Biomolecules Lecture Flashcards

A set of vocabulary flashcards defining key biomolecules, structural levels, metabolic concepts, and enzymatic terms from the lecture notes.

Acid-soluble pool

The filtrate fraction obtained by grinding living tissue in trichloroacetic acid ($\text{Cl}_3\text{CCOOH}$) and straining through cheesecloth, containing small molecular weight organic compounds ranging from $18$ to around $800\,Da$.

Acid-insoluble fraction

The retentate fraction obtained after straining ground living tissue in trichloroacetic acid, containing biomacromolecules with molecular weights of $10,000\,Da$ and above (such as proteins, nucleic acids, and polysaccharides) as well as membrane-associated lipids.

Biomolecules

All the carbon compounds that are obtained from living tissues.

Ash

The remaining material containing inorganic elements (such as calcium and magnesium) left behind when dried living tissue is fully burnt, oxidizing carbon compounds into gaseous forms ($\text{CO}_2$ and water vapour).

$\alpha$-amino acids

Organic compounds containing an amino group and an acidic carboxyl group as substituents on the same carbon (the $\alpha$-carbon), which act as substituted methanes.

Zwitterionic form

The structural state of an amino acid in solution where both the amino ($-\text{NH}_2$) and carboxyl ($-\text{COOH}$) groups are ionized, changing as a function of the $pH$ of the solution.

Essential amino acids

Amino acids that cannot be synthesized by the human body and must be supplied through dietary sources.

Non-essential amino acids

Amino acids that can be synthesized by the human body.

Palmitic acid

A saturated fatty acid containing $16$ carbons including the carboxyl carbon.

Arachidonic acid

A fatty acid containing $20$ carbon atoms including the carboxyl carbon.

Glycerol

A simple lipid compound defined chemically as trihydroxy propane.

Lecithin

A phospholipid found in cell membranes that contains phosphorus and a phosphorylated organic compound.

Primary metabolites

Biomolecules (such as amino acids, sugars, and fatty acids) present in living tissues that have identifiable physiological functions and play known roles in normal processes.

Secondary metabolites

Organic compounds found in plant, fungal, and microbial cells (such as alkaloids, flavonoids, rubber, antibiotics, and pigments) whose specific physiological roles in the host organisms are not fully understood.

Biomacromolecules

Chemical compounds found in the acid-insoluble fraction of living tissues with molecular weights in the range of ten thousand daltons ($10,000\,Da$) and above.

Collagen

The most abundant protein in the animal world, serving as intercellular ground substance.

RuBisCO

Ribulose bisphosphate Carboxylase-Oxygenase, which is the most abundant protein in the entire biosphere.

Inulin

A polymeric polysaccharide that is a polymer of fructose.

Chitin

A complex polysaccharide homopolymer that forms the exoskeletons of arthropods.

Primary structure of a protein

The sequence and positional information of amino acids in a protein chain, extending from the N-terminal amino acid at the left end to the C-terminal amino acid at the right end.

Secondary structure of a protein

The spatial arrangement formed when portions of a protein thread fold into localized patterns, such as right-handed alpha-helices or beta-pleated sheets.

Tertiary structure of a protein

The overall three-dimensional folding of a long protein chain upon itself like a hollow woolen ball, which is essential for its biological activity.

Quaternary structure of a protein

The architectural arrangement of multiple folded polypeptide subunits relative to one another (such as adult human haemoglobin consisting of two $\alpha$ and two $\beta$ subunits).

Ribozymes

Nucleic acids that behave like enzymes and exhibit catalytic activity.

Active site

A crevice or pocket in an enzyme formed by its tertiary structure into which the specific substrate fits to undergo chemical conversion.

Activation energy

The difference in average energy content between the substrate ($S$) and its high-energy transition state.

Competitive inhibitor

A chemical regulator that closely resembles the substrate in its molecular structure and competes for the substrate-binding site of an enzyme, reducing enzyme activity.

Apoenzyme

The protein portion of an enzyme that requires a non-protein co-factor to become catalytically active.

Prosthetic group

An organic co-factor that is tightly bound to the apoenzyme of an enzyme, such as haem in peroxidase and catalase.

Co-enzyme

An organic co-factor whose association with an apoenzyme is transient and occurs during catalysis, often containing vitamins such as niacin in NAD and NADP.