Topic 2 Molecular Biology

• 2.1 Molecules and Metabolism • 2.2 Water • 2.3 Carbohydrates and Lipids • 2.4 Proteins • 2.5 Enzymes • 2.8 Cell Respiration • 2.9 Photosynthesis

metabolism- anabolism

synthesising energy + small molecules → large molecules

hydrolysis and condensation reactions

metabolism- catabolism

breaking large molecules → energy + small molecules

produces energy

carbohydrates

carbon, hydrogen, oxygen (CHO)

made of saccharides in the form of glucose

lipids/fatty acids

carbon, hydrogen, oxygen (CHO)

insoluble in water, made of triglycerides (image; bonded with ester bonds; produced with condensation reaction)

saturation: saturated = all hydrogens, monounsaturated = missing one hydrogen, polyunsaturated = more than one hydrogen missing (trans is missing on different side)

proteins

carbon, hydrogen, oxygen, nitrogen, sulfur? (CHONS)

made up of 20 different amino acids (amine, carboxyl, R chain)

amino acids bonded together by ribosomes to form polypeptides (which are sequenced off DNA)

fibrous proteins are long like robes, structural eg spider silk; globular proteins are blobs, hormonal eg insulin

heat helps them activate unless there is too much in which case they denature.

nucleic acids

carbon, hydrogen, oxygen, nitrogen, phosphorus (CHONP)

alpha d glucose

in carbs

beta d glucose

every second one is flipped to create sheets

ribose

saturated fatty acid

saccharides

sugar units in carbohydrates. saccharide > disaccharide > polysaccharide. polysaccharides are made of alpha d glucose and are in chains in carbs.

disaccharides

condensation to form, hydrolysis to break

starch

stores glucose in plants, made of either unbranched amylose or branched amylopectin (branches based off on which carbon the glycosidic links are)

properties of water

adhesion, cohesion, polar, solvent, high specific heat capacity, latent heat of vaporisation

substances can either be hydrophilic or hydrophobic

hydrogen bonds

between two different hydrogens. each bond itself is weak, but there are so many bonds that together they are strong.

anaerobic cell respiration

in animals: glucose → lactic acid/lactate + ATP (minimal)

oxygen debt- must bring more oxygen into the body to break down the lactate

in yeast/plants: glucose → carbon dioxide + ethanol

similar to fermenting alcohol

aerobic cell respiration

glucose + oxygen → water + carbon dioxide + ATP (lots)

longer than anaerobic but gives more yield

ATP

adenosine triphosphate; respiration happens to produce this. the energy currency of the cell.

photosynthesis

carbon dioxide + water → glucose + oxygen

opposite of respiration. the water comes from transpiration through roots, oxygen comes from atmosphere diffusion.

endergonic reaction = relies energy input in form of light

limiting factors: temperature, light intensity, carbon dioxide concentration

absorbance/action spectra

measure wavelength of light in relation to plant productivity

chlorophyll

green pigment in plants that helps to absorb light as green is in the middle of the colour spectrum and reflects back the least of the colours.

carotenoids

help to fill in the absorption blanks where the cholorophyll can’t (cause its green)