Module 1 - Biological Molecules Flashcards
whats a monomer
a small, single-molecule, many of which can be joined together to form a polymer
whats a polymer
a large molecule made up of many identical/similar monomers joined together
whats a condensation reaction
joins 2 molecules together, eliminates a water molecule, and forms a chemical bond
whats a hydrolysis reaction
separates 2 molecules, requires the addition of water molecule, and breaks a chemical bond
whats a monosaccharide
monomers from which larger carbohydrates are made
whats disaccharide
condensation of 2 monosaccharides
whats a polysaccharide
condensation of many monosaccharides
give 3 examples of monosaccharides
glucose, fructose, and galactose
how do you make maltose
glucose + glucose
how do you make sucrose
glucose + fructose
how do you make lactose
glucose + galactose
whats the bond between disaccharides
glycosidic
what are the two isomers of glucose
alpha and beta
draw alpha and beta glucose
refer to notes
give 3 examples of polysaccharides
starch, glycogen, and cellulose
whats glycogens function
energy store in animal cells
what’s the structure of glycogen
the polysaccharide of alpha glucose with alpha 1,4 and 1,6 glycosidic bonds
relate 3 properties of glycogen to its function
branched - rapidly hydrolyzed to release glucose and provide energy for respiration
large molecule - can’t leave the cell
insoluble in water - water potential of cell not effected
whats starches function
energy store in plant cells
whats starches structure
the polysaccharide of alpha glucose - a mix of amylose and amylopectin
structure of amylose
alpha 1,4 glycosidic bonds so unbranched
structure of amylopectin
alpha 1,4 and 1,6 glycosidic bonds so branched
relate 3 properties of starch (amylose) to its function
helical - compact for storage in the cell
large molecule - can’t leave the cell
insoluble in water - water potential of cell not effected
what’s the function of cellulose
provides strength and structural support to plant cell walls
relate 4 properties of starch (cellulose) to its function
every other beta glucose molecule is inverted in a long, straight, unbranched chain
many hydrogen bonds - link parallel strands to form microfibrils
hydrogen bonds strong in high numbers - provides strength and structural support to plant cell walls
give examples of reducing sugars
all monosaccharides and maltose/lactose
give examples of non-reducing sugars
no monosaccharides and sucrose
what the benedicts test used for
reducing sugar
how to perform the benedicts test
add benedicts reagent to sample, heat in a boiling water bath
whats the positive result for the benedicts test
blue to red precipitate
how to test for non-reducing sugars
add few drops of dilute HCl, heat in boiling water bath, neutralize with NaHCO3, add benedicts reagent, and heat again
whats the positive result for the non-reducing sugars test
blue to red precipitate
how to perform a starch test
add iodine dissolved in potassium iodide to solution and shake
whats the positive test result for the starch test
blue-black color
how to determine glucose concentration
- Produce a dilution series of glucose solutions of known concentrations
- Perform Benedict’s test on each sample
• Heat with Benedict’s solution
• Use the same amount of solution for each test
• Use excess Benedict’s
• Remove precipitate by filtering - Using a colorimeter, measure the absorbance of each sample and plot a calibration curve
• Calibrate colorimeter using unreacted Benedict’s
• Use a red filter
• Less absorbance of filtrate = more sugar present (as removed precipitate)
• Plot absorbance against glucose concentration - Repeat with unknown sample (find absorbance) and use the graph to determine glucose concentration
what are the 2 types of lipid
triglycerides and phospholipids
whats a triglyceride
the condensation reaction between 1 molecule of glycerol and 3 fatty acids
what’s the bond in lipids
ester bonds
relate 2 properties of triglycerides to their structure
high ratio of C-H bonds to C atoms in hydrocarbon tail so release more energy than the same mass of carbohydrates
Insoluble - no effect on water potential of cell
how is an ester bond formed
the condensation reaction between glycerol and fatty acid (RCOOH)
whats a phospholipid
the condensation reaction between 1 molecule of glycerol, 2 fatty acids, and a phosphate group
what do phospholipids do
form bilayer in the cell membrane - allows diffusion of small/ non-polar molecules
relate 2 properties of phospholipids to their structure
phosphate heads are polar/hydrophilic so are attracted to water so face the aqueous environment on either side of the membrane
fatty acid tails are non-polar/hydrophobic so are repelled by water so face inside of the membrane and repel polar/charged molecules
what’s meant by saturated fatty acid
no C=C double bonds in the hydrocarbon chain
what’s meant by unsaturated fatty acid
one or more C=C double bonds in the hydrocarbon chain
what the emulsion test for lipids
add ethanol and shake
then add water
what the positive result for the emulsion test for lipids
milky white emulsion
whats an amino acid
the monomers from which proteins are made
whats the bond between 2 or more amino acids
peptide bond
what are the different groups of an amino acid
NH2 - amino group
COOH - carboxyl group
R group - side group –> produces 20 different amino acids
draw the amino acid general structure
refer to notes
whats a dipeptide
the condensation reaction between 2 amino acids to form a peptide bond
whats a polypeptide
the condensation reaction between many amino acids to form a peptide bond
silly little fact
a functional protein may contain one or more polypeptides
whats the primary structure of a protein
the sequence of amino acids in a polypeptide chain
whats the secondary structure of a protein
hydrogen bonding between amino acids (between carbonyl O of one and amino H of another)
causes polypeptide chain to fold into a repeating patter - alpha helix or beta plated sheets
whats the tertiary structure of a protein
overall 3d structure of a polypeptide held together by interactions between amino acids and side chains - ionic bonds, disulphide bridges and hydrogen bonds
whats the quarternary structure of a protein
some proteins made up of 2+ polypeptide chains
held together by more hydrogen, ionic, and disulfide bridges
what the test for proteins
biuret test
how to perform the biuret test
add biuret solution - NaOH + CuSO4
what the results of the biuret test
positive=purple colour
negative=stays blue
what are enzymes
a biological catalyst that lowers the activation of the reaction it catalyzes so speeds up the rate of reaction
what reactions do enzymes catalyze
intracellular and extracellular
what the induced fit model
before reaction = enzymes active site isn’t complementary to the substrate
active site changes shape as substrate binds and E-S complex forms
this distorts bonds in substrate leading to reaction
outline the specificity of enzymes
. have a specific shaped tertiary structure and active site and primary structure determine the tertiary structure
. active site complementary to a specific substrate
.only specific substrate can bind to active site, forms E-S complex
how does enzyme concentration affect ROR
Increasing enzyme conc = ROR increases
Enzyme conc = limiting factor (substrate in excess)
More enzymes more available active sites
More successful E-S collisions and E-S complex
At a certain point, rate of reaction plateaus
Substrate conc. = limiting factor (all substrates in use)
how does substrate concentration affect ROR
increasing substrate conc=rate of reaction increases
Substrate concentration = limiting factor (too few
enzyme molecules to occupy all active sites)
More successful E-S collisions and E-S complexes
At a certain point, rate of reaction plateaus
Enzyme conc. = limiting factor (all active sites
saturated; excess substrate)
how does increasing temp to optimum effect ROR
Increasing temp up to optimum= rate of reaction increases
Increase in kinetic energy
More successful E-S collisions and E-S complexes
how does increasing temp past optimum effect ROR
Increasing temp. above optimum=rate of reaction falls
Enzymes denature; tertiary structure and active site
change shape (hydrogen / ionic bonds break)
Fewer E-S collisions and E-S complexes (substrate no
longer binds to active site)
Rate of reaction 0 when all enzymes denatured
how does increasing pH above/below optimum effect ROR
rate of reaction decreases
Enzymes denature; tertiary structure and active site change shape (hydrogen and ionic bonds break)
The complementary substrate can no longer bind to active site
Fewer E-S collisions and E-S complexes
how to calculate pH
pH = - log10 [H+]
how do competitive inhibitors decrease ROR
similar shape to the substrate
binds and blocks active site so substrate cant bind
fewer E-S complexes form
how to combat the effect of competitive inhibitors
increase substrate concentration
how do non-competitive inhibitors decrease ROR
binds to the allosteric site
enzymes tertiary structure changes so active site changes shape so substrate cant bind
fewer E-S complexes form
how to combat the effect of non-competitive inhibitors
you cant - increasing substrate concentration has no effect as permanent damage done to the active site
whats the function of DNA
holds genetic information
whats the function of RNA
transfer genetic information from DNA to ribosomes
what are ribosomes made from
RNA and proteins
what the structure of a nucleotide
pentose sugar, a nitrogenous base, and a phosphate group
what bonds formed between nucleotides after a condensation reaction
phosphodiester bonds
whats DNA
2 antiparallel strands, held together by hydrogen bonds between specific complementary base pairs (A-T and C-G) twisting into a double helix
whats RNA
single RNA polynucleotide strand
give two differences between DNA and RNA nucleotides
DNA nucleotides have a deoxyribose sugar whereas RNA has a ribose pentose sugar
DNA nucleotides have the thymine base whereas RNA nucleotides have uracil
give two differences between DNA and RNA molecules
DNA is double-stranded whereas RNA is single stranded
DNA is longer whereas RNA is shorter
relate 7 DNA structure components to its function
Double-stranded = both strands can act as a template in semi-conservative DNA replication Weak hydrogen bonds between bases = unzipped for replication Complementary base pairing = accurate replication Many hydrogen bonds between bases = stable/strong molecule Double helix with sugar-phosphate backbone = protects bases Long molecule = store lots of genetic information Double helix (coiled) = compact
how to use incomplete information about the frequency of bases on DNA strands to find the frequency of other bases
% of adenine in strand 1 = % of thymine in strand 2 (and vice versa)
% of guanine in strand 1 = % of cytosine in strand 2 (and vice versa)
outline process of semi-conservative DNA replication
- DNA Helicase breaks hydrogen bonds between bases, unwinds the double helix
- Two strands which both act as templates
- Free-floating DNA nucleotides attracted to exposed bases via specific complementary base
pairing, hydrogen bonds form (adenine-guanine; guanine-cytosine) - DNA polymerase joins adjacent nucleotides on a new strand by condensation, forming phosphodiester bonds
- Replication is semi-conservative – each new strand formed contains one original template strand
and one new strand - Ensures genetic continuity between generations of cells
why does DNA polymerase move in opposite directions along the DNA strands
DNA has antiparallel strands
DNA polymerase is an enzyme with a specific shaped active site that can only bind to substrate with
a complementary shape
Can only bind to and add nucleotides to the phosphate (3’) end of the developing strand (so works in a
5’ to 3’ direction)
whats the evidence for semi-conservative replication
Meselson and Stahl
what is involved in the Meselson and Stahl experiment
Bacteria were grown in a nutrient solution containing heavy nitrogen (15N)
for several generations
• Nitrogen incorporated into bacterial DNA bases
• Bacteria then transferred to a nutrient solution containing light
nitrogen (14N) and allowed to grow and divide twice
• During this process, DNA from different samples of bacteria was
extracted, suspended in a solution in separate tubes and spun in a
centrifuge
whats the results of the Meselson and Stahl experiment
Sample 1 = DNA from bacteria grown for several generations in a nutrient solution containing 15N
DNA molecules contain 2 ‘heavy’ strands
Sample 2 = DNA from bacteria grown originally in a nutrient solution containing 15N, then transferred for one division to a solution containing 14N so DNA molecules contain 1 original ‘heavy’ and 1 new ‘light strand
Sample 3 = DNA from bacteria grown originally in a nutrient solution 15N, then transferred for two divisions to a solution containing 14N 50% DNA molecules contain 1 original ‘heavy’ and 1 new ‘light’ strand, 50% contain both ‘light’ strands
whats the structure of ATP
a ribose sugar, a molecule of adenine and, 3 phosphate groups
whats the structure of ADP
a ribose sugar, a molecule of adenine and, 2 phosphate groups
what is ATP
a nucleotide derivative
outline the process of hydrolysis of ATP
ATP is hydrolyzed into ADP and Pi and is catalyzed by ATP hydrolase and energy released when bonds between inorganic phosphate groups are broken
The inorganic phosphate released can be used to
phosphorylate other compounds -making them more reactive
outline the process of formation of ATP
ADP and Pi undergo a condensation reaction which is catalyzed by the ATP synthase
Happens during respiration
Called phosphorylation of ADP
what are the properties of ATP that make it a suitable immediate source of energy
ATP releases energy in small, manageable amounts so no energy wasted
Only one bond is hydrolyzed to release energy which is why energy release is immediate
Can ATP be stored
no
how does hydrogen bonding occur between water molecules
Water is a polar molecule so slightly negatively charged oxygen atoms attract slightly positively charged hydrogen atoms of other water molecules so hydrogen bonds form between water molecules
what are the 5 properties of water that is important in biology
high specific heat capacity, high latent heat of vaporization, cohesive, solvent, and metabolite
explain the property of high specific heat capacity
Polar so many H bonds form between water molecules
these allow water to absorb a relatively large amount of
heat energy before its temperature changes
explain the property of high latent heat of vaporization
Polar so many H bonds form between water molecules
these can absorb a lot of energy before breaking,
when water evaporates
explain the property of cohesive
Polar so many H bonds form between water molecules
so water molecules tend to stick together
explain the property of solvent
Polar (has slightly positive and negative ends) Can separate (dissolve) ionic compounds e.g. NaCl as +ve end attracted to -ve ion (Cl-) and negative end attracted to positive ion (Na+)
explain the property of metabolite
Water is reactive
whats the importance of high specific heat capacity in biology
Good habitat for aquatic organisms e.g. lakes as
temperature more stable than land
Organisms mostly made of water so helps maintain
a constant internal body temperature – important
as temperature affects enzyme activity
whats the importance of high latent heat of vaporization in biology
Evaporation of small amount of water (e.g. sweat)
is an efficient cooling mechanism
• Helping organisms maintain a constant body
temperature
whats the importance of cohesion in biology
Column of water doesn’t break when pulled up a
narrow tube e.g. xylem during transpiration
• Produces surface tension at an air-water surface so
invertebrates can walk on water e.g. pond skaters
whats the importance of solvent in biology
Can dissolve other substances e.g. inorganic ions,
enzymes, urea, etc. so water…
• Acts as a medium for metabolic reactions (which
can happen in water)
• Acts as a transport medium e.g. in xylem to
transport nitrates which are needed to make
amino acids
whats the importance of metabolite in biology
Condensation releases H2O and forms a chemical
bond; hydrolysis requires H2O to break a bond; e.g.
amino acids joined by condensation reactions to
form polypeptides
where and how do inorganic ions occur
Occur in solution in the cytoplasm and body fluids of organisms, some in high concentrations and others in very low concentrations
name the 4 inorganic ions
phosphate, hydrogen, iron and, sodium
what the role of phosphate
Attached to other molecules as a phosphate group such as in DNA nucleotides enabling nucleotides to join together forming phosphodiester bonds and in ATP as bonds between these store/release energy
what the role of hydrogen
Maintain pH levels in the body
• Too much H+ = acidic (low pH)
• Too little H+ = alkaline (high pH)
• Affects rate of enzyme-controlled reactions as can cause enzymes to denature
what the role of iron
Component of (haem group of) haemoglobin which is contained in red blood cells that transports oxygen around the body – oxygen temporarily binds to it, so it becomes Fe3+
what the role of sodium
Co transport of glucose and amino acids across cell membranes
Involved in generating nerve impulses and muscle contraction
