Unit 4: AOS 2: Glossary Flashcards
What is a genotype?
the genetic make-up or the combination of alleles for a particular gene of an organism
What is a Phenotype?
a physical characteristic determined by genotype and environment
What is Genetic diversity?
the genetic variability within a spices
What are adaptations?
the behavioural, physiological and structural features of an organism that help them survive in an environment
What is a population?
a group of individuals of the same species living in the same region at a given time
What are species?
a group of organisms that can interbreed, producing fertile and viable offspring
What is a gene pool?
the sum total of alleles present in a population of organisms
What is an Allele frequency?
the porpution of a particular allele within a population
What is evolution?
a change in the allele frequencies if a population over time
What is a mutation?
A permanent change in the nucleotide sequence of a section of DNA
What is a mutagenic agent?
agents known to cause mutations; e.g some radiation source and chemicals; also called mutagens
What is point mutation?
a change to one base in the nucleotide sequence of a section of DNA; includes base substitutions and frameshift mutations
What is Substitution mutation?
a type of point mutation that occurs when one nitrogenous base in a gene is replaced with another base; includes silent, missense and nonsense mutations
What is a silent mutation?
a mutation where the change in the nucleotide sequence doesn’t change the amino acid that is coded for
What is a Missenese mutation?
a mutation in which the base change in the nucleotide sequence of the DNA changes the amino acid that is coded for; a type of substitution point mutation
What is nonsense mutation?
a mutation that occurs when the base changes in the nucleotide sequence of the DNA codes for a STOP codon, prematurely halting the production of the polypeptide; a type of substitution point mutation
What is frameshift mutation?
a type of point mutation that occurs when one base is inserted into or deleted, causing an incorrect reading of the codons due to a shift in the reading frame
What is block mutation?
a type of mutation that affects large sections of DNA, typically containing multiple genes; also called chromosome mutation
What is Chromosome abnormality?
mutation that involves a whole chromosome, or a change in the number of chromosomes, which can be identifies using a karyotype; e.g aneuploidy and polyploidy
What is Karyotype?
a pictorial representation of chromosomes that allows a geneticist to determine size, banding pattern, shape and number of chromosomes in an individual’s somatic cell; allows the determination of diploid number, gender and chromosomal abnormalities
What is a Aneuploidy?
when a cell has one more or one less chromosome than expected, usually due to non-disjunction
What is Polyploidy?
a condition in which an organism has more than 2 full sets of chromosomes in its cells; more common in plants than animals
What is gene flow?
the exchange of genetic information, specifically alleles, between populations
What is genetic drift?
a random change in allele frequency, occurring naturally in every population, due to chance events
What is the Bottleneck effect
when a population is drastically reduced to low numbers by a random or chance event and the allele frequencies of the surviving population do not reflect the genetic diversity of the original population
What is the founder effect?
when a small sample of a large population moves away to colonise a new area and become isolated; the allele frequencies of the founder population do not represent the genetic diversity of the larger original population
What are selection pressures?
the conditions or factors that influence allele frequencies in a population by contributing to the selection of which phenotypes survive in a given environment e.g resources, environmental conditions, predators and disease
What is natural selection?
an evolutionary process whereby those individuals in a population that have a particular set of alleles are best suited to the environment and will survive, reproduce and pass on their genetic information to the next generation
What is selective advantage?
a trait or phenotype that provides a survival advantage
What is selective breeding or artificial selection
a process whereby humans intervene in the breeding of a species to keep desired features in a population that are economically beneficial or aesthetically pleasing, by selecting which organisms are to reproduce
What is bacterial resistance?
the ability of bacteria to survive and reproduce in the presence of an antibiotic that has been designed to slow their growth or kill them; arises by mutation and becomes widespread when antibiotics are overused
Whaat is conjugation?
the process by which genetic material is exchanged between a donor bacterium; occurs through a tube via direct cell-cell contact; also known as horizontal gene transfer
What is a pandemic?
the outbreak of infectious disease that occurs over a wide geographical area, affecting a large number of people
What is a epidemic?
the raid spread of an infectious disease to a large number of people within a population
What is antigenic drift?
mutations altering viral surface antigens, making the virus unrecognisable to the host’s immune system; can result in a epidemic
What is antigenic shift?
reassortment of genes on genomes from different viruses infecting the same host cell, altering viral surface antigens, resulting in novel strains that can cause pandemics
What does fertile mean?
able to reproduce
what does viable mean?
able to survive
What does speciation mean?
the evolutionary process of forming a new species from a pre-existing ancestral species