Chapter 2 Flashcards
What are atoms? What are the subunits?
- smallest unit of chemical elements
- protons (+), neutrons (0), electrons (-)
What is atomic mass?
sum of protons and neutrons
What is atomic number?
number of protons in an atom
What are electron shells?
layers around nucleus
- depends on atomic number
- first shell: 2 electrons
- second shell: 8 electrons
What are valence electrons?
those in the outermost shell
- participate in chemical reactions and form bonds
What are isotopes?
same # of protons, different # of neutrons
What are ionic bonds?
occurs when valence electrons are transferred from one atom to another
What is the difference between cation and anion?
cation: + charged
- loses electron
anion: - charged
- gains electron
What happens to ionic bonds in water?
dissociation
- water forms hydration spheres around ions
What’s the difference between hydrophilic and hydrophobic molecules?
hydrophilic: soluble in water
- glucose and amino acids
hydrophobic: nonpolar
What are covalent bonds?
atoms are sharing valence electrons
What are hydrogen bonds?
forms between adjacent water molecules
- surface tension
What are acids?
release of protons in a solution (proton donor)
What are bases?
lowers H+ levels in a solution (proton acceptor)
What is pH?
concentration of H+ in a solution
pH = -log[H+]
What are buffers?
slows changes in pH by either combining or releases hydrogens
What is normal range for blood pH?
7.35 to 7.45
What is acidosis? Alkalosis?
acidosis: pH < 7.35
alkalosis: pH > 7.45
What are organic molecules?
carbon covalently bound in hydrogen
- chains or rings
- backbone for functional groups
What does the carbonyl group form?
ketones and aldehydes
What does the hydroxyl group form?
alcohols
What does the carboxyl group form?
organic acids
- lactic acid
- acetic acids
What are carbohydrates?
CnH2nOn
- building blocks: monosaccharides
What are disaccharides?
2 monosaccharides covalently joined
- sucrose: glucose + fructose
- lactose: glucose + galactose
- maltose: 2 glucose
What are polysaccharides and why are they important?
lots of monosaccharides linked together
- starch and glycogen
- energy storage
What reaction forms disaccharides?
dehydration synthesis
What reaction breaks down polysaccharides?
hydrolysis
- opposite of dehydration synthesis
What are lipids?
hydrocarbon chains and rings
- hydrophobic
What are triglycerides?
1 glycerol + 3 fatty acids
What’s the difference between saturated and unsaturated triglycerides?
saturated: no double bonds in the hydrocarbon chains
What are phospholipids?
lipids with phosphate group
- polar (bears love water) head
- nonpolar tails
What are steroids?
nonpolar 3 6-carbon rings joined to a 5-carbon ring
- insoluble
What is the precursor for steroid hormones?
cholesterol
What are prostaglandins?
fatty acids with cyclic hydrocarbon group
- regulatory functions
What are amino acids?
amine group + carboxyl group + functional group
What are peptides?
short chains of amino acids linked by peptide bonds
- dehydration reaction
What’s the different between polypeptide and protein?
polypeptide: <100 amino acids
protein: >100 amino acids
What is primary structure of protein?
sequence of amino acids
What is secondary structure of protein?
weak hydrogen bonding of amino acids
- alpha helix or beta pleated sheets
What is tertiary structure of protein?
bending and folding of polypeptide chains to produce a 3D shape
What is the quaternary structure of protein?
2+ polypeptide chains are joined
What are nucleic acids made of?
5-carbon sugar, phosphate group, nitrogenous base
What is DNA made of?
deoxyribose bonded to guanine or adenine (purines) and cytosine or thymine (pyrimidines) and a sugar-phosphate backbone
What is RNA made of?
sugar-phosphate backbone with a ribose sugar
- guanine or adenine
- cytosine or uracil
What are the 3 types of RNA that can work on a cell?
mRNA: messenger RNA
tRNA: transfer RNA
rRNA: ribosomal RNA
