UNIT 1 SECTION 1

biochemistry

what are the names of 5 inorganic ions

magnesium, iron, nitrate, phosphate, calcium

what is the biological role of magnesium

constituent of chlorophyll, is therefore essential for photosythesis

what is the biological role of iron

constituent of haemoglobin, which transports oxygen around the body in red blood cells

what is the biological role of nitrate

nitrogen is derived from nitrate and is needed for making nucleotides, like ATP DNA and RNA. nitrogen is also needed for amino acid formation

what is the biological role of phosphate

used for making nucleotides including ATP, DNA and RNA. is a constituent of phospholipids found in biological membranes

what is the biological role of calcium

HARDENS bones and teeth. is also a component of plant cell walls

WATER

this is the water topic

what charge does oxygen have in a water molecule

slightly negative

what charge does hydrogen have in a water molecule

slightly positive

what bond is formed when opposing charges attract eachother in a water molecule

hydrogen bonds

what does dipole mean

has a positivly charged end and a negitively charged end, but no overall charge

what does polar mean

a molecule with seperated charges

are hydrogen bonds strong or weak

weak, but the very large number of them presant in water makes them very hard to seperate

how is water being a solvent essential for life

the positive and negative parts of the water molecule attract other charged particles, like ions and polar molecules like glucose. ions and polar molecules can dissolve in water, non polar molecules like lipids cannot

why is water having a high specific heat capacity essential for life

it prevents large fluctuations in water temperature - this keeps the temperature in aquatic environments stable so organisms dont have to endure extreme temperatures

why is water having cohesion important

the attraction of water molecules allows water to be transported in long columns up the xylem vessels of the tallest trees

why is water having surface tension important

hydrogen bonds form between water molecules

in water the cohesion between water and molecules supports organisms - like pond skaters allowing them to walk on water.

why is water being high in density important

water has a maximum density at 4 degrees; ice is less dense and therefore floats on the surface and insulates the water beneath. this reduces the tendency for large bodies of water to freeze completely

CARBOHYDRATES

this is the carbohydrates topic

what is the general formula of a monosaccharide

(CH2O)n

what are the three monosaccharides

triose, hexose, pentose

what is the formula for triose

C3H6o3

what is the formula for pentose

C5H10O5

what is the formula for hexose

C6H12O6

what is the function of triose

important for metabolism, triose sugars are intermediates in the reactions of respiration and photosynthesis

what is the function of pentose

Constituents of nucleotides e.g. deoxyribose in DNA, ribose in RNA, ATP and ADP.

what is the function of hexose

Glucose is a hexose sugar. Glucose is a source of energy in respiration. Carbon-hydrogen and carbon-carbon bonds are broken to release energy, which is transferred to make adenosine triphosphate (ATP).

what ar the two isomers of glucose

Beta and Alpha

what are the differences between alpha and beta glucose

in beta glucose the hydroxyl group on carbon 1 is on the top, but in alpha glucose the hydroxyl group is on the bottom

how do you break a glycosidic bond?

hydrolysis (adding water)

how do you form a glycosidic bond?

condensation reaction

what are the three disaccharides

sucrose, lactose, maltose

what is Maltose's component monosaccharide

alpha glucose + alpha glucose

what is Sucrose's component monosaccharide

glucose + fructose

what is Lactose's component monosaccharide

glucose + galactose

what is the biological role of Maltose?

Used in germinating seeds

what is the biological role of Sucrose

a product of photosynthesis which is transported in the phloem

what is the biological role of Lactose?

found in mammalian milk

describe the test for reducing sugars

1) equal volumes of benedicts and the solution are heated to around 70 degrees

2) if a reducing sugar like glucose is present the solution will change from blue - green - yellow - orange - brick red precipitate

3) but it doesn’t tell you the exact concentration of the reducing sugar

describe the benedict's test for sucrose

1. must first be hydrolysed by boiling in a dilute hydrochloric acid

2. is broken down into its constituent monosaccharides - glucose and fructose

3. it then must be neutralised with dilute sodium hydroxide

4. solution should now give a positive result

what bond is formed in polysaccharides and by what reaction

glycosidic bonds, formed by condensation reactions

what is starch made up off

alpha glucose molecules

what are the two types of polysaccharide

amylose and amylopectin

what shape is amylose

unbranched and coiled, forming c1 - c4 glycosidic bonds

what shape is amylopectin

branched, forming c1 - c4 and c1 - c6 glycosidic bonds

what type of polysaccharide is starch

amylose AND amylopectin

explain glycogen as a polysaccharide

• alpha glucose molecules, joined by c1 - c4 and c1 - c6 glycosidic bonds

• main difference between glycogen and amylopectin is that glycogen has shorter c1 - c4 glucose chains, and there are more c1 - c6 branch points

explain cellulose as a polysaccharide

• beta glucose, joined by c1 - c4, glycosidic bonds

• the beta link rotates adjacent glucose monomers by 180 degrees

• hydrogen bonds form between OH groups of adjacent parallel chains - making cellulose more stable

explain chitin as a polysaccharide

• resembles cellulose, beta c1 -c4 linked monomers

• but it has groups of amino acids added (called the acetylamine group)

• its strong waterproof and light weight

• they rotate 180 degrees

what is a common type of lipid

triglyceride (fats and oils)

what are some properties of lipids

they are insoluble in water as they are non-polar, but are soluble in other solvents like ethanol and chloroform

why are non polar molecules insoluble in water

water is a polar substance, and substances, like oil are non - polar

how are triglycerides formed

by a condensation reaction of one glycerol molecule, and three fatty acids

what bond is formed when fatty acids join a glycerol molecule

ester bonds form when three molecules of water are removed during the condensation reaction

what is the formula of a fatty acid

CH3(CH2)nCOOH

what makes up a phospholipid

one of the three fatty acid tails are replaced by a phosphate group - this phosphate group is polar (soluble in water)

what is in the phospholipid's hydrophilic head

a phosphate group and a glycerol group

what happens to a phospholipid in water

1) hydrophobic tails turn inward and form micelle

2) hydrophilic heads point outwards into water

the phospholipid bilayer forms the basis of all cell membranes

what is a saturated fatty acid

when a hydrocarbon chain has only single carbon - carbon bonds

what is an unsaturated fatty acid

hydrocarbon chains with double carbon - carbon bonds, and the chain gets a kink

what is the test for fats and oils

1) mix absolute ethanol, and shake with an equal volume of water

2) the dissolved lipids come out of the solution as they are insoluble in water

3) they form an emulsion making the sample a cloudy white

what are the main causes of heart disease

fatty deposits on the inner wall of the coronary artery (atherosclerosis) and high blood pressure

what happens if a diet is high in saturated fats?

1)Low-density lipoprotein (LDL) builds up and causes harm

2) fatty material (atheroma) gets deposited in the coronary arteries restricting blood flow

what happens if a diet is high in unsaturated fats

body makes more HDL - which carry harmful fats away to the liver for disposal

what makes proteins different to carbohydrates and lipids

they always contain nitrogen

what are proteins

polymers made of monomers called amino acids

• chains of amino acids are called polypeptides

how are peptide bonds formed

• the amino group of one amino acid reacting with th carboxyl group of another

• with the elimination of water

• condensation reaction

explain primary structure of protein structure

the specific sequence of amino acids making up a polypeptide chain.

• one gene codes for one polypeptide

explain secondary protein structure

the shape the polypeptide forms as a result of hydrogen bonding

• this causes the polypeptide to twist into an alpha helix or beta pleated sheet

Explain the tertiary structure of a protein

the alpha helix of a secondary protein, can be folded to give a more complex and compact 3D structure

• the shape is maintained by hydrogen bonds, ionic bonds, disulphide bonds and hydrophobic interactions

explain quaternary protein structure

• arises when 2 or more polypeptides are in tertiary structure

• they are associated with non protein groups (enzymes) and form complex molecules like haemoglobin

• which has 4 polypeptide chains

what are the two molecular shapes of proteins

globular and fibrous, and they determine a proteins role

describe fibrous proteins

• They are insoluble in water, and play a supportive or structural role.

• they consist of polypeptides in parallel chains or sheets with numerous cross linkages

• An example of a fibrous protein is collagen.

describe globular proteins

• compact and folded into spherical molecules

  -they are soluble in water

  -haemoglobin is a globular protein

what is the test for proteins

Biuret test - detects presence of peptide bonds

• if peptides = present copper (II) ions from a violet coloured complex

• blue to purple