Biology 101 chapters 17-21

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What macromolecule is involved in ingeritance?: DNA
What are the 2 stages in gene expression?: Transcription & Translation
How did Beadle and Tatum figure out that they had produced bread mold mutants with their X-ray treatments?: The mutants cound not survive on minimal medium.
What exceptions have been found to Beadle and Tatum's one gene-one enzume theory?: Genes code for RNA molecules that code for proteins.
What is produced during the process of transcription?: mRNA, tRNA, rRNA
What is a difference between transcription and translation in eukaryotes and prokaryotes?: In prokaryotes, transcription and translation occur together they are separate in eukaryotes; in eukaryotes, RNA is modified, becoming true mRNA.
What are codons?: Nucleotide triplets.
What codon codes for Met? What does MET stand for?: 1. AUG
2. Methionine
Is the genetic code universal? Why or why not?: It is nearly universal because there are exceptions in some unicellular eukaryotes & prokaryotes where codons specify different amino acids.
What enzyme is used in RNA transcription? What are the 3 main stages in transcription?: 1. RNA polymerase
2. Initiation, Elongation, & Termination
What are 2 differences between DNA & RNA?: RNA is a copy of DNA.
1. U in RNA; T in DNA
2. RNA is single-stranded & DNA is double-stranded.
What is a promoter & what sequence does it have in a eukaryotic cell?: 1. It signals the initiation of RNA transcription.
2. Its sequence is TATA-box-TATAAAA.
What is the difference in the termination of transcription signal in prokaryotes &= eukaryotes?: Prokaryotes: The termination signal in the DNA stops transcription.
Eukaryotes: Cuts the pre-mRNA loose 10-35 nucleotides downstream from stop signal.
What are 2 ways in which eukaryotes modify their pre-mRNA after transcription?: 1. The 5' end receives a modified nucleotide cap.
2. The 3' end gets a poly-A tail.
Where in the cell does RNA splicing occur & what stays in the mRNA, the exons or the introns?: 1. Nucleus
2. Exons
What makes up the spliceosome & what happens there?: 1. Ribosomes
2. RNA is spliced.
What are snRNPs?: Protein snRNA.
What is a ribozyme?: A catalytic RNA molecule that functions as enzymes & can splice RNA.
What RNA molecules are involved in translation? ON which type of RNA molecule do you find the anticodon?`: 1. mRNA, tRNA, rRNA
2. tRNA
What is the function of aminoacyl-tRNA synthetase?: They join amino acids to the correct tRNA.
What are ribosomes made of & what process do they take part in?: 1. Proteins
2. rRNA
What are the names and functions of the 3 binding sites on ribosomes?: 1. P site (peptidyl)-tRNA binding site
2. A site (aminoacyl)-where protein elongates
3. E site-exit site
What happens at the initiation of translation?: The initiation stage brings together mRNA, tRNA, & the 2 subunits of a ribosome.
What happpens at the elongation & termination of translation.: Elongation: Amino acids are added to preceding amino acids.
Termination: Ribosome reaches a stop codon in the mRNA & the whole thing falls apart.
What is polyribosome?: A number of ribosomes translating a single mRNA simultaneously.
How are proteins changed after translation? Give an example of change.: They undergo modificationss such as adding of carbs, lipids, or phospahates; their 3-D shape is changed.
Ex: insulin
What kind of ribosome starts translation & what does it become later if its protein is destined for export from the cell?: 1. Free ribosome
2. ER bound ribosome
What must peptides have to make sure they end up at the ER?: Signal peptidefor binding of signal recognition particals.
What kind of mutation changes one base pair in DNA? Can this lead to the production of an abnormal protein?: 1. Point mutation
2. Yes.
Is sickle cell anemia a missense or nonsense mutation?: Missense because glutamine codes to valine.
What are frameshift mutations?: The are additions/losses of nucleotide pairs in a gene so the reading frame on mRNA is changed.
What is a mutagen? Give an example of a mutagen.: 1. Physical or chemical agents that can cause mutations.
2. Tar from cigarettes.
What is the type of virus that infects bacteria?: Bacteriophages
Who first proved that viruses existed & how did he do it?: Wndell Stanley in 1935. Crystallized infectious particle known as tobacco mosaic virus (TMV)
What are viruses made of?: Nucleic acid enclosed in a protein coat, or sometimes a membraneous envelope.
What can constitute the genome of viruses?: DNA & RNA. Both the DNA & RNA can be single- or double-stranded.
What is a capsid?: Protein that encloses the viral genome.
What sometimes surrounds the capsid & in which viruses is this structure found?: 1. Membraneous envelopes
2. Influenza viruses
Describe the structure of bacteriophages.: A capsid that encloses DNA & a protein tailpiece to inject information into a host cell.
Why are viruses called obligate intracellular parasites?: Because they can reproduce only within a host cell.
What are the 2 reproductive cycles in phages & what is different about them?: 1. The lytic cycle & lycogenic cycle.
2. The lytic cycle produces new phages & results in the death of the host cell. The lysogenic cycle replicates the phage without destroying the host.
What's the difference between a virulent & a temperate phage?: Virulent uses lytic cycle while temperate uses both lytic & lysogenic cycles.
What are the 2 key variables that are used to classify animal viruses?: 1. DNA or RNA
2. Single-stranded or double-stranded.
How do animal viruses bind to their host cells?: Viral glycoproteins on the envelope bind to specific receptor molecules on the surface of the host cell.
How do retroviruses produce their DNA?: They use reverse transcriptase to convert their RNA genome into DNA.
What is a provirus & how is it different from a prophage?: A provirus is the viral DNA that is integrated into the host genome. Unlike a prophage, a provirus remains a permanent resident of the host cell.
What affects do viruses have on infected cells?: They may damage or kill cells by causing the release of hydrolytic enzymes or produce toxins.
What are emerging viruses & give an example?: 1. Those that appear suddenly.
2. SARS virus
How do plant viruses spread disease?: Horizontal Transmission & Vertical Transmission
What contributes to genetic diversity in bacteria?: Bacteria forms sex pilus & conjunction to share DNA & mutation.
What does bacterial DNA look like & what are plasmids?: Bacterial DNA is usually a circular DNA molecule with few associated proteins. Plasmids are small circular DNA that can replicate independently of the chromosome.
How do bacteria exchange genetic information?: Transformation, Transduction, Conjunction
What is conjugation between bacteria?: It's the direct transfer of genetic material between bacterial cells that are temporarily joined by by pili.
Do bacteria have male & female? Why or why not?: Yes, males have sex pilus to transfer DNA to the female.
What are R plasmids?: Plasmids that confer resistance to various antibiotics.
What are transposable elements & insertion sequences?: 1. "Jumping genes" that contribute to genetic shuffling in bacteria.
2. Simplest transposable elements that exist only in bacteria.
What are 2 ways that bacteria regulate their metabolism?: 1. Adjusting activity of metabolic enzymes.
2. Regulating genes that encode metabolic enzymes in operons.
What are operons composed of?: -An operator: "on-off" switch where repressors bind
-A promoter: where RNA polymerase binds
-Genes for metabolic enzymes
What are repressors & corepressors?: 1. Switch off proteins
2. Small molecules that work with repressors to switch an operon off
What is a repressible operon & an example?: The trp operon is a repressor operon because it is usually on.
What is an inducible operon & an example?: One that is usually off. Ex. lac operon
What are examples of negative & positive gene expression in bacteria?: 1. Repressible operons; enzymes function in anabolic pathways
2. Stimulatory activator; protein such as catabolic activator protein (CAP) in lac protein
What is the source of the DNA pieces & what kind of enzymes are used in gene cloning?: 1. The genome & Bacteria placmids.
2. Bacterial reactivation enzyme.
Why would DNA fragments be said to have sticky ends?: Because they are complementary & bind together.
What is the original plasmid called in gen cloning? What is it called after cloning?: 1. Cloning vector
2. Recombinant plasmid
What selection criteria do scientists use to figure out which bacteria contains the gene of interest after cloning?: They are identified by the lack of a blue color in bacterial colonis on a medium containing x-galand & picillin.
What is a genomic library?: Collection of recombinant vector clones produced by cloning DNA fragments from an entire genome.
What is a cDNA library?: Complementary DNA of an organisms mRNA inserted in plasmid or phage.
What can a scientist use to avoid gene expression problems that arise from using bacteria & plasmids for gene cloning?: Different expression vectors like YAC.
What is polymerase chain reaction & how does it work?: 1. It can produce many copies of a specific target segment of DNA.
2. Uses primers that bracket the desired sequence & DNA polymerase.
How do scientists separate DNA fragments after digestion with restriction enzymes? What is the basis for the separation of the fragments?: 1. Gel electrophoresis
2. Negative DNA travels toward positive electrode-small fragments travel faster than large.
What is southern blotting & what is it used for?: 1. Specific DNA fragments are identified.
2. Using labeled probes that hybridize to the DNA immobilized on a "blot" of the gel.
What are RFLPs & what can they be used for?: Differences in DNA sequences on homologous chromosomes that result in restriction fragment differences sereve as genetic markers.
What is the human genome project & what are the 2 techniques being used to complete it?: 1. Sequencing of the human genome.
2. Genetic (Linkage) Mapping & Physical Mapping
What method is used to sequence short fragments of DNA & how are these sequences put together to figure out the sequence of an entire chromosome?: 1. Dideoxy Chain-Termination Method
2. By overlapping/by computer
How do scientists compare patterns of gene expression & function?: Expression: DNA microarray assays
Function: experimental inaction
What kind of useful information can scientists get form comparative studies of genomes from different species?: Help to relate phenotypic similarities with DNA similarities or not.
What are some practical applications of DNA technology?: DNA "fingerprinting" for criminal & paternity testing & gene therapy.
What technique is used to help convict suspects & to establish paternity & what does it involve?: DNA fingerprinting analysis of tissue of body fluids by isolating DNA, digesting & run of gel then identify RFLP markers.
How have bacteria, animals, & plants been genetically engineered to benefit humanity?: Bacteria-Medicine
Animals-More meat
Plants-Healthier Crops
What are some harmful events that may happen because of DNA technology?: The developing of products or procedures that are harmful to humans of the environment.
What are 2 things that researchers hae used to deduce developmental pathways?: Mutations & Molecular genetics
What are 45 model organisms used to study the genetics development?: Fruit Fly, Nematode, Mouse, Zebrafish, & Common Wall Cress
What 3 processes are involved in transforming a zygote into an organism?: Cell division, Cell differation, Morphogenesis
What is the difference between cell differentiation & morphogenesis?: 1. Cells become specialized in structure & function.
2. Give shape to the organism & its various parts.
What determines the differences between cells in multicellular organisms? What is genomic equivalence?: 1. Gene expression
2. Means you have some genes
What does totipotent mean & what kinds of cells have this characteristic?: 1. Capable of generating a complete new organism.
2. Embryonic stem cells
What does pluripotent mean & what kinds of cells have this characteristic?: 1. Can only become certain types of cells.
2. Bone marrow cells
How do you clone an entire organism?: Nuclear Transplantation
What was the first mammal to be cloned & when was this accomplished?: Lamb (Dolly) in 1997
What are 3 problems associated with cloning animals?: 1. Few embryos survive.
2. Misplacement of DNA methylation may interfere with gene expression.
3. Often get sick at a young age.
What enables differentiated cells to carry out their specific tasks? What are 2 examples of this?: 1. Tissue specific proteins from genes.
2. Proteins from myo D in muscle cell & Cytoplasmic determinants in unfertilized egg.
What is induction & its significance in development?: 1. Inductions are signals that can cause organ development.
2. Change gene expressions.
What is pattern formation & when does it happen in plants & animals?: 1. The development of a spatial organization of tissues & organs.
2. Occurs continually in plants, but is mostly limited to embryos & juveniles in animals.
What is positional information & what does it determine in Drosophila?: 1. Molecular cues that detrmine pattern formation or cells location in body. (Segmentation genes, embryonic genes, homeotic genes)
2. Determines the body structure of the organism.
What are 3 types of genes that determine the body axis & segmints in Drosophila?: Sequencial gene expression of maternal effect genes, sementation genes, & homeotic genes.
How early in nematode development are the daughter cells induced to certain pathway? Where do the signals come from?: 1. As early as the 4-cell stage.
2. 1 cell in the embryo.
Wht is apoptosis & what are 2 examples of cells in which it happens?: 1. Programmed Cell Death
2. White blood cells & C. elegans
Where does embryonic development happen in plants & how does it differ from animal cell development?: 1. Inside the seed. Animals are an embryo too.
2. Cell lineage is less important. Homeobox genes don't function the same.
What tissue in plants contains the 3 cell types that are responsible for development?: The floral meristem
What genes in plants are analogous to homeotic genes in animals & what do they control?: 1. Organ identity genes
2. Determine the type of structure that will grow from a meristem.
What is the name of the nearly identical nucleotide sequence found in the homeotic genes of vertebrates & invertebrates?: Similar nucleotide sequence has been disolved in the homeotic genes of both vertebrates & invertebrates.
What genes control development in plants & in animals?: Hox gens in animals & mads-box genes in plants.

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