definitions Flashcards
Sexual reproduction
Genetic information comes from two sexes, and gametes must meet and fuse
Asexual reproduction
Doesn’t require an egg and sperm (gametes) to meet, and usually comes from one organism
Gamete
Gametes are cells which can give rise to a new organism when they meet with a gamete of the opposite gender.
External fertilisation
Egg and sperm meet outside the female body
Internal fertilisation
Egg and sperm meet inside the female body
Binary fission
Type of asexual reproduction where bacteria ‘split’ in half, each half becomes a new daughter cell
Budding
Type of yeast asexual reproduction where cells grow bigger until a little ‘bud’ forms on the mother cell. This bud grows bigger until it is big enough to break off.
Mitosis
the process by which a cell replicates its chromosomes and then segregates them, producing two identical nuclei in preparation for cell division.
Meiosis
Meiosis is a process where a single cell divides twice to produce four cells containing half the original amount of genetic information.
DNA replication
Making new copies of DNA so new cells can have a copy
Transcription
The process of copying information encoded in DNA into a ‘photocopy’ or RNA so the ribosome can read it
Translation
Ribosome ‘reading’ the mRNA which tells it to recruit certain amino acids. Results in a polypeptide chain
Polypeptides
Polypeptides are short proteins made up of chains of amino acids
Chromosome
a long DNA molecule with part or all of the genetic material of an organism.
Gene
A gene codes for a particular characteristic. A gene is a section of our DNA molecule
Allele
Allele is a form of a gene. For each gene, we have two alleles - one from mum and one from dad
Phenotype
This is the physical characteristic of a genotype
Genotype
the genetic makeup of an organism
Homozygous genotypes
Genotypes where the two alleles are the same
Heterozygous genotypes
Genotypes where the two alleles are different
Simple dominance
Where one allele is completely dominant over the other (the recessive allele)
Monohybrid cross
A Medelian cross where the two individuals have the same genotype
Co-dominance
Where two or more alleles have equal dominance (which gives rise to a third outcome)
Sex-linked genes
to characteristics (or traits) that are influenced by genes carried on the sex chromosomes.