BIOLOGICAL MOLECULES Flashcards
What kind of data does colorimeter provide?
Quantitative- determining conc.
Basic method of a colorimeter
1) Colorimeter shines light through sample
2) PHOTOELECTRIC CELL picks up reading from light and gives absorption/transmission based on this
3) Sample to be tested put in cuvette
4) More copper sulphate in original sample= more light transmitted
5) Tells you how much Benedicts used
Qualitative measure using benedicts
- Add 3cm3 of B solution to 3cm3 of sample
- Test tube-> boiling water- 5 mins
- Filter through fine grade filter paper (or twice)
- Low concs of reducing sugar= Unreacted copper sulphate left (read absorbance on RED light)
- High concs= increasing amount of red copper oxide in the filtrate (read on BLUE light)
What does a biosensor do
Component that takes biological or chemical variable that cannot be easily measured and converts it into an electrical signal
What does a transducer convert
One form of energy to another
What are lipids
Large complex molecules (macromolecules) with a few oxygen atoms and a lot of carbon and hydrogen atoms
Three important groups in lipids
Triglycerides (fats and oils)
Phospholipids
Sterols (eg cholesterol)
What are the functions of lipids
Energy storage
Structural (40% phospholipids in cell membrane)
Insolation
Protection
Waterproofing
Buoyancy (fat less dense than water-aquatic animals)
Hormones
What do each group of lipids contain
Hydrocarbons
All soluble in organic solvents for example alcohol
All insoluble in water
What is the test for lipids
Crushed material with ethanol and decant the suspension to remove any solid particles
Pour the ethanol mixture onto water in another test tube
Do not mix
A milky emulsion forming in the water indicates a lipid is present
What are triglycerides made up of and what bond holds them together
One molecule of glycerol attached the three fatty acid bonded by an ester bond
What are the fatty acid tails
Hydrocarbons and hydrophobic making them insoluble in water
What are triglycerides used for
Energy stores because they are rich in energy
1 g of triglyceride can release twice as much energy as 1 g of carbohydrate
What do you fatty acids always have on one end
Carboxyl acid group
What does having more than one double bond in the hydrocarbon section make the fatty acid
Poly unsaturated
How does the double bonding affect the melting point of the triglyceride molecule
More double bonds equals a lower melting point
Hence why most vegetable lipids are oils
What is esterification
The formation of a triglyceride from glycerol and three fatty acid in a condensation reaction
How do you make a phospholipid
By replacing one of the fatty acids with a phosphate group and allowing it to ionise making it attract water molecules
In a phospholipid is is the head hydrophilic or hydrophobic
Hydrophilic head
Hydrophobic tail
Making them essential in cell membranes
In which direction of the hydrophobic tails pointing towards in a phospholipid bilayer
They face inwards towards the centre of the sheet away from the water
What do you phospholipid in the cell membrane give
Stability because the hydrophobic tails will never move into a position where they are exposed to water
Selective permeability because only a small and nonpolar substances for example oxygen and carbon dioxide can move through the tails into the bilayer
What is the bond formation when making a phospholipid
Condensation reaction
What are the advantages of lipid respiration
1 g of lipid gives out twice the amount of energy during respiration compared to 1 g of carbohydrates
Lipids are insoluble in water and so can be stored in a compact way without affecting water potential
Lipids give out more water than carbohydrates which helps with metabolic reactions in organisms
What are sterols and what are they based on
Complex alcohol molecules that are based on four carbon based rings with a hydroxyl group at one end
In sterols what is the hydroxyl group
Polar therefore hydrophilic well the rest of the molecule is non-polar and therefore hydrophobic
What is the structure of cholesterol
Has a hydrocarbon ring structure attached to a hydrocarbon tail
This ring has a polar hydroxyl group attached making cholesterol is slightly soluble in water but it is insoluble in blood
What are structural features of cholesterol
Short straight molecules
Hydrocarbon tail
4 hydrocarbon rings
One oxygen atom in the hydroxyl group
Where is cholesterol found
In the biological membrane
What does cholesterol regulate
It sits between phospholipid and regulates fluidity at different temperatures
Where do we use lipids
Respiration Energy storage Thermal insulation Protection Buoyancy Waterproofing
What is the structure main role and other features of triglycerides
Three fatty acid plus a glycerol bonded by an ester bond
Compact energy storage and insoluble in water so doesn’t affect cell water potential
Stored as fat which has roles of thermal insulation buoyancy and protection of organs
What is the structure main role and other features of phospholipids
Glycerol +2 fatty acid and a phosphate group
Form is a stable part hydrophobic and part hydrophilic molecule
-making them good for cell membranes because water-soluble substances can’t easily pass through the bilayer
Phosphate groups may have carbohydrate parts attached these are involved in cell signalling
What is the structure main role and other features of cholesterol
Four carbon based rings join together
Forms a small molecule that fits into the lipid bilayer giving strength and stability
Used to form the steroid hormones e.g. progesterone and testosterone
What is the formula for nitrates and what are they necessary for?
NO3-
The component N needed for plants
What is the formula for hydrogen carbonate and what is it necessary for?
HCO3-
Maintenance of blood pH (breathing rte controlled by blood pH)
CO2 transport
What is the formula for hydroxide and what is it necessary for?
OH-
Catalysis reactions
pH determination
What is the formula for chloride and what is it necessary for?
Cl-
Balance positive charge of sodium and potassium ions in cells
What is the formula for phosphate and what is it necessary for?
PO43-
Cell membrane, bone and nucleic acid formation
What are the chemical elements found in
- carbohydrates
- lipids
- proteins
- nucleic acid
C, H & O
C, H & O
C, H, O, N & S
C, H, O, N & P
What is the biological name for sugars?
Saccharides
What is the formula for calcium and what is it necessary for?
Ca2+
Nerve impulse transmission
Muscle contractions
What is the formula for sodium and what is it necessary for?
Na+
Nerve impulse transmission
Kidney function
What is the formula for potassium and what is it necessary for?
K+
Nerve impulse transmission
Stomatal opening
What is the formula for ammonium and what is it necessary for?
NH4+
Production of nitrate ions by bacteria
What is the formula for hydrogen and what is it necessary for?
H+
Catalysis reaction
pH determination
Why do sugars dissolve in water?
Has an uneven distribution of charges between the O2 and H2 atoms, creates slightly positive and slightly negative area
Allowing sucrose to dissolve
What do hydrogen bonds restrict and what over comes them?
What does the water content of cytoplasm help with?
(high specific heat capacity)
Restrict movement-large amount of energy required to increase temp of water
Therefore water is quite stable and can withstand large temperature fluctuations making water ideal for aquatic organisms
Help buffer cells against temp change due to heat released during metabolic reactions
What is the heat energy required for?
What do lots of H bonds make it hard for water to do?
(high latent heat of vapourisation)
Help molecules break away from each other to become a gas
Evaporate
Describe hydrogen bonds
Weak interactions when a molecule contains a slightly negatively charged atom bonded to a slightly positively charged hydrogen
What are properties of water being a liquid at room temperature?
- aquatic habitats for organisms
- form major components of tissues
- provide reaction medium for chemical reactions
- effective transport medium
What makes molecules hard to escape and turn into gas?
Water molecules form H bonds, which form networks
- network constantly shifts, breaking and making new bonds
- hard to turn into gas (hence 100 degree boiling point)
What happens when temperature falls?
What does ice do?
(density)
Temperature decreases=molecules having less KE and move less
-more H2 bonds form, and don’t break easily
Starts to solidifies at 4 degrees
- semi-crystalline structure
- less dense than water; bonds that hold molecules together are further apart, so ice forms on surface and INSULATES
Description of cohesion
When water molecules are attracted to each other
-H2 bonds pull molecules in at surface and this cohesion causes surface tension (causes droplets to form)
What sort of substances dissolve in water? (and descriptions)
Polar substances
- solute has neg, and positive charges
- water molecules cluster round slightly charged parts of solutes
- helps keep the solute molecules apart-water
- at this point they dissolve and a solution is formed
What happens once a solute becomes a solution?
Molecules move around and react with other molecules
Why does salt dissolve in water?
Salt is an ionic compound
+ve ions become surrounded by water molecules with neg. oxygen atoms
–ve ions become surrounded by water molecules- positive hydrogen atoms facing them
Water molecules surround ions, keeping them apart and dissolved a solution
What are carbohydrate functions in organisms?
- energy store
- energy source
- structure
What are monosaccharides, what are the characteristics and what carbon number are the grouped in?
- simplest carbohydrate
- sweet and soluble
- triose, pentose and hexose sugars
What are disaccharides, what do they form and what are some examples?
-two monosaccharides can be joined
-sweet, soluble=crystals
glucose+glucose-maltose
glucose+fructose-sucrose
glucose+galactose-lactose
What is a glycosidic bond?
Covalent chemical bonds that link ring shaped sugar molecules to other molecules
Whats the short and long test for reducing sugar?
Reagent strip
Benedicts solution and heat
What are polysaccharides and what have the undergone?
Polymers of monosaccharides, which have undergone condensation reaction
What are properties of polysaccharides and what do they make?
-insoluble in water
-not sweet
-cant be crystallised
Properties + compact structure= good for storage
What % of amylopectin and amylose are in starch?
80% amylopectin
20% amylose
AMYLOSE
What kind of reaction, forming bonds between what glucose?
-what does this result in?
Properties?
What colour does it turn potassium iodine solution?
- condensation, (1-4=alpha) meaning straight line that coils
- compact=good for storage
- blue/black-iodine molecules become fixed in centre of helix (must be done at room temp others helix will uncoil)
AMYLOPECTIN
What kind of reaction, between what kind of glucose?
What number bonds are there more of making the structure more…
What does it have lots of?
What colour does it turn potassium iodine solution?
- condensation (1-4=alpha)
- more 1-6 bonds=branched
- ‘ends’ for glucose to attach to
- red/purple-cannot bind as much iodine because highly branched
GLYCOGON What kind of glucose? What no. bonds? What does it have lots of? It is more....than starch Where are high concentrations of glycogen found?
- alpha glucose
- 1-4 and 1-6
- ‘ends’ glucose add onto
- compact
- liver and skeletal muscle cells
CELLULOSE
What bond numbers and type of glucose?
-how to make the bond and what it forms
-what protects chains
- 1-4, beta glucose
- alternate beta glucose molecules are rooted through 180 degree, straight chains
Straight chains have lots of OH to protect them
- form hydrogen bonds, with adjacent cellulose molecules
- cellulose=stronger than starch
What. is the function of cellulose?
- plant cell walls, strengthen and support whole plant
- macrofibrils make the cell wall permeable to water
- structure/shape of cell to aid function
