2.1.2 Biological molecules Flashcards
Draw a diagram to show hydrogen bonding between two water molecules
image in file
What kind of molecule is water
polar
When do hydrogen bonds form?
Slightly negative oxygen of one molecule comes close to a slightly positively charged hydrogen in another molecule
Why does water have an unsually high boiling point
Lots of energy needed to break many hydrogen bonds
Benefits of ice being less dense than water
creates an insulating barrier for aquatic animals under water, habitat for animals such as polar bears
Explain cohesion as a property of water
Creates a high surface tension for insects to walk on
Explain the adhesion property of water molecules
waters attraction to other molecules/surfaces
Explain the solvent property of water molecules
allows mineral ions to be transported around plants and animals
Explain the transport medium property of water molecules
Allows transport of soluble substances around the body
Explain the cooling mechanism property of water molecules
evaporating water takes heat away from the body
Explain the HSHC of water & why this is good
means: need lots of energy to heat water up by one degree
good because: stable temperature, enzymes can work at optimum, gases remain soluble for aquatic organisms
Explain the HLHV of water & why this is good
means: lots of enrgy to change water from liquid to gas
good because:prevents big temperature changes in environments
Explain the capillary action property of water & why this is good
Allows water to move up narrow vessels,
When does a condenstaion reaction occcur?
When a water molecule is removed to form a covalent bond
When does a hydrolysis reaction occur?
When a water molecule is added to break a covalent bond
Give the chemical elements that make up the following:
-carbohydrates
-lipids
-proteins
-nucleic acids
Carbohydrates=C,H,O
Lipids=C,H,O
Proteins=C,H,O,N,S
Nucleic acids=C,H,O,N,P
Define a monosaccharide and give 3 common examples
one unit of sugar
examples: glucose,galactose,fructose
Define a disaccharide
made of 2 monosaccharide molecules joined together
Define a polysaccharide and give an example
long chain of monosaccharides such as starch
Draw the structure of alpha and beta glucose
Diagram in 📂
2 properties of glucose
-hexose sugar
-reducing sugar
Draw the structure of ribose
diagram in 📂
What kind of sugar is ribose? Where can it be found?
pentose sugar found in RNA
glycosidic bond btwn…
carbohydrates
peptide bond btwn…
amino acids
ester bond btwn…
fatty acids and glycerol
phosphodiester bond btwn…
nucleotides in nucleic acids
disulphide bonds btwn…
sulfur atoms in cysteine amino acids
maltose is…
alpha glucose + alpha glucose
lactose is…
beta glucose + galactose
sucrose is made of..
alpha glucose + fructose
what two polysaccharides is starch made of?
amylose and amylopectin
Fill in the gaps:
both don’t ___________ therefore don’t effect the __________ _________
dissolve, water potential
bonding in amylose?
what structure does it appear as?
alpha 1,4 glcyosdic bonds, coiled structure
bonding in amylopectin?
1,4 and 1,6 glycosidic bonds
what do the bonds in amylopectin create and why is this good?
Create: branches
Good because: allows hydrolysis of ends by enzyme to create monisaccharides available for aerobic respiration
bonds in glycogen?
alpha 1,4 and 1,6 glycosidic bonds
properties of glycogen?
won’t affect wp, compact, branched ends which can be hydrolyzed by enzymes to create alpha glucoses again
where are starch and glycogen stored?
starch=plants
glycogen=mammalian livers
cellulose is formed from….
cellulose will _____________ every _______ to form ________ ________________ ____
beta glucose
rotate,180 degreees, 1,4 glycosidic bonds
how do beta glucose molecules form beta pleated sheets?
they provide….
hydrogen bonds can form cross links to form bundles called microfibrils
a high tensile strength
draw and label the general structure of an amino acid
diagram in 📂
what is different btwn the 2o different amino acids?
the r group
explain dipeptide bonds
bond btwn 2 amino acids, water molecule released
draw 2 glycines forming a peptide bond
diagram in 📂
define primary protein structure
sequence of amino acids bonded by peptide bonds
define secondary protein structure
folding of polypeptide chain held in place by hydrogen bonds: alpha helix or beta pleated sheets
defne tertiary structure of a protein
-further folding of polypeptide chain
-held in place with hydrogen bonds,disulphide bridges, ionic bonds
-hydrophobic r groups orientate towards the center of the protein, hydrophillic ones outside
define quarternary structure
more than 1 polypeptide chain
describe fibrous proteins
-strong so provide structural roles
- e.g keratin so more disulphide bridges within the keratin, the stronger (hair)
- insoluble in water due to lots of amino acids with hydrophobic r groups
-V strong bcz many cross bridges btwn polypeptide chains
2 fibrous proteins (not keratin)
elastin=alveoli - recoils after being deformed
collagen=skin - flexible but doesn’t strech
properties of globular proteins
-compact, 3d globular shape
- soluble in water bcz amibo acids w/hydrophobic r groups in center of protein
-conjugated proteins have a prosthetic r group
what’s a prosthetic group? found in what protein?
non-polypeptide component tightly bound to a protein
- conjugated protein
3 main globular proteins
insulin=specific fixed shape
haemoglobin (conjugated) = can change shape
catalase (conjugated) = specific fixed shape
give biological uses of the following cations:
Ca2+
K+
Na+
H+
NH4+
Ca2+ - muscle contraction, bohr effect
K+ - nerve impulses
Na+ - nerve impulses, selective reabsorption
H+ - translocation,photosynthesis, respiration, co-enzymes
NH4+ - nitrogen cycle
give biological uses of the following anions:
- NO3-
- HCO3-
- Cl-
- PO4)^3-
- OH-
- NO3- nitrogen cycle
- HCO3- bohr effect
- Cl- bohr effect
- PO4)^3- DNA, RNA, ATP, phospholipids
- OH- photosynthesis
biuret test 4 proteins
blue solution turns purple if protein is present
benedicts test for reducing and non-reducing ugars
reducing: heat sample w/benedicts
non-reducing: heat sample w/benedicts, no change then heat w/hcl & add an excess of NaOH
-Heat sample w/benedicts
why do we add HCl in benedicts?
why add NaOH?
-HCl breaks glycosidic bond in non-reducing sugar to give two reducing sugars
- TO NEUTRALIZE THE ACID
Reducing sugar exxamples
glucose, lactose, galactose, ffructose
non reducing sugar to know?
sucrose
emulsion test?
-few drops ethanol
-shake
-pour over water
-lipids present = white emulsion should form
How to caibrate a calorimeter
-fill cuvette w/distilled water (blank)
-put inside calorimeter + close lid
- press cal button to set to zero
-set red filter
-measure absorbance
PEQ: Describe how the concentration of a reducing sugar can be measured uing a calorimeter (7pnts)
1)serial dilution
2)benedicts test 4 both types of sugars on KNOWN + UNKNOWN CONCS
3)filter precipitate
4)use calorimeter to determine absorbance
5) plot a calibration curve
6) high glucose conc = low absorbance
7)read graph to find unknown conc
how to do thin layer paper chromatography
- sample on pencil line (on,dry x 10)
-stationary paper= dried layer of silica gel on chromatogram - only handle edges to avoid contamination
- place sample in solvent and allow it 2 travel up
- solvent MUST be below pencil line otherwise sample will dissolve
- lighter ones travel higher
- to see amino acids, spray w/ninhydrin=purple
-draw solvent front
RF formula
sample distance/solvent distance
Tiglyceride structure? bonds? condensation or hydrolysis?
3 fatty acids + glycerol, joined w/ester bonds
condensation
draw a gglycerol and a faty acid(gg-get it😏)
diagram in 📂
difference in saturated vs unsaturated fatty acids
can’t li close 2 another unsaturated triglyceride=less dense substance
phospholipid structure?
2 fatty acids, 1 phosphate, 1 glycerol
- fatty acids non-polar and hydrophobic
- phosphate group is polar and hydrophilic
triglyceride function?
-storing enrgy bcz release water when broken down
-insoluble so don’t affect water potential
-make hormones
-waterproofing
-buouyancy
-forming insulation layers
-protective layers around organs
-myelin sheath
-aids fat absorption; fat soluble molecules
function of chloesterol
- 4 carbon ring structure
- regulate fluidity
temperature effect of cholesterol on membranes
- low temp, cholesterol increases fluidity
- high temp, cholesterol decreases fluidity
