water/biomolecules Flashcards
what is an atom
A basic unit of matter that consists of a dense, central nucleus surrounded by a
cloud of negatively charged electrons.
what is a molecule
An electrically neutral group of at least two atoms in a definite arrangement held
together by very strong (covalent) bonds
what is a compound
A pure chemical substance consisting of two or more different chemical elements
that can be separated into simpler substances by chemical reactions.
what is an element
A pure chemical substance consisting of one type of atom distinguished by its
atomic number, which is the number of protons in its nucleus
what is an ion
A charged particle formed by the loss or gain of one or more electrons.
what is an organic compound
one or more atoms of carbon are covalently linked to atoms of other elements
what is an inorganic compound
Are considered to be of a mineral, not biological origin
what is a polar molecule
has different charges across the molecule but overall is neutral
what molecules can water dissolve
polar and ionic
what is the structure of a water molecule
one slightly negative oxygen molecule and two slightly positive hydrogen molecules
how do water molecules bond together
the slightly positive hydrogen attracts the slightly negative oxygen from another molecule
how do you represent a hydrogen bond between two water molecules bonded together
with a dashed line
why is water important in animals
-used to filter kidneys
-allows solutes to be transported and dissolved in blood plasma
what is water important in plants
allows solutes to be transported and dissolved in water in xylem and phloem vessels
what is cohesion
when water molecules stick together
how do water molecules bond together
via a weak hydrogen bond (- - -)
how does cohesion of water moelcules benefit animals
allows water surface tension which lets animals walk on water
how does cohesion of water moelcules benefit plants
allows water to be pulled through xylem to top of plants
how does specific heat capacity help animals
stabalises aquatic enviroment temps
why does water have a high latent heat of vaporisation
can absorb large amounts of heat whe changing from liquid to vapour
is ice or water less dense
ice
why is ice less dense
ice particles from rigid structures so theres more space between so arent as many hydrogen bonds whereas water particles can get very close
how does ice help animals
helps protect using the insulated layer
why do living organisms need magnesium
makes chlorophyll in leaves
causes chlorosis if deficient
mamals need for bone density
why do living organisms need iron
component of haemoglobin in red blood cells and used to transport oxygen
anemia if deficient
why do living organisms need calcium
strengthening tissues bones and teeth in animals
cell walls in plants
why do living organisms need phosphate
component of nucleic acids (DNA/RNA/ATP) and phospholipids
how to test for starch
add dilute iodine
brown orange- blueblack
how to test for glucose (reducing sugar)
benedicts reagents and heat gently (1 minute)
- brick red
how to test for sucrose (non reducing sugar)
Add 1cm3 hydrochloric acid to the sample and boil
(to hydrolyse (break down) the sucrose into
glucose and fructose)
Neutralise the solution with an alkali.
Boil for one minute with Benedict’s solution.
-Blue to brick red
how to test for lipids
emulsions test- add ethonal and shake with water
- white emulsion
why do we use ethanol to test for lipids
ethonal dissolves any fats present and lipids arent insolubale in water so come out of solutions as emulsion
how to test for protein
biurets test
add sodium hydroxide and copper sulphate
blue - purple
what is the role of water as a metabolite
- a reactant in photosynthesis and hydrolysis
- a product of aerobic respiration and condensation reactions
