lecture 2 Flashcards
everything is made of ______
matter
smallest unit of matter
atom
molecules are … (2)
a group of atoms
connected by covalent bonds
Compounds are … (3)
atoms connected by chemical bonds
in a fixed ratio
chemical bonds (3)
ionic bonds
covalent bonds
hydrogen bonds
covalent bond
when two atoms share one or more pairs of electrons
ionic bond
when a metal transfers one or more electrons to a nonmetal.
or
when two ions are held together by opposite charges
compound
a substance made of two or more different chemicals combined in a fixed ratio
water is … (
held by a polar covalent bond
when there are multiple, they are held by hydrogen bonds through electronegativity
water exhibits ______
what does it mean?
cohesion
molecules tend to stick to one another
why is water good at moderating temperature?
water takes a long time to heat up because before the molecules can move (heat up), the hydrogen bonds keeping them in place must be broken
why does water expand on freezing?
hydrogen bonds forces water into an orderly fashion called a lattice while freezing, making it less dense than water
polar
a molecule with a charge on one side that is not canceled out
or
a molecule that is not symmetrical
non polar
molecules with even charge distribution and symmetrical shape
hydrophilic
water loving - phosphate group
hydrophobic
water fearing - oil
acid
a substance that increases the H+ concentration in water
base
a substance that increases the concentration of OH- in water
buffer
substances that minimize change in pH
what pH must blood be kept between
7.35-7.45
what happens when blood pH falls below 7.35 or above 7.45
below - blood acidosis
above - blood alkalosis
what do organic molecules contain
carbon
carbon skeleton
carbons connected by covalent bonds in a chain or ring
functional groups
other atoms or molecules attaches to the carbon skeleton
hydroxyl
- part of alcohols
- polar
- hydrophilic
sulfhydryl
- part of thiols including amino acids
- polar
- hydophilic
carbonyl
- part of ketones and aldehydes
- polar
- hydrophilic
carboxyl
- part of carboxylic acids and amino acids
- negatively charged (at body pH)
- hydrophilic
ester
- part of dietary fats, oils, triglycerides
- aspirin is an example of an ester
phosphate
- part of ATP and nucleic acids
- very hydrophilic
Amino
- part of amino acids
- at body pH, positively charged
- hydrophilic at body pH
different chemical structures lead to different chemical _____
properties
monosaccharides / simple sugars
monomers of carbohydrates
carbohydrates
compounds containing carbon, hydrogen, and oxygen.
major fuel for cells
dehydration synthesis
a process that takes away a water molecule and links two monosaccharides or amino acids
hydrolisis
breaking apart a disaccharide with water
glycosidic bond
the bond between monosaccharides after dehydration synthesis
disaccharides
molecules formed by joining two monosaccharides
polysaccharides
molecules made of many (100s-1000s) monosaccharides
types of glycosidic bond
alpha and beta
glycogen
bond type - alpha
structure - branched /compact
function - store energy in animals
example - muscle and liver cells
starch
bond type - beta
structure - long straight chain
function - store energy in plants
example - corn and potato cells
stereochemistry
3D arrangement of atoms and molecules
why can humans not break down starches?
humans do not possess the enzyme to break beta glycosidic bonds in starches, instead, they act as fibres to assist in digestion
lipids
hydrophobic molecules made of carbon, hydrogen, and a bit of oxygen. make up 18-25% of body mass in humans
types of lipids
fatty acids
triglycerides
phospholipids
steroids
eicosanoids
fat-soluble vitamins
fatty acids
hydrocarbon chain with a carboxyl group at one end
can be saturated of unsaturated
saturated vs unsaturated fatty acids
saturated - contains only single covalent C-C bonds
unsaturated - contains one or more C-C double bonds
- will create a kink or bend in the chain
triglycerides
three fatty acids bonded to a glycerol backbone by ester bonds
fats vs oils
fats are triglycerides solid at room temp
oils are the same but liquid at room temp
adipocytes
cells that store triglycerides
saturated fats contain mostly _____
fatty acids
unsaturated fats are either ______ or _______
monounsaturated or polyunsaturated
monounsaturated fats examples
avocado, peanuts, olives
polyunsaturated fats examples
corn, sunflower, fish oils
phospholipids
glycerol backbone covalently linked to two fatty acids and a phosphate group
Polar phosphate “head” of a phospholipid is _____
hydrophilic
fatty acid “tails” of a phospholipid are _____
hydrophobic
amphipathic
molecules with hydrophobic and hydrophilic parts
steroids
formed by 4 fused carbon rings (cholesterol = starting molecule)
sterols
steroids with at least one hydroxyl group
what does the hydroxyl group do for sterols? why is it important?
having a hydroxyl group makes sterols amphipathic, allowing them to cross the phospholipid bilayer. It also allows them to be bound by blood proteins and transported in the blood
eicosanoids
- 20 carbon rings
- includes prostaglandins and leukotrienes (immune signalling molecules)
what is the monomer of lipids?
there is no monomer for lipids, structures are too diverse
proteins
mainly made of carbon, hydrogen, oxygen, and nitrogen
make up 12-18% of body mass
monomer of protein
amino acids
how many amino acids are there?
20
amino acids consist of: (4)
central carbon atom bonded to:
- amino group (left)
- carboxyl group (acid)(right)
- R group (top) (reactive side chain)
peptide bond
a covalent bond found in amino acids
dehydration synthesis and hydrolysis occur in:
carbohydrates (monosaccharides)
and
proteins (amino acids)
peptide
a few amino acids joined together
polypeptide
many (10-2000) amino acids joined together
difference between a peptide and a protein?
small proteins can be a single polypeptide chain
large proteins can be many polypeptide chains folded in complex ways
what determines protein function?
its structure
for reverse, what does structure determine in proteins?
primary structure
amino acid sequence
determined by gene sequence
stabilized by peptide bonds
secondary structure
repeated folds of proteins
could be alpha helicies (helix)
or
beta sheets (like folded paper)
tertiary structure
- 3D shape
- determined by primary and secondary structure + bonds and forces that connects the chains
- disulphide bridges between R groups stabilize
- also supported by hydrogen and ionic bonds
what determines 3D shape in protein folding?
hydrophobic interactions
primary/secondary structure
quaternary structure
- not in all proteins
- the arrangement of polypeptide chains relative to others in multi-peptide proteins
globular proteins
round and water soluble
denaturing
when proteins lose their structure and are biologically inactive
what denatures proteins?
pH, heat, heavy metals
enzymes
biological catalysts
cofactors
nonprotein molecules that assist enzymes
coenzymes
cofactors that are organic molecules
enzymes are: (3)
highly specific
efficient
regulated (cells control activity)
active site
where chemical reactions are preformed on the enzyme
proenzymes
inactive forms of enzymes that must be processed (usually a part must be cut off) to become active
nucleic acids
encode genetic material
nucleic acids
encode genetic material
made of carbon, hydrogen, oxygen, nitrogen, and phosphorus
can be either DNA or RNA
DNA is ______ to RNA
transcribed
RNA is _______ by ribosomes to proteins
translated
nucleotides
monomer of nucleic acids
can be 1 of 3 things
- nitrogenous base
- pentose sugar
- phosphate group
nitrogenous bases (5)
A - adenine
C - cytosine
T - thymine (in DNA)
G - guanine
U - uracil (in RNA)
pentose sugars (2)
deoxyribose (in DNA)
or
ribose (in RNA)
what are the biggest nitrogenous bases?
adenine and guanine are bigger than cytosine and thymine
Purines (double ring bases)
Adenine and Guanine are:
Pyrimidines (single ring bases)
Cytosol and Thymine are:
nucleic acid pairing
A pairs with T
G pairs with C
backbone of nucleic acid molecule consists of:
phosphate group + pentose sugar
why is DNA shaped like a double helix?
due to the properties of the nucleotides
phosphate makes the backbone negative
DNA is (general definition)
the genetic material of all living things
how is DNA replicated?
double helix is opened, and each strand serves as a template for a new strand to be made off of
semi conservative DNA replication
each daughter helix consists of one old and one new DNA strand (from the old double helix splitting)
RNA types
mRNA - messenger
rRNA - ribosomal
tRNA - transfer
mRNA
acts as the messenger between DNA and protein production
starts in nucleus, moves to ribosome
tRNA
transports amino acids to ribosomes during translation
rRNA
main component of a ribosome
provides a site for protein synthesis
ATP
adenosine triphosphate
energy currency in cells
Exergonic cellular reactions
reactions in which ATP is produced
endergonic cellular reactions
reactions where ATP is consumes to do cellular work
ATP structure
Adenine bonded to ribose bonded to a phosphate group
how does ATP produce energy?
the terminal phosphate is broken off by an enzyme by hydrolysis. this leaves the ATP molecule as an ADP (adenosine DIphosphate), and releases a large amount of energy
ADP
adenosine diphosphate
forms when the terminal phosphate is broken off of an ATP molecule
can become ATP again via synthesis with a catalyst
catalyst for ADP to ATP reaction
ATP synthase
