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ch 1,6,12,13,22,23,24,25,26
bio exam 1
92
Biology
Undergraduate 1
09/18/2008

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Term
Flagellum
Definition
locomotion organelle present in some animal cells; composed of a cluster of microtubules within an extension of the plasma membrane
Term
Endoplasmic Reticulum
Definition
network of membraneous sacs and tubes; active in membrane synthesis and other synthetic and metabolic processes; has rough ribosome-studded and smooth regions.
Term
nuclear envelope
Definition
double membrane enclosing the nucleus; perforated by pores; continuous with ER, also contains proteins
Term
nucleolus
Definition
structure involved in production of ribosomes; a nucleus has one or more nucleoli
Term
chromatin
Definition
material consisting of DNA and proteins; visible as individual chromosomes in a dividing cell.
Term
plasma membrane
Definition
membrane enclosing the cell
Term
ribosomes
Definition
complexes, small brown dots, that make proteins; free in cytosol or bound to rough ER or nuclear envelope
Term
Golgi apparatus
Definition
organelle active in synthesis, modification, sorting, and secretion of cell products
Term
lysosome
Definition
digestive organelle where macromolecules are hydrolyzed
-autophagy
-phagosytosis
Term
Mitochondrion
Definition
organelle where cellular respiration occurs and most ATP is generated
Term
peroxisome
Definition
organelle with various specialized metabolic functions; produces hydrogen peroxide as a by-product, then converts it to water
Term
microvilli
Definition
projections that increase a cell's surface area
Term
cytoskeleton
Definition
reinforces cell's shape, functions in cell movement; components are made of protein. includes:
-microfilaments
-intermediate filaments
-microtubules
Term
centrosome
Definition
region here the cell's microtubules are initiated; contains a pair of centrioles whose function is unknown
Term
where do most of the cell's metabolic activities occur?
Definition
in the cytoplasm
Term
what do plants cells have that animal cells do not?
Definition
-plastids- the most important type of plastid is the chloroplast
-central vacuoles
-cell walls
-plasmodesmata
Term
what is the equivalent of a plastid in animal cells?
Definition
vacuoles carry out functions performed by lysosomes in animal cells
Term
central vacuole
Definition
prominent organelle in older plant cells; functions include storage, breakdown of waste products, hydrolysis of macromolecules; enlargement of vacuole is a major mechanism of plant growth
Term
chloroplast
Definition
photosynthetic organelle; converts energy of sunlight to chemical energy stored in sugar molecules
Term
plasmodesmata
Definition
channels through cell walls that connect the cytoplasms of adjacent cells
Term
cell wall
Definition
outer layer that maintains cell's shape and protects cell from mechanical damage; made of cellulose, other polysaccharides, and protein
Term
extracellular matrix
Definition
keeps cells together
Term
discrete characters
Definition
yes or no
Term
quantitative characters
Definition
can be described on a continuum
Term
average heterozygosity
Definition
measures the average percent of loci that are heterozygous in a population
Term
geographic variation
Definition
differences between gene pools of separate populations or population subgroups
Term
cline
Definition
a graded change in a trait along a geographic axis
Term
mutations
Definition
changes in the nuecleotide sequence of DNA
Term
point mutations
Definition
mutations in one base of a gene
Term
natural selection
Definition
Differential success in reproduction results in certain alleles being passed to the next generation in greater proportions
Term
founder effect
Definition
a few individuals separated from larger population; their gene pool becomes the basis for a new population
Term
bottleneck effect
Definition
sudden reduction in population size due to environment
Term
endemic
Definition
only lives in one place
Term
relative fitness
Definition
the contribution an individual makes to the gene pool of the next generation, relative to the contributions of other individuals
Term
directional selection
Definition
favors individuals at one end of the phenotypic range
Term
disruptive selection
Definition
favors individuals at both extremes of the phenotypic range
Term
stabilizing selection
Definition
favors intermediate variants and acts against extreme phenotypes
Term
what are the three methods of evolution?
Definition
natural selection, genetic drift, and gene flow
Term
sexual dimorphism
Definition
when organisms of the same species but of different genders look remarkably different (ie: ducks)
Term
intrasexual selection
Definition
one of the genders competes with others of the same gender for the other gender.
-battling it out among themselves for access to the females
Term
intersexual selection
Definition
this is where one of the genders gets picky.
-usually the female gender is the choosier of the two sexes
Term
good genes hypothesis
Definition
suggests that if a trait is related to male health, both the male trait and female preference for that trait should be selected for
Term
diploidy
Definition
maintains genetic variation in the form of hidden recessive alleles
Term
balancing selection
Definition
occurs when natural selection maintains stable frequencies of two or more phenotypic forms in a population
Term
heterozygote advantage
Definition
when heterozygotes have a higher fitness than do both homozygotes
-ie: recessive allele for sickle cell also protects gain malaria
Term
frequency dependant selection
Definition
the fitness of a phenotype declines if it becomes too common in the population
-ie: fish with sideways mouths
Term
neutral variation
Definition
genetic variation that appears to confer no selective advantage or disadvantage
Term
biological species concept
Definition
Requires Reproductive isolation (barriers that impede two species from producing viable, fertile offspring)
Blocks gene flow between species
Limits Hybrids (offspring of crosses between different species)
Reproductive isolation can be classified by whether factors act before or after fertilization
Term
what types of prezygotic barriers exist?
Definition
-habitat isolation
-temporal isolation
-behavioral isolation
-mechanical isolation
-gametic isolation
Term
what types of postzygotic barriers exist?
Definition
-reduced hybrid viability
-reduced hybrid fertility
-hybrid breakdown
Term
morphology
Definition
appearance
Term
ecological species concept
Definition
you look at different species based on how they function in their environment: their niche. If they eat different things, act differently they may be considered different species under this concept.
Term
phylogenetic species concept
Definition
looking at ancestry and grouping together species that share common ancestors.
Term
allopatric speciation
Definition
one species becomes two due to geographic barriers
Term
sympatric speciation
Definition
one species becomes two though both live in the same region
-ex is the flies that used to live in the hawthorne trees but some began living in apple trees
Term
polyploidy
Definition
presence of extra sets of chromosomes due to accidents in cell division
Term
autopolyploid
Definition
individual with more than two chromosome sets, derived from one species
Term
allopolyploid
Definition
multiple sets of chromosomes derived from different species
Term
punctuated equilibrium
Definition
periods of apparent stasis punctuated by sudden change
Term
developmental genes
Definition
Control the rate, timing, and spatial pattern of changes in an organism’s form as it develops into an adu
Term
allometric growth
Definition
all of your body parts don’t grow at the same speed or time
Term
heterochrony
Definition
Evolutionary change in the rate or timing of developmental events
Term
homeotic genes
Definition
determine things like where wings and legs will develop on a bird
-ex are Hox genes
Term
exaptations
Definition
structures that have evolved in one context but they begin to change their use. the original structures are still there but serve a different purpose.
-ex: we use our arms to grasp things but our ancestors used arms to walk
Term
systematics
Definition
classifies organisms and determines evolutionary relationships
Term
sister taxa
Definition
groups that share an immediate common ancestor
Term
polytomy
Definition
a branch from which more than two groups emerge
Term
homology
Definition
similarity due to shared ancestry
Term
analogy
Definition
similarities due to convergent evolution
Term
homoplasies
Definition
analogous structures or molecular features
Term
clade
Definition
a group of species that includes an ancestor and all of its descendants
Term
monophyletic clade
Definition
consists of an ancestral group and all of its descendants
Term
paraphyletic group
Definition
consists of an ancestral species and some but not all of its descendants
Term
polyphiletic group
Definition
consists of various species that lack a common ancestor
Term
shared ancestral character
Definition
a traits found in multiple descendants that could be found in the ancestor
Term
shared derived character
Definition
found in an entire clade but not in the ancestor
-phylogenies are inferred using derived characters
Term
maximum parsimony
Definition
simplest answer
Term
maximum liklihood
Definition
not the simplest answer, taking DNA into account
Term
chiasmata
Definition
region where crossing over has occurred
Term
three mechanisms of genetic variation?
Definition
-Independent assortment of chromosomes
-Crossing over
-Random fertilization
Term
recombinant chromosomes
Definition
result of crossing over
Term
smooth ER
Definition
where lipids are made, metabolizes carbs, detoxifies poisons, makes hormones and oils, stores calcium, and adds hydroxyl groups to things to make them less dangerous
Term
what goes into the endomembrane system?
Definition
Nuclear envelope
Endoplasmic reticulum
Golgi apparatus
Lysosomes
Vacuoles
Plasma membrane
These components are either continuous or connected via transfer by vesicles
Term
rough ER
Definition
Has bound ribosomes, which secrete glycoproteins (proteins covalently bonded to carbohydrates)
Distributes transport vesicles, proteins surrounded by membranes
Is a membrane factory for the cell
Term
Golgi apparatus
Definition
Modifies products of the ER
Manufactures certain macromolecules
Sorts and packages materials into transport vesicles
Term
food vacuoles
Definition
formed by phagocytosis
Term
contractile vacuoles
Definition
pump excess water out
Term
microtubules
Definition
found in the spindle of mitosis and meiosis
-biggest form of fiber in the cell
Term
microfilaments
Definition
made of actin and work at cell movement
Term
roles of cytoskeleton
Definition
-provides monorails for vesicles
-helps with motility
-supports and shapes the cell
Term
intermediate filaments
Definition
most permanent type of filament
Term
types of intercellular junctions
Definition
Plasmodesmata, plant cells
Tight junctions, animal cells; these are water tight seals
Desmosomes, similar to cells within a tissue but aren’t necessarily water tight
Gap junctions, transfer of substances and signals
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