NSW HSC Biology: Modules 5 & 6 Vocabulary Flashcards

Seventy-two vocabulary flashcards covering key terms and concepts from NSW HSC Biology Modules 5 (Heredity) and 6 (Genetic Change).

DNA (Deoxyribonucleic Acid)

Molecule that stores genetic information in most living organisms.

Meiosis

Form of cell division that produces gametes with half the chromosome number, generating genetic variation.

Chromosome

Structure composed of DNA and histone proteins that carries genetic information.

Gene

Segment of DNA that codes for a protein or polypeptide.

Genotype

The genetic constitution of an organism.

Phenotype

Observable characteristics of an organism resulting from genotype and environment.

Allele

Alternative form of a gene found at the same locus.

Recessive Allele

Allele expressed only when two copies are present.

Mutagen

Physical, chemical or biological agent that induces DNA mutations.

Point Mutation

Single-base change in DNA, such as a substitution.

Homologous Chromosomes

Chromosome pair with the same genes that synapse during meiosis.

Non-Homologous Chromosomes

Chromosomes that do not pair and carry different gene sets.

Centromere

Constricted region joining sister chromatids in a chromosome.

Chromatid

One of two identical strands of a duplicated chromosome.

Karyotype

Photographic representation of the full chromosome set of a cell.

Thymine

Nitrogenous base that pairs with adenine in DNA.

Helicase

Enzyme that unwinds DNA strands during replication.

Deoxyribose

Pentose sugar found in DNA nucleotides.

Ribose

Pentose sugar found in RNA nucleotides.

Crossing Over

Exchange of genetic material between homologous chromatids during meiosis.

Independent Assortment

Random segregation of homologous chromosome pairs during meiosis I.

Genetic Variation

Differences in allele combinations among individuals within a population.

Co-Dominance

Inheritance pattern where both alleles are fully expressed (e.g., AB blood group).

Multiple Alleles

More than two allele forms exist for a gene (e.g., IA, IB, i).

Pedigree Chart

Diagram tracing inheritance of a trait through generations.

Test Cross

Cross between an individual showing a dominant phenotype and a homozygous recessive individual to determine genotype.

Down Syndrome (Trisomy 21)

Genetic disorder caused by an extra copy of chromosome 21.

Gene Expression

Process by which information in DNA is used to produce a functional product.

Environmental Influence

Effect of external factors on gene expression and phenotype.

Sex-Linked Inheritance

Transmission of genes located on sex chromosomes.

X Chromosome

Sex chromosome that carries more genes than the Y chromosome.

Y Chromosome

Sex chromosome present only in males and carrying few genes.

Polymerase Chain Reaction (PCR)

Technique that amplifies specific DNA segments in vitro.

Homozygous

Having two identical alleles for a gene.

Autosomal Recessive Trait

Trait expressed when an individual has two recessive alleles on autosomes; often skips generations.

X-Linked Recessive Disorder

Disease caused by a recessive allele on the X chromosome; affects males more frequently.

Ionizing Radiation

High-energy physical mutagen (e.g., X-rays, gamma rays) that damages DNA.

Dihybrid Cross

Cross involving two gene loci that yields a 9:3:3:1 phenotype ratio in F₂ generation.

Chargaff’s Rule

In DNA, percentage of adenine equals thymine and guanine equals cytosine.

Frameshift Mutation

Gene mutation caused by insertions or deletions that alter the reading frame.

Polyploidy

Condition of possessing more than two complete sets of chromosomes.

Artificial Insemination

Deliberate introduction of sperm into the female reproductive tract.

Artificial Pollination

Manual transfer of pollen between plants to control breeding.

Selective Breeding

Choosing parents with desirable traits to produce improved offspring.

Somatic Cell Nuclear Transfer

Cloning method where a somatic nucleus is inserted into an enucleated egg.

Biotechnology

Application of living organisms or their components to develop useful products.

Gene Therapy

Introduction of functional genes to replace or supplement faulty ones in humans.

Recombinant DNA

DNA molecule formed by joining DNA from different sources.

Plasmid

Small circular DNA molecule in bacteria used as a vector in genetic engineering.

Restriction Enzyme

Protein that cuts DNA at specific nucleotide sequences.

DNA Ligase

Enzyme that joins DNA fragments by forming phosphodiester bonds.

Transformation (Bacterial)

Uptake and incorporation of foreign DNA by a bacterial cell.

Genetic Engineering

Direct manipulation of an organism’s genome using biotechnology.

DNA Profiling

Technique for identifying individuals based on unique patterns in their DNA.

Transgenesis

Introduction of a gene from one species into another species’ genome.

Stem Cells

Undifferentiated cells capable of giving rise to various specialized cell types.

Genetic Diversity

Variety of alleles and genotypes within a population.

Germline Mutation

DNA change in gametes that can be passed to offspring.

Gene Knock-Out

Intentional inactivation or deletion of a gene to study its function.

Genetically Modified Organism (GMO)

Organism whose genome has been altered by genetic engineering (e.g., Bt cotton).

Golden Rice

GMO rice engineered to produce β-carotene for vitamin A supplementation.

Bioinformatics

Use of computational tools to store, analyze and interpret biological data.

Antibiotic Resistance

Ability of bacteria to survive exposure to antibiotics due to genetic mutations.

Mitochondrial DNA

Circular DNA found in mitochondria, inherited from the egg cytoplasm.

Transgenic Bacteria

Bacteria carrying recombinant plasmids with foreign genes.

Forensic DNA Analysis

Use of PCR and other techniques to examine DNA in legal investigations.

Germline Gene Therapy

Genetic modification of gametes or embryos; changes are heritable.

Somatic Gene Therapy

Genetic modification of somatic cells; affects only the treated individual.

Ethical Issues in Gene Modification

Concerns about safety, consent, equity and environmental impact of genetic technologies.

Thymine Dimer

Covalent linkage of adjacent thymine bases caused by UV radiation, leading to replication errors.

Mustard Gas

Chemical mutagen that alkylates DNA bases, inducing mutations.

Amino Acid Substitution

Change in a protein’s amino acid sequence resulting from a point mutation.