Biology Lecture Notes: Genetics, Reproduction, and Disease

Vocabulary flashcards derived from biology lecture notes covering meiosis, biotechnology, reproduction, DNA replication, polypeptide synthesis, genetics, pathogens, and the human immune system.

Variability

Relates to the different forms of a gene within a population, representing the total of all alleles present in the gene pool.

Silent Mutation

A single nucleotide is accidentally switched in the DNA sequence, but it happens to code for the same protein, resulting in no actual change to the protein made.

Nonsense Mutation

A base is accidentally switched in a DNA sequence, causing a change that codes for a STOP transcription signal prematurely.

Haplotype

A set of closely linked DNA variations or genes on a particular (single) chromosome that are inherited together from one parent.

Biotechnology

The manipulation of living organisms to develop a useful product or process.

Biological Fitness

A measure of an individual's reproductive success, calculated as the average contribution to the gene pool made by a certain genotype within a population + the likelihood of those alleles being represented in future generations.

Zygote

A cell that arises from the fusion of paternal and maternal haploid gametes, changing the chromosome number from haploid to diploid.

Monotremes

Oviparous mammals that lay eggs which develop outside the mother's body after internal fertilization and are incubated externally.

Eutherians

Placental mammals where embryonic development occurs inside the mother's uterus, supplied by a placenta with nutrients and oxygen, resulting in the birth of live young.

Apomixis

A form of reproduction where plants produce offspring from special generative tissues without fertilisation or seed production, giving rise to genetically identical plantlets.

Binary Fission

The main method of asexual reproduction in unicellular organisms (prokaryotes) and protists where a cell replicates its DNA and splits into two.

Saprophytic

A type of nutrition where an organism, such as certain fungi, obtains organic nutrients from dead or decaying matter.

Androgens

Male hormones, such as testosterone, that control the development and functioning of male sex organs and secondary sex characteristics.

Menarche

A girl's first menstrual period occurring during puberty.

Rheotaxis

The attraction or movement of an organism (like sperm) through or against a fluid current.

Meristem

Plant tissue capable of dividing to form any other type of tissue.

Anaphase

The phase of mitosis that begins when proteins in the centromere cleave, allowing sister chromatids to separate and move toward opposite poles as daughter chromosomes.

Telomere

A $DNA$-protein region at the end of chromosomes that prevents them from sticking together and protects the genome from degradation.

Helicase

An enzyme that causes the $DNA$ double helix to progressively unwind and separates the strands by disrupting hydrogen bonds using $ATP$.

Okazaki Fragments

Discontinuous fragments of $DNA$ added to the lagging strand during replication, starting from the replication fork.

Introns

Large portions of non-coding $DNA$ in eukaryotic sequences that are removed during the splicing process of $RNA$ processing.

Transcription

The process where $RNA$ polymerase binds to a promoter part of $DNA$ to create a chain of $mRNA$ using the non-coding/sense strand as a template.

Locus

The specific position of a gene on a chromosome.

Epigenetics

The study of how the environment influences gene expression at a molecular level.

Synapsis

The process during prophase I of meiosis where homologous chromosomes (bivalents) wrap around each other and exchange genetic material at a chiasmata.

Co-dominance

An inheritance pattern where both alleles for a gene are expressed, creating a new phenotype where both traits are visible.

Single Nucleotide Polymorphism (SNP)

An error involving a single nucleotide incorrectly inserted into a $DNA$ sequence that occurs in at least $1\%$ of the population.

Sanger Method

Also known as dideoxy$DNA$ (dd$DNA$) sequencing, it uses chain-terminating nucleotides to determine the exact sequence of up to $1000$ base pairs per second.

Prions

Non-cellular pathogens consisting of abnormal proteins capable of inducing abnormal folding patterns in normal proteins, causing degenerative diseases of the nervous system.

Koch's Postulates

A set of four criteria used to determine whether a specific microorganism is responsible for a disease.

Innate Immunity

Genetic immunity present at birth providing non-specific responses, including physical/chemical barriers and second-line cellular responses like inflammation.

Phagocytosis

The process where phagocytes (like neutrophils and macrophages) change shape to surround and enclose a foreign body, then release enzymes to destroy it.

Antigen

Any molecule recognized as foreign by the immune system that triggers an immune response.

Incidence

The number of new cases of a disease in a population during a specified time period.

Prevalence

The proportion of a population that has a disease at a particular point in time, including both new and previous cases.