biology

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Across
  1. 3. Allele will only appear in the phenotype when dominant alleles are absent, characterized by a lowercase letter, i.e. if genotype is homozygous recessive (rr)
  2. 9. A haploid cell such as an egg or sperm. Gametes unite during sexual reproduction to produce a diploid zygote.
  3. 12. An allele that is always shown in the phenotype (masks the recessive allele).
  4. 13. A type of cell division that results in four haploid daughter gametes, each genetically different from each other
  5. 14. Combination of alleles an organism has for a specific gene
  6. 16. Exchange of alleles between homologous chromosomes during meiosis. This results in recombinant chromosomes which contain some maternal alleles and some paternal alleles.
  7. 18. A cell that is not a gamete (sperm or egg)
  8. 19. An organism or cell having only one complete set of chromosomes
  9. 21. Two different alleles for a trait
  10. 22. All the different alleles/phenotypes in a population
  11. 25. When homologous chromosomes line up independent of any rule, creating a random allocation of maternal/paternal chromosomes into the gametes.
  12. 28. A cell having two sets of chromosomes (one from each parent)
  13. 29. Individuals with the best suited alleles to that specific environment will survive to reproductive age to pass the alleles on. These alleles will then become more common in the gene pool. Those with less suited alleles are less likely to survive therefore these alleles will become rarer in the gene pool.
  14. 30. When humans decide which individuals breed together
Down
  1. 1. Figuring out what the sequence of bases is for a gene
  2. 2. Closely related individuals having offspring
  3. 4. Two chromosomes with the same genes (one from the sperm, one from the egg) but with potentially different alleles.
  4. 5. A fertilisedegg
  5. 6. A double stranded molecule, containing nucleotides that stores the genetic information required to produce the specific proteins needed for correct cell function
  6. 7. A permanent change in the DNA base sequence.
  7. 8. Short section of DNA coding for a particular trait
  8. 10. The random fusing of a haploid sperm and haploid egg to create a zygote.
  9. 11. Change in base sequence does not change the amino acid sequence so doesnt change the protein
  10. 15. Physical expression of a genotype
  11. 16. A strand of DNA that is sectioned into genes
  12. 17. Allele pairs are separated during meiosis so each gamete has only 1 instead of 2 alleles for a trait
  13. 20. Matching an individual’s genetic markers to another individual to see how they are related to each other.
  14. 23. An alternate form of a gene. They have only slightly different base sequences from one another.
  15. 24. Two of the same alleles for a trait
  16. 26. Using a genetic marker/base sequence/gene that only occurs in one species to see whether an unknown individual is that species or not.
  17. 27. Something that causes a mutation