AGRN test 4
types of reproduction
reproduction by vegitative structures
advantage of asexual repro
disadvantage of asexual repro
less genetic variability to select improved varieites
repro resulting from the fertilization of ovules and subsequent formation of viable seed
the union of pollen nucleus with the egg nuclei
transfer of pollen from the stamen to the pistil
plants where the pistil is pollinated by the stamen of the same plant
plants whose pistil is pollinated with pollen from different plants by insects or wind
unique characteristics controlled by one or more genes
unit of inheritance passed from parents to offspring located on chromosomes
forms of a gene
allele expressed only in homozygous condition
allele that expresses itself whenever present
when reproductive cells are formed, the gene pairs seperate and are distributed as units to each gamete
law of segregation
the distribution of one pair of factors is independent of the distribution of other pairs
law of independent assortment
alleles must be on different chromosomes
law of independent assortment
hybridization involving a single allele
hybridization involving two alleles
what is the purpose of plant breeding?
to produce new crop cultivars and varieties with improved agronomic traits
what is considered during plant breeding?
response to speceific situations
the extent to which a plant's phenotype is the result of the genotype rather than the environment
equation of heritability
how to figure out heritability
the greater the heritability,
the greater the chance to develop plants with that trait
factors affecting crop production that is the result of growing conditions
examples of differences in environmental variations
how do you test for environmntal influence?
grow plants with similar heredity in different environments
variation that results from genetic differences
genetic variability originates from
gene recombinations after hybridization
sudden changes in heredity material of a cell
what do mutations result from?
change in gene from one allele to another
rearrangement of chromosome material
loss or duplication of chromosome segments
typically, mutations are
are mutations dominant or recessive?
a condition in which individuals have more than 2 chromosome sets or genomes in their somatic cells
what is the significance of polyploidy
adds genetic diversity
recessive traits are more likely to appear
what is the purpose of selection?
to select a plant with superior features
the selection of a quantity of plants with similar characteristics while still maintaining some diversity in the gene pool
the improvement of a trait of a hybrid over its parents
a form of recurrent hybridization by which a superior characteristic may be added to an otherwise desirable variety
how is backcrossing done?
two parents are crossed where one is a productive variety which lacks some superior quality and another with a superior quality but is otherwise not desierable
a species is a group of organisms that
produce viable offspring
offspring also mate and produce viable offspring
members of hte same species that have become geographically isolated
an organism with one or more genes from another species
naturalists began to identify hybrids of plants (began plant breeding)
Gregor mendel- father of modern genetics
Louis Pasteur defines role of micro-organisms and establishes the science of microbiology
first in vitro culture of a whole plant
Watson & Crick discovered the double helix of DNA
green revolution-introduction of hybrid crops into food-short third world
researches able to isolate genes
discovery of plasmids and restriction enzymes in bacteria
recombinant DNA technology discovered
the ability to transfer pieces of genetic info from one organism to another
gene splicing or genetic engineering
first commercial application of gene splicing; human insulin for diabetes
first genetically engineered plant
plants ressitant to insects, viruses and bacteria; first field tests
field trial for Bt cotton
Monsanto created; approved for sale
round up ready cotton first commercialzied
YieldGard corn sold in US
GMO crops used
organisms taht have one or more genes fro ma different species using recombinant DNA technology
transgenic plants (GMO)
what is the goal of transgenic plants?
design organisms with specific characteristics by the artificial insertion of genes from other species
discrete segments of DNA that encodes the info necessary for assembly of a specific protein-trait
production of multiple copies of a gene
recombination or joining DNA segments from two different species
enzyme that cuts stands of DNA at specific places
enzyme that can join sticky ends of two strands of DNA
delivery vehicle used to introduce rDNA into a host cell
molecules of DNA that are found in bacteria seperate from the bacterial chromosome
changes in the DNA sequence of a gene
steps of genetic engineering
isolate desired gene
remove DNA from donor with restriction enzyme
transfer novel gene to the host through a vctor
a soil bacterium that causes crown galls in many plants
how does agrobacterium tumefaciens work?
in vivo infection requires wounding of the plant tissue
the bacteria attaches to the cell wall and is activated by compounds from the wounded cell
how does the gene cannon work?
minute metal beads of gold coated with DNA are shot directly into plant cells and as the plant heals, some of the DNA is incorporated into the plant
what plants are resistant to broad spectrum herbicides (round up ready)
what bacteria is the gene donor in round up ready GMOs?
how do round up ready GMOs work?
degrades herbidice inside the plant
what plants are Bt crops?
what is the gene donor in Bt crops?
how do Bt crops work?
insecticidal toxin for control of catepillars
what are the pro's of transgenic crops?
fewer pesticides needed
what are the con's of transgenic crops?
more pesticides needed
more evolutionary pressure; greater chance of resistance
possibility of transferring genetic materials to other organisms
effects on non-target organisms (allergins, toxins)
AGRN test 4