Biology - unit 2

• What are chromosomes made of?


  Linear arrangements of genes
• How do chromosomes come in pairs?


  One chromosome is inherited from each parent
• What is an allele?


  A different version of the same gene
• Give an example of a gene and its alleles.


  Gene = eye colour; Alleles = brown, blue, green, hazel
• What are stem cells?


  Undifferentiated cells that can differentiate into any other type of cell
• What are the sources of stem cells?

  Embryonic tissue and adult stem cells in some tissues
• How can stem cells be used in medicine?


  To replace damaged or diseased tissue
• Why is it preferable to use your own stem cells?


  To avoid rejection and the need for a donor
• What ethical issues are associated with embryonic stem cells?


  They raise concerns about the moral status of embryos
• What is mitosis?


  A type of cell division used for growth, repair, and replacement of cells
• How many daughter cells are produced by mitosis?


  Two daughter cells
• What is true about the daughter cells produced by mitosis?


  They are genetically identical to the mother cell
• What is the result of uncontrolled mitosis?


  Cancer
• What happens to the chromosomes during mitosis?


  DNA replicates and one copy of each chromosome goes into each daughter cell
• What is meiosis?


  A type of cell division that occurs for the formation of sex cells (gametes)
• What type of cells are formed through meiosis?


  Sex cells (gametes) like eggs and sperm
• What is the chromosome number in the mother cell before meiosis?


  4 chromosomes (2 pairs, diploid)
• What happens to the chromosomes during the first division of meiosis?


  One of each pair of chromosomes goes into a new cell
• How many new cells are formed after meiosis?


  Four new cells
• What is the chromosome number in the new cells formed by meiosis?


  They have half the chromosomes of the mother cell (haploid)
• Are the new cells formed by meiosis genetically identical to the mother cell?


  No, they are not genetically identical
• Stem cell therapy is the use of stem cells to treat or prevent diseases.
• Embryonic stem cells are derived from embryos, while adult stem cells come from various tissues such as bone marrow, blood, skin, fat, liver, brain, heart, muscle, pancreas, and umbilical cord blood.
• Adult stem cells can be used to regenerate damaged tissue and have been successfully used in clinical trials for treating conditions like diabetes, Parkinson's disease, Alzheimer's disease, spinal cord injuries, and cardiovascular diseases.
• Embryonic stem cells can be used to replace damaged tissues with healthy ones.
• The main advantage of using stem cells is that they can differentiate into any type of body tissue.
• Adult stem cells can also be used to repair damage caused by disease or injury.
• However, there are concerns about the ethics of destroying human embryos to obtain these cells.
• What do living organisms show a range of?

  Sizes, features, and complexity
• How are plants classified?

  • Flowering: daisies, roses, dandelions
  • Non-flowering: mosses, ferns
• How are animals classified?

  • Vertebrates: have a backbone (e.g., birds, snakes, humans)
  • Invertebrates: do not have a backbone (e.g., insects, spiders)
• What has been used recently to classify and name organisms?

  DNA analysis
• How many domains are there in the largest groups of organisms?

  Three domains
• What are the three domains of life?

  Eukarya, Bacteria, Archaea
• What are the five kingdoms of life?

  1. Animals
  2. Plants
  3. Fungi
  4. Single-celled organisms
  5. Bacteria
• What is the term for groups that get smaller in classification?

  Phylum
• What are adaptations in living organisms?

  • Morphological: physical features
  • Behavioral: actions or habits
• How do fennec foxes adapt to hot climates?

  They have large ears to radiate heat
• How do arctic foxes adapt to cold climates?

  They have small furry ears to reduce heat loss
• What do all organisms compete for?

  • Animals: food, territory, mates
  • Plants: light, water, minerals