Biochemistry Summaries Flashcards
(93 cards)
What is an element?
How many are there in the human body?
A substance made up of just one type of atom so it cannot be split up into simpler substances.
There are 26 different elements; the major 4 are C, H, O, N = 96% of the human body.
What is an isotope?
Are atoms of the same element but with different number of neutrons in the nucleus. This does not affect the chemical activity but changes the mass.
Describe what happens and types of radio active decay
Some isotopes have such an imbalance of protons and neutrons that is can cause the atom to become unstable leading to radioactivity.
I.e. the unstable atom needs to get rid of energy to become stable again and does this by:
- alpha decay - ejecting protons and neutrons from the nucleus
- beta decay - splitting neutrons into protons and electrons that can be ejected
- gamma decay - emitting energy as gamma rays
Describe uses of radiation in medicine
Radiotherapy uses gamma rays to target rapidly dividing cancer cells
Radioactive glucose uptake to evaluate cancer treatment
Breath test for H Pylori - the detection isotope labelled carbon dioxide in exhaled breath indicates that the urea was split and that urease is present in the stomach.
Name the four most electronegative elements?
Fluorine, Chlorine, Oxygen and Nitrogen
CL, F, O, N
What is an electrolyte and what do they do?
An ionic compound i.e. salt when dissolved in water is an electrolyte
- conduct electricity essential for nerve and muscle function
- exert osmotic pressure important for water balance allowing fluid to travel inside and outside of the cell (sodium potassium pump)
- play an important role in the acid-base balance
Main ones: Na+, Cl-, K+ (pace maker of the heart) and Mg+
Difference between an acid and a base
An acid is a substance that releases a high amount of H+ when dissolved in water, whereas a base binds hydrogen ions in solutions increasing lots of OH- (hydroxide)
What is the energy of activation?
Minimum energy that is required for a chemical reaction to occur. Can be lowered by catalysts or stopped by an inhibitor.
(Example of inhibitors are Botox or antibiotics)
What is a chemical reaction and what is is reliant on?
It’s the breaking or formation of chemical bonds. for this to occur there needs to be an opportunity for two molecules to collide.
Starting materials are reactants, end molecules are products.
Written in a formula that must balance balance in electrons on both sides i.e. A + B = AB.
Reliant on: the correct temperature, high enough concentration of reactants;
Increasing pressure can speed up reactions.
Difference between endothermic and exothermic reactions and examples
Endothermic take in heat and tend to be anabolic i.e. body building or freezing water
Exothermic release heat or energy - catabolic i.e. fire, melting ice
What’s a buffer system ? Give an example and how does it work?
Substances that maintain the H+ (pH) concentration in the body within normal limits. The most important one in the blood stream is the bicarbonate buffer.
COs (from cellular respiration) reacts with H2O in the blood = carbonic acid (H2CO3) = bicarbonate ion (HCO3-) and H+.
These reactions are reversible.Lungs and kidneys key players.
What’s a free radical?
Molecules or compounds that have an unpaired electron in its outer shell. They become destructive and steal electrons = oxidation, causing a chain reaction.
Results from normal aerobic respiration, metabolism and information; from within the body or from environment (pollution, sunlights, strenuous exercise, X-rays, smoking, alcohol.
What are antioxidants?
Group of vitamins, minerals, photo chemicals and enzymes that donate electrons without becoming unstable themselves.
ACE, Glutathione (naturally produced in our body)
Work best as a collection, so they can recycle each other.
Functional Groups
Attached to carbon skeleton contributing to structure and function
Hydroxyl: R-O-H (polar and hydrophilic)
Sulfhydryl: R-S-H (polar and hydrophilic; in some proteins)
Carboxyl: R-COOH (hydrophilic, weak acid, found in amino acids)
Esters: R-OOR’ (predominant in triglycerides)
Phosphates: C-POOOO (in ATP, very hydrophilic)
Amine: -NH2 (weak base found in amino acids)
Metabolism of fat for energy production is stimulated or inhibited by what hormones?
Stimulated by Adrenalin/epinephrine
Inhibited by insulin
What are two types of complementary bases that form nucleotides?
Purines and pyrimidines
What is the structure of an amino acid?
Formed from elements C, H, O and N (some have Sulphur)
There are 20 AAs in humans;
Everyone has a carboxyl (-COOH) and an amino (-NH2) group with different R- side chain
What are the essential amino acids? (9)
Histidine. Valine
Isoleucine. Phenylalanine
Leucine. Threonine
Lysine. Tryptophan
Methionine
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What are non-essential amino acids? (5)
Alanine Aspartic Acid Glutamic acid Serine Asparagine
My friend Alan was a spartan who ate asparagus and seriously developed an ass personality.
What are conditionally essential amino acids? (6)
Arginine Cysteine (depends on Methionine) Glutamine Glycine Proline Tyrosine
I get tired of arguing with mean ass cysts, they glide into the scene and act like pro lean body builders.
Give an example of a di-peptide?
Aspartame is made up of aspartic acid and phenylalanine
Give an example of a tri-peptide
The body’s own glutathione is made up of L-cysteine, L-glutamate and glycine.
Different protein structures
Primary structure - linear sequence held by peptide bonds
Secondary - nearby side chains interacts to cause twists and folds - alpha helix or beta pleated sheet
Tertiary - further interactions to create 3D structure via hydrogen bonds, salt bridges, disulphide bonds or non-polar hydrophobic interactions
Quaternary - larger structures made up of individual protein chains
What is an example of a quaternary structure?
Haemoglobin which is made up of 4 x protein chains.
