Chapter 47 Flashcards
1
Q
Growth
A
- Organisms are born and die (complete life cycle), may grow and reproduce in between
- Growth: irreversible increase in biomass
2
Q
Unicellular Growth (3)
A
- Division (usually) results in two daughter cells the same size as the original
- “Growth” usually refers to colony growth
- Asymmetrical division
3
Q
Asymmetrical Division
A
- Caulobacter crescents
- smaller daughter cells (swarmer) has a flagellum larger and has a stalk
4
Q
Multicellular Growth
A
Steps:
- Fertilization
- Embryo Stage
- Juvenile Stage
- Reproductive Stage (Adult)
- Senescence
- Animals: growth fastest when embryo, often stops when juvenile
- Plants: growth rates decline, but don’t stop until death
5
Q
Growth Curves
A
- Sigmoid growth pattern is very common
- Lag phase: slow growth
- Log/exponential phase: rapid growth
- Stationary phase: slow/no growth
- First derivative = rate of growth
6
Q
Development in Multicellular Organisms
A
Development: change from simple to complex/specialized form
- body plans established between fertilization and birth
- last common ancestor of plants & animals, likely single-celled
7
Q
Development in Animals (4)
A
- Zygote = totipotent (can develop into new organism)
- Cleavage of the zygote produces hollow blastula
- Cells fold/move/rearrange, producing a two-or-three-layered gastrula
- Cell and tissue types produced according to cell layer
- somatic and germ cells
- deteriorating cells need replacement
8
Q
Stem Cells (2)
A
- relatively unspecialized cell; can reproduce indefinitely and can differentiate into different types
- stem cells division produces another cell that specializes
9
Q
Embryonic Stem Cells
A
Pluripotent and wildly distributed
10
Q
Adult Stem Cells
A
- More restricted:
- spatially (brain, bone marrow, liver etc.)
- multipotent
- needed for production of cells that continuously turn-over (blood, hair etc.)
11
Q
Development in Plants (5)
A
- Embryogenesis establishes primary growth axis, first leaves, and regions of cell division.
- organogenesis in plants occur after germination - Growth-restricted in space
- Meristem = perpetually undifferentiated tissues
- Apical Meristems: shoots and roots
- Lateral Meristems: vascular and cork cambia
12
Q
Apical Meristems (3)
A
- Primary Growth
- Cell division and elongation
- increases length
13
Q
Lateral Meristems (3)
A
- Secondary Growth
- Cell division
- increases width
14
Q
Phenotypic Plasticity
A
Body plan is coded genetically, but the environment is important in determining phenotype
-temperature, nutrition, pressure/gravity, light, predators, stress, presence of con-specifics, etc.
