biological molecules Flashcards
the type of bonds in water and meanings
- covalent bonds between hydrogen and oxygen (strong, hard to break)
- hydrogen bonds between other water molecules because of opposite charges of oxygen and hydrogen (weak but there are many so has a big effect)
how do hydrogen bonds have a impact on water if they are weak
there is a high volume of hydrogen bonds meaning there must be more energy to break them
there is a overall impact
Property of water 1)
water has a high specific heat capacity
water acts as a buffer against rapid changes in temperature
water can be a habitat for aquatic organisms
property of water 2)
ice is less dense than water, so ice floats
acts as habitat , AND insulates water below, stopping it from freezing
so. organisms can live on LAND and AQUATIC AREA
property of water 3)
water has a high latent heat of vaporisation
organisms can cool down in hot temps without losing too much water (sweating)
water as a solvent
water as a solvent
- Eukaryotes and Prokaryotes have many dissolved substances that have water as a solvent e.g ENZYMES
- makes water a good habitat as oxygen can be dissolved in it
- water can be used to transport substances e.g blood plasma (glucose + amino acids + Xylem of plant
surface tension and cohesion
hydrogen bonds between oxygen and hydrogen attract other water molecules so
- cohesion in xylem allows water to travel in long columns in xylem (TRABSPORT)
- surface tension where water meets air, water good for habitat for insects
why is water important in metabolic reactions
water is a reactant in metabolic reactions e.g photosynthesis + hydrolysis
why are monosaccharides hydrophilic
they contain many OH hydroxyl groups that form hydrogen bonds with water
hydrophilic molecules all dissolve with water
example of pentose sugar
example of hexose sugar
ribose
glucose
difference between isomers beta and alpha glucose
alpha glucose has the OH hydroxyl group below the ring in carbon 1, whereas in beta glucose its above
draw alpha and beta glucose
ok
how is the water molecule formed by a condensation reaction between to monosaccharides
a hydrogen atom from one monosaccharide and hydroxyl group from another monosaccharide
the 3 disaccharides and how are they formed
alpha glucose + alpha glucose = maltose
glucose + galactose = Lactose
Glucose + Fructose = Sucrose
all about starch, structure and functions
STRUCUTRE
Amylose - Unbranched 1,4 glycosidic bonds, helical
amylopectin - branched 1,6 glycosidic bonds
alpha glucose
FUNCTION
- amylose makes a compact helix which makes it good for storage
- starch is insoluble in water, does not affect water potential so no OSMOSIS
- both are polymers - too large to diffuse the cell
- amylopectin makes starch very branched, so there’s many end for enzymes to simultaneously break down quickly for energy
all about glycogen, structure and functions
glycogen is more branched than amylopectin because its in animals, which have higher reparation rate due to movement
STRUCUTRE
- 1,4 and 1,6 glycosidic bonds
- very branched
- In liver + muscles
alpha glucose
FUNCTION
- large molecule so can not diffuse from cell
- insoluble in water, does not affect water potential, no net water movement
- highly branched, quickly hydrolysed so glucose can be transported for ATP
cellulose structure and functions
SRUCUTRE
- beta glucose
- 1,4 glycosidic bonds
- straight, long unbranched
- hydrogen bonds adjacent to long chains
FUNCTIONS/ PROPERTIES
- many Hydrogen bonds meaning that there is a strong charge overall
- continuous hydrogen bonds forms microfibrils, then macrofibrils, then fibres - add strength
- cellulose permeable to water molecules so protoplast pushes out in OSMOSIS, strength of cellulose can withstand hydrostatic pressure. Cell becomes rigid
more SA for photosynthesis
draw general structure for amino acids
ok good job
structures of a protein
primary structure - specific order of amino acids
secondary structure - the slight positive and negative charges of hydrogen + oxygen cause hydrogen bonds in primary sequence. chain twists + folds makes alpha helix + beta - pleated sheets
tertiary structure - critical for function. further folding of secondary structure, ionic, disulphide. hydrophilic interactions
quaternary structure - more than one polypeptide chain within structure
all types of bonding involved in shape of a protein - all that are in tertiary structure
hydrophilic/ hydrophobic interactions - uncharged R groups ( hydrophobic) face away from water - CENTRE OF PROTEIN
ionic bonding - between opposite charged R groups, broken by changes in pH and temp (acidic/ alkaline conditions denature AS)
Disulphide bonding - covalent interactions formed between sulfur atoms of two cysteine molecules NOT BROKEN BY pH / TEMP CHANGES
hydrogen bonds - numerous so strong but very weak
what is a prosthetic group and what type of protein does this make
prosthetic groups - non protein group that help with the function of protein,
makes a CONJUGATED protein
why is a globular protein soluble in water
globular proteins have POLAR amino acids on surface - HYDROPHILIC INTERACTIONS so they interact with H2O
hydrophobic amino acids are REPELLED by water so they are in CENTRE - hydrophobic interactions
fibrous proteins examples and structure
collagen - triple helix
- glycine hydrogen as R GROUP (small )allows other chains to wrap around tightly
elastin - stretching of skin
keratin - cysteine which has disulphide bonds which are very strong
