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
What is a triglyceride?
A glyceride backbone with 3 fatty acid chains attached by an ester bond
What are saturated fats?
carbon chains that are saturated with hydrogen atoms - straight molecules with no double bonds. Solid at room temperature
What are monounsaturated fats?
Fats that contain fatty acids with one double covalent bond between two carbons - liquids at room temperature (olive oil)
What are polyunsaturated fats?
Fats with multiple double bonds (sunflower oil, rapeseed oil, vegetable oils) easily damaged by oxygen
What is an omega 3 fat?
The omega part is furthest away from the functional group - a fat where the double bond is 3 carbons from the end
What is an omega 6 fat?
The omega part is furthest away from the functional group - a fat where the double bond is 6 carbons from the end
What are cis and trans molecules?
Cis = the hydrogen atoms are on the same side of the double bond - bent molecules
Trans = the hydrogen atoms are on opposite sides of the double bond - straight molecules
What are the features of cis and trans fat membranes?
cis = flexible
trans = stiff and prone to oxidative damage
Name three omega-3 fatty acids
alpha-linoleic acid (ALA), EPA and DHA
Name three omega-6 fatty acids
Linoleic acid (LA), GLA, AA
What are some sources of omega-3 fats?
ALA - flax seeds, walnuts, leafy greens
EPA & DHA - oily fish
What are some sources of omega-6 fats?
LA - vegetable oils, nuts and seeds
GLA - evening primrose oil
AA - meat, dairy, eggs
Which omega fats are generally higher in a western diet?
Omega 6
What are the functions of essential fatty acids?
- cell membranes
- prostaglandins
- haemoglobin
- synovium
- brain, gonads
- immune system
- nerve transmission
What processes make polyunsaturated fats into free radicals?
light, oxygen, heat - keep in dark glass in the fridge and don’t cook
Which fats can you use for cooking?
saturated fats - such as coconut oil
What is the structure of a lipoprotein?
Internally - triglycerides and cholesterol. Outside - proteins and phosphlipids
What are the features of VLDLs?
carry newly synthesised triglycerides from the liver to adipose tissue (high in overeating)
What are the features of LDLs?
carry cholesterol from the liver to body cells. for cellular repair, cell membranes and the production of hormones
What are the features of HDL?
collect cholesterol from the body’s tissues, bringing it back to the liver
What are the features of phospholipids?
a glycerol part and two fatty acid chains. it is hydrophilic on one end and hydrophobic on the other
What are steroids?
lipids formed from cholesterol - they are formed of four rings of carbon atoms. it is used to create oestrogen, testosterone, cortisol etc. it can be made and does not need to be ingested
How many amino acids are there in the human body?
20
What groups does an amino acid have?
carboxyl group (COOH), amine group (NH3)
What is aspartame?
A chemical sweetener that is a dipeptide. it is a neurotoxin
What is glutathione?
A tripeptide antioxidant made from L-cysteine L-glutamate and glycine
How do polar and non-polar amino acids behave in water?
non-polar amino acids are hydrophobic (tryptophan)
polar amino acids are hydrophilic (tyrosine)
Name some functions of proteins
- collagen
- actin and myosin
- haemoglobin
- ferritin
- albumin
- enzymes
- hormones - insulin
- immunoglobulins
- clotting factors
- cell membrane receptors and transporters
How are proteins denatured?
Can be by pH, heat, heavy metals
How is protein digested in the body?
pepsin breaks down peptide bonds in the stomach - it is released by gastric chief cells in the form pepsinogen and is activated by the low pH of the stomach.
trypsin and chymotrypsin break it down further in the small intestine
What are the three components of a nucleotide?
a phosphate group, a 5-carbon sugar (deoxyribose) and a nitrogen base
What are the four nucleotide bases in DNA?
Adenine (purine), Cytosine, Guanine (purine), Thymine AT, CG
What bonds connect the base pairs in DNA?
hydrogen bonds - weak
What is the structure of RNA?
single stranded, ribose is the sugar, uracil instead of thymine
What is transcription?
mRNA copying the gene from DNA
What is translation?
the production of a protein from mRNA - occurs in the ribosome
What do the tRNA do?
They carry amino acids to the mRNA to help produce the protein chain
What are telomeres?
The end sections of DNA - they get shorter with aging and stress, poor nutrition, poor sleep etc
What is a mutation?
A change in the DNA sequence
What clotting factors do the mutations of haemophilia involve?
Haemophilia A - CF8
Haemophilia B - CF9
What micronutrients are key in altering gene expression?
vitamin A, D, essential fatty acids, zinc (+fibre)
What levels can be checked to see if someone is methylating correctly?
homocysteine
What are the molecules at the start and end of an enzymatic reaction called?
start - substrates
end - products
Which part of the enzyme does the substrate attach?
The active site
What are cofactors?
Usually minerals or vitamins that help enzymes with activity
Why is it important to have a balance of omega 3 and 6?
They are both converted into active forms by the same enzyme, if there is too much omega 6, this will be favoured and less omega 3 will be converted
What pH does salivary amylase work best at?
7
What pH does pepsin work best at?
2
What enzymes are present in the stomach?
gastric lipase, pepsin (secreted as pepsinogen)
What enzymes are made by the pancreas?
amylase, lipase, proteases
What enzymes are present on the intestinal villi?
sucrase, maltase and lactase
Why is it better to have gaps between meals?
To replenish the enzyme stores so foods can be digested, and to help the gut microbiome
How do bitters help with digestion?
They trigger release of cholecystokinin, which causes the release of bile acids. increasing pancreatic enzymes. bitter foods cause mouth to water and stimulate digestion
Which foods contain high levels of enzymes?
sprouts, kiwi (protease), pineapple (proteases), avocado (lipases), garlic (alliinase - crush garlic to mix the enzyme and substrate)
Why is it important to have raw foods?
it preserves the enzymes which can aid digestion
it has higher levels of vitamins, minerals and antioxidants
Which two antioxidants are more bioavailable in cooked foods?
lycopene (tomatoes) and beta-carotene (carrots and orange veg)
this is because the cell membrane gets broken down and it is released
Which enzymes are involved in mediating the creation of prostaglandins and leukotrienes?
COX-1 and 2 and lipoxygenase-5 (LOX-5)
What is needed to help absorb curcumin?
black pepper - stops enzymes in the intestine destroying the curcumin before absorption
fats - it is fat-soluble
How do you maximise the effect of ginger?
use as a powder or grate into hot water and let it steep for 10 minutes
What is systemic enzyme therapy?
taking a large dose of proteolytic enzymes (bromelain/serrapeptase) on an empty stomach so some of the enzymes enter the bloodstream intact
What enzyme can be used to reduce inflammation?
serrapeptase - thins blood, interferes with pain signals and clear away inflammatory cytokines
How is ATP broken down?
A hydrolysis reaction, removing a phosphate group
Give two examples of energy carriers
NAD and FAD (become FADH2 and NADH when they hold energy) NADH = 3 atp, FADH2 = 2atp
Why is magnesium important in energy production?
ATP is usually bound to magnesium, which alters the shape of ATP facilitating energy release. low magnesium makes it harder for ATP to be released.
What is NAD made from?
Vitamin B3 or tryptophan and aspartic acid
What is FAD made from?
Vitamin B2
What are the three stages of glucose metabolism?
glycolysis (in cytosol and anaerobic)
formation of Acetyl-CoA
Krebs cycle
Electron transport chain
(last three occur in mitochondria and require oxygen)
What occurs in glycolysis?
Glucose is split into two pyruvate
It needs - 2atp, magnesium and B3
It produces - 4atp and 2NADH
What is needed for acetyl-CoA formation?
Vitamin B5 reacts with pyruvate
requires B1 and lipoic acid as cofactors
requires B3 to make NADH
Which nutrients are needed in the krebs cycle?
magnesium, manganese, iron, B1, B2, B3
What does the electron transport chain do?
It turns energy from NADH and FADH2 into ATP
heavily reliant on oxygen
What do each of the four enzyme complexes in the electron transport chain need to work?
1: iron and sulfur
2. CoQ10
3. Iron
4. Copper
What is the net amount of atp made from one glucose molecule?
38
time
1hr 28
What medication decreases CoQ10?
Statins
What are some ways to support the mitochondria?
reduce toxic load
Increase nutrient cofactors
increase production of glutathione (by increasing sulphur and selenium-rich foods)
support detoxification and elimination
What process turns fatty acids into acetyl-CoA?
beta-oxidation (occurs in the liver)
What is needed for fat metabolism?
B (CoA), magnesium, L-Carnitine - to get fatty acids into the cell
betaoxidation - B2, B3, sulphur
What does the brain use for energy in fasting states?
Ketones
Why is a ketogenic diet good for kids with epilepsy?
It increases GABA in the brain, which inhibits overactivity
What nutrients are required to make energy from proteins?
vitamins B3 and B6 - for deamination
Which co-factor is important in gluconeogenesis?
Biotin
What effect does garlic have on clotting?
It inhibits platelet aggregation and can have an additive effect when taken with antiplatelets and anticoagulants and increases the risk of bleeding
What effect does liquorice have on electrolytes?
It can cause hypokalaemia and therefore increases risk of digoxin toxicity
