Chapter2&3 Flashcards
atoms two regions
- nucleus:
protons
-pos charge
-number determines the type and characteristic of the atom
nuetrons
-no charge - electron shells
-regions around the nucleus where elctrons (neh charge) exist
-the number of electrons is associated with a type of atom can change
shells
1st shell- 2 electrons
2nd- 8 electrons
3rd- 8 electrons
atoms
anything that takes up space/weighs
properties of atoms
- protons attract an equal amount of electrons
- when the outermost shell of an atom is unfilled, the atom is unstable
- unstable atoms interact to become stable- they gain, or lose electrons
- the amount of energy an electon holds can change
chemical bonds
- interactions of electrons between atoms
- for any atom, the number of potential bonds is determined by the number of electrons needed to fill unfilled shells
- type of bond is determined by the affinity of each atom for electrons
types of chemical bonds
ionic: electron transferred from one atom to another
(the result is known as an ion)
covalent bond: sharing of electrons between atoms
( the result is molecules)
double bond
the sharing of two pairs of electrons results in the formation of a double bond
polar covalent bond
a type pf covalent bond where electrons are not shared equally
atoms within the molecule have slight charge
ex) ozygen hydrogen bond
bonds
hydrogen- 1 bond
carbon- 4 bonds
nitrogen- 3 bonds
oxygen- 2 bonds
properties of water
polar covelent bonds result in:
1. water acting ad a solvent for ionic polar covalent substances
hydrophllic and hydrophobic
2. presence of hydrogen bonds
hydrophillic
substances that dissolve in water (ionic)
hydrophobic
substances that dont mix or dissolve in water (covalent)
hydrogen bonds result in:
- cohesion
- high specific heat
- high heat of vapourization
- expansion on freezing
two types of pH
acidic: donates h+ to a solution
basic: absorbs h+ from a solution
pH scale
water pH = 7 (neutral) < 7 = acidic > 7 = basic each unit represents a 10x change in h+ most chemical reactions in living things are sensitive to pH changes but many reactions in living things produce acids or bases
buffer
substances that absorbs or releases H+
minimizes pH changes of solutions (do this by donating H+)
organic molecules
molecules that contain carbon:
carbon atoms form 4 bonds
the characteristic of an organic molecule is affected by its functional groups (combination of particular atoms)
hydro carbons
contain only C and H -hydrophillic
alcohols
contain a hydroxyl functional group - hydrophobic
organic acids
contain a carboxyl (COOH)
amines
contain an amino acid (NH2)
amino acid
contain an amino and a carboxyl group
polymers
large molecules consisting of smaller repeated units (monomers)
monomers are bonded together through the process of dehydration synthesis
hydrolysis
removal of monomers from a polymer
3 main groups of organic molecules
- carbohydrates
- proteins
- ?
carbohydrates
contain numerous hydroxyls (OH) and a carbonyl (=O)
used for: energy structure
ploysaccharides
polymers of carbohydrates
starch, glycogen, cellulose
chitin
is the main structural component of exoskeletons and fungi cells
lipids
hydrophobic organic compounds
main functions of lipids
- energy storage
- membrane structure
- vitamins
- chemical signaling (hormones)
fats
lipids made of 1 glycerol molecule and 3 fatty acids
main function is energy storage but also used in water proofing and temp regulation
fatty acids
long chain organic acids
2 types: saturated and unsaturated
white and brown fat tissue
brown: not as much of this, heats body by burning fat, cellular reproduction, lots of blood vessels -when you’re young
waxes
long carbon chain hydrophobic molecules
used as waterproof coating
malleable: change shape under pressure
phospholipids
gycerol molecule with:
2 fatty acids and a phosphate group (PO4) hydrophillic
principal component of membranes
lipids with ring structure
diverse functions pigments membrane structures vitamins hormones (steroids)
high levels of cholesterol in the blood can lead to
a hardening and narrowing of the arteries
proteins
most diverse molecules in living organisms
polymers of amino acids
how many types of different amino acids
20 side chains contain: polar covalent bonds covelent bonds ionic bonds
structure of protein
primary: amino acid sequence
secondary: coiling or folding pattern
teriary: overall three dimensional shape
a protein depends on
its shape to create its function
proteins shape depends on
- the amino acid sequence
- enviornmental conditions 9pH, salt concentration, temp, water content)
- interactions with other molecules
the shape of a protein can change
functions of proteins
- structure
- storage
- movement
- defense
- signaling hormones
- transport
- enzymes
enzymes
control the rate of chemical reactions
chemical reactions
rearrangement of bonds between molecules
reaction with an enzyme
active sites: bind reactants
binding of reactants causes
the enzyme to change shape
once the product is formed
it can no longer bind to the enzyme. the enzyme returns to its original shape
enzymes act as
catalysts: increases the rate of chemical reactions but are not modified
if the enzyme cannot bind to the reactant
no chemical reaction occurs
feedback control
regulates rates of reactions
when the concentration of the product is high
the rate of the reaction is low
when the concentration of the product is low
the rate of the reaction is high ( this leads to homeostatis of reactants and products)
denaturing proteins
permanently changing the shape of the protein
caused by chnages in pH, salt concentration
water content, chemical reactions
