Genetics Vocabulary (essential)

Vocabulary flashcards for Genetics

Adaptations

Traits/phenotypes which allow an organism to better survive in its environment.

Allele

An alternative version of a gene.

Amino acids

The building blocks of proteins.

Asexual reproduction

Requires only one parent. All offspring are genetically identical to the parent.

Bases

The part of DNA that stores genetic information A, T, G, C.

Chromosome

A long strand of DNA containing a specific set of genetic information. Chromosomes are stored in the nucleus of each cell.

Complementary Base Pairs

A:T and G:C. Ensures the genetic code is replicated correctly during DNA replication.

Crossing-over

Swapping of DNA between homologous chromosomes during meiosis. Increases genetic variation through reshuffling of alleles

DNA

DNA is a long molecule that contains your genetic code. DNA stores your genetic code using combinations of four nucleotide bases: adenine, thymine, guanine and cytosine. Each base has a complementary base that connects to form complementary base pairs; adenine pairs with thymine, while guanine pairs with cytosine.

Diploid

Describes a cell with two copies of each chromosome.

Dominant allele

An allele whose trait always shows up in the organism when the allele is present.

Evolution

The change in the gene pool within a population over many generations

Fertilisation

The process where the DNA from an egg and sperm fuse together.

Gametes

Sex cells containing half the chromosomes of the parent.

Genome

All the DNA in a single cell of an organism.

Gene

A short segment of DNA that codes for a particular protein/phenotype. The base sequence (triplet code) of the gene determines the amino acid sequence, which in turn determines the protein.

Gene Pool

The combination of alleles within genes within a population

Genetic diversity

Is the total amount of genetic variation present within a population or a species.

Genetic Code

The bases of a gene are read in sets of three and each triplet codes for an amino acid, which in turn, are joined to make a protein.

Genetic Variation

The total number of different alleles in a population of organisms.

Genotype

The combination of alleles for a gene e.g.: BB, Bb, bb.

Genotypic ratio

The ratio of the genotypes that appear in offspring

Haploid

Describes a cell with only one copy of each chromosome

Heterozygous

Two different alleles in a genotype: e.g.: Bb.

Homozygous

Two alleles in a genotype are the same: e.g.: BB or bb.

Independent assortment & segregation

The arrangement of homologous chromosomes randomly lining up and separating independently during the process of meiosis

Meiosis

A type of cell division which produces egg and sperm cells (gametes) with half the number of chromosomes of the parent cell (haploid)

Mitosis

A type of cell division that produces identical cells. This enables organisms to grow and/or produce clones through asexual reproduction.

Mutation

A permanent change in the DNA that can make new alleles.

Natural Selection

A mechanism of evolution

Offspring

The resulting individuals of reproduction.

Organism

A living thing.

Pedigree chart

A diagram which shows several generations of related families and how traits are passed down through the offspring.

Phenotype

How a gene is expressed as a protein/phenotype/trait.

Population

Number of organisms of the same species living in a defined area.

Population Bottleneck

Is an event that drastically reduces the size of a population.

Punnett square

A method of showing the probability of all the potential offspring genotypes and phenotypes that can occur from mating two individuals.

Recessive

An allele that is masked when a dominant allele is present and only expressed in the phenotype when the genotype is homozygous (eg: bb).

Selective pressure

Factors that affect the ability of organisms to survive and reproduce in their environment.

Sexual reproduction

Reproduction involving two parents. Offspring inherit half their DNA from each parent.

Species

A group of organisms that can breed with each other and produce fertile offspring.

Fitness

The ability to pass genetic material on to offspring.

Proteins

Polymers of amino acids

Pedigree chart

A diagram which shows several generations of related families and how traits are passed down through the offspring.

Gene marker

A short segment of DNA that can be used to follow the inheritance of a trait or determine the relatedness of different organisms.