reproduction, inheritance, genetic modification

• Allele

  • Different versions of the same gene e.g. blue eye allele (b), brown eye allele (B). Represented using letters
• Haploid

  A term for a cell that has single, unpaired chromosomes. This is half the number of chromosomes that appear in a diploid or somatic cell. Gametes are haploid e.g. in humans have 23 chromosomes
• Evolution

  A change in the inherited characteristics of a population over time through a process of natural selection which may result in the formation of a new species
• DNA

  Deoxyribonucleic acid, the genetic material contained in chromosomes. It is a polymer made up of two strands forming a double helix
• Gene

  A section of a chromosome which codes for a particular characteristic
• Menstruation
• Ovary

  Female reproductive organ that contains the eggs
• Dominant

  A characteristic which is expressed regardless of the paired allele
• Antibiotic resistance
• Genetic modification

  The process of taking genes from one species and introducing them into the genome of another species
• Mitosis

  A type of cell division that produces two identical daughter cells
• Fertilisation

  The fusion of a haploid male gamete/sperm with a haploid female gamete/egg to make a diploid zygote
• Heterozygous

  The alleles for a particular characteristic are different
• Mutation

  A change in a gene or chromosome
• Chromosome

  A structure made from DNA found in the nucleus of a cell
• Homozygous

  Both alleles for a particular characteristic are identical
• Foetus

  An unborn human usually is called a fetus during the period from three months after fertilization to the time of birth
• Egg Cell

  Also known as ovum, a female gamete
• Genotype

  The genes and alleles which determine the characteristics of an organism
• Oviduct
• Diploid

  A term for a cell with pairs of chromosomes in the nucleus e.g. humans have a diploid number of 46 (23 pairs)
• Embryo

  A large group of identical cells, all formed from an original zygote. The zygote divides by mitosis to form an embryo which then develops into the fetus in humans
• Gamete

  A haploid reproductive cell. Sperm and egg cells are male and female gametes
• Gestation

  The period between fertilization and birth during which the unborn offspring develops in the uterus
• Meiosis

  A type of cell division that produces four genetically different gametes
• Natural selection

  The theory of evolution that states all species of living things have evolved from simple life forms that first developed more than three billion years ago
• Natural selection
• Recessive

  A characteristic which is only expressed if paired with an identical allele
• Species

  A group of organisms that can interbreed to produce fertile offspring
• Vagina

  A passage from the uterus to the outside of the body. The entrance to the vagina from the uterus is called the cervix
• Cell division

  Process that produces two identical daughter cells
• Testes

  The pair of male reproductive organs located in the scrotum, a skin-covered sac that hangs from the groin
• Phenotype

  The physical expression of the characteristics in an organism
• Selective breeding

  Selecting parents with particular characteristics to breed together so that the offspring have desirable characteristics
• Secondary sex characteristics

  Unique traits that mark an individual as male or female but are not manifested in the sexual organs themselves. In males: Facial hair, deep voice, pubic hair, muscle growth. In females: Breast development, pubic hair, hip widening
• Oviduct

  Where fertilisation takes place. Also known as fallopian tube. Females have 2 oviducts. They are tubes lined with ciliated cells that create a current to transport the egg to the uterus from the ovary
• Uterus

  Also known as the womb. Where an embryo implants and is nourished to develop into a fetus during a successful pregnancy
• Zygote

  A diploid cell formed by the fusion of two gametes
• Sperm Cell

  A male gamete
• Sexual reproduction

  One of the two major varieties of reproduction, along with asexual reproduction. Involves two organisms. Occurs when male and female gametes undergo fusion, known as fertilization, and produce genetically different cells