(U1) Molecules Flashcards
Why is water a good solvent?
- Due to their polarity, water molecules are attracted to other polar molecules
- this allows them to form clusters around the solute and therefore dissolve them
What is a polar molecule?
Why is water a polar molecule?
- A molecule where individual atoms have slight, opposite charges due to uneven distribution of covalent bonds (electron slightly more attracted to one of the molecules)
- the oxygens have a slight -ve charge, hydrogens slight +ve
In what 3 ways is water used within the body?
- most of the reactions in cells take place in aqueous solutions (in water)
- water acts as a transport medium
- it has different effects on hydrophobic and hydrophilic molecules (e.g. fat won’t dissolve in water) - key for membrane structure
What are calcium ions used for by humans and plants? (4)
- helps produce calcium pectate for use in plant cell walls
- a component of bones and teeth
- key in blood clotting
- key in muscle contraction
What are Iron ions used for by humans and plants? (2)
- in the haem group of haemoglobin (oxygen carrier in RBCs)
- key constituent of electron carriers in respiration
What are magnesium ions used for in plants?
Helps make chlorophyll able to absorb light
What are potassium ions used for in humans?
Maintaining electrical gradients across neurones
What are nitrate ions used for by humans and plants?
A component of amino acids, nucleic acids and chlorophyll
What are phosphate ions used for by humans and plants? (2)
- helps form phospholipids for cell membranes
- component of bio molecules like ATP (adenosine triphosphate) and nucleic acids
What are Hydrogencarbonate ions used for by humans and plants?
Used as a natural buffer
What are buffers? (2)
Why are they needed?
- Chemicals or substances that resist changes to pH - meaning pH is maintained
- when small volumes of acid/alkali are added
- pH changes can result in enzyme denaturation, buffers prevent this and allow enzymes to operate at their optimum pH
Give 2 examples of buffers
- HCO3- ions
- blood proteins e.g. albumin
What are ions?
Charged particles
Name 7 inorganic ions
and
state their formula
- calcium - Ca2+
- iron - Fe2+
- magnesium - Mg2+
- potassium - K+
- nitrate - NO3-
- phosphate - PO43-
- hydrogen-carbonate - HCO3-
What are organic molecules?
Name 3 examples
- complex carbon containing molecules
- carbohydrates, proteins and lipids
What are monomers and polymers?
What is the name of the process used to form polymers?
and
what does it entail?
- mono - individual subunits
- poly - many subunits joined together
- polymerisation - adding monomers together to form polymers
What elements are contained in carbohydrates?
- carbon
- hydrogen
- oxygen
What is the ratio between the number of hydrogen and oxygen atoms in carbohydrates?
2 hydrogen : 1 oxygen
What are the 3 types of carbohydrates?
- monosaccharides
- disaccharides
- polysaccharides
What are monosaccharides?
Which 3 categories are biologically important?
- simple sugars with different categories depending on no. of carbons
- important ones:
- trioses (3 carbons),
- pentoses (5 carbons) and
- hexoses (6 carbon)
What are disaccharides? (2)
- Double sugars formed from 2 monosaccharide monomers
- which join through condensation reactions
What are polysaccharides? (2)
- Complex molecules consisting of many monosaccharide monomers
- bonded through condensation reactions
What is DNA Helicase
and
How does it work? (3)
- An enzyme
- breaks hydrogen bonds between complementary bases (ATCG),
- separating into 2 polynucleotide strands
What is DNA polymerase
and
How does it work?
- an enzyme
- joins mononucleotides together to form a new polynucleotide strand