Chapter One: Biochemistry Flashcards
What are the relative masses and charges of the 3 subatomic particles?
Proton: 1, +1
Neutron: 1, 0
Electron: 0, -1
Why are atoms in the elemental state neutral?
Equal number of protons and electrons
What does electron configuration determine?
How atoms of an element react with another type of atoms
What are atoms called when their electrons are in the lowest available energy level?
Ground state
When do electrons move to higher energy levels?
When they absorb energy
What is the state of electrons in higher energy levels?
Excited state
Explain how chlorophyll molecules make sugar using idea of energy
Chlorophyll absorbs light energy, excited electrons provide energy to make sugar as they release energy while returning to ground state
What are isotopes?
Atoms of the same element that vary only with neutron number
State uses of radioisotopes
Estimating age of fossils, medical diagnosis and treatment
When is a bond formed?
When nuclei attract the same electrons
Why are bonds made?
To obtain stability/full valency
State what happens to energy when bonds are made/broken
Made: released
Broken: supplied
How are ionic bonds formed? Which elements are ionic bonds formed in?
Electrons are transferred
In metals
What are anions and cations
Gains electrons: Anion: negative ion
Loses electrons: Cation: positive ion
How are covalent bonds made?
Electrons are shared to form molecules
What makes bonds non polar? (3+1)
Electrons are shared equally, and form between alike atoms ( mono/diatomic, *and C-H), and are symmetrical
What makes bonds polar? (3+1)
Electrons shared unequally, formed between unalike atoms, especially hydrogen bonds, asmmetrical
What is intermolecular force of attraction?
Force between molecules
What is polar-polar attraction? Determine the strength of polar molecules compared to that of non polar molecules
Attraction between positive and negative ends of polar molecules. Polar ones are stronger
Explain non polar molecule attraction
Balanced, and linear in terms of symmetry so they have the weakest attraction
Describe the terms hydrophobic and hydrophilic
Phobic:Water hating
Philic:Water loving
Non polar substances such as lipids do not dissolve in water. Why?
Like dissolves like.
State which things give water it’s special characteristics
It is asymmetrical->highly polar, strong intermolecular attractions->strong hydrogen bonding
Water has a high specific heat capacity. What does this mean?
It takes a lot of heat in order to raise the temperature of 1gram of water by 1°C
Water has a high heat of vaporisation. How does this apply in the cooling effect?
When sweat evaporates it takes along with it a lot of heat from the body
Why is water the universal solvent?
It is highly polar and can dissolve all polar and ionic substances
Why does ice float on water?
It is less dense
Explain the phenomenon of spring overturn
During winter, ice layers water and insulates and moderates climate for life below. When it melts in spring it becomes denser water and sinks and causes water circulation. This makes oxygen reach the depths, and nutrients from bacteria reach the surface. It is crucial for lake health
Explain what it means by water having strong cohesion tension
Water molecules stick to each other via hydrogen bonds. Oxygen has a higher EN value than hydrogen so it tends to pull electrons with more force and has a partial negative charge. This oxygen attracts to an opposite hydrogen in another molecule which is partially positive via electrostatic force of attraction. This dipole dipole interaction is the hydrogen bond. The intramolecular bond between oxygen and hydrogen in the same moleceule is polar covalent as electrons are shared unequally.
How is it possible for bugs to walk on water?
Cohesion forces and surface tension
What is water adhesion?
When water molecules cling to substances via hydrogen bonds
How is adhesion useful in plants?
Responsible for capillary action (water moves up a plant. Additionally, due to trnaspirational pull cohesion tension this can be done without spending energy)
State the general principle relating H+ ions to pH
As the concentration of H+ increases, pH decreases
What is pH?
A measure of acidity or alkalinity of a solution
What is unit for pH?
Concentration of H+ ion in moles per litre
How is pH regulated by human blood?
Bicarbonate hydrogen ions
What is the chemical formula for bicarbonate hydrogen?
HCO3-
What is a buffer?
A pH regulator, which can absorb excess or donate hydrogen ions
Which pollutants cause acid rain?
SO2, CO2, SO4
What is electronegativity?
The ability of an atom to attract electrons to obtain a full outer she’ll
Which type of elements are electronegative/postive
- = non mentals \+ = metals
What is the EN value for H?
2.1
What is the EN value of C?
2.5
What is the EN value for N?
3.0