낱말카드 WK1 LEC2: Chemistry of Life

Molecules: FIX

H2O

Structure:

- Polar covalent O-H bonds with assymetric shape results in net dipole moment. H-bonding between molecules results in water.

Chemical Properties (Mostly due to H-bonds)

- Polarity: very important

- Cohesion: Emergent property -> high surface tension

- High specific heat: Emergent property -> high heat of vaporisation -> Temperature moderation

- Expansion on freezing: Emergent property -> less dense than liquid so ice floats

Biological Function

- Universal Solvent, all reactions occur in presence of water

- Transportation of nutrients, waste, chemical msgs within organisms.

Molecules:

Nucleotides

Structure:

Phosphate + Pentose Sugar + Nitrogenous Base

Phosphodiester bonds between 5'C above to 3'C forms backbone.

Nitrogenous base affects function.

Pyramidines: ATU

Purines: CG

Chemical Properties:

- -ve charge overall due to phosphate group.

- In DNA H-bonding between base pairs AT & CG.

Biological Function:

- Nucleotides: Energy Storage, Metabolic regulation, signalling, immune function

DNA - Genetic material

RNA - Genetic messaging

Molecules:

Carbohydrates

Structure:

- Composed of C,H,O in linear of cyclic shape

- Glycosidic (covalent OH) bonds between monomer (monosaccharide) units

- Carbonyl carbon position C=O determines classification

Chemical Properties:

- High oxygen content -> high polarity -> hydrophilic

Biological Function:

Monosaccharides: fast energy

Disaccharides: Easily transported, fast energy

Polysaccharides: Energy storage (starch/glycogen), Structure (Chitin/Cellulose)

Molecules:

Lipids

Structure:

C, H, O nonpolar molecules

Carboxylic Acid with long Hydrocarbon Chain/Tail

Chemical Properties

- Nonpolar -> Hydrophobic

- Increased saturation increases melting temp by increasing stability

Function:

- Large energy release (Triacylglycerols)

- Molecular signalling (Steroids)

- Protection (Waxes)

- Membranes (Phospholipids/Glycolipids/Cholestrol)

- Phospholipid Bilayer (Polar Phosphate head, non-polar lipid tail -> amphipathic): separate aqueous environments

Molecules:

Amino Acids

Structure:

Nitrogen (Amine) + α-carbon (centre) + carboxyl group

NCC

R-side branch from α-carbon identifies which amino acid it is specifically & affects the charge of the molecule overall.

Chemical Properties

- Charge of amino-acid determined by R-group affects function under different pH.

- In nature, neutral solution @pH 7, all groups are ionised (NH3+ and COO-)

Biological Function:

- Protein building blocks

- Proteins act as precursor to hormones, neurotransmitters, metabolic regulation, alternative cellular energy

Explore the properties of living organisms and appreciate the common origins and makeup of the molecules of life.

1. Order (Linked structure & function)

2. Energy processing (chemical energy conversion)

3. Growth & Development (Functions develop over time)

4. Sensitivity to stimuli (Chemical/Light)

5. Reproduction (Sexual/Asexual)

6. Regulation & Homeostasis (Internal conditions maintained regardless of envrionment)

7. Adaptation (Behavioural/Physical features to help survival)

8. Evolution (Adaptation over generations)

"Organisms (Order) Eat (Energy), Grow (Growth), Sense (Stimuli), Reproduce, Regulate (Homeostasis), Adapt, Evolve.

Prokaryotes: DNA is spread throughout

Eukaryotes: Nucelus with DNA

Common Origin:

- Genetic material encodes information about molecules that control all biological processes.

- All species share common genes & cellular functions -> common origin

2. Identify the elements particularly important for life, and define the properties used to describe how they interact.

C,H,N,O (majority w/covalent bonding)

Ionic Minerals (Na+, Mg2+, K+, Ca2+, P3-, S2-, Cl-)

Trace Elements & Transition metals (in small amounts as ions)

Molecules and H2O based on partial charge

- Hydrophobic (C-H, neutral molecules)

- Hydrophilic (Polar molecules)

- Amphipathic (Polar head, non-polar tail)