2.2 - Biological Molecules Flashcards
1
Q
What is a covalent bond?
A
The sharing of electron pairs between atoms.
2
Q
How does a Condensation reaction occur?
A
When two molecules are joined together with the removal of water.
3
Q
How does a Hydrolysis reaction occur?
A
When ma molecule is split into two smaller molecules with the addition of water.
4
Q
What is a monomer?
A
A small molecule which binds to many other identical molecules to form a polymer.
5
Q
What is a polymer?
A
A large molecule made from many smaller molecules called monomers.
6
Q
State the 3 main biological molecules studied in this chapter, along with the elements found in those molecules, and its respective monomer and polymer.
A
Carbohydrates - C, H, O - Monosaccharides - Polysaccharides
Proteins - C, H, O, N, S - Amino acids - Polypeptides and proteins
Nucleic acids - C, H, O, N, P - Nucleotides - DNA and RNA
7
Q
What are hydrogen bonds and how do they occur?
A
A weak interaction that can occur wherever molecules contain a slightly negatively charged atom bonded to a slightly positively charged hydrogen atom.
8
Q
What are the 7 properties of water?
A
- Liquid
- Density
- Solvent
- Cohesion and surface tension
- High specific heat capacity
- High latent heat of vaporisation
- Reactant
9
Q
Explain why water is a liquid at room temperature.
A
The hydrogen bonds between water molecules make it more difficult for them to escape to become a gas.
10
Q
State 4 benefits of water being a liquid.
A
- Provides habitats for aquatic organisms.
- Forms a major component of the tissue in living organisms.
- Provides a reaction medium for chemical reaction.
- Provides an effective transport medium, e.g. in blood and vascular tissue.
11
Q
Explain why ice is less dense than water.
A
Water becomes more dense as it gets colder until about 4 C. From 4 C to freezing point, due to its polar structure, the water molecules align themselves in a structure which is less dense than liquid water (open lattice).
12
Q
State 2 benefits of ice being less dense than a water.
A
- Aquatic organisms have a stable environment in which to live through the winter.
- Ponds and other bodies of water are insulated against extreme cold. The layer of ice reduces the rate of heat loss from the rest of the pond.
13
Q
Explain how water is a good solvent for many substances found in living things.
A
Because water is polar, the positive and negative parts of the water molecules are attracted to the negative and positive parts of the solute.
The water molecules cluster around these charged parts of the solute molecules/ions, and will help to separate them and keep them apart. They are then dissolved so a solution is formed.
14
Q
State 2 benefits of water being a good solvent.
A
- Molecules and ions can move around and react together in water.
- Molecules and ions can be transported around living things whilst dissolved in water.
15
Q
Explain how cohesion and surface tension in terms of water works.
A
Cohesion - where the hydrogen bonding between the water molecules pull them together (e.g. a drop of water on a flat surface is spherical)
Surface tension - where the water molecules at the surface are all hydrogen-bonded to the molecules beneath them, and hence more attracted to the water molecules beneath than to the air molecules above. Thus, the surface of the water contracts and it gives the surface of the water an ability to resist force applied to it.
16
Q
State 2 benefits of cohesion and surface tension.
A
- Columns of water in plant vascular tissue are pulled up the xylem tissue together from the roots.
- Insects like pond-skaters can walk on water.
17
Q
Explain why water has a high specific heat capacity.
A
Water molecules are held together tightly by hydrogen bonds. A lot of heat is energy is required to increase their kinetic energy and temperature. This means that water does not heat up or cool down easily.
The specific heat capacity of energy to raise the temperature of 1 kg of water by 1 C is 4.2 kJ.
18
Q
State 2 benefits of water having a high specific heat capacity.
A
- Living things, e.g. prokaryotes/eukaryotes, need a stable temperature for enzyme-controlled reactions to happen properly.
- Aquatic organisms need a stable environment in which to live.
19
Q
Explain why water has a high latent heat of vaporisation.
A
The molecules are held together quite tightly by hydrogen bonds so a relatively large amount of energy is needed for water molecules to evaporate.
20
Q
State 1 benefit of water having a high latent heat of vaporisation.
A
- Helps cool living things and keep their temperature stable (e.g. mammals cooled when sweat evaporates and plants cooled when water evaporates from mesophyll cells).
21
Q
What is the general formula for carbohydrates?
A
C n H 2n O n
22
Q
What are the three main functions of carbohydrates?
A
- A source of energy (e.g. glucose)
- A store of energy (e.g. starch/glycogen)
- Structural units (e.g. cellulose in plants and chitin in insects)
23
Q
What are monosaccharides? What are they particularly important in? Why are they well suited to this role?
A
The simplest carbohydrates (monomers). They are particularly important in living things as a SOURCE of energy. They are well suited to this role because of the large number of C-H bonds.
24
Q
Describe how monosaccharides taste like and their solubility.
A
They are sugars so they taste sweet.
They are soluble in water but insoluble in non-polar solvents.
25
What are three forms that monosaccharides can exist as?
Straight chained, ring, cyclic.
26
What do monosaccharides have a backbone of? What is the name of the group formed?
Single-bonded carbon atoms with one double-bonded to an oxygen atom to form a CARBONYL group.
27
What do monosaccharides join to make?
Disaccharides or polysaccharides.
28
In solution, triose and tetrose sugars exist as ........
| Pentoses and hexoses are more likely to be found as......
In solution, triose and tetrose sugars exist as straight chains.
Pentoses and hexoses are more likely to be found as a ring or cyclic form.
29
Glucose can exist as isomers. What are isomers?
Molecules with the same formula but whose atoms are arranged differently in space.
30
How are disaccharides made?
When two monosaccharides join together.
31
```
State what is named when the following monosaccharides are joined together:
a-glucose + a-glucose = .......
a-glucose + fructose =.......
b-glucose + a-glucose = ......
b-glucose + b-glucose = ......
```
a-glucose + a-glucose = MALTOSE
a-glucose + fructose = SUCROSE
b-glucose + a-glucose = LACTOSE
b-glucose + b-glucose = CELLOBIOSE
32
When monosaccharides join together, what is formed?
A CONDENSATION REACTION occurs to form a GLYCOSIDIC BOND.
33
Explain how a glycosidic bond is formed when monosaccharides join together.
Two hydroxyl groups line up next to each other, from which a water molecule is removed. This leaves an oxygen atom acting as a link between the two monosaccharide units.
34
How are disaccharides broken into monosaccharides?
By a HYDROLYSIS REACTION, which requires the ADDITION OF WATER. The water provides a hydroxyl group (-OH) and a hydrogen (H) which help the glycosidic bond to break.
35
What is the molecular formula of glucose (both alpha and beta)?
C6H12O6
36
What is the role of a-glucose in the body?
Energy SOURCE. COMPONENT of starch and glycogen, which act as energy STORES.
37
What is the role of b-glucose in the body?
Energy SOURCE. COMPONENT of cellulose, which provides structural support in plant cell walls.
38
What is the molecular formula of Ribose?
C5 H10 O5
39
What is the role of ribose in the body?
COMPONENT of ribonucleic acid (RNA), ATP and NAD.
40
What is the molecular formula of Deoxyribose?
C5 H10 O4 (one less oxygen atom than ribose, hence DEoxyribose)
41
What is the role of deoxyribose in the body?
COMPONENT of deoxyribonucleic acid (DNA).
42
What type of sugar is both alpha and beta glucose?
| What type of sugar is both ribose and deoxyribose?
Alpha and Beta Glucose: HEXOSE
| Ribose and Deoxyribose: PENTOSE
43
What are polysaccharides?
POLYMERS of MONOSACCHARIDES.
44
What are homopolysaccharides? Give one example.
Polysaccharides made solely of one kind of monosaccharide.
| Example: STARCH
45
What are heteropolysaccharides?
Polysaccharides made of more than one monosaccharide.
| Example: HYALURONIC ACID
46
If you join lots of glucose molecules together into polysaccharides, what can you create?
A STORE of energy.
47
How do plants store energy?
Plants store energy as STARCH (amylose and amylopectin) in CHLOROPLASTS.
Humans store energy as GLYCOGEN in cells of the muscle and liver.
48
Give 4 reasons why polysaccharides form good stores of monosaccharides.
1. Glycogen and starch are compact so they do not occupy a large amount of space.
2. Polysaccharides hold glucose molecules in chains so they can be easily 'snipped off' from the end of the chain by hydrolysis when required for respiration.
3. Branched chains, such as amylopectin, tend to be more compact. They also offer the chance for LOTS of glucose molecules to be snipped off by hydrolysis at the SAME TIME, when lots of energy is required QUICKLY.
4. Polysaccharides are less soluble in water than monosaccharides. If many glucose molecules did dissolve in the cytoplasm, the water potential would reduce and excess water would diffuse in. They are less soluble because not only of their size but because regions which could hydrogen-bond with water are hidden away inside the molecule.
49
What is Amylose?
It's a type of starch in plants. It is a long chain of a-glucose molecules. Like maltose, it has glycosidic bonds between carbons 1-4.
50
Describe the structure of amylose. Explain its properties due to its structure.
Amylose coils into a spiral shape with hydrogen bonds holding the spiral in place. Hydroxyl groups on Carbon-2 are situated on the inside of the coil, making the molecule less soluble and allowing hydrogen's bonds to form to maintain the coil's structure.
51
What is Amylopectin?
It's a type of starch in plants. It is similar to amylose in that it has glycosidic bonds between carbon 1-4 but it also has BRANCHES formed by glycosidic bonds between carbon 1-6.
52
Describe the structure of amylopectin.
Amylopectin also coils into a spiral shape, held together with hydrogen-bonds but with branches emerging from the spiral.
53
What is Glycogen?
It is like amylopectin with glycosidic bonds between carbon 1-4 with branches formed by glycosidic bonds between carbon 1-6.
54
Describe the structure of glycogen. (Hint: compare it with amylopectin).
The 1-4 bonded chains tend to be smaller than in amylopectin, so glycogen has LESS TENDENCY TO COIL. However, it has MORE BRANCHES which makes it more compact. It is also easier to remove monomer units as there are more ends.
55
What is cellulose? How is cellulose made?
It forms the cell walls of plants. It is a TOUGH, INSOLUBLE and FIBROUS substance.
It is a homopolysaccharide made from long chains of up to 15K B-glucose molecules bonded together through condensation reactions to form glycosidic bonds.
56
What is the difference in the general structure between cellulose chains and a-glucose.
Cellulose chains are straight and lie side by side.
57
Give 2 reasons why cellulose chains are straight in comparison to a-glucose molecules.
1. The Hydrogen and hydroxyl groups on carbon 1 are inverted in B-glucose. So every other B-glucose molecule in the chain is rotated by 180 degrees. So the B 1-4 glycosidic bond helps to prevent the chain spiralling.
2. Hydrogen bonding between the rotated B-glucose molecules in each chain gives the chain additional strength, preventing the spiralling.
58
When 60 to 70 cellulose chains are bound together, what do they form?
MICROFIBRILS
59
How long are microfibrils in terms of diameter?
10-30 nm
60
What is formed when lots of microfibrils (i.e. 400) bundle together?
MACROFABRILS which are embedded in pectins to form plant cell walls.
61
Why is cellulose an excellent material for plant cell walls?
1. Microfibrils and macrofabrils have VERY HIGH TENSILE STRENGTH, both because of the strength of the glycosidic bonds but also because of the hydrogen bonds between chains.
2. Macrofibrils run in all directions, like a mesh, criss-crossing the wall for extra strength.
3. It is difficult to digest cellulose because the glycosidic bonds between the glucose molecules are less easy to break.
62
Give 4 reasons as to why the properties of cellulose help the plant cell wall to do its job.
1. Plants do not have a rigid skeleton so each cell needs to have strength to support the plant as a whole.
2. There is space between macrofibrils for water and mineral ions to pass on their way into/out of the cell, making the cell wall fully permeable.
3. The cell wall has high tensile strength which prevents plant cells from bursting when they are turgid, helping to support the plant as a whole.
4. The macrofibril structure can be reinforced with other substances for extra support or to make cell walls waterproof (e.g. cutin and suberin).
63
Describe what lipids are.
Lipids contain large amounts of carbon and hydrogen, and smaller amounts of oxygen. They are insoluble in water because they're non-polar. They do not attract water molecules but can dissolve in alcohol.
64
What are the three most important lipids in living things?
| What are they examples of?
1. Triglycerides
2. Phospholipids
3. Steroids
They are examples of MACROMOLECULES (not polymers)
65
Describe the structure of a triglyceride.
Made up of glycerol and fatty acids.
66
What are essential fatty acids?
Fatty acids that must be ingested 'complete'.
67
Describe the structure of glycerol.
It has three carbon atoms. It is an alcohol: it has 3 -OH groups. This is partially why the final structure is called TRIglycerides.
68
Describe the structure of fatty acids.
They have a carboxyl group (-COOH) on one end, attached to a HYDROCARBON TAIL.
69
Why are fatty acids 'acids'?
The carboxyl group ionises into H(+) and a -COO(-) group. This structure is therefore an acid because it can produce free H+ ions.
70
If a fatty acid is saturated, what does that mean?
| If a fatty acid is unsaturated, what does that mean?
If a fatty acid is saturated, there are no C=C bonds in the molecules.
If a fatty acid is unsaturated, there is a double bond between two of the carbon atoms instead. This means fewer hydrogen atoms can be bonded to the molecule.
71
What is the difference between a monounsaturated fatty acid and a polyunsaturated acid?
Monounsaturated fatty acid: A single C=C bond is present (e.g. oleic acid)
Polyunsaturated fatty acid: More than one C=C bond is present (e.g. linoleic acid)
72
Why do unsaturated fatty acids have lower melting points than that of saturated fatty acids?
The C=C bonds in unsaturated fatty acids change the shape of the hydrocarbon chain, giving it a kink where the double bond is. Because these kinks push the molecules apart slightly, it makes them more fluid.
73
How many fatty acids are bonded to the one glycerol molecule in a triglyceride?
THREE
74
Describe how an ESTER BOND is formed in triglycerides.
A CONDENSATION REACTION happens between the -COOH group of the fatty acid and the -OH group of the glycerol. Because there are THREE -OH groups, THREE fatty acids will bond (hence 'triglyceride').
A water molecule is also produced. The covalent bond formed is known as an ESTER BOND.
75
What are 4 functions of triglycerides?
1. Energy SOURCE: Triglycerides can be broken down in respiration to release energy and generate ATP.
The ester bonds are hydrolysed and then both glycerol and the fatty acids can be broken down completely to carbon dioxide and water.
2. Energy STORE: Triglycerides are insoluble in water so they can be stored without affecting the water potential of the cell. 1g of fat releases twice as much energy as 1g of glucose. This is because lipids have a higher proportion of hydrogen atoms than carbohydrates and almost no oxygen atoms.
3. INSULATION: Adipose tissue is a storage location for lipid in whales (blubber). Lipid in nerve cells acts as an electrical insulator. Animals preparing for hibernation store extra fat.
4. BUOYANCY: Fat is less dense than water so it is used by aquatic mammals to help them stay afloat.
5. PROTECTION: Humans have fat around delicate organs to act as a shock absorber. The peptidoglycan cell wall of some bacteria is covered in a lipid-rich outer coat.
76
Describe the structure of phospholipids.
They have the same structure as triglycerides, except that one of the fatty acids is replaced by a phosphate group.
77
Where does the condensation occur in a phospholipid to form an ester bond?
A condensation reaction between an -OH group on a phosphoric acid molecule (H3 PO4) and one of the three -OH groups on the glycerol forms an ester bond.
78
Describe the behaviour of phosopholipids in water.
When surrounded by water, the phosphate group has a negative charge, making it polar (attracted to water). However, the fatty acid tails are non-polar so are repelled by water.
79
Which part of the phospholipids is hydrophilic and hydrophobic?
The phosphate HEADS are HYDROPHILIC (water-loving).
| The fatty acid tails are HYDROPHOBIC (water-hating).
80
Why are phospholipids AMPHIPATHIC?
They have a hydrophobic part and a hydrophilic part.
81
What kind of structure do phospholipids organise themselves as when in water?
MICELLES - tiny balls with the tails tucked away inside, and the head pointing outwards into the water.
82
How do amphipathic phospholipids arrange themselves as when forming membranes?
As a PHOSPHOLIPID BILAYER (a row of ampthipathic phospholipids on one side and a row beneath it, with fatty acid tails hidden inwards)
83
Explain, due to the structure of phospholipids, why the cell membrane is stable.
The individual phospholipids are free to move around in their layer, but will not move into any position where their hydrophobic tails are exposed to water.
84
What are the benefits of having a membrane that is selectively permeable?
It is only possible for small and non-polar molecules to move through the tails in the bilayer, e.g. oxygen/CO2. This lets the membrane control what goes IN and OUT of the cell, and keeps it functioning properly.
85
Describe cholesterol (4)
- it is a steroid alcohol (sterol), a type of lipid which is not made from glycerol or fatty acids
- Consists of four carbon-based rings or isoprene units.
- small and hydrophobic molecule, so it can sit in the middle of the hydrophobic part of the bilayer
- regulates the fluidity of the membrane, preventing it form becoming too fluid or stiff.
86
Where is cholesterol made in animals?
| Where is cholesterol made in plants?
Cholesterol is mainly made in the liver in animals.
Plants also have a cholesterol derivative in their membranes, called stigmasterol (it has a double bond between C-22 and C-23).
87
Name 3 steroid hormones that cholesterol makes.
1. Testosterone
2. Oestrogen
3. Vitamin D
88
What are proteins?
Large polymers comprised of long chains of AMINO ACIDS.
89
Name 3 functions that the properties of proteins enable.
1. They form STRUCTURAL COMPONENTS of animals in particular, e.g. muscles made from protein.
2. Their tendency to adopt specific shapes make proteins important as ENZYMES, ANTIBODIES and some HORMONES.
3. Membranes have protein constituents that act as carriers and pores for active transport across the membrane and facilitated diffusion.
90
Animals can make some amino acids, but must ingest others. What are these amino acids called?
ESSENTIAL AMINO ACIDS
91
Plants can make ALL the amino acids they need, but only if....
...they can access fixed nitrogen (e.g. nitrate)
92
How many of the 500 amino acids are PROTEINOGENIC (found in proteins)?
20
93
Describe the structure of an amino acid.
Each protein chain of amino acids has:
(A) An AMINO GROUP (-NH2) at one end
(B) A CARBOXYL GROUP (-COOH) at the other end.
(C) An R GROUP which is different in each amino acid.
94
What is the name of the bond when amino acids are joined together by covalent bonds?
PEPTIDE BOND
95
How is a (di)peptide bond formed between two amino acids?
A CONDENSATION REACTION OCCURS between the -OH part of the -COOH and the -H part of the -NH2.
Water is eliminated and a peptide bond is formed, where an oxygen is double-bonded to Carbon and a Hydrogen is bonded to Nitrogen.
96
How is a (di)peptide bond broken between two amino acids?
A HYDROLYSIS REACTION OCCURS which requires the addition of water which breaks the (O=C-N-H) bond.
97
What is the Primary Structure of proteins?
The sequence of amino acids in a protein chain.
98
What is the Secondary Structure of proteins?
The coiling or folding of an amino acid chain, which arises often as a result of hydrogen bond formation between different parts of the chain. The main forms of secondary structure are the a-helix and the B-pleated sheet.
99
Which bonds support the a-helix?
Held together by HYDROGEN BONDS between the -NH group of one amino acid and the -CO Group of another four places ahead of it in the chain.
100
Which bonds supports the B-pleated sheet?
Hydrogen bonds between the -NH group of one amino acid and the -CO group of another further down the strand.
101
What is the Tertiary Structure of proteins?
The overall 3D shape of a protein molecule. Its shape arises due to bond interactions.
102
What is the Quaternary Structure of proteins?
Where a protein consists of more than one polypeptide chain, e.g. insulin
103
What are the 4 types of bonds found in proteins?
1. HYDROGEN BONDS (found in all structures)
2. HYDROPHOBIC AND HYDROPHILIC INTERACTIONS
3. IONIC BONDS
4. DISULFIDE LINKS/BRIDGES
104
Where are hydrogen bonds formed between a polypeptide chain of amino acids?
In hydroxyl, carboxyl and amino groups.
105
Describe hydrophobic and hydrophilic interactions in proteins.
Hydrophobic parts of the R-group tend to associate together in the centre of the polypeptide to avoid water.
Hydrophilic parts are found at the edge of the polypeptide to be close to water.
This behaviour causes the twisting of the amino acid chain.
106
Describe ionic bonds in proteins.
- forms between carboxyl and amino groups that are part of R-groups.
- these ionise into NH3+ and COO- groups, forming an ionic bond.
107
Describe disulfide links in proteins.
The R-group of the amino acids cysteine contains sulfur. Disulfide bridges are formed between the R-groups of two cysteines. These are strong covalent bonds.
108
Describe what FIBROUS PROTEINS are.
- have regular, repetitive sequences of amino acids.
- usually insoluble in water.
- these features enable to form fibres which tend to have a structural function.
109
Give three examples of fibrous proteins.
1. COLLAGEN
2. ELASTIN (connective tissue)
3. KERATIN
110
Describe what GLOBULAR PROTEINS are.
- tend to roll up in an almost spherical shape.
- any hydrophobic R-groups are turned inwards towards the centre of the molecule, while hydrophilic groups are on the outside, making the protein water soluble.
- have a very specific amino acid sequence, thus a specific shape.
111
Give 2 examples of globular proteins.
1. Haemoglobin
| 2. Insulin
112
State 4 functions of collagen.
Provides MECHANICAL STRENGTH:
1. In artery walls, a layer of collagen prevents the artery bursting when withstanding high blood pressure.
2. Tendons are made of collagen and connect muscles to bones, allowing them to pull on bones.
3. Bones are made from collagen (reinforced with calcium phosphate), making them hard.
4. Cartilage and connective tissue are made from collagen.
113
Why is keratin very strong?
It is rich in cysteine so it has lots of disulfide bridges forming between its polypeptide chains ON TOP OF hydrogen bonding.
114
State the function of keratin.
Found wherever a body part needs to be hard, e.g. finger nails, hair, claws, etc. It provides mechanical protection and also provides an impermeable barrier to infection.
115
Why is elastin very strong?
Cross-linking and coiling make the structure of elastin very strong.
116
State the function of keratin.
Found in living things where they need to be stretched, e.g. skin, lungs when they inflate and deflate, bladder when it expands to hold urine, blood vessels when they stretch, etc.
117
What is the quaternary structure of haemoglobin made up of?
FOUR POLYPEPTIDES: 2 a-globin chains and 2 b-globin chains. Each of these has its own tertiary structure, but when fitted together form one haemoglobin molecule.
118
What is included within a haemoglobin molecule? What are these known as?
A HAEM GROUP is present which contains an iron ion.
| Groups like these are known as PROSTHETIC GROUPS.
119
What is a PROSTHETIC GROUP?
A non-protein component that forms a permanent part of a functioning protein molecule.
120
State the function of haemoglobin.
To carry oxygen from the lungs to the tissue.
121
Describe the structure of insulin.
TWO POLYPEPTIDE CHAINS: The A-Chain begins with a section of a-helix, and the B-chain ends with a section of B-pleat. Both chains fold into a tertiary structure, and are then joined together by disulfide links.
122
Describe the function of insulin.
-binds to glycoprotein receptors on the outside of muscle and fat cells to increase their uptake of glucose from the blood, and to increase their rate of consumption.
123
Describe the function of pepsin.
- an enzyme that digests protein in the stomach.
- it has 43 amino acids with acidic R-groups.
- this helps to explain why it is so stable in the acidic environment.
- the tertiary structure is held by hydrogen bonds and two cysteine bridges.
124
What are the two types of protein modelling?
1. Ab-initio protein modelling: a model is built based on the physical and electrical properties of the atoms in each amino acids in the sequence.
2. Comparative protein modelling: where the amino acid sequence is scanned against a database of solved structures and produces a set of possible models which would match that sequence.
125
What are the 5 inorganic cations you need to know?
1. Calcium, Ca+
2. Sodium, Na+
3. Potassium, K+
4. Hydrogen, H+
5. Ammonium, NH4+
126
State 6 functions of Ca+.
1. Increases rigidity of bone, teeth and cartilage and is a component of the exoskeleton of crustaceans.
2. Important in clotting blood and muscle contraction
3. Activator for several enzymes, e.g. lipates, ATPase...
4. Stimulates muscle contraction and regulates transmission of nerve impulses.
5. Regulates permeability of cell membranes.
6. Important for cell wall development in plants, and formation of middle lamella between cell walls.
127
State 4 functions of Na+.
1. Involved in regulation of osmotic pressure, control of water levels in body fluid and maintenance of pH
2. Affects absorption of carbohydrate in the intestine, and water in the kidney
3. Contributes to nervous transmission and muscle contraction
4. Constituent of vacuole in plants which helps maintain turgidity.
128
State 6 functions of K+.
1. Involved in control of water levels in body fluids and maintenance of pH.
2. Assists active transport of materials across the cell membrane.
3. Involved in synthesis of glycogen and protein, and breakdown of glucose.
4. Generates healthy leaves and flowers in flowering plants.
5. Contributes to nervous transmission and muscle contraction.
6. Component of vacuoles in plants, helping to maintain turgidity.
129
State 3 functions of H+.
1. Involved in photosynthesis and respiration.
2. Involved in transport of oxygen and carbon dioxide in blood.
3. Involved in regulation of blood pH.
130
State 4 functions of NH4+.
1. A component of amino acids, proteins, vitamins and chlorophyll
2. An essential component of nucleic acids.
3. Involved in maintenance of pH in the human body.
4. Component of the nitrogen cycle.
131
State the 5 inorganic anions.
1. Nitrate, NO3-
2. Hydrogencarbonate, HCO3-
3. Chloride, Cl-
4. Phosphate, PO4 3-
5. Hydroxide, OH-
132
State 4 functions of NO3-.
1. A component of amino acids, proteins, vitamins and chlorophyll.
2. An essential component of nucleic acids.
3. Some hormones are made of proteins which contain nitrogen, e.g. insulin
4. A component of the nitrogen cycle.
133
State 2 functions of Hydrogencarbonate, HCO3-.
1. Involved in regulation of blood pH
| 2. Involved in transport of carbon dioxide into and out of the blood.
134
State 5 functions of Cl-.
1. Helps in production of urine in the kidney, and maintaining water balance.
2. Involved in transport of carbon dioxide into and out of the blood.
3. Regulates affinity of haemoglobin to oxygen through allosteric effects on the haemoglobin molecule.
4. Involved in regulation of blood pH
5. Used to produce hydrochloric acid in the stomach
135
State 4 functions of PO4 3-.
1. Increases rigidity of bone, teeth and cartilage and is a component of the exoskeleton of crustaceans.
2. Component of phospholipids, ATP, nucleic acids and several important enzymes.
3. Involved in regulation of blood pH.
4. Helps root growth in plants.
136
State 1 function of OH-.
1. Involved in regulation of blood pH.
