chapter 3- water, carbs, general bm (inc chemical structures) Flashcards
explain the charges in a water molecule
the oxygen atom is slightly negative and the hydrogens are slightly positive so they are attracted
how is water made very stable
hydrogen bonds are weak but collectively strong so water is made very stable as adjacent water molecules are attracted. this is vital in living organisms
what type of bonds do water molecules have
covalent
how is water used in reproduction (2 things)
used to bring male and female gametes together in fertilisation, in mammals the foetus develops in a water filled sac providing physical and thermal stability
how does water provide support in animals
water filled tissues provide skeletal support , eg annelids hydrostatic skeleton allows muscles to contract, provides buoyancy for aquatic organisms
how does water provide support in plants
in plant cells it provides turgidity to maintain ariel parts of the plant to prevent wilting. maintain max leaf surface area for light absorption for photosynthesis
what is an ionic bond
a chemical bond formed by the attraction between 2 oppositely charged ions
what is a covalent bond
a strong chemical bond where 2 atoms share a pair of electrons
what is a hydrogen bond
a weak chemical bond between the partial positive charge on a hydrogen atom and the partial negative charge on the adjacent molecule
Any bond with partial charges is called a…
polar bond
define cohesion
the force of attraction between water molecules which makes them stick to each other
explain how the polar properties of water molecules cause cohesion
a positively charged H atom of one water molecule is attracted to the negatively charged O atom of another water molecule forming a H bond between the two molecules
describe the process of adhesion in plants
water molecules are attracted to the impermeable wall of xylem tissue
what is a monomer
the smaller unit from which larger molecules are made
what is a polymer
a molecule made from a large number of monomers chemically joined together
what is a condensation reaction
a reaction that forms a chemical bond between 2 molecules and eliminates a water molecule
what is a hydrolysis reaction
a reaction that breaks a chemical bond between two molecules and uses a water molecule
what does amphipathic mean
a molecule that has both hydrophobic and hydrophilic parts
explain why alcohol is used in antiseptic wipes
alcohol can disrupt and dissolve bacterias plasma membrane due to their non polar nature, killing them
true or false: some polymers are composed of several monomers that are similar in structure but not identical
true
What is an organic substance?
An organic substance is a molecule that contains carbon and at least one other element.
what is a skeletal formula and what is represented
they represent each carbon as a corner on a zig zag line and the hydrogens bonded to each carbon arent included
What does an ‘R group’ represent in a skeletal formula?
The rest of the molecule
lipids, polysaccharides, nucleic acids and proteins are all macromolecules, true or false for the following statements:
all macromolecules are formed in hydrolysis reactions
lipids are not polymers but polysaccharides, nucleic acids, and proteins are polymers
lipids are polymers of fatty acids and glycerol
macromolecules consist of repeating units of monomers
false
true
false
false
