Biochemistry 1 Flashcards
What is an atom.
Name the three subatomic particles and give their weight and charge.
Atoms are the small particles that make up matter.
They are comprised of 3 subatomic particles.
protons: +ve charge and mass of 1 in the nucleus of the atom.
Neutrons: no charge and mass of 1 in the nucleus of the atom.
Electrons: -ve charge and virtually no weight. They buzz around the outside of the nucleus creating an electron cloud.
There are an equal number of protons (+ve) and electrons (-ve) giving an overall neutral charge to the atom
Protons and neutrons together form the nucleus and electrons are in shells around the outside in an arrangement of up to 2 electrons in the inner shell and eight electrons in each of the three potential outer shells.
What is an element?
An element is made up of atoms of the same type.
The periodic table is made up of elements.
How many elements in the human body and which are the most common?
There are 26 elements in the human body
CHON - Carbon (18%), hydrogen (10%), oxygen (65%) and nitrogen (3%) make up 98%.
They are found in big molecules in the body such as proteins, carbs, and fats.
List 4 fun facts about electrons…
- They have a negative charge.
- They move in groups around the nucleus known as electron shells.
- Within their shell electrons pair up. they don’t like to be on their own.
- If they are on their own, they will try to find a way to pair up through chemical bonds
What is a free radical?
This is when electrons become unpared.
Atoms or molecules that have an unpaired electron will frantically search for a partner and in doing so damage other atoms by stealing electrons or creating other free radicals.
It is a chain of damage which can eventually lead to us damaging big molecules like DNA
For this element, what is the atomic number, how many protons, how many electrons and how many neutrons . what is the atomic weight?
This is the element for chlorine.
The 17 refers to its atomic number and also the number of protons.
If there are 17 protons there are also 17 electrons.
The number of neutrons is the total mass rounded up or down minus the atomic mass so in this case it is 18
What is the periodic table and how is it arranged?
A list of all the currently known elements arranged in columns and rows that show us which elements
- share similar reactivity
- share physical properties/size
Elements in the same column tend to react in the same way but with different levels of reactivity.
Their number refers to the number of protons in the nucleus
- All of the elements in column 1 react with water. Hydrogen, sodium, potassium for example. As you go down the line, the reaction becomes more vigorous .
- the middle column is transition metals such as iron zinc and copper.
- the right side is for more structural elements like carbon nitrogen and oxygen
- group 7 are halogens. Fluorine chlorine, bromine and iodine for example. They all have a similar reactivity but as you move up the line, the reaction becomes more vigourous as opposed to group one which is as you go down the line. Fluorine at the top is very vigourous and very reactive. Iodine is milder.
How is knowledge of the periodic table relevant for suggesting supplements?
And understanding of how elements are grouped together on the periodic table can help to understand whether there might be competition for absorption between nutrients that are essential for human function.
In the middle of the periodic table, we have transition metals such as iron, zinc and copper. They can interfere with each other’s absorption and compete with each other for transporters because they are a similar size and a similar chemical reactivity.
If suggesting a supplement in this area, consider how long and the balance with other minerals. For example if we were to supplement zinc for a long time someone could be become ??? defficient.
How might thyroid hormones T3 and T4 be affected by elements?
Iodine is essential for the functioning of the thyroid gland and the release of thyroid hormones T3 and T4. If it is not being absorbed, it can lead to an ineffective thyroid – hypothyroidism.
Iodine is in group 7 on the periodic table and lower down on the list than elements such as fluorine and chlorine. More reactive elements such as fluorine and chlorine outcompete for resources leaving iodine in lower levels
Flourine at the top is very vigourous and very reactive compared to the milder iodine. Therefore, if a body is exposed to a lot of fluorine, in the form of fluoride, it will elbow the iodine out of the way making it difficult for the thyroid to absorb it properly.
The same thing can happen with chlorinated water as chlorine is above iodine on the table and will elbow it out of the way
What is the fundamental thing that drives chemistry?
It is that electrons seek a partner. Without a partner, it makes an atom reactive.
Atoms are always trying to
- fill or empty their outer shell
- pair up with electrons.
What affects reactivity in an atom?
All reactivity is down to.
- The interactions between the positive charge in protons and the negative charge in electrons
- The atoms quest to fill it outer shell or pair all of its electrons up
Explain why sodium is a reactive element
Sodium is element number 11, which means that it has 11 protons and 11 electrons.
The inner shell has a pair of two protons, the next shell has four pairs of two protons and the next shell has a single proton.
Sodium will try to get rid of the single electron. It seeks out water to shed it and this way it becomes sodium ion and the outer shell is made up of four pairs of electrons.
What is an isotope?
Different versions of the same atom but a different weight are called isotopes.
They have a different number of neutrons in the nucleus which changes the mass but doesn’t affect the chemical activity of the atom. They still behave the same, have the same chemical reactions and the same bonds but a different physical property.
For example, we have carbon 12 which is very common and which is made up of six protons and six neutrons. There are also smaller amounts of carbon 14 which has Six protons and eight neutrons.
What happens when there is an imbalance of protons and neutrons in the nucleus of an isotope?
It causes the atom to become unstable and the atom will want to lose energy.
The atom will emit energy and particles in the form of radioactivity.
How are isotopes used in medicine?
- PET scan where the patient is injected with a radioactive isotope that is short-lived and emits radiation to help image tissues in the body
- Radiotherapy which uses gamma rays from radioactive isotopes to target rapidly dividing cells… And therefore is highly damaged to healthy tissues too. The wavelength is so small that they were able to get inside the cell nucleus and disrupt DNA making the cell unviable.
- The breath test for h.pylori which is a bacteria that can live in the stomach and uses urea as its food source.
How do electrons hang out in an atom?
They hang out in particular numbers of 2:8:8:8. These are the optimum number of electrons in the shells going from inner to outer.
Electrons always want to be in pairs and if unpaired will go out of their way to find an electron to pair up with.
What drives all chemical bonding reactions?
All of the reactions that happened in chemistry are driven by atoms trying to end up with a stable and full outer shell either by
- Stealing
- Giving away (donating
- Sharing
electrons
Which is the simplest atom of all?
Hydrogen.
It contains one proton, one electron and no neutrons.
however hydrogen electrons are very reactive because they only have one electron. In nature hydrogen doesn’t exist on its own. It will always pair up with another hydrogen atom in order to share an electron and create a full outer shell.
Define an inert element
These are elements that do not easily react as they have their outer shell filled with the perfect number of paired electrons.
They are rarely involved in chemical reactions because there is no impetus for that atom or element to go find a partner
What are the two types of bonding in chemistry? Give an example of each
- Ionic bonding – where atoms transfer electrons. One donates and one receives carrying a +ve and a -ve charged ions that are attracted to each other.
An example of this is sodium which has 11 electrons with only one in its outer shell and therefore seven spaces. It is much more energy efficient for it to give away one electron than to gain seven.
On the other hand, chlorine has seven electrons in its outer shell. In this case it makes more sense in energy efficiency terms to gain an electron therefore chlorine is likely to steal an atom to fill it out of shell.
Combining these two elements
Is mutually beneficial and we get a matrix of NA and Cl. - sodium chlorine or table salt - NaCl
- Covalent Bonding
Covalent bonds occur when two elements share electrons so that they both have the number that they are looking for.
It makes sense when
- lots of atoms need to be discarded or gained in order to have a stable out of Shell
- Atoms are quite similar to each other in electron pulling power and therefore they share rather than steal.
It is a common bond for carbon and hydrogen. Carbon has four single electrons in its outer shell and shares them with four individual hydrogen atoms that will have one electron each. We end up with CH4.
Explain what is meant by an ion?
An ion is a charged atom. There’s an atom that has either gained or lost an electron.
Ions are written with a corresponding + or - charge.
Ca2+ has donated to electrons to another element and now has a positive charge
Cl- has been given one electron from another element and now has a negative charge
What is a polar bond?
A type of covalent bond between two atoms in which electrons are shared unequally leading to an uneven distribution of charge.
It is like a tug-of-war between two atoms in a molecule, where one atom has more pulling power (is more electronegative) and pulls the shared electrons closer to itself.
This uneven sharing of electrons makes the bond “polar.” A polar bond is like a tug-of-war between two atoms in a molecule, where one atom pulls the shared electons closer to itself creating a kind of mini magnet within the molecule. .
Think of a celebrity with a kind of aura that attracts everyone to their side of the room leaving it fairly empty for the unknown person at the other end.
Elements that have a strong positive centre are referred to as electronegative.
Polar bonds are common in molecules like water (H₂O), where the oxygen atom is more electronegative than the hydrogen atoms.
Other examples
Flourine - F
Chlorine - Cl
Nitrogen - N
Oxygen - 0
Why are polar bonds important in chemistry?
** They create little magnets in our molecules that allow molecules to stick to each other.
For example water molecules act like magnets and are attracted to each other.
** They will dissolve easily in water… the universal solvent. Humans are 70% water and therefore most chemical reactions are happening in a water medium.
Anything ionic or a polar bond is hydrophilic.
The opposite of this is hydrophobic or water hating. Think of fats that sit in globals on top of water.
What is the chemical symbol for …
Potassium
Sodium
Calcium
Hydrogen
carbon
magnesium
Iron
Phosphate
Bicarbonate
Potassium - K
Sodium - Na
Calcium - Ca
Hydrogen - H
carbon - C
magnesium - Mg
Iron - Fe
Phosphate - P
Bicarbonate - C+H+O - HCO3-
Describe the association between iodine and flourine.
They are both in the same column ((7) on the periodic table and have similar chemical reactivity but Fluorine is more powerful than iodine and will win out when competing for resources.
Therefore, if somebody consumes high levels of fluoride, it will affect iodine levels because there will be elbowed out of the way.
This can affect thyroid function because it interferes with T3 and T4 production
Describe what happens in ionic bonding.
One atom donates electrons and the other receives it.
It is more likely to happen when there are a small number of electrons in an outer shell for one atom and more electrons but not all paired up in another atom.
It is the most efficient bonding from an energy perspective when there is not a lot of electrons being moved around
What are the four most electronegative elements?
Elements that have lots of protons compared to the number of electron shells, in other words that have a strong positive Centre are referred to as electronegative because they tend to pull the shared electrons towards themselves.
The 4 most common electron atoms are:
F - Fluorine
Cl - Chlorine
O - Oxygen
N - Nitrogen
Give an example of a polar molecule.
The most common one that makes up 70% of the human body is water.
Therefore, most chemical reactions in the human body happen in a watery medium .
Explain what is meant by the universal solvent
This is referring to waters unique ability to dissolve anything with polar bonds or with positive and negative ions
What does CH4… Methane look like?
How is an electrolyte formed?
When ionic compound dissolves in water, an example of this would be salt which is made up of sodium (Na) and chlorine (Cl).
Give three functions of electrolytes in the human body
- Nerve and muscle function so and the heartbeat for example
- Osmotic pressure (water balance)and therefore blood pressure
- PH balance
Match the chemical structure to the correct functional group
