Chapter 1: Inorganic Ions/Water Flashcards
What is a cation?
an ion with a positive charge
What is an anion?
an ion with a negative charge
What is the role of the calcium ion in the body?
- involved in the TRANSMISSION of nerve impulses
- the release of insulin from the pancreas
- acts as a cofactor for many enzymes (e.g in blood clotting)
- important for bone formation
What is the role of sodium ions in the body?
- important for GENERATING nerve impulses
- muscle contraction
- regulating fluid balance in the body
What is the role of potassium ions organisms?
- important for generating nerve impulses for muscle contraction
- regulating fluid balance in the body
- activates essential enzymes needed for photosynthesis in plant cells
What is the role of hydrogen ions in organisms?
- affects the pH of substances (more H, more acidic)
- important for photosynthesis reactions- that occur in the thylakoid membrane (inside chloroplasts)
What is the role of ammonium ions and nitrate ions in organisms?
- absorbed from the soil by plants
- important source of nitrogen (then used to make amino acids and nucleic acids)
What is the role of hydrogencarbonate ions in organisms?
- acts as a buffer
- helps to maintain the pH of blood
What is the role of chloride ions in organisms?
- involved in the chloride shift (helps maintain the pH of blood during gas exchange)
- acts as a cofactor for amylase
- involved in some nerve impulses
What is the role of phosphate ions in organisms?
- involved in photosynthesis and respiration rxns.
- needed for the synthesis of many biological molecules
(e. g-nucleotides, phospholipids and calcium phosphate which strengthens bones)
What is the use of hydroxide ions in organisms?
affects pH
more OH- ions than H+ ions in a solution creates an alkali
What type of molecule is water?
-dipolar
O atom has slight -ve charge
H atom has slight +ve charge
What are the IMF between water molecules?
hydrogen bonding between the +ve H and the lone pairs on O atom (attraction between oppositely charged poles), this causes water mol. to stick together
What is the S.H.C of water (relative) and why?
very high
because water mol stick together, so it takes more energy to separate molecules
Why is it beneficial for water to have a high S.H.C?
it acts as a buffer against sudden temperature variations
making an aquatic environment stable
also, buffers internal temp. in mammals from changing too much-good temp. for enzyme function
What are the properties of water? (5)
- important metabolite
- high S.H.C (buffer for temp)
- important solvent (dipolar nature)
- large latent heat of vaporisation (cooling effect)
- strong cohesion between water mol (due to Hydrogen bonding)
Why is a high latent heat of water useful?
evaporation of water from an animal (sweat) transfers a lot of energy to the surroundings, so it is effective for cooling as the body heat is used to evaporate water
Why is water cohesive and why is it useful?
- tendency of mol. to stick together due to hydrogen bonding
- allows water to be pulled through columns (xylem)
- creates surface tension, can support small animals such as pond skaters
What is the importance of water for living organisms? (5)
- metabolite
- solvency
- cooling
- provides support to cells
- transparent
How is water used as a metabolite?
- used for hydrolysis reactions (to break down many complex mol.)
- chemical reactions take place in aqueous solutions
- water is a major raw material in photosynthesis
How is water used as a solvent?
water readily dissolves other substances:
- gases such as CO2 and O2
- wastes such as ammonia and urea
- dissolves inorganic ions and small hydrophilic mol (amino acids, ATP, monosaccharides)
- dissolves enzymes
How can water provide support?
not easily compressed so provides support to cells
e.g- hydrostatic skeleton of earthworms, turgor pressure in herbaceous plants
How is it useful that water is transparent?
aquatic plants can photosynthesise
aquatic animals can see because light rays can penetrate jelly-like fluid in eye and hit retina
