October Flashcards
What is chemistry?
The science of the composition and properties of substances and matter
What is biochemistry?
The science of the chemical and physiochemical processes and substances within living organisms
What is matter?
Anything that has a mass and occupies space
What are the four main elements of the body and their percentages?
Nitrogen - 3%
Hydrogen - 10%
Oxygen - 65%
Carbon - 18%
Why may you not supplement transition metals for a long period of time?
They compete with each other in terms of absorption, so supplementation of one could cause a deficiency of another
What is a free radical?
An atom or molecule with an unpaired electron
What does the element number correspond to?
The number of protons
What happens to the reactivity of the elements as you go down column 1?
It increases
All react with water
What happens to the reactivity of halogens as you go down the column?
It decreases
Fluorine can displace Chlorine which can displace Iodine
What is an isotope?
Atoms of the same element with different numbers of neutrons
When are radioactive substances used in medicine?
PET scans
Radiotherapy
H-Pylori breath test - C13/14 labelled urea
What is an ionic bond?
A bond where one atom donates some of its electrons to another and then they are bonded
What is ionisation?
The process of giving or gaining electrons
Oxidation - loses electrons
Reduction - gains electrons
What is a covalent bond?
When two elements share electrons
What is an electronegative element?
An atom with a large group of protons so they tend to pull electrons towards them
What are polar bonds?
Bonds caused by polarisation of molecules
What features of water are caused by polar bonds?
Surface tension, ability to dissolve many substance
What are hydrophobic molecules?
non-polar molecules that do not dissociate easily in water
What are the four most electronegative elements?
Fluorine, chlorine, oxygen, nitrogen
What is an ion?
A charged atom
What is a universal solvent?
Waters ability to dissolve anything with polar bonds or ionic compounds
What is an electrolyte?
a solution of an ionic compound in water - can conduct electricity
What is an acid?
A substance that releases H+
What is a base?
A substance that binds to hydrogen ions - creates OH-
What is the optimum pH of the stomach?
2-3
What food increase acidity in the body?
refined sugars, carbohydrates, fruits
What are the two ways to test body pH at home?
Urine or saliva litmus test
aiming for a slightly alkaline or neutral result
What type of medication is a statin?
HMG-Co A reductase inhibitor
What are anabolic and catabolic reactions?
anabolic - building up molecules (using energy)
Catabolic - break down molecules (releasing energy)
What is a hydrolysis reaction?
The use of a water molecule to split another molecule
What is dehydration synthesis?
The removal of water from molecules to form a new bond
What is the equation for the buffer reaction?
CO2 + H2O = H2CO3 = HCO3- + H+
carbonic anhydrase used as buffer in the first part of the reaction
What are oxidation and reduction?
Oxidation is Loss
Reduction is Gain (of electrons)
How does an antioxidant work?
It donates an electron to free radicals to convert them to harmless molecules without being damaged themselves (it stays stable)
What is the optimum way for antioxidants to work?
As a collection of different antioxidants - they can recycle each other - supplements of individual antioxidants don’t always work well
What is a hydroxyl group?
-OH added. for example alcohols - they are polar and hydrophilic
What is a sulfhydryl group?
-SH added. found in some protein chains e.g. cysteine. polar and hydrophilic
What is a carboxyl group?
C=O group - found in amino acids, hydrophilic and act as a weak acid
What is an amine group?
NH2 - found in amino acids can act as a weak base, hydrophilic
What is an ester group?
a C=O in the middle of a carbon chain - found in triglycerides
What is a phosphate group?
PO4H2 - found in ATP, very hydrophilic and can form a negative charge
What are the main features of carbohydrates?
made of CHO, normally arranged in a ring, many OH groups
Name some monosaccharides
glucose, fructose, galactose, deoxyribose, ribose
Name some disaccharides
sucrose = glucose + fructose
lactose = glucose + galactose
Maltose = glucose + glucose
Name some polysaccharides
glycogen, starch, cellulose
What are the names of the families of monosaccharides?
triose = 2 carbons
pentose = five carbons
hexose = 6 (glucose/fructose)
heptose = 7
What is an isomer?
Molecules with the same chemical formula but different structures
What is the chemical formula for fructose, glucose and galactose?
C6H12O6 - they are isomers
What two polysaccharide units is starch made from??
Amylose (a single chain of glucose units - breaks down slowly so does not spike glucose as much) and amylopectin (branch-like structure of glucose units - breaks down quickly increase blood sugar)
How can you change the amount of amylose in a carbohydrate?
Cook the food then cool it, and some of the amylopectin turns to amylose
Can humans break down cellulose?
no - it acts as a fibre. gut bacteria can break it down
Where does carbohydrate digestion occur?
starts in the mouth using salivary amylase (works at a neutral pH). then continues in the small intestine with the release of pancreatic amylase. enzymes on the brush-border of the small intestine break down lactose, maltose and sucrose
What are the features of lipids?
They are hydrophobic, made from CHO but in a different ratio to carbohydrates
What are lipoproteins?
lipids attached to proteins to allow them to be transported in the body