IB Biology 2025 SL Section C1 - Interaction & Interdependence

carbon compounds

carbon compounds

carbohydrates, lipids, nucleic acid, proteins

Metabolism

the chemical processes (enzyme catalyzed) that occur within a living organism in order to maintain life.

Anabolism

the synthesis of complex molecules in living organisms from simpler ones, including ther formation of macrolmes from monomers by condensation reactions

Catabolism

the breakdown of complex molecules into simpler molecules, including the hydrolysis of macromolecules into monomers.

Subcomponent of carbohydrates

monosaccharides

subcomponent of lipids

Glycerol, fatty acids, phosphate groups

Subcomponent of proteins

amino acids

Protein examples

enzymes, antibodies, peptide hormones

Monosaccharide examples

glucose, fructose, galactose, ribose, deoxyribose

Disaccharide examples

sucrose, lactose, maltose

polysaccharide examples

starch, glycogen, cellulose, chitin

phospholipid example

bilayer of cell membrane

Steroid examples

cholesterol, testosterone, estrogen

hydrogen bond

Attraction between a slightly positive hydrogen atom and a slightly negative atom.

polar covalent bond

bond between the oxygen atom and the two hydrogen atoms of a signle water molecule; A covalent bond in which electrons are not shared equally

Electrons

Negatively charged particles

covalent bond

A chemical bond formed when two atoms share electrons

Cohesion

Attraction between molecules of the same substance

Adhesion

An attraction between molecules of different substances

high specific heat capacity

A property of water. Water can absorb lots of heat before changing temperature

Hydrophilic

water loving

Hydrophobic

Water fearing

monosachharides

monomer of carbohydrates; linked together by condensation reactions to form disaccharides

Types of fatty acids

saturated, monounsaturated, polyunsaturated

Triglycerides

formed by condensation from three fatty acids and one glycerol

condensation reaction

Cellulose

major component of cell walls, helps give rigidity support to roots, stems, and leaves

Starch

A storage polysaccharide in plants consisting entirely of glucose; usually located in roots

Glycogen

Storage form of glucose in animals; usually located in liver and muscle tissue

saturated fatty acid

carbons are saturated with hydrogen atoms; generally solid at room temperature; no double bonds

monounstaturated fatty acids

one double bond exists in the chain of a hydrocarbon; cause one "kink" or bend in the molecule

polyunsaturated fatty acid

two or more double bonds in the carbon chain; usually liquid at room temperature

cis fatty acids

Two covalent single C-C bonds angle in the same direction adjacent to the C=C double bond

trans fatty acids

fatty acids with hydrogens on opposite sides of the double bond

amino acids

a simple organic compound containing both a carboxyl (—COOH) and an amino (—NH2) group; linked together by condensation to form polypeptides.

Ribosomes

site of protein synthesis; amino acid linkage

peptide bond

The chemical bond that forms between the carboxyl group of one amino acid and the amino group of another amino acid

Enzymes

proteins that act as biological catalysts; speed up chemical reactions that take place in cells by lowering the activation energy; act on specific substrates

Denature

destroy the characteristic properties of (a protein or other biological macromolecule) by heat, acidity, or other effects that disrupt its molecular conformation.

Organelle

A tiny cell structure that carries out a specific function within the cell

Compartmentalization

Membrane-bound organelles allow different parts of the cell to perform different functions at the same time

stem cells

unspecialized cells that are able to renew themselves for long periods of time by cell division

Pluripotent

Cells that are capable of developing into most, but not all, of the body's cell types

totipotent

Stem cells with the potential to differentiate into any type of cell.

Multipotent

cell with limited potential to develop into many types of differentiated cells

stem cell niche

an area of a tissue that provides a specific microenvironment, in which stem cells are present in an undifferentiated and self-renewable state.

surface area to volume ratio

a variable that decreases as cells grow, so that it sets a limit to the size of cells.

Phopholipids

A glycerol linked to a phosphate group and to two fatty acids

amphipathic

having both a hydrophilic region and a hydrophobic region

Differentiation

process in which cells become specialized in structure and function

Hypertonic

Having a higher concentration of solute than another solution.

Hypotonic

Having a lower concentration of solute than another solution

Isotonic

Having the same solute concentration as another solution.

Aquaporins

water channel proteins

Cholesterol

A steroid present in the plasma membranes of animal cells. It affects membrane fluidity.

Endocytosis

process by which a cell takes material into the cell by infolding of the cell membrane

Exocytosis

Process by which a cell releases large amounts of material

active transport

membrane transport in which the movement of solute molecules or ions across a membrane is coupled directly to an exergonic chemical reaction, most commonly the hydrolysis of ATP

Diffusion

Movement of molecules from an area of higher concentration to an area of lower concentration.

facilitated diffusion

Movement of specific molecules across cell membranes through protein channels

Osmosis

Diffusion of water through a selectively permeable membrane

integral proteins

Proteins that span the membrane.

peripheral proteins

The proteins of a membrane that are not embedded in the lipid bilayer; they are appendages loosely bound to the surface of the membrane.

Glycoproteins

Membrane carbohydrates that are covalently bonded to proteins.

Glycolipids

Membrane lipids with one or more covalently attached carbohydrates

turgor pressure

The pressure that water molecules exert against the cell wall

cell lysis

rupturing membranes of cells

Plasmolysis

Collapse of a walled cell's cytoplasm due to a lack of water

normal saline

A general phrase referring to a sterile solution of sodium chloride (NaCl, more commonly known as table salt) in water, but is only sterile when it is to be placed parenterally (such as intravenously); otherwise, a saline solution is a salt water solution.

contractile vacuole

The cell structure that collects extra water from the cytoplasm and then expels it from the cell

Solvation

The process of surrounding solute particles with solvent particles to form a solution

dilute

Less concentrated liquid

concentration gradient

A difference in the concentration of a substance across a distance.

dynamic equilibrium

Result of diffusion where there is continuous movement of particles but no overall change in concentration

Solvent

A liquid substance capable of dissolving other substances

Solute

A substance that is dissolved in a solution.

Solution

A homogeneous mixture of two or more substances

fluid mosaic model

model that describes the arrangement and movement of the molecules that make up a cell membrane