids in living things
- triglycerides
- phospholipids
- steroids
154
describe some functions of lipids
- energy: respiratory substrate
- thermal insulation: blubber
- electrical insulation: myelin sheath
- membranes: phospholipids
- buoyancy: in large water mammals as fat less dense than water
- protection: outside + around delicate organs
- hormones: steroids
- metabolic water: desert animals
155
how are lipids used as a respiratory substrate
- triglycerides are broken down to release energy
- you hydrolyse ester bonds and glycerol + fatty acids can be broken down to CO2 + H2O
> respiration of lipid produces more water than resp of a sugar
156
describe the structure of triglycerides
- made up of combining 1 glycerol + 3 fatty acids
157
what are essential fatty acids
- the fatty acids that can't be made in our bodies so has to be consumed as we can make many fatty acids in our bodies called non-essential fatty acids
158
describe the structure of glycerol
- an alcohol, so contains free -OH groups
- there are 3 -OH groups which are important to the structure of triglycerides
- glycerol has 3 Carbon atoms
159
describe the structure of fatty acids
- have an acidic carboxyl group (-COOH) on one end attached to a hydrocarbon tail made of carbon + hydrogen atoms only
- can contain anywhere from 2-20 carbons
- the tail determines properties such as insolubility as they're hydrophobic
160
why are fatty acids acidic
- carboxyl group ionises into H+ and a -COO- group
> so fatty acids are acidic because it can produce free H+ ions
161
what is the difference between a saturated and unsaturated fatty acid
- saturated contains no C=C bonds
- unsaturated contains C==C bonds
> meaning fewer hydrogen atoms can be bonded to a molecule
162
how does unsaturated fatty acid affect structure
- changes shape of hydrocarbon chain giving it a kink (bend), where double bond is
> kinks push molecules slightly apart making them more fluid
> more unsaturated fatty acids, the lower melting point as structure is more fluid
163
where does the condensation reaction take place in triglyceride formation + what is produced
- between the -COOH group of fatty acid and -OH group of glycerol
> because there are 3 -OH groups, three fatty acids will bond
- water molecule is produced
164
what is the bond known as in a triglyceride formation
- the covalent bond is known as an ester bond
165
describe how you can test for a lipid
- mix sample with ethanol (dissolves the lipid)
- shake well
- pour into tube filled with water
- if lipid present, a white milky emulsion will form as a layer on top
166
describe the structure of a phospholipid
- 1 glycerol + 2 fatty acids + 1 phosphate group
- most fatty acids found on phospholipids have even number of carbon atoms (16/18)
167
what elements does phospholipids contain
- phosphorus, carbon, hydrogen, oxygen
168
where does the condensation reaction occur to form phospholipid + what bond is formed
- between OH group on phosphoric acid molecule (H3PO4) and one of the three -OH groups on glycerol
- forms ester bond
169
are phosphate ions in phospholipids soluble or insoluble
- soluble
- PO4 3-
> have extra electrons so making the more soluble in water
170
describe a phospholipids behaviour in water
- have charged end (hydrophilic phosphate head) and non-polar end (hydrophobic fatty acids)
- hydrophobic tails repel water and hydrophilic head attracts water
- phospholipids can form a layer on surface of water with heads in water + tails sticking out
> because of this they're called surface active agents or surfactants
> can also form micelles - tiny balls with tails tucked inside + heads pointing out
171
describe the structure of a phospholipid bilayer
- phospholipids for bilayers with 2 rows of phospholipids, hydrophobic tails facing inwards and hydrophilic heads pointing outwards
172
why are phospholipids excellent at forming membranes
- because inside + outside of the cell membrane is aqueous solution
173
how does phospholipids give membrane stability
- individual phospholipids are free to move around in the layer but won't move into any position where there hydrophobic tails are exposed to water
174
give a feature of the phospholipid membrane
- membrane is selectively permeable allowing small + non-polar molecules to move through tails in bilayer
> lets membrane control what enters/leaves cell + keeps it functioning properly
175
describe structure + function of glycolipids
- made of carbohydrates attached to lipids
> carbohydrate forms polar head to molecule
- important in maintaining cell stability in cells by attracting to water molecules (hydrogen)
- acts as receptor molecule
176
describe what sterols are + function
- sterols aka steroid alcohols are another type of lipid
- not made from glycerol or fatty acids
- sterols consist of 4 carbon based rings with hydroxyl (OH) group at one end
> they're complex alcohol molecules
177
are sterols hydrophilic or hydrophobic
- hydroxyl group is hydrophilic + polar
- rest of molecule is hydrophobic
178
describe what cholesterol is + function
- small hydrophobic molecule manufactured primarily in liver + intestines
- can sist in middle part of bilayer
- regulates fluidity of membrane, preventing from becoming too fluid at high temps
179
what are plants derivative of cholesterol in cell membranes
- stigmasterol
> only difference is that it had double bond between Carbon 22 + C23
180
what are some things that made from cholesterol
- steroid hormones:
> testosterone
> oestrogen
- vitamin D
181
steroids being abundant in plants means
- on ingestion and absorption some steroids can be converted into plant hormones
182
where is cholesterol not founded in
- prokaryotic membrane
183
what are inorganic ions
- essential constituents of skeletal structure, involved in maintenance of osmotic pressure and are structural constituents of soft tissue
184
what are inorganic ions important for
- nerve impulse transmission
- muscle contraction
- playing vital role in maintaining pH balance of body
- serve as essential components + activators of enzymes, vitamins and hormones
185
name the cations (incl symbol)
- calcium: Ca2+
- sodium: Na+
- potassium: K+
- hydrogen: H+
- ammonium: NH4+
186
name the anions (incl symbol)
- nitrate: NO3-
- hydrogen carbonate: HCO3-
- chloride: Cl-
- phosphate: PO4 3-
- hydroxide: OH-
187
name the function of calcium and what it's necessary for
- increases rigidity of bone, teeth, cartilage + component of exoskeleton of crustaceans
- important in clotting blood + muscle contraction
- activator for several enzymes
- stimulates muscle contraction + regulates transmission of nerve impulses
- regulates permeability of cell membranes
- important for cell wall development in plants + formation of lamella between cell walls
188
name the function of sodium and what it's necessary for
- involved in regulation of osmotic pressure, control of water levels in body fluid + maintenance of pH
- affects absorption of carbohydrates in intestines + water in kidney
- nerve impulse + muscle contraction
- constituent of vacuole in plants to help maintain turgidity
189
name the function of potassium and what it's necessary for
- involved in control of water levels in body fluid + maintenance of pH
- assists active transport of materials across cell membrane
- involved in synthesis of glycogen + protein and breakdown of glucose
- generates healthy leaves + flowers in flowering plants
- contributes to nerve impulse transmission + muscle contraction
- stomal opening
190
name the function of hydrogen and what it's necessary for
- involved in photosynthesis + respiration
- involved in transport of oxygen + CO2 in blood
- involved in regulation of blood pH
- catalysis of reactions
191
name the function of ammonium and what it's necessary for
- component of amino acids, proteins, vitamins, chlorophyll
- some hormones made of proteins
- essential component of nucleic acid
- involved in maintenance of pH in human body
- component of nitrogen cycle
- production of nitrate ions by bacteria
192
name the function of nitrate and what it's necessary for
- component of amino acids, protein, vitamins, chlorophyll
- essential component of nucleic acids
- some hormones made of proteins, which contain nitrogen
- component of nitrogen cycle
- nitrogen supply to plants for amino acid + protein formation
193
name the function of hydrogen carbonate and what it's necessary for
- involved in regulation of blood pH
- involved in transport of CO2 in + out of blood
194
name the function of chloride and what it's necessary for
- helps in production of urine in kidney + maintaining water balance
- involved in transport of CO2 in + out of blood
- regulates affinity of haemoglobin to oxygen through allosteric effects on haemoglobin molecule
- involved in regulation of blood pH
- used to produce hydrochloric acid in stomach
- balance positive charge of sodium + potassium ions in cells
195
name the function of phosphate and what it's necessary for
- increase rigidity of bone, teeth, cartilage, + component of exoskeleton of crustaceans
- component of phospholipids, ATP, nucleic acids + several important enzymes
- involved in regulation of blood pH
- helps root growth in plants
- cell membrane formation + bone + nucleic acid + ATP
196
name the function of hydroxide and what it's necessary for
- regulation of blood pH
- catalysis of reactions
197
What is used to test for starch + results
- iodine solution (must say solution!)
- brown —-> blue - black
198
What is used to test for reducing sugars + results
- Benedict’s Reagent (+ heat)
- blue —-> brick - red precipitate
- results can be green (low conc) + yellow (med conc)
- blue because contains Cu (II) ions that reg reduced to Cu
199
What is used to test for non-reducing sugars
- Boil with HCl (acid)
- Benedict’s reagent
- blue —-> brick - red precipitate
200
What is used to test for proteins + results
- Biuret’s solution
- blue —-> purple
