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Cell
the fundamental unit of structure and function
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prokaryotes
single cells, circular chromosomes
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cell as unit of function
capacity for growth and differentiation, self replication, evolution
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a capacity for change at two levels
phenotype & genotype
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unicellular
largely autonomous, capable of growth reproduction, and communicates and responds to its government
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multi-cellular
has the ability for cells to adhere to one another and be able to communicate with each other
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multi-cellular behavior
meets the needs of the organism as a whole
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chromoplasts
contain pigments
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unique characteristics of plant cell
cell wall, plastids, chloroplasts, central vacuole
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cell wall
middle lamellae, plasmodesmata, parallel chain of cellulose associate to form microfibrils
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chloroplasts
site of photosynthesis
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central vacuole
storage of proteins and inorganic ions, dispocal, pigments, protection, and cell enlargement
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process of cellular differentiation
different cell types form specific tissues from organs, and organs form plant body.
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3 basic cell types
parenchyma, collenchyma, and sclerenchyma
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parenchyma performs
most important metabolic functions: photosynthesis: cholorenchyma & stores various organic products
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collenchyma cells
alive at maturity
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sclerenchyma cells
dead cells that have thick 2 degree walls, often lignified
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2 major types of sclerenchyma cells
fibers and sclereids
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2 types of fibers
extraxylary and xylary
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plant body's 3 type of organs
roots, stems, and leaves
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different cell types form three tissue systems of plants
dermal, ground, and vascular
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dermal tissue (epidermis)
forms the fucntion of the plant covering parts of roots, stems, and leaves
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functions of dermal tissue
depends on location of plant
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above ground
cuticle that prevent plant from crying out by secreting waxy layer
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underground parts
absorb water and nutrients
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on leaves and stems
creates openings like stomata that regulates passages of gases and moisture into and out of the plant
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cortex
has all three types of plant cells, parenchyma making up most of the ground tissue system
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vascular system
carries water and nutrients in the plant
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xylem
water and minerals conducting and contains trancheids and vessels
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phloem
food conducting and sieve tubes and companion cells
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vessels
have long tubular cells with grate like openings at the end
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trancheids
tapered at the end
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roots
anchor the plant in soil, absorb, minerals and water, and store food
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shoot systems
vegetative and reproductive
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stem
an alterntive system of nodes and internodes
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axillary bud
at the angle formed by each leaf and stem, with potential to form a vegetative branch
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shoot apex
contains terminal bud, area of active growth
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simple leaves
have single, undivided blades
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compound leaves
have several leaflets attached to the petiole
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plant's structure reflects
interactions with environment of two time scales
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Example of desert plants
leaves are reduced and the stem is the primary photosynthetic organ
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primary growth is a product of
cel division, elongation, and differentation
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apical meristems:primary growth
found at tips of roots and shoots and increases length of a plant
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lateral meristems: secondary growth
add girth (width) by producing wood and bark
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advantages of asexual reproduction
offspring of plant are genetically identical and can be made at any time
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disadvantages of asexual repdroduction
diseases and insects are more likely to be transferred on asexual parts on seeds
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function of a flower
produce gametes, mediate the union of male and mediate union of male and female gametes, site of seed set
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double fertilization
- process by which two sperm fuse with with two cells
- of the embryo sac
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endosperm
forms food storage tissue within the seed
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self (in breeding)
male anf female gametes from the same plant from zygote
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cross (out) breeding
male and female gametes from diff plants of zygote
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how do plant get pollen from one plant to another
flowers are adapted to attract pollinators
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outbreeding advantages
increases genetic variability, allows adaptation to changing conditions
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outbreeding disadvantages
destroys well adapted genotypes, relies of effective cross pollination, seed dispersal and establishment
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genetics
science of heredity
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heredity
the handing down of certain traits from parents to their offspring
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until 19 century
theory of inheritance was blending inheritence
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Traits have
two forms that can breed true. one form must be hidden when plants with each trait are interbred
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dominance/ recessiveness
when an individual has two unlike factors, the dominant factor will determine the phenotype, masking the other, recessive factore
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segregation
factors segregate during gamete formation so that each gamete receives only one pair. when female and male gametes fuse (fertilization) the double number is retored
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principle of independent assortment
each pair of alleles segregate independently during gamete formation
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gene
organized unit of hereditary material
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chromosomal theory
genes have specific locations on chromosomes, chromosomes underego segregation and independent assortment, and genes on the same chromosome are linked together and don't exhibit independent assortment
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crossing over
recombinationof alleles between two homologous chromatids in meiosis
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genetics in the 21st century
science of heredity and involves investigation of molecules, cells, organisms, and populations, utilizing diverse experimental approaches
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alleles
alternate forms of the gene (P vs.p)
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phenotype
physical appearance of a trait
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what describes the plants genotype
letters indicating the two alleles in a plant, such as Pp or pp
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homozygous
when both alleles are the same (PP or pp)
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heterozygous
when is possess 1 copy of 2 different alleles for a locus
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DNA
double stranded molecule consisting of two anti parallel polynucleotide chains
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genes occur
in a linear order on chromosomes
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genetic variation
sum of natural heritable variation observed between the genomes of individuals or populations of a given species
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genome
comprises all the genetic material that an organism possesses
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polyploidy
basic set of chromsomes (x) is represented more than 2 times per cell
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autopolyploidy
polyploids whose chromosome sets are all derived from the same ancestral source
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allopolyploids
contain chromosome sets from different, but related species
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