B12: reproduction

• allele


  _____________ (singular) - different forms of the same gene sometimes referred to as variants.
• asexual


  _______________________ reproduction involves only one parent/cell and the offspring is identical to the parent.
• cystic fibrosis


  ________ ________________ (two words) is an inherited disorder that affects the lungs, digestive, and reproductive system and is inherited through a recessive allele.
• dominant


  A ________ allele is always expressed even if there is another allele present.
• engineering


  Genetic _________________ is the process by which scientists can add or remove genes from the genotype of an organism.
• genotype


  the genetic makeup of an individual for a particular characteristic, for example hair or eye colour. Dominant alleles are represented by capital letters.
• heterozygous


  individual who are __________________ have 2 different alleles for a characteristic.
• homozygous


  individual who are ________________ have two identical alleles for a characteristic.
• meiosis


  __________________is involved in making gametes for sexual reproduction. 4 daughter cells are produced.
• phenotype


  the physical appearance / biochemistry of an individual for a particular characteristic. is called the _________________________
• polydactyly


  _________ is a dominant inherited disorder that results in babies born with extra fingers and/or toes.
• Punnett


  A _____________________ square diagram is a way of modelling a genetic cross and predicting the outcome using probability
• recessive


  a ________________ allele will only be expressed if an individual has 2 copies of it.
• y


  The x and __ chromosomes are called the sex chromosomes and carry the information that determines the sex of an individual.
• sexual


  ___________ reproduction involves the joining (fusion) of male and female gametes (nuclei) producing genetic variation in the offspring
• 23


  Human gametes have _____ (number) chromosomes.
• 46


  Human body cells have ___ (number) chromosomes.
• mitosis


  normal body cells reproduce using ____________ and produce identical daughter cells.
• variation


  genetic _______________ results from sexual reproduction but not from asexual reproduction.
• Genome


  The entire sequence of genetic information for an organism is called its ______________
• gene


  A ______________ codes for a sequence of amino acids that make up a specific protein.
• screened


  Embryos can be ___________________ to identify genetic disorders
• • Cells in the reproductive organs divide by meiosis to form the gametes (sex cells).
  • Body cells have two sets of chromosomes, gametes have only one set.
  • In meiosis, the genetic material is copied and then the cell divides twice to form four gametes, each with a single set of chromosomes.
  • All gametes are genetically different from each other.
  • Gametes join at fertilisation to restore the normal number of chromosomes. The new cell divides by mitosis. The number of cells increases and as the embryo develops, the cells differentiate.
• • The genome of an organism is the entire genetic material of that organism.
  • The whole human genome has now been studied and this will have great importance for medicine in the future.
  • The genetic material in the nucleus of a cell is composed of DNA. DNA is a polymer made up of two strands forming a double helix.
  • A gene is a small section of DNA on a chromosome. Each gene codes for a particular sequence of amino acids, to make a specific protein.