1.1 chemical elements and biological compounds Flashcards
(46 cards)
what are the four key inorganic ions?
magnesium, iron, phosphate, calcium.
what is magnesium
needed for in plants? why?
it is essential for photosynthesis as it is a constituent of chlorophyll.
what is iron a constituent of?
haemoglobin.
what is phosphate used to make?
it is used to make nucleotides such as ATP, DNA, and RNA.
what is phosphate a constituent of?
phospholipids found in biological membranes.
what do phosphate and calcium do to bones (and teeth for calcium)?
harden them.
why is calcium in plant cells?
it strengthens the cell wall.
what is a polar molecule? an example?
a molecule that has no overall charge due to it having both a positively charged end and a negatively charged end. water molecules are polar (often called dipole).
what kind of bonds form to make a molecule of water and where?
hydrogen bonds form between the + on a hydrogen atom of one molecule and the - on the oxygen atom of another molecule.
what is an organic ion?
a molecule that has a high proportion of carbon and hydrogen atoms.
what is an inorganic ion?
a molecule or ion that has no more than one carbon atom.
what is a micronutrient? some examples?
minerals needed in minute concentrations, e.g copper and zinc.
what is a macronutrient?
minerals needed in small concentrations.
why is water a good solvent?
because of their polarity, water molecules are attracted to other water molecules and charged particles. this helps charged particles dissolve in water.
why is water referred to as the universal solvent?
a large number of substances can easily dissolve in water.
why is water a metabolite?
it is used in many biochemical reactions as a reactant.
what does high specific heat capacity mean?
a large amount of heat energy is needed to raise its temperature.
why does water have a high specific heat capacity?
hydrogen bonds between water molecules restrict their movement, resisting an increase in kinetic energy so the temperature does not increase.
why is it beneficial that water has a high specific heat capacity?
it prevents large fluctuations in water temperature to keep aquatic habitats stable and to allow enzymes to work efficiently in cells.
what does high latent heat of vaporisation mean?
a lot of heat energy is needed to change water from a liquid to a vapour.
why is it beneficial that water has a high latent heat of vaporisation?
it is important in temperature control - heat is used to vaporise water from sweat on the skin/leaf’s surface. the surface cools as sweat evaporates.
how is water cohesive?
water molecules attract eachother, forming hydrogen bonds. the large amount of hydrogen bonds stick the molecules together to form a lattice.
what is a benefit of water being cohesive?
it allows volumes of water to be drawn up xylem vessels.
how and why does water have a high surface tension?
cohesion between water molecules at the surface of a body of water produce tension to support the bodies of insects.
