Biology terms for memorising level 1 Flashcards
Adaptions
Traits/phenotypes which allow an organism to better survive in its environment
Allele
An alternative version of a gene
Ancestor
An organism (or species) from which other organisms (or species) have evolved
Amino acids
The building blocks of proteins
Antiparallel
The two strands of a DNA molecule run in opposite directions
Asexual reproduction
Requires only one parent. All offspring are genetically identical to the parent
Bases
A, T, G, C
Chromosome
A long strand of DNA containing a specific set of genetic information
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 the meiosis process. Increases genetic variation
Deoxyribonucleic acid (DNA)
A molecule that carries the genetic code
DNA sequencing
The process of finding out the exact order of bases on a length of DNA
Dominant
An allele that is always expressed when it is present. Represented using capital letters. E.g. BB, Bb
Evolution
Gradual change in the genetic code of organisms over a long period of time. May result in formation of new species
Fertilisation
The process where the DNA from an egg and sperm fuse together
Gametes
Sex cells containing half the chromosomes of the parent (haploid cells)
Genome
All the DNA in a single cell of an organism
Gene
A short segment of DNA that codes for a particular protein/phenotype
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.
Gene marker
A short segment of DNA that can be used to follow inheritance of a trait (especially if it is not visible) or determine relatedness of different organisms
Genetic variation
The total number of different alleles in a population of organisms
Genotype
The combination of alleles for a gene: BB, Bb, bb
Genotype ratio
The predicted ratio of inheritance of alleles from mating of two individuals
Heterozygous
Two different alleles in a genotype: e.g. Bb
Homologous pairs of chromosomes
Two chromosomes in a cell with the same genes on them. One chromosome is inherited from each parent
Homozygous
Two alleles in a genotype are the same: e.g. BB or bb
Independent segregation
Homologous chromosomes line up at random and independently or other homologous chromosomes during the process of meiosis
Karyotype
A picture of all the chromosomes in a cell, ordered from largest to smallest in homologous pairs
Meiosis
A type of cell division which produces egg and sperm cells (gametes) with half the number of chromosomes of the parent cell
Mutation
A permanent change in the DNA
Offspring
The resulting individuals of reproduction
Pedigree chart
A branching tree diagram that tracks alleles/traits being passed through a family
Phenotype
How a gene is expressed as a protein/phenotype/trait
Phenotype ratio
The predicted ratio of phenotypes of offspring of a genetic cross
Phylogenetic tree
A diagram that orders organism in relationship to how closely related they are. Usually starts with a common ancestor on the far left
Proteins
Polymers of amino acids that make up our traits
Punnett square
A method of showing the probability of all the potential offspring genotypes and phenotypes that can occur from mating two individuals
Population
Number of organisms of the same species living in a defined area
Recessive
An allele that is only expressed in the phenotype when the genotype is homozygous (bb)
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
Trait
A feature of an organism (phenotype)
Triplet code
Bases of genes are read in threes (triplets), each triplet codes for an amino acid to build a protein
