Inorganic and Organic Molecules: The Molecules of Life

Comprehensive practice flashcards covering organic and inorganic molecules, macromolecules, cytoplasm physiology, enzymes, and vitamin classifications.

What is the primary structural difference between inorganic and organic molecules?

Inorganic molecules do not contain carbon, whereas organic molecules do contain carbon and form more complex structures arranged in rings or chains.

How is biochemistry defined, and what field is it closely linked to?

Biochemistry is the chemistry of living things and is closely linked to organic chemistry.

What are macromolecules, and what are the four important kinds found in living systems?

Macromolecules are very large organic molecules. The four important kinds are carbohydrates, proteins, nucleic acids, and lipids.

What is the definition of a polymer, and which macromolecules qualify as polymers?

Polymers are combinations of many smaller, similar building blocks called monomers bonded together. Carbohydrates, proteins, and nucleic acids are all polymers.

What is dehydration synthesis?

Dehydration synthesis is a reaction that combines two molecules through the removal of one molecule of water.

How do functional groups interact during a dehydration synthesis reaction?

Two functional groups come close enough to have an $-OH$ removed from one and an $-H$ removed from the other, combining to form water while the remaining segments unite to form a macromolecule.

What is hydrolysis, and how does it relate to dehydration synthesis?

Hydrolysis is the reverse of dehydration synthesis; it is the process of splitting a larger organic molecule into two or more parts by adding water.

What reaction occurs during the hydrolysis of sucrose?

Sucrose ($C_{12}H_{22}O_{11}$) reacts with water ($H_2O$) to yield glucose ($C_6H_{12}O_6$) and fructose ($C_6H_{12}O_6$).

What is the hierarchy of chemical organization from simplest to most complex?

Atoms $\rightarrow$ molecules $\rightarrow$ monomers $\rightarrow$ polymers (macromolecules) $\rightarrow$ carbohydrate, protein, or nucleic acid.

Who discovered the cytoplasm, and in what year was it discovered?

Cytoplasm was discovered in the year $1835$ by Robert Brown and other scientists.

In cell biology, what do the terms ectoplasm and endoplasm refer to as depicted in cytoplasmic flow?

The ectoplasm (or cell cortex) is the outer clear and glassy layer of the cytoplasm, while the endoplasm is the inner granular, fluid mass.

What is ergatoplasm?

Ergatoplasm refers to the basophilic areas of the cytoplasm that stain with basic dyes.

What is the difference between plasmagel and plasmosol in the cytoplasm?

Plasmagel is the thick, jelly-like peripheral zone of cytoplasm capable of absorbing and removing water, whereas plasmosol is the thin, liquefied area surrounding the nuclear zone.

What proportion of cytoplasmic proteins are soluble proteins, including enzymes?

$20\%$ to $25\%$ of cytoplasmic proteins are soluble proteins, including enzymes.

What are the three main constituents of cytoplasm?

The cytosol, organelles, and cytoplasmic inclusions.

What is macromolecular crowding in the cytosol?

It is the effect caused by a dense network of fibers and high concentrations of dissolved macromolecules (like proteins) that influences how cytoplasmic components interact.

What are cytoplasmic inclusions, and what are common examples?

They are tiny, non-soluble particles suspended in the cytosol, including calcium oxalate or silicon dioxide crystals in plants, storage granules (starch, glycogen), and lipid droplets.

How much of protoplasm is composed of water, and what is the difference between free water and bound water?

Water makes up $65\%$ to $80\%$ of protoplasm. Free water constitutes $95\%$ and acts as a solvent; bound water constitutes $5\%$ and is loosely linked to proteins by hydrogen bonds.

What crucial physiological roles do electrolytes play in the protoplasm?

They maintain osmotic pressure and acid-base equilibrium, serve as enzymatic cofactors (e.g., $Mg^+$), and provide energy as part of $ATP$ (phosphate ion, $PO_4$).

Where do specific non-electrolyte minerals like iron, calcium, iodine, and fluorine function in living systems?

Iron ($Fe$) is in haemoglobin, ferritin, cytochromes, and catalase; calcium ($Ca$) is in blood, protoplasm, and bones; iodine is essential for thyroid metabolism; and fluorine is essential for enamel metabolism.

What distinguishes a homo-polymer from a heteropolymer?

A homo-polymer contains similar kinds of monomers, whereas a heteropolymer is composed of different kinds of monomers.

What are the defining elements and stoichiometric ratio of carbohydrates?

They are composed of carbon, hydrogen, and oxygen in a ratio of $1:2:1$ ($C_6H_{12}O_6$).

Which monosaccharide ring structure is represented in this diagram?

Glucose ($C_6H_{12}O_6$), the most abundant carbohydrate and human blood sugar.

What are the primary biological roles of carbohydrates in living cells?

They act as an immediate source of energy, provide cellular shape (e.g., cellulose in plant cell walls), and serve as components of coenzymes, antibiotics, and nucleic acids ($DNA$ and $RNA$).

How are complex carbohydrates categorized based on the number of bonded simple sugars?

Disaccharides contain two simple sugars, trisaccharides contain three, and polysaccharides contain more than three simple sugars bonded together.

What structural carbohydrate composed of parallel chains linked by hydrogen bonds is depicted here?

Cellulose, which provides structural support for plant cell walls and is indigestible by humans.

What are the storage polysaccharides in plants versus animals?

Starch is the storage polysaccharide in plants, while glycogen is the storage polysaccharide in animals.

What covalent linkage is formed between amino acid monomers during protein synthesis?

A peptide bond, formed via a dehydration synthesis reaction between adjacent amino acids.

What causes a protein to become denatured?

Energy in the form of heat or light breaks hydrogen bonds that maintain higher levels of protein structure.

What is an enzyme, and what is its acting target called?

An enzyme is a specialized protein that acts as a biological catalyst to influence reaction rates without being consumed; the substance it acts upon is the substrate.

What are the six major classes of enzymes?

Oxireductases, Transferases, Hydrolases, Lyases (Lysases), Isomerases, and Ligases (Synthetases).

What chemical reactions do hydrolases and ligases catalyze?

Hydrolases cleave complex molecules into two compounds by adding water across the cleaved bond; ligases catalyze the linkage of two molecules by splitting a phosphate bond.

What are the three structural components of a nucleotide?

A $5$-carbon simple sugar (deoxyribose or ribose), a phosphate group, and a nitrogenous base.

What subunits combine to form the characteristic "E" shape of typical lipid molecules?

One glycerol molecule combined with three fatty acid chains.

How do saturated and unsaturated fats differ in their physical state at room temperature?

Saturated fats are solid at room temperature, whereas unsaturated fats are liquid (oils) at room temperature.

What amphipathic molecules make up the cellular membrane bilayer shown here?

Phospholipids, consisting of hydrophilic heads and hydrophobic fatty acid tails.

Why must vitamins be obtained through food intake?

Cells cannot synthesize vitamins from standard food; they are required in minute amounts to serve as coenzymes or biological catalysts.

What are the four fat-soluble vitamins?

Vitamin A, Vitamin D, Vitamin E, and Vitamin K.

What is the chemical nature, deficiency condition, and function of Vitamin A?

Chemical nature: Carotenoid. Deficiency: Xerophthalmia, hardening of cornea, night blindness, and growth interference. Function: Maintains epithelial integrity, forms rhodopsin (visual purple), and promotes growth.

What is the chemical nature, deficiency condition, and function of Vitamin D?

Chemical nature: Sterol. Deficiency: Bone defects such as rickets and osteomalacia. Function: Regulates calcium and phosphorus metabolism.

What are the chemical natures and deficiency diseases of Vitamin E and Vitamin K?

Vitamin E (Tocopherol) causes sterility in male rats; Vitamin K ($1\text{-}4$ naphthaquinone acetate) causes haemorrhage due to impaired prothrombin synthesis for blood clotting.

What deficiency disease is caused by a lack of Vitamin $B_1$ (Thiamine), and what is its cellular function?

Deficiency causes beriberi and loss of appetite. Function: Coenzyme for pyruvate metabolism in cellular respiration and carbohydrate metabolism.

What clinical conditions result from a deficiency of Vitamin $B_2$ (Riboflavin)?

Cataracts, lesions in the mouth, tongue, nose, and eyes, and cheilosis.

What deficiency disease is linked to Niacin (Nicotinic acid), and what is its coenzyme function?

Deficiency causes pellagra. It functions as part of dehydrogenase coenzymes ($NAD$ and $NADH$) that control cellular functions.

What deficiency symptoms are associated with Pantothenic acid and Biotin (Vitamin H)?

Pantothenic acid deficiency leads to dermatitis and spectacle eye; Biotin deficiency causes dermatitis (in rat, pig, fowl), paralysis, and muscle pain.

What are the deficiency diseases of Folic acid and Vitamin $B_{12}$ (Cyanocobalamin)?

Folic acid deficiency causes anaemia; Vitamin $B_{12}$ deficiency causes pernicious anaemia.