Lecture 3: Biochemistry I Flashcards
Definition of Chemistry
the science that deals with the composition and properties of substances and various
elementary forms of matter (gas, liquid, solid).
Definition of Biochemistry
the science concerned with
the chemical and physicochemical processes
& substances that occur within living organisms.
What is Matter?
is everything around us that has mass and occupies space.
What’s atoms?
Atoms are small particles that make up matter - the “Lego bricks” that make up everything in our universe.
Atoms are made up of electrons, protons & neutrons.
What is an element?
An element is a substance made up of just one type of atom so it cannot be split up into simpler substances.
How many elements in the human body?
26 different elements are normally present in the human body.
4 major elements in the human body?
carbon, hydrogen, oxygen and nitrogen, which account for 96% of the human body
What atoms are made of?
Each atom is made up of subatomic particles called protons, neutrons and electrons.
Name the THREE subatomic particles and give their weight and charge.
Protons have a positive charge and a mass of approximately 1 atomic unit.
Neutrons have no charge and a mass of approximately 1 atomic unit.
Electrons are negatively charged particles
that ‘buzz’ around the outside of the nucleus,
creating an electron cloud. They have virtually no mass at all.
What properties of an atom make it react chemically?
All the chemical properties of an atom are down to its number of protons and electrons. The neutrons just add weight to the atom; they don’t significantly change how it chemically reacts.
What determines where each element is on the periodic table?
Elements are arranged in columns and rows that show which elements share similar reactivity and physical properties.
What is the atomic number?
The number that is assigned to each
element tells us how many protons and, therefore, how many electrons each atom has.
What is the large number on on each element of the period table?
The larger number is always the mass number (the weight in atomic units). It tells us how much the atom weighs so it can be used to work out the number of neutrons (remembering that electrons weigh nothing).
Column 7 - The Halogens?
Fluorine, Chlorine, Bromine, Iodine, Astatine.
Describe the association between Iodine and Fluorine.
They both in the same group in the periodic table - they are both in group 7 so they have similar chemical reactivity but fluorine is much more powerful than iodine. Fluorine in excess on our daily lives can force iodine out of the way and it can compromise thyroid function.
Explain what is meant by an ‘ion’?
It’s a charged atom- An Ion is an atom that gives or receives an electron.
Give the chemical symbol for Potassium.
K
Name the THREE subatomic particles and give their weight and charge.
Protons which has a positive charge and weighs 1/ Neutrons which has a neutral charge and weighs 1/ Electrons which has a negative charge and weighs 0
Explain what is meant by an ‘isotope’. Give ONE example.
The same element that has a different atomic mass. Ie. Carbon 12 and Carbon 14
How many electrons are required to fill the second electron shell?
8 electrons to fill the second shell
Describe what happens in ionic bonding.
This is where 1 atom gives an electron to another atom creating a positive and a negative charged ions that are attracted to each other.
Name the FOUR most electronegative elements.
Fluorine, Chlorine, Oxygen and Nitrogen
Give an example of a polar molecule.
The most common is water
Explain what is meant by the ‘universal solvent’.
It is water unique ability to dissolve anything with polar bonds or with ionic compound- things with positive and negative charge.
Atomic number
number of protons
Mass number
number of protons + number of neutrons.
Number of neutrons
Mass number (always bigger) – atomic number
How Isotopes are used in medicine? Give an example.
Some diagnostic techniques in medicine use radioactive tracers which emit gamma rays from within the body. ie. Radiotherapy and H. pylori test
What makes chemical reactions on an atom?
Electrons always want to be in pairs. All of the reactions that happen in Chemistry are driven by atoms trying to end up with a stable and full outer shell either by stealing, giving away (donating) or sharing electrons.
What is the simplest atom of all and why?
Hydrogens is the simplest atom because it only contains one proton and one electron and no neutron.
What is bonding in chemistry?
Atoms that are trying to become stable by bonding with other atoms so that they can get just the right number of electrons in their outer shell.
What are the 2 main types of bonding?
Ionic bonding – atoms transfer electrons (1 donates, 1 receives).
Covalent bonding – occurs when atoms share electrons.
What is an ionic bonding?
Ionic bonds occur when one atom donates some of its electrons to another.
What is an Ion?
If an atom gives up or gains electrons to fill its outer shell, it becomes an ion.
What is covalent bonds?
occur when two elements share electrons so that they both have the “magic number” they are looking fo
What is Polar bonds?
Polar covalent bonds form where electrons are shared unequally.
What is electronegative elements?
Some elements have lots of protons compared to the number of electron shells i.e. a strong positive centre. These elements are referred to as ‘electronegative’ because they tend to pull the shared electrons towards themselves.
What’s a Hydrogen Bonding?
One of the most important examples of a polar bond are the bonds between Oxygen and Hydrogen in water.
• The oxygen pulls the electrons towards itself, resulting in a negatively charged area over the oxygen and
a positively charged area over each hydrogen.
