Test 2 Study Guide

Question 1

Frequency of recombination

Answer 1

number of recombinant offspring/ total # of offspring x 100%; the percentage of times a crossover event occurs between two specific genes during meiosis

Question 2

Calculation of map distance using frequency of recombination

Answer 2

map distance between 2 linked genes = number of recombinants (offspring with certain phenotypes) / total number of offspring x 100%

Question 3

Different types of chromosomes based on the position of the centromere

Answer 3

telocentric
acrocentric
submetacentric
metacentric

Question 4

Auto ploidy level

Answer 4

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

Question 5

Allo ploidy level

Answer 5

have more than two sets of chromosomes that are from different species

Question 6

Nutritional requirements and growth of bacteria

Answer 6

water (cell contained 80% total weight of water), source of carbon and nitrogen, and inorganic salts

Question 7

Cotransformation mapping

Answer 7

process in which two or more genes are taken up together during cell transformation

Question 8

F plasmids/ F factor

Answer 8

circular plasmid that allows genes to be transferred between bacteria lacking the factor through conjugation

Question 9

Modes of gene transfer in bacteria

Answer 9

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)

Question 10

Gene mapping using partial chromosome

Answer 10

identifying the location of specific genes on a limited section of a chromosome (somatic cell hybridization)

Question 11

Characteristics of genetic materials

Answer 11

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

Question 12

Fred Griffith’s experiment

Answer 12

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

Question 13

Chargaff’s ratio of bases in DNA

Answer 13

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

Question 14

Hershey and Chase’ experiment using radio labeled bacteriophage

Answer 14

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

Question 15

Characteristics of DNA, form A

Answer 15

right-handed helical structure of DNA that exists when little water is present

Question 16

Characteristics of B-DNA

Answer 16

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

Question 17

Characteristics of Z-DNA

Answer 17

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

Question 18

Structure of nucleotides

Answer 18

a nitrogen containing base, five carbon sugar (either ribose in RNA or deoxyribose in DNA), and phosphate group

Question 19

Gel electrophoresis

Answer 19

technique for separating charge molecules (proteins or nucleic acids) on the basis of molecular size or charge or both

Question 20

Southern blotting

Answer 20

technique by which DNA is transferred from a gel to a solid support, such a nitrocellulose or nylon filter

Question 21

Important characteristics of bacterial cloning vectors

Answer 21

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

Question 22

Vectors for cloning inserts of various sizes

Answer 22

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)

Question 23

Ti plasmid as a tool for genetic engineering of plants

Answer 23

can be used to carry foreign/ desired genes into plant cells

Question 24

Origin of Orthologs

Answer 24

homologous genes in different species that evolved from the same gene in a common ancestor; same genes found in different species

Question 25

Origin of Paralogs

Answer 25

homologous genes arising by duplication of a single gene in the same organism; same genes in the same species

Question 26

Origin of Homologs

Answer 26

genes that are evolutionary related

Question 27

Origin of Analogous genes

Answer 27

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

Question 28

Analysis of microarray results

Answer 28

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

Question 29

Linked genes

Answer 29

genes located close together on the same chromosome

Question 30

Genetic map

Answer 30

approximate locations of genes relative to the location of other genes based on the rate of recombination; limitations are accuracy and resolution

Question 31

Test cross

Answer 31

cross between an individual with an unknown genotype and an individual with the homozygous recessive genotype

Question 32

Crossing over

Answer 32

exchange of genetic material between homologous but nonsister chromatids

Question 33

Aneuploidy

Answer 33

change in the number of individual chromosomes; most often an increase or decrease of one or two chromosomes

Question 34

Polyploidy

Answer 34

possession of more than two sets of chromosomes

Question 35

Prototrophs

Answer 35

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

Question 36

Auxotrophs

Answer 36

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

Question 37

Recombinant DNA technology (genetic engineering)

Answer 37

set of molecular techniques for locating, isolating, altering, combining, and studying DNA segments

Question 38

Linkers

Answer 38

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

Question 39

PCR, and real time PCR

Answer 39

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

Question 40

Expressed sequence tags (EST)

Answer 40

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

Question 41

Contig

Answer 41

set of two or more overlapping DNA fragments that have been assembled in the correct order to form a continuous stretch of DNA sequence

Question 42

Metagenomics

Answer 42

a field of genetics in which the genome sequences of an entire group of organisms that inhabit a common environment are sampled and determined

Question 43

Single nucleotide polymorphism (SNP)

Answer 43

a site in the genome where individual members of a species differ in a single base pair

Question 44

Basic local alignment search tool (BLAST)

Answer 44

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

Question 45

cDNA (complementary DNA library)

Answer 45

collection of bacterial colonies or phages containing DNA fragments that have been produced by reverse transcription of cellular mRNA

Question 46

Differences between A, B, and Z DNA

Answer 46

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