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150 Cards in this Set
- Front
- Back
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what is DNA composed of
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nucleotides
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what is a nucletoide made of
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deoxyribose sugar, Phosphate, base
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what are the 4 bases in DNA
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adanine, thymine, cytoscine and guanine
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what is the structure if DNA
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a anti–paralell duoble stranded helix
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what are the nucleotied help together by
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a sugar phosphate backbone
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what are the strands held togteher by
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hydrogen bonds between complantntory bese pairs
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what number is phospate represented by
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C5 or 5
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what number is deoxyribose sugar
represented by |
C3 or 3
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what number is the base represented by
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C1 or 1
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what numbers is the left and right line
represented by |
left – 5' to 3'
right 3' to 5' |
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how is DNA organised in prokaryotes?
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a singular circular chromo and smaller circular plasmids
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how is DNA organised in eukaryotes?
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liner chromosomes in the nucleus, tightly coiled and packed with histones, also contain circular chromosomes in their mitochondria and chloroplasts
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why is yeast a special eukaryote
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it has plasmids
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what is a mutation?
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a random change in genetic material
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what can mutations result in?
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no protein or an altered protein being synthesised
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what is a single gene mutation?
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involve the alteration of a DNA nucleotide
sequence |
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what is an example of a single gene mutation?
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substitution, insertion or deletion
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what are the different types of nucleotide substitutions?
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missense, nonsense and splice–site mutations
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what is a nucleotide substitution?
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when one nucleotide is replaced by another
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What's a missense mutation?
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when one amino acid is changed for another
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what could a missense mutation cause?
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a non–functioning protein or would have little effect
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what does nonsense mutation result in?
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a premature stop codon being produced,
making a smaller protein |
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what is a splice site mutation?
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when some introns are retained or some exons are cut out of a mature transcript
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what do nucleotide insertions and deletions
result in? |
a frameshift mutation
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what is an insertion mutation?
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when one or more nucleotides are inserted into a DNA sequence
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what is a deletion mutation?
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when one or some nucleotides are removed for a DNA sequence
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what do frameshift mutations cause?
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all of the codons and all of the amino acids after the mutation to be changed
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what does a frameshift mutation effect?
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the structure of the protein produced
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what are chromosome structure mutations?
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duplication, deletion, inversion and translocation
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what kind of mutations are often lethal?
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chromosome mutations
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what is an inversion mutation?
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when a section of a chromosome is reversed
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What is a translocation mutation?
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when a section of a chromosome is added to a different chromosome, not its homologous partner
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what is a duplication mutation?
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when a section of a chromosome is added to its homologous partner
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why is a duplication mutation important?
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allows potential beneficial mutations to occur in a duplicated gene whilst the original gene can still be expressed to produce its protein
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what is DNA replicated by
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DNA polymers
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what do DNA polymers need
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primers
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what do DNA polymers do
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adds DNA nucleotides, using complementary base pairing, to deoxyribose (3’) end of the new DNA strand which is forming
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what is a primer
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a short strand of nucleotides which binds to the 3’ end of the template DNA strand allowing DNA polymerase to add DNA nucleotides.
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what is he first step of DNA replication
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DNA is unwound and the hydrogen bonds are broken from two separate template strands
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what is the seccond step of DNA replication
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a primer beinds to the 3' end of the DNA strands
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what is the third step in DNA replication
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DNA plymers adds DNA nucleotides using complamentory bases to the 3' end of the strand
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what is the furth step in DNA replication
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DNA polymerase can only add DNA nucleotides in one direction resulting in the leading strand being replicated continuously and the lagging strand replicated in fragments.
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what is the fith step of DNA replication
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fragments of DNA are joined togther using ligase
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what is PCR [polymers chain reaction]
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it amplifyes DNA using complamentory primers for a specific target sequence
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what are primers in PCR
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short strands of nucleotides which are
complementary to specific target sequences at the two ends of the region of DNA to be amplified. |
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what happens during PCR
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the repeated heating and cooling of an
amplified part of DNA |
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what is the first step of PCR
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DNA is heated to between 92 and 98°C to
separate the strands. |
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what is the second step of PCR
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It is then cooled to between 50 and 65°C to allow primers to bind to target sequences.
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what is the third step of PCR
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It is then heated to between 70 and 80°C for heat–tolerant DNA polymerase to replicate the region of DNA.
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what is required for a PCR reaction
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DNA, nucleotides, primers, polymers, buffer
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what is PCR used for
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solving crimes, paternity testing and diagnosing genetic disorders
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what does gene expression involve
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the transcription and translation of DNA sequences.
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what do transcription and translation involve (types of RNA)
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mRNA tRNA rRNA
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what is the structure of RNA?
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single–stranded, composed of RNA nucleotides
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what do RNA nucleotides consist of
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ribose sugar, phosphate one of four bases
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what are the four bases in RNA?
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cytosine, guanine, adenine and uracil
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what is mRNA (messenger RNA)
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RNA that carries a copy of the DNA code from the nucleus to the ribosome
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what is tRNA (transfer RNA)
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carries a specific amino acid to the ribosome.
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how does tRNA fold
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complementary base pairing
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what is rRNA (ribosomall RNA)
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one of the things that form a ribosome
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what forms a ribosome
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rRNA and proteins
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what does RNA polymerase do
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moves along the DNA unwinding the double
helix, breaking the hydrogen bonds between the bases |
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what does RNA polymer synthesis
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a primary transcript of mRNA from RNA nucleotides mRNA from RNA nucleotides
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how do RNA polymers synthesise a primary transcript?
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by complementary base pairing
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what is uracil complementary to
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advance, it replaces thymine
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what does RNA splicing form
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a mature RNA transcript
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what are introns
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non–coding regions and are removed from the mature transcript
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what are exons
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coding regions joined together in the mature transcript
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what happens to the exon order
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it remains unchanged during splicing
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what is alternative RNA splicing?
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when different proteins are expressed from one gene
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what can be produced for the same primary transcript?
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different mature RNA transcripts
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how are different mature RNA transcripts produced?
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due to the exons that are retained
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what translation is tRNA involved in
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the translation of mRNA into a polypeptide at a ribosome.
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what is mRNA
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mRNA is transcribed from DNA in the nucleus
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what is mRNA translated into
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into proteins by ribosomes in the cytoplasm
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what is each triplet of bases on a mRNA
molecule called |
a codon
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what does a codon do
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codes for a specific amino acid
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what has an anticodon on one end
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a tRNA molecule
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what is an anticodon?
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an exposed triplet of bases
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what is on the other side of tRNA
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an attachment site of a specific amino acid
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what does translation start and end
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at a start codon and an end codon
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what do anticodons bond to and how
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to codons by complementary base pairing
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what does anticodon and codon bonding cause
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the translation of the genetic code into a
sequence of amino acids |
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what joins the amino acids together
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a peptide bond
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what does tRNA do after the amino acids join
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it leaves the ribosome as the polypeptide is formed
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what do the bonded amino acids make
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a polypeptide
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what do polypeptide chains fold into
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the three dimensional shape of a protein
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what are these proteins held together by
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hydrogen bonds and other interactions between individual amino acids
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what determines a proteins function
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its three dimensional shape
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what determines a proteins phenotype
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the proteins produced as the result of gene expression
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what also effects the phenotypes
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environmental factors
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what is cellular Differentiation?
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a process when a cell is expressed to produce genes to produce protein characteristics for that type of cell
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what does this allow cells to do?
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carry out specialised functions
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what is a meristem in a plant?
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a region of unspecialised cells in a plant that can divide or differentiate
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what are stem cells in animals?
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unspecialised cells in animals that can divide or differentiate
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what is an embryonic stem cell?
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cells in a very early embryo
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what can embryonic stem cells do?
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differentiate into all cell types
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what does pluripotent mean
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the stem cell and differentiate into any cell type
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what happens when the genes in these cells are switched on
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the cells can differentiate into any type of cell
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what is a tissue stem cell used for
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growth and repair of tissues and renewal of the cells in that tissue
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what does multipotent mean
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they can turn into all of the types of cells found in a particular tissue type.
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what cells are pluripotent
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embryonic stem cells
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what cells are multipotent
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tissue stem calls
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an example of multipotent cells
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blood stem cells located in bone marrow can give rise to all types of blood cell
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what are the therapeutic uses of stem cells?
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corneal repair is the regeneration of damaged skin, the repair of damaged or diseased organs or tusse
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what are the research uses of stem cells?
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studying how diseases develop or drug testing
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what can stem cells in an embryo do under the right conditions
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self renew
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what does stem cell research tell us
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cell processes such as cell growth and how
differentiation and gene regulation work |
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what are the ethical issues of using embryonic stem cells?
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they can provide useful treatment for disease or injury
but it involves the destruction of an embryo |
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what is a genome?
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the entire hereditary information encoded in the DNA of an organism
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what is a genome made up of
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genes and other DNA sequences that do not code for proteins
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what does most eukaryotic genomes have
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noncoding sequences
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what is a gene?
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a DNA sequence that codes for a protein
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what do other non–coding sequences do
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regulate transcription, are transcribed but not translated
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what are the non–translated forms of RNA?
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rRNA and tRNA
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what is evolution
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the changes in an organism over generations
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what is natural selection?
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non–random increase in frequency of DNA
sequences that increase survival non–random reduction in the frequency of deleterious sequences. |
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what changes the phenotype frequency
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directional selection, stabilising selection and disruptive selection
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what is stabilising selection?
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more common phenotypes survive, the more dramatic phenotypes do not
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what is directional selection?
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one extreme is selected
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what is disruptive selection?
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when two or more phenotypes are selected
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where is natural selection more rapid?
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in prokaryotes
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what direction can prokaryotes exchange genetic material?
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horizontally, across the way
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what does horizontal reproduction result in
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a fast evolutionary change
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what is horizontal gene transfer?
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when genes are transferred between organisms of the same generation
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What is vertical gene transfer?
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where genes are transferred from parent to child
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when does speciation occur
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after part of a population becomes separated by an isolation barrier
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what are the different types of isolation barriers?
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GeographicalEcologicalbehavioural.
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what is a species?
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a group of organisms capable of interbreeding and producing fertile offspring, and which does not normally breed with other groups
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what is speciation
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the generation of a new species by evolution as a result of isolation, mutation and selection
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why are isolation barriers important?
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important in preventing gene flow between populations during speciation
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what is sympatric speciation?
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when behavioural or ecological barriers led to speculation
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what is allopatric speciation?
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when geological barriers lead to speciation
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what is used to identify base sequences?
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computers
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what do computers look for?
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sequences similar to genes
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what is bioinformatics?
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when sequence data is compared using
computer and statistical analysis techniques |
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what does the comparison of genomes show?
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that many species share genomes
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how do you tell how closely related species are?
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The greater the number of conserved sequences between species
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what is Phylogenetics used for?
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to determine the main sequence of events in evolution
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what is Phylogenetics?
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the study of evolution history and relationships
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what can sequence data be used to study?
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evolutionary relatedness among groups of organisms
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what is sequence divergence?
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the time since lineages diverged
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what are the 3 domains of life?
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Bacteriaarchaea eukaryotes
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what is used to determine the main sequence of events in the evolution of life?
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sequence data and fossil evidence
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what are molecular clocks used for?
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to determine the main sequence of events in evolution.
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what remains constant with molecular clocks?
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the mutation rate
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what do molecular clocks show?
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differences in DNA sequences or amino acid sequences.
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what is pharmacogenetics?
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the use of genome information in the choice of drugs
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what can analysing someone's genome tell you?
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the likelihood of developing certain diseases
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why is personalised medicine useful?
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it can be used to select the most effective drugs and dosage to treat their disease
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