unit 1.1 chemical elements + biological molecules

organic

molecules that have a high proportion of carbon atoms (2 or more) eg carbs, proteins + lipids

Inorganic

a molecule or ion that has no more than one carbon atom

dipole

a polar molecule with a positive + negative charge sparated by a very small distance

hydrogen bond

weak attractive force between a hydrogen atom with a partial positive charge and an atom with a partial negative charge, usually oxygen or nitrogen

Monosaccharides

an individual sugar molecule

isomers

molecules with the same chemical formulae but a different arrangement of atoms (structural formulae)

polymer

large molecule compromising of repeated units/monomers, bonded together

ester bond

an oxygen atom joining two atoms, one of which is a carbon atom attached by double bond to another oxygen atom

peptide bond

chemical bond formed by a condensation reaction between the amino group of one amino acid and the carboxyl group of another

what do living organisms need

a variety of inorganic ions to survive

what are inorganic ions also known as

electrolytes and minerals - important in many cellular processes

what are the different cellular processes

including muscle contraction, nervous coordination and maintaining osmotic pressure in cells and blood

Macronutrients

needed in small concentration - millergrams

micronutrients

needed in minute trace concentrations eg copper + zinc

what are the 4 types of macronutrients

magnesium, iron, phosphate, calcium

whats the function of magnesium

important constituent of chlorophyll and therefore essential for photosynthesis. plants without magnesium in the soil cannot make chlorophyll so leaves are yellow. growth often stunted from lack of glucose. mammals need mg for bones

chlorosis

condition when there is insufficient magnesium so the soil cant make chlorophyll so leaves are yellow

whats the function of iron

constituent of haemoglobin, which transports oxygen in red blood cells. Lack of iron in the human diet lead to anaemia

whats the function of phosphate

used for making nucleotides, including ATP and are a constituent of phospholipids, found in biological membranes

whats the function of calcium

important structural component of bones and teeth in mammals and is a component of plant cell walls, providing strength

how much of each human is made from water

70% of each individual

what is the water molecule

dipole

dipole

means that it has a positively charged end (hydrogen) and a negatively charged end (oxygen) but no overall charge.

polar molecule

a molecule with separated charges - charges are very small and they are written as δ+ and δ-, to distinguish them from full charges written as + and -

what is water made up of

2 hydrogen atoms and an oxygen atom, covalently bonded together. within the covalent bonds the electrons are not evenly shared. Oxygen end of molecule is slightly negative charge and hydrogen end of molecule has a slight positive charge is called a dipolar molecule

where can the hydrogen bonds form

can form between the δ+ on a hydrogen atom of one water molecule and the δ- on an oxygen atom of another

what are the hydrogen bonds

weak, but the very large number of them present in water makes the molecules difficult to separate and gives the water a wide range of physical properties vital to life

what are the different properties of water

solvent, metabolite, hydrolysis, condensation, high specific heat capacity, high latent heat of vaporisation, cohesion, high surface tension, high density

water as a solvent

excellent solvent - water molecules are dipoles, they attract charged particles like ions, other polar molecules like glucose. then they dissolve in water so chemical reactions take place in solution. water acts as a transport medium. non polar molecules like lipids don't dissolve in water

Water is a metabolite

(anything involved in reaction) water is used in many biochemical reactions as a reactant eg with co2 to produce glucose in photosynthesis

what do many reactions in the body involve

hydrolysis - where water splits a molecule

condensation - water is a product

high specific heat capacity

large amount of heat energy is needed to raise temp. because the hydrogen bonds between water molecules restrict their movement, resisting increase in kinetic energy, resisting an increase in temp.

what does high specific heat capacity prevent

prevents large fluctuations in water temp, which is important in keeping aquatic habitats stable, so organisms don't have to adapt to extremes of temp. allows enzymes within cells to work efficiently

high latent of vaporisation

lot of heat energy needed to change it from liquid to vapour. important for temp control, where heat is used to vaporise water from sweat on the skin or from a leaf's surface. as water evaporates the body cools. so much energy is required to vaporise all the water - rarely happens to aquatic habitats

cohesion

water molecules attract each other forming h+ bonds. individually they are weak, because there are many of them the molecules stick together in a lattice. Sticking together its called cohesion. allowing columns of water to be drawn up xylem vessels in plants

high surface tension

in pond, cohesion between water molecules at surface produces surface tension so that the body of an insect, like pond skater is supported

high density

water has a max density at 4oc - water denser than air providing a buoyancy for aquatic organisms. Its a good insulator + prevents large bodies of water losing heat + freezing completely organisms beneath survive.

(ice less dense that water)

Water is transparent

allowing light to pass through, letting aquatic plants photosynthesise effectively

trioses

n=3

pentoses

n = 5

hexoses

n=6

carbohydrates

organic compounds containing carbon, hydrogen, oxygen

whats the basic unit of a carbohydrate

monosaccharide

what do 2 monosaccharides combine to form

disaccharide

what do many monosaccharides combine to form

polysaccharide

what are Monosaccharides

small organic molecules, the building blocks for the larger carbohydrates.

monosaccharides general formula

CnH2nOn -names are determined by number of carbon atoms

what formula do all hexose sugars share

C6H12O6 - but differ in their molecular structure

what does the carbon atom of monosaccharides make

ring when the sugar dissolves in water - can alter their binding making straight chains with the rings and chains in equilibrium

what are the 2 isomers of glucose

alpha and beta glucose - based on the positions of (OH) and (H)

hexose

source of energy in respiration. carbon - hydrogen + carbon-carbon bonds are broken to release energy - which is transferred t make atp

all

building blocks for larger molecules. Glucose, is used to make the polysaccharides starch, glycogen and cellulose

trioses

intermediates in reactions eg trioses are intermediates in reactions of respiration + photosynthesis

function of pentoses

constituents of nucleotides eg deoxyribose in dna, ribose in rna, ato + adp

what are disaccharides composed of

2 monosaccharides units bonded together with formation of a glycosidic bond and the elimination of water - example of condensation reaction

maltose

(reducing) a-glucose + a-glucose - biological role is in germinating seeds

sucrose

non-reducing sugar - a-gluocse + fructose - its biological role is transport in phloem of flowering plant

lactose

reducing - a-glucose + galactose - in biological role is in mammalian milk

what does the benedicts test detect

reducing sugars in a solution - including all monosaccharides + some disaccharides

how is the test carried out

equal vol of benedicts reagent + the solution being tested is heated to at least 70os - if reducing sugar like glucose is present the solution will turn form blue, green, yellow, orange + finally a brick red precipitate forms

Test for non-reducing sugars

-test with benedicts - get negative result stays blue

-boil with acid (hydrolyse it)

-neutralise with alkali - reset with benedicts - get positive result to brick red

word diagram for maltose

a-glucose + a-glucose ----> maltose + water

equation for maltose diagram

C6H12O6 + C6H12O6 --> C12H22O11 + H2O

Qualitative

yes or no answer eg starch test - is it present or not

semi - quantitative

can't give actual measurement but can judge on diff beakers like colour changes etc

Quantitative

fully numerical specific reading

what are the 2 types of polysaccharides

What are polysaccharides?

large, complex polymers. They are formed from very large number of monosaccharide units which are their monomers linked by glycosidic bonds

whats the main source of energy in cells

glucose is the main source of energy in cells and it must be stored in an appropriate form - its soluble in water, so increases the concentration of the cells contents, drawn in by osmosis

whats the problem with glucose

glucose is water soluble so he problem is avoided by converting the glucose into a storage product - the polysaccaride starch

starch is..

-insoluble so has no osmotic effect

-cannot diffuse out of the cell

- a compact molecule and can be stored in a small space

-carries a lot of energy in its c-h and c-c bonds

starch

main store of glucose for plants. starch grains are found in high concentrations in seed and storage organs like potato tubers

what is starch made of

a-glucose molecules bonded together in two different ways, forming the 2 polymers, amylose and amylopectin

amylose

is a linear, unbranched molecule with a-1-4 glycosidic bonds forming between the first carbon atom, on one glucose monomer + 4th carbon atom on adjacent one. - repeated forming a chain which coils to an a-helix

amylopectin

chains of glucose monomers joined with a-1,4 glycosidic bonds + fit inside the amylose. They are cross linked with a-1,6 glycosidic bonds + fit inside the amylose. when a glycosidic bond forms a side branch has been made

testing for presence of starch

iodine solution reacts with starch resulting a colour change from orange - brown to blue - black. (qualitative test - accurate concentration can't be determined, but depth of the colour gives an indication to the relative concentration)

what is iodine solution

iodine dissolved in an aqueous solution of potassium iodidie

glycogen

main storage product in animals is glycogen - has a-1,4 and a-1,6 bonds, the difference is that glycogen molecules have shorter a-1,4 linked chains so more branched than amylopectin

what is cellulose

-structural polysaccaride

-beta glucose molecules

-only one polysaccharide

-cellulose is unbranched

-1-4 glycosidic bonds

-cellulose in straight chains

-cellulose in straight chains

-cellulose has many parallel chains linked with hydrogen bonds

-in cellulose adjacent glucose molecules rotated

what type of material is cellulose

its presence in plant cell walls makes it most abundant organic molecule on earth

chitin

structural polysaccaride found in exoskeleton of insects + in fungal cell walls. resembles cellulose with long chains of b-1,4 linked monomers, but derived from amino acids added

what is the material of chitin

strong, waterproof, lightweight

what do lipids contain

carbon, hydrogen and oxygen but in proportion to the carbon + hydrogen they contain much less oxygen

what are the lipids

non polar compounds and so insoluble in water but dissolve in organic solvents like propane and alcohols

non polar

insoluble in water but can dissolve in alcohols + acetones

How are triglycerides formed?

by the combination of one glycerol + 3 molecules of fatty acids. the glycerol molecule in a lipid is always the same but fatty acid component varies

how does the fatty acid join to glycerol

by condensation reactions, where 3 molecules of water are removed + ester bonds are formed between the glycerol and fatty acids

phospholipids

special type of lipid - each molecule has one end that is soluble in water. one side has many oxygen atoms and so reacts with the water being known as hydrophilic - polar head of the molecule

what do the fatty acid tails not contain

contain no oxygen atoms - don't interact with water so they are hydrophobic + non polar

waxes

lipids + melt above 45oc - have a waterproofing role in both animals like the insect exoskeleton + plants in leafs cuticle

what does it mean when the hydrocarbon chain only has single carbon - carbon bond

the fatty acid is saturated - all carbon atoms are linked to the maximum possible number of hydrogen atom

what happens if the carbon - carbon bond are not a single bond

the molecule is unsaturated and the chain gets a kink - they can't align uniformly so the lipids don't readily solidify

Roles of lipids - Phospholipids

-in biological membranes

-electrical insulation - myelin sheath that surrounds the axons of nerve cells

Roles of lipids- Triglycerides

- energy reserves in both plants + animals because lipids contain more carbon-hydrogen bonds than carbs

-thermal insulation

-protection

-metabolic water

thermal insulation

when stored under the skin lipids insulate against heat loss in the cold or heat gain when it is very hot

protection

fat is often stored around delicate internal organs like kidneys, protecting against physical damage

metabolic water

this is water released during chemical reactions in the body. triglycerides produce a lot of metabolic water oxidised

waterproofing

in terrestrial organisms, waxes reduce water loss like in insect exoskeleton + in cuticle of plants

testing for fats test - emulsion test

sample mixed with absolute ethanol, dissolving lipids present, shaken with an equal vol of water. the dissolved liquid comes out of the solution, because they are insoluble in water. forming an emulsion make sample cloudy white

what implication can occur due to saturated fats for human health

atherosclerosis, hypertension