G.C.E. (Advanced Level) Biology Resource Notes

These flashcards cover essential biological concepts including the chemical and cellular basis of life, metabolism, photosynthesis, and cellular respiration.

Essential Elements

Approximately 20-25 elements are essential for life, including Oxygen (O), Carbon (C), Hydrogen (H), and Nitrogen (N), which make up 96% of living matter.

Hydrogen Bonds

Weak attractions between polar molecules, significant for water's properties.

Cohesion

Attraction between water molecules due to hydrogen bonding; important for water transport in plants.

Specific Heat of Water

Water can absorb or release large amounts of heat with minimal temperature change, acting as a thermal buffer.

Density of Ice

Water expands upon freezing, making ice less dense than liquid water, allowing it to float.

Solvent Properties of Water

Due to its polarity, water can dissolve many polar and ionic substances, making it a versatile solvent.

Carbohydrates

Organic compounds composed mainly of C, H, and O, with a general formula of C(H2O)n; includes monosaccharides, disaccharides, and polysaccharides.

Monosaccharides

The simplest sugars with a general molecular formula of (CH2O)n; they are crystalline in form and soluble in water.

Disaccharides

Sugars formed by the condensation of two monosaccharides, linked by a glycosidic bond.

Polysaccharides

Long chains of monosaccharides serving as storage (starch, glycogen) or structural (cellulose) components.

Lipids

Hydrophobic biological molecules including fats, phospholipids, and steroids, important for energy storage and cellular structure.

Proteins

Polymers made from amino acids, with functions including catalysis (enzymes), structure (collagen), and transport (hemoglobin).

Nucleic Acids

Polymers of nucleotides, including DNA and RNA, responsible for storing and transmitting genetic information.

Cell Theory

States that all organisms are composed of cells, the cell is the basic unit of life, and all cells come from pre-existing cells.

Prokaryotic Cells

Simple, unicellular organisms without membrane-bound organelles, e.g., bacteria.

Eukaryotic Cells

Complex cells with membrane-bound organelles and a true nucleus, can be unicellular or multicellular.

Mitosis

A process of cell division that results in two genetically identical daughter cells.

Meiosis

A type of cell division that reduces chromosome number by half and produces four non-identical haploid daughter cells.

Photosynthesis

The process by which green plants, algae, and some bacteria convert light energy into chemical energy stored in glucose.

Cellular Respiration

The biochemical process that converts glucose and oxygen into ATP, carbon dioxide, and water.

ATP (Adenosine Triphosphate)

The primary energy currency of the cell, used to power various cellular processes.

Enzymes

Biological catalysts that speed up chemical reactions by lowering the activation energy required.

Feedback Inhibition

A regulatory mechanism in which the end product of a metabolic pathway inhibits an earlier step in the pathway, preventing overproduction.

C4 and CAM Pathways

Alternative photosynthetic pathways that allow plants to fix CO2 more efficiently under conditions of water stress.

Glycolysis

The process of breaking down glucose into pyruvate, yielding a small amount of ATP and NADH.

Krebs Cycle

A series of chemical reactions used by all aerobic organisms to release stored energy through the oxidation of acetyl-CoA.