unit 4 biology

• what does "replicate" mean


  create again
• before what process will dna need to be replicated

  cell devision
• why is it important for dna to be replicated before cell devision


  ensures that each daughter cell gets a copy of the genome, and therefore, successful inheritance of genetic traits
• what is a daughter strand

  A daughter strand refers to the newly synthesized DNA strand.
• what does semi conservative mean


  Half old strand; half new strand
• What is complimentary base pairing?

  Adenine only pairs with thymine

  Guanine only pairs with cytosine
• what is dna polymerase

  an enzyme that joins individual nucleotides to produce a new strand of DNA
• what is dna helicase

  the enzyme that breaks the h-bond between the two strands of DNA to "unzip" double helix
• which enzyme links the new strand of dna together

  dna polymerase
• what enzyme unwinds the two strands

  helicase
• how does helicase unwind the 2 strands

  breaking the hydrogen bonds between the complementary bases
• What is elecrophoresis?

  movement of charged particles in an electric field
• how is electrophoresis used

  An electric current is used to move the molecules through a gel or other matrix.
• why is electrophoresis used

  to separate DNA, RNA or protein molecules based on their size and electrical charge.
• what is the relationship between the size of a dna fragment and the rate at which it moves through the gel

  In gel electrophoresis, smaller DNA fragments move faster through the gel matrix compared to larger fragments due to experiencing less resistance.
• what are the two common methods of visualizing dna in electrophoresis

  adding radioactive isotopes, adding fluorescent markers
• how would adding radioactive isotopes work

  by allowing the radioactivity to stain the photographic film causing dna to show up as dark bands
• how would adding fluorescent markers work

  the dna fragments would show up as colored lights when the gel is illuminated in ultraviolet light
• what does non coding dna mean

  refers to regions of DNA that do not directly encode proteins, but may still have regulatory, structural, or other functional roles in the genome.
• what does STR stand for

  short tandem repeats
• what do STRs do

  serve as genetic markers and may have roles in genome stability, gene regulation, and genetic disorders.
• What are STRs?

  sections of a chromosome in which DNA sequences are repeated
• How does DNA profiling work?

  -Restriction enzymes cut DNA at specific sequences, producing different sized fragments

  -If mutations have occurred in some sections then they will not be cut so the size and position of fragments will be different

  -Gel electrophoresis can be used
• what technique can be used to make many copies of dna samples from victims and suspects

  PCR cycle
• what is a gene

  segment of DNA that codes for a protein
• what does polypeptide mean

  more than one peptide
• define protein

  large macromolecules consisting of more than one amino acid chain
• which component of dna contains the genetic information

  nucleotides
• why do nucleotides contain the genetic info in dna

  because their specific sequence determines the sequence of amino acids in proteins
• inn eukaryotic cells where in the dna found

  cell nucleus
• why is the dna in the cell nucleus

  The DNA is located in the cell nucleus to protect and organize the genetic material while facilitating gene regulation and control over gene expression.
• how much of the dna is unwound during transcription

  only a short bit of the strand
• what is added during transcription as rna is made

  rna polymerase
• What is RNA polymerase?

  an enzyme that binds to DNA during transcription and separates or unwinds the DNA strands.
• how many strands of dna are being producedd during transcription

  1
• how many strands of dna are used during transcription

  1
• what is genetic code

  collection of codons of mRNA, each of which directs the incorporation of a particular amino acid into a protein during protein synthesis
• what level of protien structure is determined by the sequence of amino acids

  the primary structure of a protein.
• WHAT TYPE OF CODE is the genetic code

  triplet code
• what does triplet code mean

  three bases code for one amino acid