Introduction to Biochemistry, Membrane Structure, and Carbohydrates

Comprehensive vocabulary flashcards covering basic biochemistry concepts, origin of life theories, cell membrane structures, historical perspectives, and the processes of photosynthesis and carbohydrate classification.

Biochemistry

The study of the chemical substances, structures, reactions, and processes occurring within living organisms, combining biology and chemistry to provide a molecular basis for biological processes.

Biogenesis

The theory that life originated from pre-existing living things.

Abiogenesis/Spontaneous Generation Theory

The theory that living things could have directly evolved from non-living matter.

Marine Theory

The theory that the first form of life was formed under the sea; it identifies blue-green algae, or cyanobacterium, as the first organism to colonize the Earth.

Cosmozoic/Interplanetary Theory (Panspermia)

The theory that life originated from some source in the universe or outer space in the form of resistant spores.

Physico-chemical Theory

The theory that life was formed by the combination of elements, such as hydrogen and oxygen forming water, then combining with carbon.

Endosymbiotic Theory

The theory explaining how complex eukaryotic cells evolved from simpler prokaryotes through the ingestion of aerobic bacteria (which became mitochondria) and cyanobacteria (which became chloroplasts).

Carbohydrates

Macromolecules with the formula $(CH_2O)_n$ where $n \geq 3$; they are polyhydroxy aldehydes, polyhydroxy ketones, or compounds that yield these upon hydrolysis.

Nucleotides

Molecules composed of a five-carbon sugar, a nitrogen-containing ring, and one or more phosphate groups.

Amino Acids

Organic compounds containing an amino group ($-NH_2$) and a carboxylic group ($-COOH$).

Peptide bonds

The amide bonds that link amino acid residues to each other in proteins.

Antoine Lavoisier (1743-1794)

The scientist who identified the chemical bases of respiration and metabolism.

Friedrich Wöhler (1800-1882)

The scientist who first synthesized urea.

Emil Fischer (1852-1919)

The scientist who proposed the lock-and-key model of enzyme action.

Hans Krebs (1900-1981)

The scientist who discovered the Citric Acid Cycle, also known as the Krebs Cycle.

James Watson and Francis Crick

The scientists who proposed the double-helix structure of DNA in 1953.

Cell Theory

The scientific theory stating that all living organisms are composed of one or more cells, the cell is the structural unit of life, and cells arise only by division from pre-existing cells.

Glycerophospholipids

Membrane lipids built on a glycerol backbone, including lecithins (phosphatidylcholine) and cephalins (phosphatidylethanolamine).

Sphingomyelin

A sphingophospholipid found mainly in nerve cells and a major component of the myelin sheath.

Cholesterol

A type of sterol in eukaryotic cell membranes characterized by a rigid four-ring structure, one polar hydroxyl group ($-OH$), and a short nonpolar hydrocarbon tail.

Micelles

Small, spherical structures formed by cone-shaped amphiphilic molecules where hydrophobic groups are hidden from water and hydrophilic heads face outward.

Liposomes

Small, spherical sacs made of bilipid layers, measuring approximately $40-100\,nm$ in diameter, used as models of cell membranes and as drug delivery vehicles.

Lipid Rafts

Small areas of the membrane that act as interaction sites where proteins and lipids work together to help cells communicate and respond to signals, such as B-cell receptor dimerization.

Glycogenesis

The process by which the body creates glycogen from glucose molecules.

Glycogenolysis

The process by which the body breaks down glycogen to form glucose.

Chloroplasts

The specific site of photosynthesis in plants, algae, and some bacteria.

Light-dependent Reactions

The first stage of photosynthesis occurring in the thylakoid membrane that captures sunlight and uses water to create $ATP$ and $NADPH$, releasing oxygen.

Calvin Cycle

The light-independent reactions occurring in the stroma that convert carbon dioxide into sugar using $ATP$ and $NADPH$.

3-Phosphoglycerate (3-PGA)

The first stable 3-carbon product of the Calvin cycle, formed when $CO_2$ is attached to $RuBP$ by the enzyme $RuBisCO$.

Glyceraldehyde-3-phosphate (G3P)

The product of the reduction phase of the Calvin cycle, where one molecule is used to make glucose and five are used to regenerate $RuBP$.

C4 Plants

Plants such as corn and sugarcane that separate $CO_2$ fixation and the Calvin cycle in different cells (mesophyll and bundle sheath) to minimize photorespiration.

CAM Plants

Plants such as cactus and pineapple that separate $CO_2$ fixation (at night) and the Calvin cycle (during the day) to adapt to hot, dry environments.