Biochemistry 1 Flashcards
What is ‘matter’?
Everything around us that has mass and occupies space.
What is chemistry?
The science and study of matter (gases, liquids and solids)
List 3 forms of ‘matter’.
Gases
Liquids
Solids
What is ‘biochemistry’?
The science and study of the chemical and physiochemical processes and substances within LIVING organisms.
What is the difference between chemistry and biochemistry?
Chemistry is the science concerned with substances and various forms of elementary matter, whilst biochemistry is the science concerned with the same in LIVING organisms.
What 3 things are atoms made up of?
Electrons, Protons and Neurons
What are atoms?
Small particles that make up ‘matter’. They’re like lego bricks that make up everything in our universe
‘bio’ = ______
Life
An ‘element’ is a substance made up of just one type of _____.
Atom
Why can’t elements be split up into simpler substances?
Because elements are substances made up of just one type of atom (lots of identical lego bricks together)
All the elements we know of are in the ______ ______
Periodic Table
What is the chemical symbol for carbon?
C
What is the chemical symbol for hydrogen?
H
What is the chemical symbol for calcium?
Ca
What is the chemical symbol for magnesium?
Mg
Name 4 elements from the periodic table
Carbon
Hydrogen
Calcium
Magnesium
What is the name given to a group of individual atoms joined together by bonds?
A molecule
How many different elements are normally present in the human body?
26
There are 4 major elements which account for 96% of the human body. Name them.
Carbon
Hydrogen
Oxygen
Nitrogen
What is Fe?
Iron
Name 3 ‘transition metals’
Iron
Zinc
Copper
Why do transition metals and some other groups of elements on the periodic table interfere with each others absorption?
Because they are a similar size and similar chemical reactivity, so compete for the same transporters.
Name 3 halogen elements
Fluorine
Chlorine
Iodine
What are subatomic particles?
The components of an atom.
How many subatomic particles are there? List them.
3 - Protons, neutrons, electrons
Which subatomic particles together form the nucleus of an atom?
Protons and neutrons
Which of the subatomic particles carries a positive charge?
Protons
Which of the subatomic particles carries no charge?
Neutrons
Which of the subatomic particles carries a negative charge?
Electrons
Which of the 3 subatomic particles is the smallest?
Electrons
State the individual masses of the 3 subatomic particles.
Protons = 1 atomic unit Neutrons = 1 atomic unit Electrons = virtually no mass at all / nothing
An element will have an equal number of protons and electrons. True or false?
True
What are electron shells?
Layers of electrons moving in groups around the nucleus of an atom.
What happens to an atom if it has an electron that isn’t paired? What name is given to that atom in this situation?
It becomes very stable.
Free radical
When does an atom become reactive?
If its outer electron shell isn’t full, or if it loses an electron.
What are free radicals?
Atoms or molecules that have an unpaired electron.
What is the difference between atoms and molecules?
Atoms are single neutral particles.
Molecules are neutral particles made of 2 or more atoms bonded together.
Are atoms and molecules positive, negative or neutral?
Neutral.
Do protons have a positive or negative charge?
Proton = Positive
Do electrons have a positive or negative charge?
Electrons = Negative
How many electrons can be found in the first electron shell (nearest the nucleus of the atom)?
2
How many electrons can be found in the second electron shell?
Up to 8
How many electrons can be found in the third electron shell?
Up to 8
What is the periodic table?
A list of all the currently known elements
Why is the periodic table arranged in particular columns and rows?
To show which elements share similar reactivity and physical properties.
In the periodic table, what does the number assigned to each element tell us?
The atomic number tells us the number of protons in the nucleus
Potassium (K) has an atomic number of 19. What does this tell us?
That there are 19 protons in the nucleus of a single atom of potassium.
A single atom of potassium (K) has 19 protons in it’s nucleus (atomic number 19). How many electrons does it have?
- The number of protons always matches the number of electrons.
What does the second (bigger) number attached to an element on the periodic table tell us?
The mass / atomic weight of one atom of that particular element.
Potassium carries the atomic number 19, and has an atomic mass of 39. How many neutrons does it have in its nucleus?
20
39 - 19
All of the elements in column 1 (Group 1) of the Periodic Table react with ______
Water
All of the elements in column 1 (Group 1) of the Periodic Table have how many electrons in their outer shell?
1
This means they’re very reactive.
What name is given to the elements in column 7 of the Periodic Table?
The halogens
List 3 elements in the halogen group?
Fluorine, Chlorine, Iodine. Bromine, Astatine
Why is iodine important when it comes to thyroid health?
Because it is required to make the thyroid hormones T3 and T4
What’s different about Column 7 (the halogens) of the Periodic Table, versus the other columns?
The reactivity tends to be higher at the top of the column, rather than at the bottom.
i.e, fluorine is more vigorous in its reactivity than iodine is.
Explain why fluorine and chlorine present a risk to thyroid health.
Fluorine and Chlorine are more reactive than iodine, but the thyroid will uptake all of them.
The more reactive halogens will elbow the iodine out of the way, creating problems with the body absorbing and using the iodine properly.
This can cause hypothyroidism.
Which of these assigned to an element is always bigger; the atomic mass or the atomic number?
The atomic mass
Atomic number = number of _______
Protons
Mass number = number of ______ + number of ____
Protons + neutrons
The total mass of an atom is always in its nucleus
Number of neutrons = _______ number minus ______ number
Mass number - atomic number
What are isotopes?
Atoms of the same element which have a different number of neutrons in their nucleus.
Essentially, isotopes are different versions of the same atom.
The chemical reactivity stays the same, but the atomic weight varies. i.e, isotopes are lighter and heavier versions of the same atom.
For every element on the periodic table, there is often more than one version (various isotopes). Give an example of an element to which this applies and describe its isotopes.
Carbon.
Most of the carbon in the universe is carbon 12 (6 protons and 6 neutrons)
But small amounts of Carbon 14 (8 neutrons) exist.
What causes an isotope to become radioactive?
An imbalance of protons and neutrons in its nucleus.
The imbalance causes the atom to become unstable, so it’s tries to rebalance itself by releasing particles of energy. This is radiation.
Name 1 way in which radioactive isotopes are used in medicine.
PET scans (via injected short-lived radioactive isotopes)
What is the difference between short-lived and long-lived radioactive isotopes?
Short-lived isotopes release their excess energy quickly (over hours / days), so don’t remain radioactive for long.
Long-lived radioactive isotopes release their energy slowly (over days / weeks / months / years), so remain radioactive for much longer.
Name 2 diagnostic tests / medical treatments that use radioactive tracers
- Radiation
2. H-Pylori breath test
What are radioactive tracers?
Radioactive isotopes that emit gamma rays from within the body
What is gamma radiation?
Very high energy wavelengths that damage rapidly dividing cells.
The wavelengths in this type of radiation are so small that they can actually get into the nucleus of the cell, damaging the DNA and making it unviable.
What is the downside to medical treatments that utilise gamma radiation?
Gamma radiation is not just specific to unhealthy / cancer cells. It also damages healthy cells.
What is the food source for H-Pylori in the stomach?
Urea
Electrons always want to be in ______
Pairs
What makes one atom want to bond with another?
The drive to pair electrons and end up with a stable/full outer shell.
All of the reactions that happen in chemistry are driven by…..
Atoms trying to get a stable/full outer shell of electrons
either by donating one, stealing one (or more), or sharing
There are 3 ways in which atoms can obtain a stable/full outer shell of electrons. What are they?
- Donate
- Steal
- Share
Name the ‘simplest atom’ and explain why it has that name.
Hydrogen is the ‘simplest atom’
Because it has 1 proton, 1 electron and no neurons
Why is hydrogen very reactive?
Because it only has 1 electron.
In nature, hydrogen atoms don’t exist on their own. Why not?
Because they’re so reactive (with only 1 electron) that hydrogen always pairs with itself via sharing of electrons, or bonds to something else.
What is an ‘inert’ element?
An element with a full outer shell of electrons.
Why are inert elements rarely involved in chemical reactions?
Because they have a full outer shell of electrons, so are not highly reactive.
Name the 2 main types of bonding.
- Ionic bonding
2. Covalent bonding
Describe what happens in ionic bonding.
Electrons are transferred from one atom to another
What is the difference between ionic and covalent bonding?
In ionic bonding, electrons are transferred from one atom to another, in order to form electron pairs.
In covalent bonding, electrons are shared between atoms, in order to form electron pairs.
When does Na- become Na+ ?
When it gives away its spare electron.
The charge changes, as it then has more protons (+ve charged) than electrons (-ve charged).
What is ‘ionisation’?
The process of giving or gaining electrons
What does + or - written next to an ion (i.e, Cl-) indicate?
Their positive or negative charge after bonding.
A +ion has more protons than electrons
A -ion has more electrons than protons
Remember: a raw atom has an equal number of protons and electrons (parents and children!)
An ion is also known as a _______ particle.
Charged particle.
Sometimes atoms give away more than one electron. How might you see this written?
Calcium
Ca2+ is a calcium atom that has given away 2 electrons.
Name the 4 most electronegative elements.
- Fluorine
- Chlorine
- Oxygen
- Nitrogen
Some elements have lots of protons compared to their number of electron shells (i.e, a strong positive centre). These elements are referred to as _________
Electronegative
What is the name given to an element that has a strong positive centre and tends to pull shared electrons towards itself?
Electronegative
What is the name given to covalent bonds where the electrons are shared, but unequally?
Polar bonds
Why do polar bonds occur?
Become some atoms have more electron ‘pulling power’ than others. They pull shared electron clouds towards themselves.
Why are polar bonds important in Chemistry?
Because they create little magnets in our molecules, which allow molecules to stick to each other.
Give an example of one of the most important polar bonds in biochemistry.
Oxygen and hydrogen (water)
________ bonding is an example of polar bonding, and gives water its surface tension and ability to dissolve so many things.
Hydrogen bonding
________ bonding is an example of polar bonding, and gives water its magnetic surface tension (i.e, sticking a glass to a coaster) and ability to dissolve so many things.
Hydrogen bonding
What serves as the medium for most chemical reactions in the body?
Water
What is the ‘Universal Solvent’?
Water
Hydrophilic molecules are molecules that have _____ covalent bonds.
Polar
Hydrophobic molecules are molecules that have ____-____ covalent bonds.
Non-polar
What type of bonds are magnetic-creating bonds?
Polar bonds
What is an ion?
A charged particle. It is an atom that has either gained an electron, or given one away.
Explain what is meant by an isotope.
Isotopes are chemical elements that are the same elements but with a different number of neutrons. So they have different atomic masses.
i.e, carbon 14, versus carbon 12
Describe the association between iodine and fluorine.
They’re both halogens (Group 7 on the periodic table). However fluorine is more reactive/powerful than iodine, so an excess of fluorine in the body can push iodine out of the way and compromise thyroid function.
How many electrons are required to fill the second electron shell?
8
Describe what happens in ionic bonding.
One element (atom) gives an electron to another element, resulting in 2 positive and negatively charged atoms that are attracted to each other.
Give an example of a polar molecule.
Water.
Explain what is meant by ‘The Universal Solvent’.
Water’s unique ability to dissolve anything with polar bonds, or ionic compounds (things with positive and negative ions).
Electrolytes can conduct ________
Electricity
Solutions of ionic compounds are called ________
Electrolytes
Name 4 of the key electrolytes in the body.
- Sodium
- Potassium
- Chloride
- Calcium
- Magnesium
- Phosphate
- Bicarbonate
When / how is an electrolyte formed?
When an ionic compound (i.e, salt) dissolves in water
List 3 functions of electrolytes within the body.
- Conducting electricity (essential for nerve and muscle function)
- Exerting osmotic pressure (essential for water balance)
- Some play an important role in acid-base balance.
Our bodies essentially run on electrical chemistry. True or false?
True
Our acid-base balance within the body is often referred to as our _H
pH
What does pH stand for?
Potential of Hydrogen
What is an acid?
A substance that releases a high amount of hydrogen (H+) ions when dissolved in water.
What is a base?
A substance that binds to hydrogen ions in solution.
What is the difference between an acid and a base?
An acid releases a high amount of hydrogen ions when dissolved in water, whilst a base binds to hydrogen ions in a solution.
What is the pH of water?
7
More more hydrogen a substance releases in water, the ____ its pH, and the more acidic it is.
Lower
What is OH-?
Hydroxide
Water is a neutral solution because for every H+ released, an ____ is created.
OH-
Anything below pH 7 is an _____
Acid
Anything above pH 7 is an ______
Base (alkali)
What pH is neutral?
pH 7
The pH of blood is carefully maintained and balanced within what range?
7.35 - 7.45 pH
What is the optimum pH of the stomach?
2-3 pH
Why do we need the body to maintain particular pH levels?
Because it provides the perfect conditions for essential enzymes to work correctly.
Why might a lot of fruits and vegetables have a low pH if measured before consumption?
Because they contain organic acids.
These are metabolised by the body and intestinal bacteria to become alkaline.
List 3 alkaline minerals.
- Magnesium
- Potassium
- Calcium
Before consumption, dairy is not very acidic and is also high in calcium, an alkaline mineral. So why does it have an acidic effect of the body once consumed?
Because it has a high content of protein and sulphur amino acids. These cause the formation of sulphuric acid in the body, which disrupts blood pH.
Why does dairy consumption cause loss of calcium leaching, even though it is high in calcium itself?
Because dairy contains a high level of sulphur amino acids. These cause formation of sulphuric acid in the body, which disrupts blood pH; drawing more alkaline calcium from the bones to neutralise the acid, and increasing calcium loss in urine.
Why does meat (organic or not) have an acid-forming effect on the body?
Because of its high sulphur amino acid and purines content, which causes the formation of sulphuric acid and uric acid within the body.
Cancer thrives in an acidic environment. It is thought that a tissue pH of ___ or above would start to kill cancer cells.
8
List 2 ways in which we can measure the pH of the body.
Via saliva & urine testing on litmus paper
When do chemical reactions occur?
When new chemical bonds are formed between molecules, or old bonds are broken.
Every chemical reaction involves the transfer of energy to either _______ (stored) energy, _______ energy or _____.
Potential energy, kinetic energy, or heat
What are ‘reactants’?
The starting materials in a chemical reaction.