science - term 1 (DNA)

• what is a karyotype??


  it is a picture of all the chromosomes in a cell, arranged in pairs and in order of size.
• what are chromosomes?


  they are strands of DNA tightly coiled into structures called cromosomes
• recognise abnormalities?

  down syndrome: 3x chromosome 21

  Klinefelter syndrome: xxy

  turners syndrome: single x in a female
• chloroplast?


  The site of photosynthesis only found in plants
• ribosomes?


  function is to produce proteins from DNA
• Golgi body?


  function is to sort and package proteins( usually to release them out of the cell)
• vacuale?


  temporary storage space in a cell for water, food and waste
• cell membrane?


  all cells have it, it controls the movement of substances in and out of the cell
• what is a gene?


  it is just one section of DNA and it codes for a specific protein that determines your traits eg. hair colour
• what is the function of DNA?


  DNA contains the instructions needed for and organism to develop, survive and reproduce
• endoplasmic reticulum?


  moves things around the cell (rough - with ribosomes)(smooth - without ribosomes)
• autosomes?


  are chromosomes that don't determine your sex eg. the first 22 pairs of chromosomes
• homozygous, dominant example?


  RR
• homozygous, recessive example?


  rr
• heterozygous example?


  Rr
• who are the scientists who discovered the structure of DNA?

  Francis Crick, Rosalind Franklin, James Watson and Maurice Wilkins
• diploid?


  double of every chromosome
• haploid?


  half of the no. of chromosomes
• homozygous?


  2 of the same allele eg. BB or bb
• heterozygous?


  have one of each allele eg. Bb and are called carriers, hey have an allele for the recessive trait in their genotype but dont show it in their phenotype
• genotype?


  the particular combination of alleles of a gene
• how many chromosomes are there?


  there are 23 pares (2 of each)
• sex chromosomes?


  pair 23 - xx = female xy= male
• draw and label the features of a DNA double helix?

  (the nitrogenous bases are connected by hydrogen bonds)

  
• nuclius?


  controls all the cell activities and contains genetic material
• mitocondria?


  it's function is to produce energy through cellular resporation
• allele?


  are the different versions of the same gene
• what are the 4 nitrogenous bases?

  adenine, thymine, cytosine, guanine
• draw and label a nucleotide?


  .

  
• what dose DNA stand for?

  deoxy - ribo - nucleic acid.
• punnet squares?


  .

  
• pedigree?


  is a family tree diagram that shows the phenotypes of the individuals in a family across multiple generations