biology 10

• what enzyme separates 2 DNA strands and what does it create?

  helicase, replication fork
• the enzyme primase starts replication and creates RNA called a primer. this is the starting point of a new dna strand
• the enzyme dna polymerase binds to the primer and makes a new strand starting from 5'-3' end --> adds nucleotides
• in the 3'-5' end,

  1. dna polymerase makes this strand in small chunks called okazaki fragments
  2. each fragment is started with an rna primer
  3. dna polymerase adds a short row of dna bases in 5'-3' direction
  4. primer (primase) is added further down the lagging strand
  5. another okazaki fragment is made and process is repeated
• exonuclease removes rna primers from both strands
• another dna polymerase enzyme then fills the gaps left behind with DNA
• dna ligase seals up fragments of dna to form a continuous double strand
• dna replication is semi-conservative. why?


  because each DNA molecule is made up of one conserved strand and one new strand
• what enzymes are involved in dna replication?

  5 total: helicase, DNA polymerase, exonuclease, DNA ligase
• 5'-3' end replicates faster and smoother which is why it is called the leading strand
• 3'-5' end has to be added in chunks going the opposite direction of 5'-3' end, replicates slower and needs okazaki fragments, giving it the name of the lagging strand
• okazaki fragments come in at the 3'-5' end and are chunks of DNA that get added to the strand
• the replication fork is the intersection where old DNA splits into two using helicase
• protiens are molecules that create the structure of the body and regulate it
• dna molecules contain genes that contain instructions to make protiens
• transcription is the first step of making protiens
• transcription occurs in the nucleus

  1. rna polymerase separate strands into small section of DNA molecule that contains a gene
  2. then it uses one strand of DNA molecule as a template to make molecule called messenger rna (mRNA)
  3. mRNA is similar to DNA but it has one strand and once its produced it separates from DNA template and leaves the nucleus and into the cytoplasm
  4. contains uracil instead of thymine
• translation: when mRNA goes to the cytoplasm, translation begins

  1. translation is the process where ribosomes create protiens
  2. ribosomes translate mRNA into a long amino acid chain which eventually folds together to form protien
  3. every mRNA molecule contains protein coding region
  4. these coding regions are divided into triplet bases called codons
  5. amino acid type is determined by the codons on mRNA molecule
  6. transfer rna (tRNA) carries specific amino acids to the ribosome
  7. each tRNA has a anti-codon that are complimentary to the codons on mRNA molecule
• translation as 3 phases

  initiation: the ribosome assembles around the mRNA molecule and the first tRNA is arrached at the start codon

  elongation: each tRNA transfers an amino acid to the ribsome and the ribosome moves to the next mRNA codon to continue the process which creates an amino acid chain

  termination: when a stop codon is reached the ribosome releases the amino acid chain and it folds together to make a protien
• what is the difference between a genotype and phenotype?

  Genotype: genetic makeup Phenotype: physical traits
• where is dna located?

  in the chromosomes in the nucleus
• dna makes genetic code that codes traits and allows for evolution and genetically diverse group of people
• dna is the blueprint that determines what cells become
• dna is 2 intertwined strands that run in the opposite direction to each other and form a double helix
• what is a genome?

  The complete set of genetic material in an organism.
• what is in a nucleotide?

  phosphate group, sugar group, nitrogenous base
• what are the nitrogenous bases that have 2 rings?

  Adenine and Guanine
• what are the nitrogenous bases that have 2 hydrogen bonds?

  adenine and thymine
• what are the nitrogenous bases that have 3 hydrogen bonds?

  guanine and cytosine
• humans are diploid organisms which mean we have 2 copies of each chromosome. one from dad one from mom. ther are 46 total and 23 pairs
• chromosomes are made up of chromatin that is made up of DNA and proteins
• karyogram is the gerneral appearance of the complete set of chromosomes
• what is the difference between alleles and DNA?

  Alleles: Different forms of a gene (i.e. eye colour gene: blue and brown are the alleles) DNA: Molecule that carries genetic information
• is allele 1 dominant or recessive?

  dominant
• is allele 2 dominant or recessive?

  recessive
• homozygous AA is dominant
• homozygous aa is recessive
• heterozygous Aa usually takes the dominant phenotype
• organisms can only grow if cell division happens
• protiens make up most of the bodily functions such as hair, bone and muscle

  they are made of long chains of 20 amino acids and determine what a cell does