IBDP Biology 2025 Basic Knowledge Questions

This set of flashcards covers key vocabulary and concepts from IBDP Biology 2025 Basic Knowledge Questions.

Cohesion

The attraction between water molecules due to hydrogen bonding.

Adhesion

The attraction between water molecules and other polar or charged molecules.

Hydrophilic substances

Substances that can dissolve in water due to their charges or polarity, e.g., glucose and amino acids.

Hydrophobic substances

Substances that cannot dissolve in water due to lack of charges or polarity, e.g., fats and steroids.

Methane

A non-polar molecule that does not form hydrogen bonds and has a very low boiling point.

Polarity

The distribution of electrical charge over the atoms joined by the bond.

Nucleotide

The basic building block of nucleic acids, consisting of a nitrogenous base, a sugar, and a phosphate group.

DNA

A double-stranded molecule that carries genetic information for living organisms.

RNA

A single-stranded nucleic acid that plays a role in the synthesis of proteins.

Hydrogen bonds

Weak bonds that form between water molecules, contributing to its unique properties.

Buoyancy

The ability of objects to float in fluid; more buoyant in water than in air.

Gravitational field

The force exerted by the Earth that holds water close to its surface.

Thermal conductivity

The ability of a substance to conduct heat; water has a higher thermal conductivity than air.

Specific heat capacity

The amount of heat required to raise the temperature of a substance; water has a high specific heat capacity.

Covalent bond

A strong chemical bond formed by sharing electrons between atoms.

Phosphodiester bond

A covalent bond that links the phosphate group of one nucleotide to the sugar of another.

Purines

Nitrogenous bases that include adenine (A) and guanine (G).

Pyrimidines

Nitrogenous bases that include cytosine (C) and thymine (T).

Complementary base pairing

The specific pairing of nitrogenous bases in DNA, where adenine pairs with thymine and guanine pairs with cytosine.

Base sequence

The order of nucleotides in a DNA or RNA molecule.

Histones

Proteins around which DNA is coiled to form chromatin.

Chromatin

The relaxed form of DNA found in the nucleus of eukaryotic cells.

Transcription

The process of synthesizing RNA from a DNA template.

Translation

The process of synthesizing proteins from mRNA.

Polypeptide chain

A series of amino acids linked by peptide bonds, forming a protein.

Signal transduction

The process by which a cell responds to external signals through a series of molecular events.

Gene expression

The process by which information from a gene is used to synthesize RNA and proteins.

RNA splicing

The process of removing non-coding introns from the RNA transcript and joining exons to form a mature mRNA.

Codon

A three-nucleotide sequence in mRNA that corresponds to a specific amino acid.

Anticodon

A three-nucleotide sequence in tRNA that pairs with a complementary codon in mRNA.

Polymorphic

A term used to describe a gene with multiple alleles.

Dominant allele

An allele that is expressed even in the presence of another allele.

Recessive allele

An allele that is only expressed in the homozygous state.

Polygenic trait

A trait that is controlled by multiple genes, leading to continuous variation.

Sickle cell disease

A genetic disorder caused by a mutation in the hemoglobin gene, resulting in abnormal red blood cells.