LO 2 Flashcards
Chemicals are in the form of ______ which are composed of ________
Molecules, atoms
Regions surrounding the atoms nucleus and contain electrons are called _________
Energy levels (orbitals)
What determines the atomic number of an element?
The number of protons
What determines the atomic mass of an element?
Number of protons and neutrons
How many electrons may be contained in each orbital?
2 in the first, 8 in all following
Energy of electrons increases with ________
Distance from the nucleus
Define element
A pure substance made of only one kind of atom
Define molecule
A group of atoms bound together to form a larger chemical unit - e.g. H2O
Define compound
Substances whose molecules have more than one kind of atom
Living organisms require about ____ elements
20
Which 4 elements are most abundant in the human body?
Oxygen, carbon, hydrogen, and nitrogen - about 96% of body weight
Ionic bonds form between atoms that have ____ electrons in their outer shell and atoms that have _____ electrons in their outer shell
1 or 2; 6 or 7
Define ion
Atom or group of atoms with a positive or negative electric charge
Ionic bonds form when _____ attracts each other
A positive and negative ion (donation of electrons leave them with similar opposite charges)
Define electrolyte
Ionic molecules usually dissolved in water and dissociate to form free ions
Do covalent bonds dissociate in water?
No, because they share electrons they are closer together
Define hydrogen bond
A relatively weak electrostatic force of attraction between hydrogen atom and a more electronegative doner atom or group
Define organic compounds
Contain carbon-carbon covalent bonds and/or carbon-hydrogen covalent bonds
Define inorganic compounds
Do not contain the carbon-carbon or carbon-hydrogen bonds found in organic compounds
The most abundant solvent is ______
Water
Define solvent
A liquid into which solutes are dissolved, that forms an aqueous solution
Define dehydration synthesis
Water is removed from small molecules so they can be strung together to form a larger molecule (e.g. formation of bio molecules from monomers)
Define hydrolysis
Water is added to the subunits of a large molecule to break it into smaller molecules (e.g. bio molecules breaking down into monomers)
_______ is either stored or released in every chemical reaction
Energy
Define acid
Substances that shifts the H+/OH- balance in favour of H+
Define base
Substances that shifts the H+/OH- balance against H+
What numbers are neutral, basic, and acidic on the pH scale?
- 7 is neutral
- > 7 are basic
- < 7 are acidic
What is neutralization?
When strong acids and strong bases mix and form salts and water
What are buffers?
Chemical systems that absorb excess acids or bases and thus maintain a relatively stable pH (homeostasis)
What are “strong” acids?
Acids that completely dissociate in water
Should you add acid to water or water to acid?
Acid to water
What are the 4 major groups of organic compounds in the human body (biomolecules)?
- Carbohydrates
- Lipids
- Proteins
- Nucleic acids
What are the 3 types of carbohydrates with examples?
- Monosaccharides - glucose, fructose, ribose
- Disaccharides - sucrose, maltose, lactose
- Polysaccharides - glycogen
What is the function of carbohydrates in the body?
Provide energy - energy is stored in their bonds and released when broken
What are the 3 types of lipids?
- Triglycerides
- Phospholipids
- Steroids (cholesterol
Triglycerides are made of 3 fatty acids attached to ________
1 glycerol unit
What are phospholipids made of?
1 glycerol, 2 fatty acids, 1 phosphorous-containing group
(Hydrophilic head, hydrophobic tails)
Cholesterol is converted into ______ in humans
Steroid hormones (estrogen, testosterone, and cortisone)
What is cholesterol’s structure and how does it impact cell membranes?
- Core of 20 carbons in 4 fused rings
- Stabilizes phospholipid tails in cellular membranes
What are proteins?
Large molecules made of amino acids held together in long, folded chains by peptide bonds
Proteins can be divided into ______
Structural and functional
Define structural proteins with examples
Form structure of the body (e.g. collagen and karatin)
Define functional proteins with examples
Participate in the body’s chemical reactions/processes (e.g. hormones, cell membrane channels and receptors, enzymes)
Describe enzymes
Chemical catalysts using lock and key model to act on specific molecules - no processes in the body could happen fast enough without them
What could cause an enzyme to denature?
Drastic changes in pH or temperature
What are RNA and DNA made of?
Sugar, phosphate, nitrogen bases
What is the sugar in DNA?
Deoxyribose
What does RNA do?
Used as a temporary “working copy” of a gene
