Storing and Using Genetic Information Flashcards
<p>What is a phenotype?</p>
<p>Physical manifestation of genotype</p>
<p>What is a genotype?</p>
<p>All of the genes in our DNA, even the ones that are not expressed</p>
<p>Why are proteins functionally different?</p>
<p>Due to their different structures</p>
<p>What does the structure of a protein depend on?</p>
<p>The primary structure (sequence of amino acids)</p>
<p>What is DNA?</p>
<p>A chain of nucleotide monomers that contains all of our genetic information</p>
<p>What does each nucleotide contain?</p>
<p>Sugar</p>
<p>Base</p>
<p>Phosphate group</p>
<p>What structure does DNA form?</p>
<p>Double helix</p>
<p>How many bases is there per turn of the helix?</p>
<p>10</p>
<p>How do polypeptide chains of DNA run to each other?</p>
<p>Antiparralel to one another</p>
<p>How are the groves in DNA described?</p>
<p>Major and minor groves which is important for the interaction of proteins</p>
<p>What is the pairing of bases called?</p>
<p>Compliment base pairing</p>
<p>What bases pair with what in DNA?</p>
<p>Thymine paires with adenine</p>
<p>Guanine pairs with cytosine</p>
<p>What does compliment base pairing happen?</p>
<p>Due to the structures of the bases:</p>
<p>Thymine pairs with ademine due to both forming 2 hydrogen bonds</p>
<p>Guanine pairs with cytosine due to both forming 3 hydrogen bonds</p>
<p>What bases form 3 hydrogen bonds with each other?</p>
<p>Cytosine and guanine</p>
<p>What bases form 2 hydrogen bonds with each other?</p>
<p>Thymine and adenine</p>
<p>What is the site of a cells genetic information (DNA)?</p>
<p>Nucleus</p>
<p>Where does the first step of protein production take place and what is this?</p>
<p>DNA replicaiton which takes place in the nucleus</p>
<p>What does each nucleus contain?</p>
<p>A nucleolus which can take up to 25% of its volume and is where transciption and assemble of rRNA takes place</p>
<p>Where does transcription and assemble of rRNA take place?</p>
<p>Nucleolus</p>
<p>What is DNA packaged into?</p>
<p>Thread like structures called chromosomes</p>
<p>When are chromosomes visible?</p>
<p>During cell division</p>
<p>What is a chromosome?</p>
<p>Single piece of DNA containing many genes, regulatory elements and other nucleotide sequences</p>
<p>How many chromosomes does a human have?</p>
<p>46</p>
<p>What can the structure of chromosomes be described as?</p>
<p>Highly ordered to contain vast amounts of DNA</p>
<p>What is the process of packaging chromosomes?</p>
<p>1) Chromatin is the double stranded helical structure of DNA</p>
<p>2) DNA is packed with histones to form nucleosomes, with each consiting of 8 histones</p>
<p>3) Binded with H1 histone to form chromatosome</p>
<p>4) Folded up and tightly coiled to produce fibre called chromatid of the chromosome</p>
<p>What is chromatin?</p>
<p>Mixture of DNA, proteins and RNA thay packages DNA within the nucleus</p>
<p>What are the 2 forms of chromatin?</p>
<p>Heterochromatin (condensed)</p>
<p>Euchromatin (extended)</p>
<p>What must the chromatin do for transcription and replication to occur?</p>
<p>Open up to allow enzymes to access the DNA template</p>
<p>What are the 2 mechanisms for opening up chromatin to allow replication or transcription to occur?</p>
<p>Histones can be enzymatically modified</p>
<p>Histones can be displaced by chromatin remodelling complexes</p>
<p>What should be noted about both processes of opening up chromatin?</p>
<p>They are reversible</p>
<p>What does it mean that DNA replication is semi conservative?</p>
<p>Half of each new molecule is old DNA and half is new DNA</p>
<p>What does it mean that DNA replication is bi-directional?</p>
<p>DNA polymerase is onlty able to add new nucleotides onto the 3' end of the growing strand (replication occurs in the 5' to 3' direction)</p>
<p>In what direction does DNA replication occur?</p>
<p>In the 5' to 3' direction</p>
<p>What fragments are formed on the lagging strand and how are they koint together?</p>
<p>Okazaki fragments which are joined together by DNA ligase</p>
<p>What are the 2 stages of cellular division?</p>
<p>Prometaphase</p>
<p>Metaphase</p>
<p>When are chromosomes most compacted?</p>
<p>During metaphase where the chromatin fibres are folded into multiple loops and coils (1000 times more compact than other stages)</p>
<p>What percentage of bases in people are the same?</p>
<p>99.9%</p>
<p>Roughly how many genes are there in the genome?</p>
<p>22000</p>
<p>What percentage of the genome codes for proteins?</p>
<p><2%</p>
<p>What are exons?</p>
<p>Coding region</p>
<p>What are introns?</p>
<p>Non-coding regions</p>
<p>What is a codon?</p>
<p>Set of 3 bases</p>
<p>What does each codon specify?</p>
<p>A particular amino acid</p>
<p>How many different codons and amino acids are there (found in proteins)?</p>
<p>64 codons</p>
<p>20 amino acids</p>
<p>What occurs due to there being 64 codons but only 20 amino acids?</p>
<p>Degeneracy</p>
<p>What is degeneracy?</p>
<p>More than one codon codes for the same amino acid</p>
<p>What are codons that code for the same amino acid refered to as?</p>
<p>Synonyms which tend to be very similar</p>
<p>Where do variations of synonyms tend to occur?</p>
<p>The third base</p>
<p>What does degeneracy minimise?</p>
<p>The effect of genetic mutations as the change is less likely to change which protein is coded</p>
<p>What do all polypeptides begin with?</p>
<p>Methionine (initiation codon)</p>
<p>What is methionine?</p>
<p>Initiation codon</p>
<p>What often happens to methionine (initaiton codon)?</p>
<p>Removed at a later stage</p>
<p>What can single point mutations cause?</p>
<p>A dysfunctional protein</p>
<p>What is an example of a single point mutation causing a dysfunctional protein?</p>
<p>Mutated haemoglobin gene causing sickle cell anaemia</p>
<p>What is the major role of RNA?</p>
<p>To participate in protein synthesis</p>
<p>What are the 3 kinds of RNA?</p>
<p>Messanger RNA (mRNA)</p>
<p>Transfer RNA (tRNA)</p>
<p>Ribosomal RNA (rRNA)</p>
<p>What is mRNA?</p>
<p>Transcribed from DNA and carries genetic information for protein synthesis</p>
<p>How can the same gene produce many different proteins?</p>
<p>Due to splicing which occurs after the synthesis of mRNA</p>
<p>What is alternative splicing?</p>
<p>Process where exons of the RNA prdouced by transcription of a gene (primary gene transcript) are reconnected in multiple ways during RNA splicing</p>
<p>What is the RNA strand before splicing occurs called?</p>
<p>Primary gene transcript</p>
<p>What determines the reading frame of the RNA sequence?</p>
<p>Initiation codon</p>
<p>What is the space between the start and stop codon called?</p>
<p>Open reading frame</p>
<p>Where does transcription, alternative splicing, protein synthesis and post translational modifications take place?</p>
<p>Transcription in the nucleolus</p>
<p>Alternative splicing in the nucleus</p>
<p>Protein synthesis in the ribosome</p>
<p>Post translational modifications in the endoplasmic reticulum</p>
<p>What is tRNA?</p>
<p>Major role is to translate mRNA sequence into amino acid sequence</p>
<p>What are the complimentary 3 bases on tRNA refered to as?</p>
<p>Anticodon</p>
<p>What is rRNA?</p>
<p>Component of ribosomes, are produced in the nucleus and transported to the cytoplasm where they form a ribosome</p>
<p>What is a polysome?</p>
<p>What is produced when several ribosomes can trasnlate mRNA at one time</p>
<p>What base is present in mRNA instead of what?</p>
<p>Uracil is present instead of thymine</p>
