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Molecular bonding Flashcards

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1
Q

Describe covalent bonds

A

-atoms consist of a nucleus surrounded by shells of electrons
-most atoms tend to be stable when outermost shell has 8 electrons
-atoms of different elements have different numbers of electrons in their outermost shell
-by sharing electrons with other atoms the atoms outermost shell can be filled and becomes strongly bonded with other atom - this is a covalent bond

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2
Q

Condensation and hydrolysis reactions

A

-condensation reaction occurs when two molecules are joined together with removal of water
-in same way, two molecules can be split apart with addition of water - hydrolysis

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3
Q

Describe monomers and polymers

A

-condensation and hydrolysis reactions are responsible for linking and splitting apart biological molecules
-the units which are joined together they form a dimer
-when lots monomers join together they form a polymer

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4
Q

List the monomer and polymer of carbohydrates, proteins and nucleic acids

A

CARBOHYDRATES
monomer= monosaccharides (e.g. glucose)
polymer=polysaccharide (e.g. starch)
PROTEINS
monomer=amino acids
polymer=polypeptides and proteins
NUCLEIC ACIDS
monomer=nucleotides
polymer= DNA and RNA

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5
Q

Describe hydrogen bonds

A

-a hydrogen bond is weak interaction which happens wherever molecules contain slightly negative charged atom bonded to slightly positively charged hydrogen atom
-the bond is weaker than a covalent bond
-in some polymers, thousands and thousands of hydrogen bonds form between chains of monomers
-having many bonds like this help stabilise the structure of some biological molecules

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6
Q

WATER PROPERTIES: transparent liquid

A

-0-100 degrees celcius
1) Habitat - aquatic animals can move/swim
2) photosynthesis can occur - plants can live at depth
3) cytoplasm - reactions occur in solution
4) transport - blood, in xylem

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7
Q

WATER PROPERTIES: solvent due to polar molecule

A

1) solutes can dissolve - reactions can occur in cytoplasm of cells
2) molecules and ions can be transport - e.g. in blood
3) plants/fish can absorb minerals from water

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8
Q

WATER PROPERTIES: ice less dense than water

A

-ice less dense than water therefore ice floats on water
-below 4 degrees
-H bonds form lattice
-deeper water insulated
-prevents ponds from completely freezing

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9
Q

WATER PROPERTIES: cohesion and surface tension

A

-cohesion - water column in xylem
-surface tension - insect walk on water
-adhesion - capillary action in xylem

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10
Q

WATER PROPERTIES: high specific heat capacity

A

-energy required to raise 1kg by 1 degree=4.2kJ
-takes a lot of energy to heat water up
-therefore thermally stable aquatic environment for aquatic organisms
-stable environment in cells - enzymes work efficiently

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11
Q

WATER PROPERTIES: high latent heat of vaporisation

A

-energy required to break H bonds and cause evaporation
-evaporation from skin takes a lot of heat energy - effective cooling, sweating and panting

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12
Q

WATER PROPERTIES: reactant

A

-water is part of metabolic reactions e.g. hydrolysis

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13
Q

Carbohydrate function

A

-carbohydrates contain carbon, hydrogen and oxygen
-hydrated carbon - for ever carbon there are 2 hydrogens and 1 oxygen atom
-functions: act as source of energy (e.g. glucose), store of energy (e.g. starch) and structural units (e.g. cellulose in plants and chitin in insects)
-some carbohydrates are also part of other molecules such as nucleic acids and glycolipids
-three main groups of carbohydrates: monosaccharides, disaccharides and polysaccharides

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14
Q

Describe monosaccharides

A

-monosaccharides are simplest carbohydrates
-they’re important in living things as source of energy
-soluble and sweet and reducing sugars therefore turn benedict solution red
-well suited due to large number of carbon-hydrogen bonds
-they’re sugars, soluble in water, insoluble non polar solvent
-can exist as straight chains (triose and tetrose)
-or can ring or cyclic forms (pentoses and hexoses)
-have backbone of single bonded carbon atoms with one double bonded to oxygen atom to form carbonyl group
-different sugars have different numbers of carbon atoms
-hexose=6/ pentose=5/ triose=3
-monosaccharide hexose sugars like glucose, are monomers of more complex carbohydrates and they bond to form disaccharides or polysaccharides

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15
Q

Describe disaccharides

A

-disaccharides are sweet and soluble
-the most common are maltose (malt sugar), sucrose and lactose (milk sugar)
-disaccharides are made when two monosaccharides join together
-alpha glucose+ alpha glucose - maltose
-alpha glucose+ fructose - sucrose
-B galactose +alpha glucose - lactose
-B glucose + B glucose - cellobiose
-sucrose = non reducing sugar
-lactose and maltose = reducing sugar

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16
Q

Formation of disaccharides

A

-when they join, condensation reaction occurs to form glycosidic bond
-2 hydroxyl groups line up next to each other from which water molecule removed
-this leaves oxygen atom acting as link between two monosaccharide units

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17
Q

Breakdown of disaccharides

A

-disaccharides are broken into monosaccharides by a hydrolysis reaction, which requires addition of water
-water proves a hydroxyl group (OH-) and hydrogen which help break glycosidic bond

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18
Q

Alpha glucose

A

-hexose sugar
-energy source
-component of starch and glycogen (energy store)

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19
Q

Beta glucose (C6H12O6)

A

-hexose sugar
-energy source
-component of cellulose, provides structural support in plant cell walls

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20
Q

Ribose (C5H10O5)

A

-pentose sugar
-component of ribonucleic acid (RNA), ATP and NAD

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21
Q

Deoxyribose (C5H10O4)

A

-pentose sugar
-component of deoxyribonucleic acid (DNA)

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22
Q

Function of polysaccharides

A

-e.g. starch, glycogen, chitin, peptidoglycan
-energy source - glucose for respiration
-energy store - starch in plants, glycogen in animal cells
-structure - cellulose in plants, chitin in fungi, peptidoglycan in bacteria
-form part of larger molecules, e.g. nucleic acids, glycoproteins, glycolipids

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23
Q

Polysaccharides as energy stores and sources

A

-polysaccharides are polymers of monosaccharides
-glucose is source of energy as its reactant for respiration
-if you join lots of glucose molecules together into polysaccharides, you can create store of energy
-plants store energy as starch in chloroplasts and membrane bound starch grains
-humans store energy as glycogen
-structure of some polysaccharides make good stores
-glycogen in animals and starch in plants (comprised of amylose and amylopectin) occur within cells in form of large granules

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24
Q

Why are polysaccharides good store of monosaccharides

A

-glycogen and starch compact meaning they do not take up large amount space
-polysaccharides hold glucose molecules in chains so can easily be ‘snipped’ off from end by hydrolysis when required for respiration
-amylose unbranched however amylopectin and glycogen branched
-branched chains tend to be more compact and offer chance for lots of glucose molecules to be snipped off by hydrolysis for quick release of lots of energy
-amylase responsible for hydrolysing 1-4 glycosidic bonds and glucosidase responsible for hydrolysing 1-6 glycosidix bonds
-polysaccharides less soluble in water than monosaccharides - therefore water potential less affected

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25
Q

POLYSACCHARIDES: amylose structure

A

-a long chain of alpha glucose molecules coils into spiral shape, with hydrogen bonds holding spiral in place
-hydroxyl groups on carbon 2 are situated on inside of coil, making molecule less soluble and allowing hydrogen bonds to form to maintain coiled structure

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26
Q

POLYSACCHARIDES: amylopectin structure

A

-amylopectin also coils into spiral shape, held together with hydrogen bonds but with branches emerging from spiral

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27
Q

POLYSACCHARIDES: glycogen

A

-1-4 glycosidic chains
-glycogen has less tendency to coil
-have more branches meaning more compact
-easier to hydrolyse monomer units as more ends

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28
Q

What is cellulose

A

-cellulose is found in plants, forming the cell walls
-it is a tough, insoluble and fibrous substance
-its a polysaccharide made from long chains of B glucose molecules bonded together through condensation reactions to form glycosidic bonds

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29
Q

Structure of cellulose as a direct result of bonding

A

-hydrogen and hydroxyl groups on carbon 1 are inverted in B glucose - this means that every other B glucose molecule in the chain is rotated by 180 degrees
-this and the B1-4 glycosidic bond helps prevention of chain spiralling
-hydrogen bonding between the rotated B glucose molecules in each chain also gives the chain additional strength and stops it spiralling
-hydrogen bonding between the rotated B glucose molecules in different chain gives whole structure additional strength
- the hydroxyl groups on carbon 2 sticks out enabling hydrogen bonds to be formed between the chains
-when 60-70 cellulose chains bound together they form microfibrils which are 10-30nm in diameter
-these bundle together into macrofibrils containing up to 400 microfibrils which are embedded in pectins to form plant cell walls
-macrofibrils run in all directions, criss crossing the wall for extra strength

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30
Q

Describe the structure and function of plant cell walls

A

-microfibrils and macrofibrils have very high tensile strength due to glycosidic bonds and because of hydrogen bonds between chains
-macrofibrils are stronger than steel wire of same diameter
-macrofibrils run in all directions, crisscrossing the wall for extra strength
-it is difficult to digest cellulose because the glycosidic bonds between the glucose molecules are harder to break

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31
Q

How do the features of cellulose help the plant function

A

-plants do not have a rigid structure therefore each cell needs strength to support the whole plant
-there is space between macrofibrils for water and mineral ions to pass in and out of the cell
-cell wall is fully permeable
-high tensile strength prevents plant cells from bursting when they are turgid giving support - turgid cells press against each other, supporting plant structure as a whole
-macrofibril structure can be reinforced with other substances for extra support or to make walls waterproof e.g. cutin and suberin are waxes that block spaces in the cell wall to make it waterproof

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32
Q

What are other examples of structural polysaccharides

A

-bacterial cell wall - peptidoglycan made from long polysaccharide chains that lie in parallel, cross linked by short peptide chains
-exoskeletons - insect and crustacean exoskeletons are made from chitin
-it differs from cellulose as had acetylamino group (NH.OCCH3) rather than a hydroxyl group on carbon 2
-it forms cross links between long parallel chains of acetlyglucosamine in a similar way to cellulose

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33
Q

How do humans exploit cellulose

A

-cotton is 90% cellulose
-cellophane and celluloid are derived from cellulose
-one of main components of paper is cellulose
-rayon is a semi-synthetic fibre produced from cellulose

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34
Q

What are lipids

A

-lipids contain large amounts of carbon and hydrogen and smaller amounts of oxygen
-they are insoluble in water because they are not polar and so do not attract water molecules, but do dissolve in alcohol
-3 most important lipids - triglyceride, phospholipid and steroid - these are not polymers but do have different components bonded together - they are examples of macromolecules

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35
Q

TRIGLYCERIDES: glycerol

A

-glycerol has three carbon atoms
-it is an alcohol which means it has free -OH groups
-there are three -OH groups which are important to the structure of triglycerides

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36
Q

TRIGLYCERIDES: fatty acids

A

-fatty acids have a carboxyl group COOH on one end attached to a hydrocarbon tail made of only carbon and hydrogen atoms
-the carboxyl group ionises H+ and a COO group- this structure is therefore an acid as it can produce free H+ ions
-a single C=C bond makes a fatty acid monounsaturated e.g. oleic acid
-more than one bond makes it polyunsaturated e.g. linoleic acid
-having one or more C=C bonds changes 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
-animal lipids contain lots of saturated fatty acids which are often solid at 20 degrees
-if there are more unsaturated fatty acids the melting point is lower

37
Q

Compare saturated and unsaturated fatty acids

A

-if a fatty acid is saturated this means there are no C=C bonds in the molecule
-if a fatty acid is unsaturated there is a double bond between two of the carbon atoms instead, meaning fewer hydrogen atoms can be bonded to the molecule
-an unsaturated fatty acid will have a kink in its tail
-unsaturated fatty acids result in a more fluid membrane as the kinks create larger gaps between the heads and therefore cell membrane more permeable

38
Q

What are ester bonds

A

-a triglyceride consists of one glycerol molecule bonded to 3 fatty acids
-a condensation reaction happens between the COOH group of fatty acid and the OH group of glycerol and 3 H2O is released
-because there are 3 OH groups, 3 fatty acids will bond hence the name triglyceride
-because it is a covalent bond formed and a condensation reaction with water molecule produced, it is an ester bond

39
Q

TRIGLYCERIDE FUNCTION: energy source

A

-triglycerides can be broken down in respiration to release energy and generate ATP
-the first step is to hydrolyse the ester bonds and then both glycerol and fatty acid can be broken down completely to carbon dioxide and water
-respiration of a lipid produces more water than respiration of a sugar

40
Q

TRIGLYCERIDE FUNCTION: energy store

A

-because triglycerides are insoluble in eater they can be stored without affecting the water potential in the cell
-mammals store fat in adipose cells under the skin
-1kg of fat releases 2x as much energy as 1kg of glucose
-this is because lipids have a higher proportion on hydrocarbon atoms than carbohydrates and almost no oxygen atoms

41
Q

TRIGLYCERIDE FUNCTION: insulation

A

-adipose tissue is a storage location for lipid in whales acting as a heat insulator
-lipid in nerve cells acts as an electrical insulator around neurones
-animals preparing for hibernation store extra fat

42
Q

TRIGLYCERIDE FUNCTION: buoyancy

A

-because fat is less dense than water, it is used by aquatic mammals to help them stay afloat

43
Q

TRIGLYCERIDE FUNCTION: protection

A

-humans have fat around delicate organs such as kidneys to act as shock absorber
-the peptidoglycan cell wall of some bacteria is covered in lipid rich outer coat
-also waxy cuticle on leaf
-used in membranes e.g. phospholipids

44
Q

Describe the phospholipid structure

A

-phospholipids have the same structure as triglycerides except that one of fatty acids is replaced by a phosphate group
-a condensation reaction between an OH group on a phosphoric acid molecule (H3PO4) and one of three OH groups on glycerol forms on ester bond
-most of fatty acids found in phospholipids have even number of carbon atoms
-commonly one of these chains is saturated and one unsaturated

45
Q

Behaviour of phospholipids in water

A

-when surrounded by water, the phosphate group has a negative charge making it polar (attracted to water)
-the fatty acid tails are non polar so repelled by water
-the head is hydrophilic and tail is hydrophobic which means phospholipid is amphipathic
-membrane lipids tend to be amphipathic whereas those involved in storage are not
-the phospholipids that are amphipathic have very distinct properties in water
-they may form a layer on the surface of water with heads in water and tails sticking up out
-they may also form micelles - tiny balls with tails tucked away inside and hearts pointing outwards into water

46
Q

What is a phospholipid bilayer

A

-amphipathic phospholipids are excellent at forming membranes around cells and organelles
-inside and outside a cell membrane is an aqueous solution
-the phospholipids form a bilayer with two rows of phospholipids tails pointing inwards and heads pointing outwards into solution
-between 20-80% of membranes of plants and animal cells are made of phospholipids

47
Q

Properties of the phospholipid bilayer

A

-individual phospholipids are free to move around their layer but will not move into any position where their hydrophobic tails are exposed to water. This gives the membrane some stability
-the membrane is selectively permeable. It is only possible for small and non polar molecules to move through tails in bilayer such as oxygen and carbon dioxide. This lets membrane control what foes in and out of the cells and keeps functioning properly

48
Q

What is cholesterol

A

-cholesterol is a steroid alcohol - a type of lipid which is not made from glycerol or fatty acids
-it consists of four carbon based rings or isoprene units
-cholesterol is a small and hydrophobic molecule which means it can sit in the middle of the hydrophobic part of the bilayer
-it regulates the fluidity of the membrane preventing it from becoming too fluid or stiff

49
Q

How is cholesterol formed

A

-cholesterol is mainly made in the liver in animals
-plants also have a cholesterol derivative in their membranes
-it is called stigmasterol and different from cholesterol in only one respect; it has a double bond between carbon 22 and carbon 23

50
Q

What does cholesterol form

A

-the steroid hormones testosterone, oestrogen and vitamin D are all made from cholesterol
-because they are all small and hydrophobic part of the cell membrane which is hydrophobic can pass through and any other membrane inside the cell
-steroids are also abundant in plants and on ingestion and absorption some can be converted to animal hormones

51
Q

What are proteins

A

-proteins are large polymers compromised of long chains of amino acids
-they form structural components of animals in particular e.g. muscles made of proteins
-their tendency to adopt specific shapes makes proteins important as enzymes, antibodies and hormones
-membranes have protein constituents that act as carriers and pores for active transport across the membrane and facilitated diffusion

52
Q

Describe the structure of amino acids

A

-each amino acid contains the elements carbon, hydrogen, oxygen and nitrogen
-some amino acids contain sulfur
-there are over 500 different amino acids but only 20 of them are proteinogenic which means that they are found in proteins
-each protein chain of amino acids has an amino group NH2 at one end and a carboxyl group at the other COOH
-they have an R group which can vary in size, charge and polarity

53
Q

Describe the peptide bond

A

-amino acids are joined together by covalent bonds called peptide bonds
-making a peptide bond involves a condensation reaction and breaking a peptide bond involves hydrolysis
-enzymes catalyse these reactions
-protease enzymes in the intestines break peptide bonds during digestion
-they also break down protein hormones so their effects are not permanent
-amino acids join together in same way, whatever R group they have
-two amino acids join together by a dipeptide and longer chains form polypeptides
-a protein may consist of a single polypeptide chain or more than one chain bonded together
-polypeptides have a repeating backbone of N-C-C-N-C-C-N-C-C-N
-sequence of amino acids determines shape of polypeptide

54
Q

Functions of amino acids

A

-structural= keratin, actin, collagen
-catalytic = enzymes
-signalling= hormones and receptors
-immunological=antibodies
-transport = haemoglobin

55
Q

How are amino acids absorbed and removed

A

ABSORBED
-nitrates absorbed from soil to make amine group
-amino acids come from diet for animals
-soya contains all essential amino acids
REMOVAL
-animals cannot store excess amino acids
-amine group make them toxic
-amino group removed via deamination in liver -ammonia - urea - urine

56
Q

Define the primary structure

A

-the sequence of amino acids found in a protein chain
-number and order of amino acids can change shape and function of the protein

57
Q

Define the secondary structure

A

-the chain of amino acids is not straight but twists into a shape called secondary structure
-some chains coil into an alpha helix with 36 amino acids per 10 turns of helix
-the helix is held together by hydrogen bonds between the NH group and the CO group
-other chains fold very slightly in zigzag structure
-when one such chain folds over on itself this produces a B pleated sheet
-hydrogen bonds between NH and CO further down strand hold the sheet
-although hydrogen bonds are relatively weak, many formed which makes both Alpha helix and B pleated sheet stable structures at optimal pH and temperature

58
Q

Describe the tertiary structure

A

-when these coils and pleats start to fold, along with areas of straight chains of amino acids, this forms tertiary structure
-the tertiary structure is a very precise shape held firmly by close together bonds between amino acids
-the tertiary structure may adopt a supercoiled shape (fibrous) or spherical shape (globular)
-has hydrogen, disulphide bridges, ionic, hydrophilic/phobic interactions

59
Q

Describe the quaternary structure

A

-many proteins are made up of more than one polypeptide chain - the quaternary structure describes how multiple polypeptide chains are arranged to make the complete protein molecule

60
Q

What is protein bonding

A

-the primary structure of proteins, the chain of amino acids, is held together by peptide bonds which are very strong covalent bonds
-other types of bonds form between amino acids in different parts of the polypeptide chain
-these hold together the secondary, tertiary and quaternary structures

61
Q

Describe hydrogen bonds

A

-hydrogen bonds form between hydrogen atoms with a slight positive charge and other atoms with a slight negative charge
-in amino acids these form in hydroxyl, carboxyl and amino groups

62
Q

Describe ionic bonds

A

-ionic bonds can form between those carboxyl and amino groups that are part of R groups
-these ionise into NH3+ and COO groups
-positive and negative groups like this are strongly attracted to each other to form an ionic bond

63
Q

Describe disulfide links

A

-the R groups of the amino acid cysteine contains sulfur
-disulfide bridges are formed between R groups of two cysteines
-these are strong covalent bonds

64
Q

Describe hydrophobic and hydrophilic interactions

A

-hydrophobic parts of the R group tend to associate together in the centre of the polypeptide to avoid water
-the same way, hydrophilic parts are found at the edge of the polypeptide to be close to water
-hydrophobic and hydrophilic interactions cause twisting of amino acid chain which changes the shape of protein
-these interactions can be very important influence given most proteins found to be surrounded by water in living organisms

65
Q

What is a fibrous protein

A

-has a relatively long thin structure
-insoluble
-long chains
-high tensile strength
-structural proteins

66
Q

FIBROUS: collagen

A

-function of collagen is to provide mechanical strength
-in artery walls layer of collagen prevents artery from bursting when withstanding high blood pressure
-tendons are made of collagen and connect muscles to bones allowing them to pull on bones
-bones are made from collagen and reinforced with calcium phosphate which makes them ahrd
-cartilage and connective tissue made from collagen

67
Q

FIBROUS: keratin

A

-keratin is rich in cysteine so lots of disulfide bridges form between polypeptide chains
-alongside hydrogen bonding, this makes molecule strong
-keratin is found wherever a body part needs to be hard and strong
-it is found in fingernails, hair, hooves, claws etc
-it provides mechanical protection but also provides an impermeable barrier to infection and being waterproof prevents entry of water born pollutants

68
Q

FIBROUS: elastin

A

-cross linking and coiling make the structure of elastin strong and extensible
-it is found in living things where they need to stretch or adapt their shape as part of like processes
-skin can stretch around bones and muscles due to elastin
-without elastin, skin would not go back to normal after being pinched
-elastin in our lungs allows them to inflate and deflate and in bladder helps hold urine
-elastin helps our blood vessels to stretch and recoil as blood pumped through them and maintains pressure

69
Q

Define globular protein

A

-has molecules relatively spherical shape
-often have metabolic roles
-soluble in water
-complex 3D spherical shape
-specific shape for enzymes
-functional

70
Q

GLOBULAR: haemoglobin structure

A

-the quaternary structure of haemoglobin is made up of four polypeptide - 2 alpha globin chains and 2 beta globin chains
-each of these has its own tertiary structure but when fitted together, form haemoglobin molecule
-shape of molecule held together and interactions between polypeptides
-on outside of each chain there is space in which haem group held
-this group is a prosthetic groups - essential part of molecule that could not function without
-the haem group contain an iron ion and therefore they are known as a conjugated protein

71
Q

BLOBULAR: haemoglobin function

A

-function of haemoglobin is to carry oxygen from lungs to tissues - in lungs an oxygen molecule binds to iron in each of four haem groups in haemoglobin molecule
-when it binds, turns from purple red to bright red
-oxygen released by haemoglobin when reaches tissues

72
Q

GOLOBULAR: insulin

A

-insulin is made of two polypeptide chains
-The A chain begins with a section of alpha helix and B chain ends with a section of B pleat
-both chains fold into a tertiary structure and are then joined together by disulfide links
-amino acids with hydrophilic R groups are on outside of molecule, which makes it soluble in water
-insulin binds to glycoprotein receptors on the outside of muscle and fat cells to increase their uptake of glucose from blood and to increase rate of consumption of glucose

73
Q

GLOBULAR: pepsin

A

-pepsin is an enzyme that digests protein in the stomach
-the enzyme is made up of a single polypeptide chain of 327 amino acids but its folds into a symmetrical tertiary structure
-pepsin has very few amino acids with basic R groups whereas it has 43 amino acids with acidic R groups
-this helps explain why it is so stable in the acidic environment of the stomach as there are few basic groups to accept H+ ions, and therefore there can be little effect on the enzymes structure
-the tertiary structure is also held together by hydrogen bonds and 2 disulfide bridges

74
Q

Define prosthetic group

A

a non protein component that forms a permanent part of a functioning protein molecule

75
Q

Why is computer modelling used in molecular bonding

A

-e.g. to identify binding sites on a protein and develop medicines to block pathogens
-sequencing of amino acids allows us to predict shape
1) Ab initio - model properties of atoms and predict shape, often give too many possibilities
2) comparative - allows us to compare sequences to known examples

76
Q

Macromineral uses

A

-potassium - nerve impulse, muscle contraction
-chlorine - production of hydrochloric acid in stomach
-sodium - helps with nerve impulses
-calcium - bones
-phosphorus - DNA and ATP
-magnesium- processing ATP for bones

77
Q

Uses of traceminerals

A

-iron- required for proteins e.g. haemoglobin and enzymes
-zinc - required for enzymes
-manganese - cofactor in enzyme function

78
Q

How does deficiency occur in humans

A

-in humans and plants some ions are required in large amounts (macronutrients) and some in small amounts (micronutrients or trace elements)
-both humans and plants can display deficiency symptoms if they do not consume enough of ions
-for example deficiency of trace element cobalt causes anaemia whilst copper causes young shoots to die

79
Q

CATIONS: calcium Ca2+

A

-increases rigidity of bone, teeth and cartilage and is component of exoskeleton
-important in clotting blood and muscle contraction
-activator for several enzymes
-stimulates muscle contraction and regulates transmission of nerve impulses
-regulates permeability of cell membranes
-important for cell wall development in plants and formation of middle lamella between cell walls

80
Q

CATIONS: sodium Na+

A

-involved in regulation of osmotic pressure, control of water levels in body fluid and maintenance of pH
-affects absorption of carbohydrate in the intestine and water in the kidney
-contributes to nervous transmission and muscle contraction
-constituent of vacuole in plants which helps maintain turgidity

81
Q

CATIONS: potassium K+

A

-involved in control of water levels in body fluid and maintenance of pH
-assists active transport of materials across cell membrane
-involved in synthesis glycogen and protein and breakdown of glucose
-generates health leaves and flowers in plants
-contributes to nervous transmission and muscle contraction
-component of vacuoles in plants, helping maintain turgidity

82
Q

CATIONS: hydrogen H+

A

-involved in photosynthesis and respiration
-involved in transport of oxygen and carbon dioxide
-involved in regulation of blood pH

83
Q

CATIONS: ammonium NH4+

A

-a component of amino acids, proteins, vitamins, chlorophyll
-some hormones are made of protein e.g. insulin
-an essential component of nucleic acids
-involved in maintenance of pH in body
-component of nitrogen cycle

84
Q

ANIONS: nitrate NO3-

A

-a component of amino acids, proteins, vitamins, chlorophyll
-an essential component of nucleic acids
-some hormones made of proteins which contain nitrogen
-component of nitrogen cycle

85
Q

ANIONS: hydrogencarbonate HCO3-

A

-involved in regulation of blood pH
-involved in transport of carbon dioxide into and out of blood

86
Q

ANIONS: chloride Cl-

A

-helps in production of urine in kidney and maintains water balance
-involved in transport of carbon dioxide in and out
-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

87
Q

ANIONS: phosphate PO4,3-

A

-increase rigidity of bone, teeth and exoskeletons
-helps root growth in plants
-involved in regulation of blood pH

88
Q

ANIONS: hydroxide OH-

A

-involved in regulation of blood pH

Biology (13 decks)

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