Chapter Nine (quiz five) – Flashcards
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| Genetics is? |
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| the study of the inheritance of living things -transmission of traits from parent to offspring -expression and variation of those traits -structure and function of the genetic material -how this material changes |
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| Levels that genetic study occurs on? (4) |
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| 1. Organismal 2. Cellular 3. Chormosomal 4. Molecular |
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| How do cells self-replicate |
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| either by binary fission or budding |
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| All cells have all the same genetic material... how does that work? |
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| every cell has the "book" but different cells "read" different "chapters" to have different characteristics ex. skin cell versus cardiac cell |
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| What is a Genome? |
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| a collection of all DNA present in an organism ex. bacterial genomes= .4-9.4 million nucleotides human genome= 4 billion nucleotides |
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| Chromosomes? |
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| genomes are set up in these. Prokaryotes have one which contains entire genome Eukaryotes may divide genome into many chromosomes |
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| How many chromosomes do humans have? |
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| 46 total.. 23 pairs -22 autosomes - a pair of sex chromosomes |
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| Gene definition? |
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| DNA sequences that have a defined function OR a certain segment of DNA that contains the necessary code to make a protein of RNA molecule |
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| Eukaryotes nonchromosomal DNA |
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| mitochondria and chloroplasts contain their own DNA |
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| Prokaryotes (and fungi) nonchromosomal DNA |
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| have plasmids that are nonessential, circular pieces of DNA |
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| Size and packaging of genomes? |
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| the stretched out DNA can be 1,000 times longer than the cell each cell contains 6feet of DNA so it must be packaged tightly |
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| Eukaryotic chromosomes |
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| -DNA molecules tightly wound around HISTONE proteins - located in nucleus - vary in number from a few to hundreds - can occur in pairs or singles -linear |
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| Pairs of chromosomes are called |
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| diploid |
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| Singles of chromosomes are called? |
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| haploid |
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| Bacterial Chromosomes |
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| -condensed and secured by means of histone-like proteins -located in nucleiod region of cytoplasm -single, circular chromosome |
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| Karyotyping |
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| is the number and appearance of chromosomes in the nucleus of a eukaryotic cell |
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| What can genes code for? |
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| 1. structural genes: code for proteins 2. rRNA or tRNA 3. Regulatory genes: control gene expression |
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| Genotype? |
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| entire collection of genes in an organism ATCG |
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| Phenotypes |
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| the traits of an organism, which are an expression of the genotype ex. eye color |
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| Who discovered basic DNA structure? |
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| James Watson and Francis Crick in 1953 |
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| Basic unit of Nucleotides |
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| phosphate deoxyribose sugar nitrogenous base |
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| Options for nitrogenous base? |
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| Adenine, Guanine, Thymine or Cytosine |
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| Purine bases? |
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| two rings-- A and G |
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| Pyrimidine bases? |
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| one ring-- T and C |
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| How are the nitrogenous bases paired? |
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| hydrogen bonds |
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| What must occur to the bonds in order for reading to occur |
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| they must be broken or "unzipped" |
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| What is Adenine paired with? |
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| Thymine |
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| What is Gaunine paired with? |
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| Cytosine |
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| What do nucleotides bound too? |
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| a sugar-phosphate linkage... covalently boned to |
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| what is the ribbon backbone arrangement called |
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| antiparallel. the 5' end of end strand matches up with the 3' end of the other end |
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| DNA replication? |
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| the process of duplicatating the genetic code so it can be passed to the offspring |
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| The 3 main actions of enzymes with DNA replication? |
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| 1. separate the strands 2. copy its template 3. produce two new daughter molecules |
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| Helicase does? |
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| unzipping the DNA helix, breaks the H+ bonds |
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| Primase action? |
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| synthesizing an RNA primer |
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| DNA polymerase III |
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| adding bases to the new DNA chain; proofreading the chain for mistakes |
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| DNA polymerase I |
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| removing primer, closing the gaps, repairing mismatching |
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| Ligase |
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| final binding of nicks in DNA during synthesis and repair |
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| Topoisomerase I and II |
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| supercoiling and untangling |
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| What is semiconservative replication> |
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| Each strand acts as a template, the result is on strand of old and one strand of new this allows for accurate replication 5' to 3' direction |
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| 3 stages of DNA replication? |
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| 1. Initiation 2. Elongation 3. Termination |
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| Initiation step of DNA replication |
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| -helicases separate the DNA at the origin -primases produce RNA primers -DNA polymerase III begins adding DNA nucleotides |
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| Elongation step of DNA replication |
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| -DNA polymerase III continues adding DNA bases -DNA bases can only be added to the 3' prim end, requiring leading and lagging strands |
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| Termination step of DNA replication |
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| -ligases link new DNA strand into a circle |
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| Leading strand? |
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| made from the 3' to 5' stand of DNA, continuously made headed straight toward the origin of replication |
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| Lagging strand? |
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| made from 5' to 3' stand of DNA, needs many RNA primers, moving away origin, synthesized discontinuously by a series of fragments. |
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| okazaki fragments? |
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| are short, newly synthesized DNA fragments that are formed on the lagging template strand during DNA replication |
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| What is central dogma? |
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| DNA -> mRNA -> protein |
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| Transcription? |
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| the master code of DNA is used to synthesize an RNA molecule DNA -> RNA |
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| Translation? |
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| the information in the RNA is used to produce proteins RNA -> proteins |
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| Exceptions to central dogma? |
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| viruses and retroviruses |
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| Do you remember what reverse transcription is? |
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| RNA to DNA, only occurs in retroviruses |
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| What are triplets? |
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| three consecutive bases on the DNA strand -each triplet represents a code for a particular amino acid |
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| What do proteins ultimately determine? |
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| phenotype |
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| What are 3 bases of mRNA called? |
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| codon! |
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| How is RNA different from DNA |
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| -single stranded molecule -contain uracil instead of thymine -the sugar is ribose instead of dioxyribose |
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| What RNA is translated into a protein molecule? |
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| mRNA |
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| tRNA? |
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| brings in the amino acids, for each of the 20 amino acids there is at least one specialized type of tRNA to carry it |
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| tRNA structure? |
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| cloverleaf? |
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| Bottom loop of the tRNA |
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| anticodon! designates the specificity of the tRNA, binds to the condon of the mRNA |
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| Where does the amino acid bind on the tRNA |
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| the opposite end of the molecule from the anticodon |
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| What role does ribosome play in all this? |
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| it is a mobile molecular factory for translation "gets everyone together and allows for string to be made correctly" |
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| RNA polymerase? |
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| uses the 3' to 5' strand of DNA to make mRNA |
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| What are the 5 stages of Translation? |
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| 1. initiation 2. elongation 3. termination 4. protein folding 5. protein processing |
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| What initiates translation? |
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| -mRNA molecule leaves DNA transcription site -mRNA transported to ribosomes in the cyoplasm -ribosomal subunits are specifically adapted to assembling and forming sites to hold the mRNA and tRNA |
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| What is Redundancy of the genetic code? |
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| a particular amino acid can be coded for by more than a single codon |
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| What is wobble? |
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| Wobble baby, wobble baby, wobble baby, wobble -in many cases, only the first two nucleotides are required to encode the correct amino-acid, thought to permit some variation or mutation without altering the message ex: acu, acc, aca, acg all encode for threonine |
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| what is the start nucleotide? |
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| AUG |
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| What kind of bonds are made between amino acids during initiation? |
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| peptide bonds-- convalent bond |
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| what terminates protein synthesis? |
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| a termination codon or nonsense codon |
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| What happens when the termination codon in reached? |
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| the bond is broken between, the final tRNA and the finished polypeptide chain. releasing it from the ribosome |
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| What happens before the protein is released? |
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| it starts to fold up upon itself to achieve the biologically active tertiary conformation. |
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| What sort of posttranslation modifications may be needed? |
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| -starting amino acid clipped off -cofactors added -join with proteins to form quaternary levels of structure |
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| Examples of points that pathogens affect to screw things up. |
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| - changes the shape of 30S portion, causes the code on mRNA to be read wrong -interferes with attachment of tRNA to mRNA-ribosome complex -binds to 50S portion, prevents trans-location movement of ribsome along mRNA -binds to 50S protion and inhibits formation of peptide bonds |
