M2, C3 Biological Molecules Flashcards
what are all living things primarily made of
carbon
hydrogen
oxygen
nitrogen
phosphorus and sulphur are also important
whats a covalent bond
when two atoms share a pair of electrons. present in the outer orbitals of the atoms
what are the bonding rules for carbon, nitrogen, oxygen and hydrogen?
carbon - 4 bonds
nitrogen - 3 bonds
oxygen - 2 bonds
hydrogen - 1 bond
whats the displayed formula for:
a) carbon dioxide
b) hydrogen
c) water
a) O=C=O
b) H-H
c) H-O-H
what’s a cation
when an atom or molecule loses one or more electrons and it gets a net positive charge
what’s an anion
when an atom or molecule gains electrons and it gets a net negative charge
what are ions in solutions called
electrolytes
what is an ionic bond
when an atom loses or gains electrons
forms positive or negative ions
held together because of the attraction of opposite charges
what are the uses of calcium ions?
nerve impulse transmission
muscle contraction
what are the uses of sodium ions?
nerve impulse transmission
kidney function
what are the uses of potassium ions?
nerve impulse transmission
stomatal opening
what are the uses of hydrogen ions?
catalysis of reactions
pH determination
chemiosmosis
what are the uses of ammonium ions?
production of nitrate ions by bacteria
what are the uses of nitrate ions?
nitrogen supply to plants for amino acid and protein formation
what are the uses of hydrogen carbonate ions?
maintenance of blood pH
what are the uses of chloride ions?
electrolyte balance
what are the uses of phosphate ions?
cell membrane formation
nucleic acid
ATP formation
bone formation
what are the uses of hydroxide ions?
catalyst of reactions
pH determination
define polymer
long chain molecules made by linking monomers.
give examples of monomers
glucose, amino acid, nucleotide
give examples of polymers
glycogen, protein, DNA, starch
what does it mean saying a water molecule is polar
the oxygen atom is slightly more negative and the hydrogen atoms are slightly more positive
this means it forms hydrogen bonds
what are the 5 properties of water
High specific heat capacity- stable temp for aquatic organisms High latent heat of vaporization- sweat Good solvent- transport of molecules Ice less dense than water Cohesive & Adhesive
what does the universal solvent property in water mean
water can dissolve many substances
enables many chemical reactions to occur in the cell cytoplasm. And enables substances to be transported eg. xylem
what does the liquid at room temp property in water mean
provides a liquid environment both within cells and for aquatic organisms
what does the specific heat capacity property in water mean
water has a high specific heat capacity so it needs lots of energy to increase the temperature - the energy is needed to break the hydrogen bonds
water resists temperature changes, providing a more stable environment within cells and aquatic organisms
what does the latent heat of vaporisation and latent heat of fusion property in water mean
needs lots of heat to turn water into a gas and needs a large lack of heat for water to freeze
evaporation of water from the surface of organisms eg. sweating/transpiration - can provide a significant cooling effect
water within cells and aquatic habitats is slow to freeze providing a more stable environment
what does the density property in water mean
water is less dense as a solid than a liquid
when a water freezes each molecule forms hydrogen bonds with four others. this creates a lattice that holds molecules further apart than a liquid.
Ice therefore floats on water, enabling aquatic organisms to survive in water underneath the ice of frozen lakes and ponds
what does the capillarity property in water mean
water can move up a narrow tube against gravity by capillarity/capillary action
helps plants move water from their roots to their shoots
adhesion/surface tension/cohesion
what does the surface tension property in water mean
at a water-air interface, water molecules form hydrogen bonds with other water molecules but not with air. This uneven distribution results in surface tension.
causes surface of water to form a ‘skin’ which can support aquatic plants and insects
define cohesion and adhesion
cohesion - water molecules stick together because they form hydrogen bonds with each other
adhesion - water can stick to other polar substances and this is the reason why water is wet
what is hydrogen bonding in water
the negative charge of an oxygen atom of one molecule attracts the positive charge of the hydrogen on other molecules
what makes up carbohydrates
carbon
oxygen
hydrogen
what is a monosaccharide and give some examples
a single sugar unit
eg. glucose, fructose and ribose
what is a disaccharide and give examples
when two monosaccharides join together
eg, lactose and sucrose
what is a polysaccharide and give examples
when more than two monosaccharides join together
eg. glycogen, cellulose and starch
what is the formula is glucose and what type of monosaccharide is it?
C6H12O6
hexose monosaccharide
how do you label carbons on a molecular structure diagram
start from the carbon on the right and go clockwise
what is different in the structure between alpha and beta glucose
the OH (hydroxyl) group in carbon 1 is in opposite directions in alpha glucose the OH is on the bottom whereas beta glucose has the OH on top on carbon 1
why are glucose molecules polar and soluble in water
this is due to the hydrogen bonds that form between hydroxyl groups and water molecules
what is a condensation reaction between glucose
when 2 alpha glucose molecules are next to each other, 2 hydroxyl groups interact.
two hydrogen atoms and an oxygen atom are removed from glucose monomers and join to form a water molecule. A bond forms between carbon 1 and carbon 4 (a 1-4 glycosidic bond)
glucose + glucose = (a)
(bi) + (bii) = lactose
glucose + (c) = sucrose
a) maltose
b) glucose + galactose
c) fructose
what is amylose
formed by alpha glucose 1-4 glycosidic bonds
helix
much less soluble than glucose
found in starch
what is amylopectin
the other starch polysaccharide
formed by alpha glucose 1-4 glycosidic bonds and alpha glucose 1-6 glycosidic bonds
branched