Test 2 Study Guide Flashcards
Frequency of recombination
number of recombinant offspring/ total # of offspring x 100%; the percentage of times a crossover event occurs between two specific genes during meiosis
Calculation of map distance using frequency of recombination
map distance between 2 linked genes = number of recombinants (offspring with certain phenotypes) / total number of offspring x 100%
Different types of chromosomes based on the position of the centromere
telocentric
acrocentric
submetacentric
metacentric
Auto ploidy level
condition in which all the sets of chromosomes of a polyploid individual are derived from a single species; individual has more than two complete chromosome sets from a single genome
Allo ploidy level
have more than two sets of chromosomes that are from different species
Nutritional requirements and growth of bacteria
water (cell contained 80% total weight of water), source of carbon and nitrogen, and inorganic salts
Cotransformation mapping
process in which two or more genes are taken up together during cell transformation
F plasmids/ F factor
circular plasmid that allows genes to be transferred between bacteria lacking the factor through conjugation
Modes of gene transfer in bacteria
transformation (uptake of free DNA from the environment), conjugation (direct transfer of DNA between bacteria through cell to cell contact), transduction (transfer of DNA mediated by a bacteriophage)
Gene mapping using partial chromosome
identifying the location of specific genes on a limited section of a chromosome (somatic cell hybridization)
Characteristics of genetic materials
1) ability to replicate accurately
2) structural and chemical stability
3) capacity for mutation to enable evolution
4) ability to be expressed when needed
5) capability to be transmitted from parent to offspring without significant alteration
Fred Griffith’s experiment
injected mice with different strains of streptococcus pneumoniae bacteria, demonstrating that a non-virulent strain could be transformed into a virulent strain when mixed with a heat killed virulent strain; if you heat kill a type S strain and injected it into a mouse, the mouse lived, if you mix a killed type S with a live type R bacteria, the mouse will die
Chargaff’s ratio of bases in DNA
adenine is always equal to thymine (apple to tree), and guanine is equal to cytosine (garage to car); 1:1 ratio between base pairs in DNA molecule; base pair rule
Hershey and Chase’ experiment using radio labeled bacteriophage
to prove that DNA, not protein, is the genetic material by showing that when a bacteriophage infects a bacterial cell, it is the phage’s DNA that enters the cell and becomes incorporated while the protein coat remains outside. They labeled DNA with radioactive phosphorus and protein with radioactive sulfur, and observing where the radioactivity ended up after infection
Characteristics of DNA, form A
right-handed helical structure of DNA that exists when little water is present
Characteristics of B-DNA
right handed helical structure of DNA that exists when water is abundant; the secondary structure described by Watson and Crick; most stable configuration and common DNA structure
Characteristics of Z-DNA
left handed double helix structure of DNA, zigzag pattern in its backbone, forming when there are alternating purina-pyrimidine sequences; more elongated than B-DNA and lacks major groove and the minor groove is very narrow and deep
Structure of nucleotides
a nitrogen containing base, five carbon sugar (either ribose in RNA or deoxyribose in DNA), and phosphate group
Gel electrophoresis
technique for separating charge molecules (proteins or nucleic acids) on the basis of molecular size or charge or both
Southern blotting
technique by which DNA is transferred from a gel to a solid support, such a nitrocellulose or nylon filter
Important characteristics of bacterial cloning vectors
small size for easy manipulation, origin of replication (ori) to enable self replication within a host cell, selectable marker gene (like antibiotic resistance) for identifying transformed bacteria, multiple cloning site with unique restriction enzyme recognition sequences to insert foreign DNA, and the ability to be easily isolated and purified from the host organism
Vectors for cloning inserts of various sizes
plasmids for small inserts (up to 10 kb), bacterial artificial chromosomes for medium sized inserts (100-300 kb), yeast artificial chromosomes for very larger inserts (greater than 300 kb)
Ti plasmid as a tool for genetic engineering of plants
can be used to carry foreign/ desired genes into plant cells
Origin of Orthologs
homologous genes in different species that evolved from the same gene in a common ancestor; same genes found in different species
Origin of Paralogs
homologous genes arising by duplication of a single gene in the same organism; same genes in the same species
Origin of Homologs
genes that are evolutionary related
Origin of Analogous genes
originate from convergent evolution, where two unrelated species independently evolve similar traits or genes due to similar environmental pressures, rather than sharing a common ancestor with those traits; they converge on a similar solution to the same problem even though their genetic pathways to achieve it are different
Analysis of microarray results
clustering analysis used for interpreting microarray data (gene expression and genetic variation by binding a nucleic acid sample to a solid surface with thousands or millions of known DNA fragments); hierarchical, K-means, self organizing map
Linked genes
genes located close together on the same chromosome
Genetic map
approximate locations of genes relative to the location of other genes based on the rate of recombination; limitations are accuracy and resolution
Test cross
cross between an individual with an unknown genotype and an individual with the homozygous recessive genotype
Crossing over
exchange of genetic material between homologous but nonsister chromatids
Aneuploidy
change in the number of individual chromosomes; most often an increase or decrease of one or two chromosomes
Polyploidy
possession of more than two sets of chromosomes
Prototrophs
capable of using a carbon source, essential elements such as nitrogen and phosphorous, certain vitamins, and other required ions and nutrients to synthesize all the compounds needed for growth and reproduction; a prototrophic bacterium can grow on a minimal medium
Auxotrophs
possessing a nutritional mutation that disrupts the ability to synthesize an essential biological molecule; an auxotrophic bacterium cannot grow on a minimal medium to which has been added the biological molecule that it cannot synthesize
Recombinant DNA technology (genetic engineering)
set of molecular techniques for locating, isolating, altering, combining, and studying DNA segments
Linkers
small synthetic DNA fragment that contains one or more restriction sites; can be attached to the ends of any piece of DNA and used to insert it into a vector; stretch of DNA separating two nucleosomes
PCR, and real time PCR
method of enzymatically amplifying DNA fragments; modification of the polymerase chain reaction that is used to measure the starting amount of nucleic acid, the amount of DNA amplified is measured as the reaction proceeds
Expressed sequence tags (EST)
short DNA sequences that are used to identify gene transcripts and determine gene sequences; fragments of mRNA sequences derived through single sequencing reactions performed on randomly selected clones from cDNA libraries
Contig
set of two or more overlapping DNA fragments that have been assembled in the correct order to form a continuous stretch of DNA sequence
Metagenomics
a field of genetics in which the genome sequences of an entire group of organisms that inhabit a common environment are sampled and determined
Single nucleotide polymorphism (SNP)
a site in the genome where individual members of a species differ in a single base pair
Basic local alignment search tool (BLAST)
a computer program that compares biological sequences to identify regions of similarity; compares nucleotide or protein sequences to sequence databases and calculates the statistical significance of matches
cDNA (complementary DNA library)
collection of bacterial colonies or phages containing DNA fragments that have been produced by reverse transcription of cellular mRNA
Differences between A, B, and Z DNA
A = 11 base pairs, right handed duplex, can form under conditions of low humidity
B = 10 base pairs, right handed duplex, most stable DNA, wide major groove and narrow minor groove
Z = 12 base pairs, left handed duplex, zigzag pattern in the sugar phosphate backbone
