Basic Flashcards
4 major elements in human body
Carbon
Hydrogen
Oxygen
Nitrogen
All elements made up of
Atoms
Atoms made up of 3 particles:
Protons
Neutrons
Electrons
Protons charge
Positive
Neutrons charge
Neutral
Electrons charge
Negative
Mass of protons and neutrons
Mass of 1 each
Mass of electrons
No mass
Location of protons and neutrons
In atoms nucleus
Location of electrons
In electron shell
Group around the nucleus
Atoms of same element but with different numbers of neutrons in nucleus called
Isotopes
Do isotopes of same element have same charge and mass
Yes
Simplest atom of all is
Hydrogen
Structure of hydrogen
1 proton
1 electron
No neutrons
How does only having 1 electron affect behaviour of hydrogen
Will always look for another so will easily fact with other atoms
Why don’t inert atoms easily react with others
Because outer shell already filled with perfect number
What is ionisation
Process of giving atoms positive/negative charge
What happens to the molecule that donates an electron
Becomes positive as electron is negative
What happens to molecule that receives electron
Becomes negative
What is oxidation
Removal of electrons
What effect does oxidation have on energy
Decreases
What is reduction
Gaining electrons (reducing charge)
What effect does reduction have on energy
Increases
Oxidation and reduction together called
Redox
What are free radicals
Molecules/compounds with unpaired electron in their shells
Why are free radicals destructive
They want to stabilise so steak electrons from other stable molecules - oxidation.
This makes the other molecule unstable causing chain reaction of oxidative damage
Where do free radicals come from
Aerobic respiration Metabolism Inflammation Pollution Sunlight X Ray's Smoking Alcohol Ageing
How do chain breaking antioxidants work
Neutralise free radicals by donating an electron - makes them harmless
Define ionic bond
One element donates electron to other
Describe covalent bond
2 elements sharing electrons
The more electronegative the element the more
Pulling power
4 highly electronegative elements are
Fluorine
Chlorine
Oxygen
Nitrogen
Describe polar bond
Uneven charge
1 part of molecule slightly + other slightly -
Describe hydrogen bond
H bonded to more electronegative atom
Unequal sharing of electrons puts partial + charge on H
H+ then attracted to negatively charged atom
What type of bond occurs in water
Hydrogen bonds
Why is water the ideal solvent to dissolve chemicals into their individual ions
Because of the polar bonds
What type of bonds do hydrophilic molecules have
How first his affect their behaviour
Polar bonds
Eg alcohol
Dissolves easily in water
What bonds do hydrophobic molecules contain
How does this affect their behaviour
Non-polar covalent bonds
Fats
Don’t dissolve easily in water
What is an electrolyte
Ionic compound dissolved easily in a solution
3 functions of electrolytes
Can conduct electricity - essential for nerve function
Exert osmotic pressure - important for water balance
Act as buffers in acid-base balance
What does acid release when dissolved in water
Lots of H+ ions
How does a base behave in a solution
Binds H ions
Creates high OH
What is high pH
High levels of H+ as caused by acid
What is low pH
Low H ions
High OH
as caused by base
Which scale measures concentration of hydrogen ions in a solution
pH scale
Where is water on pH scale
Neutral at 7
Lower than 7 on pH scale is
Acid
Higher than 7 on pH scale is
Alkaline
What maintains H+ concentration in body to maintain homeostasis
Buffers
How do buffers behave
Some bind to H+ others to OH-
Starting materials in chemical reactions are
Reactants
End molecules in chemical reactions are
Products
How to catalysts speed up reactions
By lowering activation energy required
What does an anabolic reaction do
Build up
What does a catabolic reaction do
Break down
What skeleton do all molecules in the body contain
Carbon skeleton
What is the other bit in a human molecule called - not the carbon skeleton
Functional group
No of elements in human body
26
