Reproduction

• What is an allele?

  a version of a particular gene
• What is asexual reproduction?

  Reproduction that involves only one individual with no fusing of gametes to produce the offspring and the offspring are identical to parent
• What are chromosomes?

  Thread-like structure carrying the genetic information found in the nucleus of a cell
• What is cystic fibrosis?

  A genetic disease which affects the lungs, digestive and reproductive system and it is inherited through a recessive allele
• What is DNA?

  Deoxyribonucleic acid - the material of inheritance
• What does it mean to be dominant?

  The characteristic that will show up in the offspring even if only one of the alleles is inherited
• What’s fusion?

  The combining together of cells, nuclei, or cytoplasm
• What are gametes?

  Sex cell which has half the chromosome number of an ordinary cell
• What is a gene?

  A short section of DNA carrying genetic information
• What is heterozygous?

  Where the two alleles of a specific gene are different versions of the gene
• What is homozygous?

  Where the two alleles of a specific gene are exactly the same version of the gene
• What is human genome?

  All the genes that exist in the chromosomes of a single cell of a human
• What’s inbreeding?

  Mating between closely related individuals
• What is meiosis?

  A type of cell division that gives rise to four reproductive cells(gametes) each with half the chromosome as the mother cell
• what is mitosis?

  the division of a cell to form two daughter cells each having a nucleus containing the same number and kind of of chromosomes as the mother cell
• What is a monohybrid cross?

  A genetic cross between two parents that differ in the alleles they possess for one particular gene, one parent having two dominant alleles and the other having two recessive alleles
• What is a phenotype?

  The observable characteristics of an organism
• What is polydactyl?

  The condition of having more than the normal number of fingers or toes
• What does it mean to be recessive?

  The allele that is not expressed in the phenotype when two different alleles are present in the cells of an organism
• What are ribosomes?

  A small spherical body within the cell which is the site of protein synthesis
• Mitosis and meiosis

  • Mitosis is a type of nuclear division that gives rise to cells that are genetically identical
  • It is used for growth, repair of damaged tissues, replacement of cellsand asexual reproduction
  • Meiosis is a type of nuclear division that gives rise to cells that are genetically different
  • It is used to produce gametes (sex cells)
• Sexual reproduction

  • Sexual reproduction is a process involving the fusion of the nuclei of two gametes (sex cells) to form a zygote (fertilised egg cell) and the production of offspring that are genetically different from each other
  • The gametes of animals are the sperm cells and egg cells
  • The gametes of flowering plants are the pollen cells and egg cells
  • Fertilisation is defined as the fusion of gamete nuclei, and as each gamete comes from a different parent, there is variation in the offspring
  • The formation of gametes involves meiosis
• Asexual reproduction

  • Asexual reproduction does not involve sex cells or fertilisation
  • Only one parent is required so there is no fusion of gametes and no mixing of genetic information
  • As a result, the offspring are genetically identical to the parent and to each other (clones)
  • Asexual reproduction is defined as a process resulting in genetically identical offspring from one parent
  • Only mitosis is involved in asexual reproduction
• What process do cells in reproductive organs undergo to form gametes?

  Meiosis
• Why must the number of chromosomes be halved when forming gametes?

  To prevent double chromosomes after fertilization
• What is the term used to describe the halving of chromosome number during meiosis?

  Reduction division
• What is the chromosome number change during meiosis?

  From diploid to haploid
• How does meiosis contribute to genetic diversity?

  It results in genetically different cells
• What happens to chromosomes at the start of meiosis?

  They double themselves
• Where do chromosomes line up during meiosis?

  In the center of the cell
• How many times do cells divide during meiosis?

  Twice
• What do we call gametes in terms of chromosome number?

  Haploid
• How many haploid cells are produced by meiosis?

  Four
• What are the key stages of meiosis?

  1. Chromosomes double
  2. Chromosomes line up in the center
  3. Cells divide twice
  4. Four haploid cells are produced
• What shape do duplicated chromosomes form?

  X-shaped chromosomes
• What happens during the first division of meiosis?

  Chromosome pairs line up and are pulled apart
• How many copies of each chromosome does each new cell receive after the first division?

  One copy of each chromosome
• What occurs during the second division of meiosis?

  Chromosomes line up and arms are pulled apart
• How many haploid daughter cells are produced by meiosis?

  Four haploid daughter cells
• What types of gametes are produced in animals through meiosis?

  Sperm cells and egg cells