S1-L2: Introduction to Biological Molecules Flashcards
What are carbon-based compounds?
-Basic units of biological molecules
Outline the purpose of functional groups
-determine molecule’s function
What is the difference between monomers and polymers?
-simple VS complex molecules
Why is water important?
refer to figure 1
-for the sustenance of life
Briefly describe life as being “carbon based”
refer to figure 2
- Carbon-basis of living material due to to ability to form 4 bonds with
- ->other atoms and/ or wide variety of molecules
How do carbon-based molecules vary?
refer to figure 3
-vary from simple to complex molecules
Describe large carbon-based molecules like graphite and diamond
- held together via strong covalent bonds
- -> e- charge clouds merge to form covalent bonds
Briefly outline the composition of a carbon atom and its outer most orbital
- 6 protons (+)/ 6 neutrons/ 6 electrons (-)
- outer e- orbital lacks 4 of 8 electrons which need filling
How do carbon atoms form covalent bonds with themselves or other atoms?
- Either with themselves or other e- deficient atoms-form covalent bonds
- ->share electron pair-more than 1 e- needed to fill outer orbital
- ->shared e- pair form covalent bond
- ->bonds can be single/double/triple
Which atoms can Carbon form covalent bonds with?
-Carbon (C) Hydrogen (H)/ Oxygen (O)/ Nitrogen (N)/ Sulfur (S)
What does “valence” mean and how is it significance along with low atomic weight?
- Valence- is the n. of missing e-‘s
- valence and low atomic weight–>give unique properties which account for diversity + stability of C-containing compounds and its role in biological molecules
Outline the significance of “functional groups” and their effect on carbon based compounds
- Each functional group has specific properties and so a specific function
- functional groups are able to attach to C-based compounds and control atom’s function
What do cellular chemical reactions often invove?
-involve functional group transfer (loss or gain of them)
How are covalent bonds in carbon-based compounds significant for life and give an example?
- covalent bond breakage in C-based compounds releases energy
- ->this energy used to sustain life
- EXAMPLE: CO2 (O=C=O) –> only contains 2 C=O bond with low energy
Briefly outline the key features of the following functional groups:
1-Alkene 2-Alkyne 3-Alcohol 4-Ether 5-Haloalkane
1- C=C/ “-ene”/ E.G: 2HC=CH2–> ethene (ethylene)
2- C-(x3)C/ “-yne”/ E.G: HC-(x3)CH/ ethyne (Acetylene)
3- C-O-H (2 lone pairs on O)/ “-ol”/E.G: CH3-OH methanol (methl alcohol)
4- C-O-C (2 lone pairs on O)/ “ether” / E.G: CH3-O-CH3/ dimethyl ether
5- C-X (X= halogen)/ “halo-“/ E.G: CH3-Cl/ chloromethane (methyl chloride)
Continued:
6- Amine 7-Aldehyde 8-Ketone 9-Carboxylic Acid 10-Ester
6- C-N/ “-amine”/ E.G: CH2-CH-NH2/ ethylamine
7- H-C=O/ “-al”/ E.G: CH3-CO-H/ Ethanal
8- C-C=O-C/ “-one”/ CH3-CO-CH3/ Propanone
9- O=C-OH/ “-oic acid”/ CH3-CO-OH/ ethanoic acid
10- O=C-O-C/ “-oate”/ CH3-COOCH3/ methyl ethanoate
Similarly, briefly outline the following functional groups
1-Thiol
2-Phosphate
3-Amide
1- R-S-H/ Sulphydryl
2- RO-RO-(P)=O-OR/ Phospahte
3- R-(C)=O-NR2 (R= alkyl/ other organic substitute)
Explain the basics as to what all our complexity comes down to
- All complexity comes down to C and H2O molecules
- -> which interconnected through array of functional groups
What are functional groups usually classified as?
-classified as hydrophobic/hydrophilic depending on their charge/ polarity
Define the term “macromolecules”
-Large biological molecules with repeating sub-units & many functional groups
What are 4 main biologically important macromolecules?
-carbohydrates/ lipids/ proteins/ nucleic acids
Outline the meaning of “monomers” and “polymers” in the context of macromolecules
- monomers: macromolecules composed of building blocks
- polymers: monomers joined via covalent bonds to from long chain/macromolecules
Describe the process of dehydration synthesis through which polymers are formed
- water molecule formed and removed from reactants joined during reaction
- ->requires energy in ATP form (adenosine 5’ triosephosphate)
Similarly outline the process of Hydrolysis through which polymers are broken down
- bonds between reactants broken through water molecule addition (H2O)
- -> energy released from bond stored as ATP
- hydrolysis process is the opposite of dehydration synthesis
Why do big molecules like starch need to be broken down and what is needed to aid this process?
- need to be broken down in to smaller units to be easily digested AND absorbed across gut
- ->this hydrolysis reaction needs enzymes help
Define the term “enzymes”
-biological catalyst which increases chemical reaction rate without being used up
Give brief background to the water molecule and its involvement in organisms
- H2O is it’s chemical formula
- most abundant molecule in body–> 60-95% of fresh mass of living organisms
- Medium- cellular chemical reactions occur here
- major role in living systems-growth/reproduction/ hydration/ nutrition/ hygiene and health
How does water act as a Universal Solvent and Transporter?
- all body fluids mostly water
- aids movement of chemical reactions during diffusion
How may water act as a Lubricant?
- In joints and on tissues
- also moistens epithelial surfaces like the eye/mouth
Outline how water can act as a Shock Absorber
- In the brain-very sensitive to CFS changes
- ->small amount removed would require it to be recovered
Describe how water Regulates Body Temp
- water needs heat to turn to vapour
- sweat absorbs heat from skin when evaporating
How much water do we need?
- Body tissue is approximately 62% of water
- we need approximately 1.5L/ day
What happens when we lack the required amount of water in the body?
- Leads to dehydration
- -> which associated with many conditions like diarrhoea/vomiting
- dehydration can be fatal so needs to be treated as soon as possible
- ->through fluid replacement therapy (example) OR oral intravenous (IV)
Describe Capillary Refill Time (CRT)
-Time taken for colour to return to external capillary bed after pressure applied to cause blanching (make white/pale)
What is the Capillary Refill Test?
-test to check hydration status of blood flow
How is CRT measured?
- hold hand higher than heart level
- press on soft pad of finger/nail until turns white
- note time taken for colour to return
- ->should be around 2 s for normal people and 5 s new born infants
- ->if time longer than should be indicates dehydration
What is the typical structure of water molecule like?
- Simple oxygen molecule
- ->one oxygen molecule atom bonded by single C-bond to 2 H atoms
Outline the atomic structure of O and H and how it affect the covalent bonding in H2O’s structure
- O atom contains 8 (+) protons in nucleus
- each H atom contains 1 (+) proton in nucleus
- ->results in shared e- pair in each covalent bond in H2O to be more strongly attracted to O than to either H nuclei
How is a water molecule polar/charged?
- slight (-) pole near O (delta -) and slight (+) pole near H (delta +)
- ->makes water molecule polar as a result
How does hydrogen bonds form between two water molecules?
-Delta (+) near H atoms attracted to delta (-) near O atom of nearby water molecules
Why is water a liquid?
- H bonds relatively weak–> 5-10% strength of covalent bonds
- also easily broken–> 1/100,000,000,000 of second)
- H bonding creates fluid as molecules constantly change patterns
Explain how water is a powerful solvent
- NaCl (salt) lattice of Na+ ions ionically bonded to Cl- ions
- -> delta (+) H’s attracted to Cl- AND delta (-) O’s attracted to Na+ ions
- ->lattice pulls apart and salt dissolves in water
How does water act as a universal solvent?
- all polar (charged) molecules and ions water soluble as able to form H bonds with water
- ions + polar molecules able to move and interact freely
- ->also able to take part in cellular chemical reactions
What are non-polar molecules and why are they hydrophobic?
- Have no electrical charge AND unable to from H bonds with water
- ->these molecules repel water molecules so are hydrophobic
What does Hydrophilic mean in terms of water?
-polar molecules which attract water molecules like Cl- and Na+
Define the term Amphiphilic
-Some molecules have mix of both hydrophobic and hydrophilic properties
What is the effect of Hydrophobic forces on biological molecules?
-these forces influence 3D shape of biological molecules
Describe the phospholipid bilayer plasma membrane
- polar head and non-polar tail
- ->non-polar tails face inwards while polar tails face outwards
Outline the permeability of the plasma membrane
- Hydrophobic and small molecules pass through easily
- hydrophilic molecules can’t pass through easily
Where does the plasma membranes unique properties come from?
-come from it’s fluidity and polarity
Define “surface tension”
- tension of surface of film of liquid caused by attraction of particles in surface layer as to reduce S. Area
- elastic tendency of fluid surface
AT LIQUID- What are air interfaces and what results in them?
- Air interfaces-point two systems meet/interact
- -> results from greater interaction of liquid molecules to each other (due to cohesion) than to air molecules
Define and describe the use of “surfactants”
- Substances which reduce s. tension between 2 liquids/ between gas & liquid OR between liquid and solid
- ->surfactants may act as detergents/ wetting agents/ emulsifiers/ foaming agents and dispersants (disperse small particles in a medium)
Describe the link between lung’s collapsing and S. Tension
- S. tension tends to make lung alveoli collapse
- ->alveoli secrete surfactants-to break surface tension
How may premature babies lung’s collapse and what treatment may be prescribed?
- they lack surfactants–>lung collapses (atelectasis) as surface tension cant be reduced
- -> prescribed surfactant inhaler therapy
Summary of lecture
- Valence + low atomic weight of C–> lets it form chains & link functional groups important for biological macromolecular generation
- biologically important macromolecular groups–> carbohydrates/ proteins/ lipids/ nucleic acids
- biological polymers generated from monomers via dehydration synthesis
- biological polymers broken down via hydrolysis
- water universal for life–>universal solvent/polarity/ H-bonding
