Biological molecules

List x5 main important functions of water inside+outside the cell?

1) water is a reactant: in chemical reactions (including hydrolysis reactions). 2) Water is a solvent:substance dissolve in it 3) Acts as a transport substance. 4) Water helps with temperature control 5) Water is a habitat

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How does water help with 'temperature control'?

It has a high specific heat capacity + high latent heat of evaporation.

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How does water make a 'Habitat'?

Helps with temperature control, is a solvent + becomes less dense when freezes meaning many organisms survive + reproduce.

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A molecule of water?

x1 atom = oxygen + x2 atoms= hydrogen by shared electrons

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What type of molecule do we refer to water?

Polar molecule: partial negative + partial positive

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What attraction occurs when slightly negative-charged O2 atom attracts to slightly positively-charged hydrogen atom of other water molecules?

Attraction: Hydrogen bonding = gives water useful properties.

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What do 'hydrogen bonds' give water?

High specific heat capacity + High latent heat of evaporation

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What is meant by 'high specific heat capacity'?

The energy (heat) needed to raise the temperature.

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Function of 'High specific heat capacity'?

1). H+ bonds can absorb a lot of energy (takes a lot of energy to heat up) 2). Water doesn't experience rapid temperature changes: making it a good habitat.

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What is meant by 'High latent heat of evaporation'?

Takes a lot of energy (heat) to break the H+ bonds between the water molecules.

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Function of 'High latent heat of evaporation'?

1) Lot of energy used when water evaporates. 2). means water is goof for cooling things, i.e -when mammals sweat.

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List x2 aspect of how 'water polarity' has an effect on the water?

Makes it very cohesive + Makes it a good solvent.

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What is 'Cohesion'?

The attraction between molecules of the same type(i.e- X2 water molecules). Water molecules are very cohesive due to them being very polar.

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What does 'cohesion' help?

1) Helps water to flow, making it good for transporting substances 2). Helps water to be transported up plant stems and in the transpiration stream.

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How does 'water polarity' work?

1) substances are ionic- x1 positively +x1 negatively charged atom means the ions will get totally surrounded by water molecules (dissolve)

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List a useful aspect of 'water polarity' ?

Useful as a solvent in living organisms , i.e - in humans: as important ions can dissolve in the water in the blood + then be transported around the body.

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When is water less dense?

Water less dense when it's solid- Water molecules are held further apart in ice than liquid

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What makes ice less dense than water?

Water molecules form x4 H+ bonds to other water molecules= produces lattice shape which makes ice less dense than liquid and making ice float.

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What is useful about ice being less dense than water?

1). cold temperatures, ice forms = insulating layer on top of the water 2). water below this doesn't freeze, so organisms can still live there.

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What are most carbohydrates?

polymer

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What is a polymer?

A molecule made up of many similar smaller molecules bonded together , called monomers.

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What are 'monomers' made up of?

Carbohydrates called monosaccharides

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List x1 example of a 'monosaccharide'?

Glucose- with six carbon atoms. = Hexose monosaccharide

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Two forms of 'glucose'?

alpha + Beta

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List x1 feature of 'glucose' structure?

Structure makes in soluble so it can be easily transported

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List x1 example of a 'monosaccharide'?

Ribose- five carbon atoms = pentose monosaccharide

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What three chemical elements are all carbohydrates made up of?

Carbon , Hydrogen, Oxygen. x1 carbon atom= x2 hydrogen atom + x1 oxygen atom

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What type of bonds are 'monosaccharides' joined together by?

Glycosidic bonds

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Define a 'condensation' reaction?

H+ stom on x1 monosaccharide bonds to a hydroxyl (OH) group on the other releasing a molecule of water.

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Define a 'hydrolysis' reaction?

A molecules of water reacting with the glycosidic bond , breaking it apart.

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When is a disaccharide formed?

When two monosaccharides join together

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When is a polysaccharide formed?

When more than two monosaccharides join together.

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What do plants store excess glucose as?

Starch - able to break down starch to release glucose.

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Main function of 'starch'?

The main energy storage materials in plants

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Starch is a mixture of which two polysaccharides of alpha- glucose?

1) Amylose. 2) Amylopectin

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List 3 features of 'Amylose'?

1) long, unbranched chain of a-glucose 2). coiled structure 3). compact-good for storage due to being able to fit more in a small place

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List 3 features of 'Amylopectin'?

1) lone, branched chain of a-glucose 2). side branches

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What do the 'side branches' allow in the 'Amylopectin'?

Side branches: allow enzymes that break down molecule to get to glycosidic bonds easily: this means glucose can be released quickly.

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Main function of 'Glycogen'?

The main energy storage material in animals.

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What do animals store excess 'Glucose' as?

Glycogen (polysaccharide of alpha-glucose)

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List 3 features of 'Glycogen'?

1) similar to amylopectin 2) A lot of side branches. 3) very compact=good storage

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What's the advantages of lots of 'side branches' in 'Glycogen'?

stored glucose can be released quickly, essential for energy release in animals.

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Main function of 'Cellulose' ?

Major component of cell walls in plants

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List 1 features of 'Cellulose'?

1) long, unbranched chains of beta- glucose

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What happens when beta- glucose molecules bond?

Form a straight cellulose chain. - linked together by hydrogen bonds to form strong fibres called 'microfibrils'

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What do the strong fibres 'microfibrils' provide for cellulose?

Provides structural support for cells (i.e-in plant cell wall)

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What are 'Triglycerides'?

kind of lipid + are 'macromolecules'

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List the structure of 'Triglycerides'?

x1 molecule of glycerol, x3 fatty acids attached to it (fatty acid molecules= 'hydrophobic' tail

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What bond is located between each 'fatty acid' and 'Glycerol' molecule?

Ester Bonds

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What reaction is each 'Ester Bonds' formed by?

Condensation reaction - water molecule is released

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How is a 'Triglyceride' broken down?

When 'Ester Bonds' are broken by 'Hydrolysis reaction'

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What are the x2 types of fatty acids?

Saturated + unsaturated

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List x2 Structural features of 'saturated fatty acids'?

1) No double bonds between carbon atoms 2). fatty acid 'saturated' with hydrogen

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List x1 Structural features of 'unsaturated fatty acids'?

1) At least one double bond between carbon atoms = causes kink in chain

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What are 'Phospholipids'?

Macromolecules + similar to 'Triglycerides' expect x1 fatty acid replaced with 'Phosphate group'

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Which x2 features are the 'Phosphate group' located on 'Phospholipids'?

Hydrophilic + Hydrophobic

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What are 'Proteins' made from?

1) Long chains of Amino Acids. 2). Proteins are 'Polymers' 3). Proteins are made up of one or more polypeptides

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What type of molecules are 'Amino Acids in 'Proteins''?

Monomers in proteins

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What is a 'Dipeptide' ?

x2 Amino acids join together

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What is a 'Polypeptide' ?

More than x2 amino acids are joined together.

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General structure of an 'amino acid'?

Carboxyl group (-COOH) , Amino group(-NH2) attached to a Carbon atom.

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What makes each 'Amino acid' different?

R- group is the variable;e group

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What chemical elements do al 'Amino acids' contain?

Carbon, Oxygen, hydrogen + nitrogen. (contains some Sulfur)

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What bonds join 'Amino acids' together?

Peptide bonds (forming 'dipeptides' + 'polypeptides')

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What type of reaction breaks a 'Peptide bond'?

Hydrolysis reaction

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'Primary structure' of a 'Protein'?

1) The sequence of amino acids in polypeptide chain 2). Different proteins = different sequences of amino acids 3). change in x1 amino acid may cause a change in whole structure.

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'Secondary structure' of a 'Protein'?

1) polypeptide chain =not flat + straight 2). Hydrogen bonds form between amino acids in chain. 2) coiled in alpha helix OR folded into beta pleated sheets.

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'Tertiary structure' of a 'Protein'?

1) coiled + folded further chain of animo acids 2). More bonds formed between different parts of polypeptide chain 3) Proteins made of : Single polypeptide chain creates a 3D STRUCTURE

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'Quaternary structure' of a 'Protein'?

1). Way Polypeptide chains are assembled together 2). 3D structure 3) Determined by Tertiary structure

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List x1 example of a 'Quaternary structure'?

Haemoglobin made of x4 polypeptide chains bonded together.

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'Primary structure'?

Held together by peptide bonds between amino acids

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'Secondary structure'?

Held together by hydrogen bonds.

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What x4 features effect the 'Tertiary structure'?

1) Ionic bonds 2). Disulfide bonds 3). Hydrophobic + Hydrophilic interactions 4). Hydrogen bonds

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'Quaternary structure'?

Determined by Tertiary structure

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'Globular proteins'?

1). Round + compact 2). Hydrophilic R groups pushed to the outside of the molecule (Hydrophilic + hydrophobic interactions) 3). Hydrophilic + hydrophobic interactions makes protein soluble + easy transported in fluids.

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What does a 'Haem' group contain?

Iron which binds with oxygen

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'Fibrous proteins'?

1) tough + rod-shaped. 2). soluble + strong. 3). fairly unreactive.

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List x3 'Fibrous proteins'?

1)Collagen-found in animal connective tissue(bond,skin,muscles),strong+minerals bind to increase rigidity. 2).Keratin-external structures of animals(skin,hair,nails) flexible or hard+tough 3).Elastin-connective tissue(skin,liagments),like elastic.

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What is an 'ion'?

Atom (or group of atoms) that has an electric charge

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What is an 'ion' with a 'positive' charge called?

Cation

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What is an 'ion' with a 'negative' charge called?

Anion

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What's an 'inorganic ion'?

1). Atom that doesn't contain carbon 2). V.important in biological processes

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What does the 'Benedict's test' test for?

Sugar

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List x2 main examples of reducing sugars?

1) All monosaccharides (glucose) 2). some disaccharides (maltose+lactose)

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How would you test for 'Reducing sugars'?

1) Add Benedict's reagent(blue colour)to sample+heat in a water bath that is brought to boil. 2) positive test:form a coloured precipitate 3)higher conc of reducing sugar the further the colour change: compare amount of reducing sugar.

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In 'Reducing sugars' what colour changes does the precipitate form?

Blue-Green-Yellow-Orange-Brick red

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What accurate experiment could be used to compare the amount of 'reducing sugars' in different solutions?

Filter the solution + weigh the precipitate.

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Give x1 example of a Non-reducing sugar?

Sucrose- have to break down the Monosaccharides

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How would you test for 'Non-Reducing sugars'?

1) new sample of test solution, add dilute hydrochloric acid+heat in water bath. 2). Neutralise with sodium hydrogencarbonate. 3). If test is negative it will stay blue- doesn't contain any sugar.

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Give an example of a test which tests for 'Glucose'?

1). Test stripes coated in 'Reagent' 2). change colour if glucose is present 3). colour can be compared on a chart to highlight concentration of glucose present.

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List x1 of when a 'Test stripe for glucose' might be necessary.

Testing a person's urine for glucose - indicating whether someone has diabetes

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'Iodine Test for Starch'?

1) Add iodine dissolved in potassium iodide solution to test a sample. 2). starch present=changes from browny orange to dark,blue-black colour. 3). No starch =stays browny-orange

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'Biuret Test for proteins'?

1) add a few drops of Sodium hydroxide solution-makes solution alkaline 2). Add Copper sulphate solution- protein present =purple / protein not present = stay blue

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'Emulsion Test for lipids'?

1) Shake substance with ethanol for 1 min+pour solution into water. 2). lipid present=milky/ more lipid =more milky /no lipid=solution stays clear

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What's a calorimetry used to determine?

The concentration of a glucose solution

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What reagent is used in a 'calorimeter'?

Benedict's reagent+calorimeter can be used to get a quantitative estimate of how much glucose (other reducing sugars is present.

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How does a 'calorimeter' measure the strength of the solution?

Measures the strength of the coloured solution to see how much light passes through it.

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What does a 'calorimeter' measure?

Measures the absorbance (the amount of light absorbed by the solution). More concentrated the colour of the solution , the higher the absorbance.

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When is it easier for the 'calorimeter' to measure the concentration of the 'blue Benedict's solution'?

The 'blue Benedict's solution' left after the test (paler the solution the more glucose present). Higher the glucose concentration, the lower the absorbance of the solution.

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What do 'Biosensors' detect?

Chemicals in a solution

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List x3 main stages of how 'Biosensors' work?

1)Device that uses biological molecule(i.e,enzyme)to detect chemicals 2)Biological molecule produces a signal(chemical signal)then converted to an electrical signal by a transducer part of biosensor)3)electrical signal produced to work out other info

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List x2 purposes of 'chromatography'

1) separate stuff into a mixture 2) once split can identify the components .

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List examples of what 'chromatography' can be used to separate out + identify biological molecules?

Amino acids, Carbohydrates, vitamins + nucleic acids

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List x2 types of 'chromatography' you must know?

Paper 'Chromatography' + thin layer 'Chromatography'

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Biological molecules

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