Module 5 – Heredity Biology Notes Vocabulary

Vocabulary flashcards covering key terms from Module 5 Heredity notes, spanning reproduction, cell replication, genetics, molecular biology, biotechnology and evolutionary models.

Heredity

The passing of genetic traits from parents to offspring, ensuring species continuity.

Gamete

A haploid sex cell (sperm or egg/pollen/ovule) that fuses with another during fertilisation.

Zygote

Diploid cell formed by the fusion of two gametes at fertilisation.

External Fertilisation

Fusion of male and female gametes outside the female body, common in aquatic organisms.

Internal Fertilisation

Fusion of gametes inside the female body, providing protection from dehydration and predation.

Vegetative Propagation

Asexual plant reproduction from roots, stems or leaves without seeds.

Runner

A modified horizontal stem (stolon) that forms roots and shoots at nodes to make clonal plants.

Rhizome

Underground horizontal stem producing new shoots at nodes; can be divided to form new plants.

Apomixis

Asexual formation of seeds or plantlets without fertilisation, producing clones of the parent.

Pollination

Transfer of pollen from anther to stigma in flowering plants.

Pollen Tube

Structure grown by pollen grain through style to deliver male gamete to ovule.

Seed Dispersal

Distribution of fertilised seeds via wind, water, animals, or self-propulsion.

Budding

Asexual reproduction where a new individual forms as an outgrowth of the parent (e.g., yeast).

Spore

A haploid reproductive cell capable of developing into a new organism without fusion.

Binary Fission

Asexual division of a prokaryotic cell into two identical daughter cells.

Ovulation

Release of a mature egg from the ovary into the fallopian tube.

Implantation

Embedding of the early embryo into the endometrium of the uterus.

Endometrium

Uterine lining that nourishes the implanted embryo.

Placenta

Organ forming during pregnancy that exchanges nutrients and wastes between mother and fetus.

Umbilical Cord

Structure connecting fetus to placenta for nutrient and gas exchange.

Menstrual Cycle

Monthly hormonal cycle preparing female body for pregnancy.

Follicular Phase

Early menstrual phase in which follicles mature and estrogen rises.

Ovulation Phase

Mid-cycle release of a mature egg triggered by LH surge.

Luteal Phase

Post-ovulation phase dominated by progesterone; prepares uterus for implantation.

Progesterone

Hormone maintaining uterine lining and pregnancy; produced by corpus luteum and placenta.

Estrogen

Hormone stimulating follicle growth, uterine lining thickening and fetal development.

Luteinizing Hormone (LH)

Pituitary hormone triggering ovulation and corpus luteum formation.

Follicle-Stimulating Hormone (FSH)

Pituitary hormone stimulating follicle maturation in ovaries.

Human Chorionic Gonadotropin (hCG)

Placental hormone maintaining corpus luteum and progesterone production early in pregnancy.

Relaxin

Pregnancy hormone that loosens uterine muscles and pelvic ligaments.

Oxytocin

Pituitary hormone initiating uterine contractions and milk let-down during birth.

Selective Breeding

Human-mediated mating of organisms with desired traits to enhance those traits in offspring.

Artificial Insemination

Placement of semen directly into female reproductive tract without natural mating.

Artificial Pollination

Manual transfer of pollen to stigmas to control plant breeding.

Genetic Engineering (Plants)

Insertion of specific genes into a plant genome to confer new traits such as pest resistance.

Mitosis

Nuclear division producing two genetically identical diploid daughter cells.

Prophase

Mitosis stage where chromatin condenses into chromosomes and spindle forms.

Metaphase

Mitosis stage where chromosomes line up at the cell equator on the spindle.

Anaphase

Mitosis stage where sister chromatids separate to opposite poles.

Telophase

Mitosis stage where chromosomes decondense and nuclear envelopes re-form at poles.

Cytokinesis

Division of cytoplasm yielding two separate daughter cells after mitosis/meiosis.

Meiosis

Cell division producing four genetically unique haploid gametes, introducing variation.

Diploid

Cell containing two sets of chromosomes (2n).

Haploid

Cell containing one set of chromosomes (n).

DNA (Deoxyribonucleic Acid)

Double-helical molecule storing genetic information in living organisms.

Nucleotide

DNA/RNA subunit consisting of sugar, phosphate and nitrogenous base.

Complementary Base Pairing

Specific hydrogen bonding of A–T and C–G in DNA (A–U in RNA).

DNA Helicase

Enzyme that unwinds and unzips the DNA double helix during replication.

DNA Polymerase

Enzyme that assembles new DNA strands using existing strands as templates.

DNA Ligase

Enzyme that seals nicks in DNA backbone, joining Okazaki fragments.

Transcription

Process of synthesising mRNA from a DNA template in the nucleus.

Messenger RNA (mRNA)

RNA molecule carrying genetic code from DNA to ribosomes for protein synthesis.

Translation

Process of assembling amino acids into a polypeptide using mRNA code at a ribosome.

Transfer RNA (tRNA)

Adapter RNA that carries specific amino acids to the ribosome; has anticodon.

Codon

Three-base sequence on mRNA specifying a particular amino acid or stop signal.

Anticodon

Three-base sequence on tRNA complementary to an mRNA codon.

Polypeptide

Chain of amino acids linked by peptide bonds; folds into functional protein.

Primary Protein Structure

Linear sequence of amino acids in a polypeptide chain.

Secondary Protein Structure

Local folding into α-helices or β-sheets stabilised by hydrogen bonds.

Tertiary Protein Structure

Three-dimensional folding of a single polypeptide due to R-group interactions.

Quaternary Protein Structure

Association of two or more polypeptide chains into a functional protein complex.

Independent Assortment

Random orientation of homologous chromosome pairs in meiosis I, generating variation.

Crossing Over

Exchange of genetic material between non-sister chromatids of homologous chromosomes during prophase I.

Random Segregation

Chance separation of alleles into gametes during meiosis.

Self-Fertilisation

Fusion of male and female gametes from the same individual, reducing variation.

Cross-Fertilisation

Fusion of gametes from different individuals of the same species, increasing variation.

Mutation

Any change in DNA sequence; source of new alleles.

Allele

Alternative form of a gene located at the same locus on homologous chromosomes.

Dominant Allele

Allele expressed in phenotype when at least one copy is present.

Recessive Allele

Allele expressed phenotypically only when two copies are present.

Codominance

Inheritance pattern where both alleles are fully expressed in heterozygotes.

Incomplete Dominance

Inheritance producing an intermediate phenotype between two alleles (blending).

Sex Linkage

Gene location on sex chromosomes affecting inheritance patterns.

X-Linked Inheritance

Transmission of genes on the X chromosome; recessive traits affect males more often.

Y-Linked Inheritance

Transmission of genes on the Y chromosome; passed father to son only.

Multiple Alleles

Presence of more than two allelic forms of a gene in a population (e.g., ABO blood).

Short Tandem Repeat (STR)

Non-coding DNA region with repeating units; used in DNA profiling.

Single Nucleotide Polymorphism (SNP)

Variation at a single nucleotide position in DNA among individuals.

Polymerase Chain Reaction (PCR)

Technique that amplifies specific DNA segments, producing millions of copies.

DNA Sequencing

Determination of the exact order of nucleotides in a DNA molecule.

Sanger Method

Chain-termination DNA sequencing technique using fluorescent dideoxy nucleotides.

DNA Profiling

Comparison of individuals’ DNA patterns (e.g., STR sizes) for identification.

Population Genetics

Study of allele frequency changes in populations over time.

Koala Genome Sequencing

Analysis of koala DNA revealing genes for eucalyptus toxin breakdown and disease resistance.

Phenylketonuria (PKU)

Recessive metabolic disorder causing toxic phenylalanine buildup due to faulty enzyme.

Regional Continuity Theory

Multiregional model proposing parallel evolution of Homo erectus to H. sapiens worldwide.

Out of Africa Theory

Model stating modern humans evolved in Africa and replaced archaic humans elsewhere.

Mitochondrial DNA (mtDNA)

Maternal-inherited DNA in mitochondria, used to trace evolutionary lineages.

Y Chromosome

Paternally inherited sex chromosome useful for tracing male lineages.

Genome

Complete set of an organism’s genetic material.

Gene Pool

All alleles of all genes in a breeding population.

Chromosome

DNA-protein structure carrying genetic information; visible during cell division.

Sister Chromatid

Identical copies of a chromosome joined by a centromere after DNA replication.

Spindle Fibres

Microtubules that separate chromosomes during mitosis and meiosis.

Amniotic Sac

Fluid-filled membrane that cushions and protects the developing embryo/fetus.

Embryo

Early developmental stage of a multicellular organism post-implantation.

Genetic Diversity

Variety of genetic characteristics in a population, enhancing adaptability.

Enzyme

Protein catalyst speeding up biochemical reactions, often produced via polypeptide synthesis.

Ribosome

Cell organelle where translation and polypeptide synthesis occur.