Plants - Unit 5 Flashcards
(37 cards)
What are the 5 characteristics of all plants?
- Eukaryotic: nucleus and organelles present
- Multicellular: with tissues
- Autotrophic: make own food through photosynthesis
- Cell wall: cellulose (lack mobility)
- Reproduction: sexual (seedless/seeds)
What did plants evolve from? Characteristics of ancestor?
Plant-like protists: green algae
- mobile
- unicellular & multicellular
(green)
- cellulose cell walls
- energy storage - starch
- lives in water
What are the advantages and disadvantages of plants evolving to survive on the land?
Advantages:
- More direct sunlight on land
- More nutrients and minerals on land
- More CO2 is present in air
Disadvantages:
- Limited water
> Problem for photosynthesis & reproduction
What are the 3 types of plants?
- Non vascular
- Seedless Vascular
- Seed producing vascular
What are non-vascular plants called? What are their traits?
Non vascular plants: Bryophytes
- Depend on diffusion for transport
- Limits size so low to ground
- Reproduce with spores (need water)
What are the traits of seedless vascular plants?
- Vascular system (xylem + phloem)
- Grow taller
- Prominent leaves
What are the traits of seed-producing vascular plants? What are the two types of seed-producing vascular plants?
- Seed plants produce seeds containing an embryo
- Have a seed coat for protection
- Two types:
> gymnosperm
> angiosperm
What are the traits of gymnosperm plants?
- Conifers
- Grow in cool dry climates
- Thin needles and waxy cuticle
- Seeds exposed on scales of cones
- Pollen and eggs are produced in male and female cones
- Fertilized eggs form seeds that land on ground and germinate
What are the traits of angiosperm plants?
- Reproduce through flowers
- Seeds are enclosed in fruit
- Fruit offer protection for seeds
- Zygote grows into an embryo
- Embryo is nourished by seeds called cotyledons
- Divided into monocots and dicots
What are the traits of shoot system?
- Above ground
- Functions:
> photosynthesis
> reproduction
> storage
> transport
> hormone production
What are the traits of the root system?
- Below ground
- Functions:
> anchorage
> absorption
> storage
> transport
> production of hormones
What are the 3 types of differentiated plant cells?
- Parenchyma cells
- Collenchyma cells
- Sclerenchyma cells
Describe parenchyma cells?
- Traits:
> living
> flexible
> thin-walled cells
> can or cannot contain chloroplasts - Functions:
> storage (in roots and stem)
> photosynthesis
> gas exchange in leaves
> protection in dermal tissue - Shape depends on environment
Describe collenchyma cells?
- Traits:
> elongated
> cylindrical
> living
> lack chloroplasts - Play a support role in the tissue of plant
- THICK primary cell walls (flexibility w/o breaking)
- Cross section
> can look like a stone wall
> can look like thick pipes
Describe sclerenchyma cells? What are the two types of sclerenchyma cell?
- Strong, structural with a primary cell wall and thick secondary cell wall
- Dead at maturity, no cytoplasm
- Contain LIGNIN that binds to, stiffens and stabilizes the cellulose in cell wall
- Two types:
> sclereids
> fibres
Describe each type of sclerenchyma cell?
Sclereids
- short
- irregular shape
> large circular, big gaps, and red star shapes
Fibres
- thin
- elongate
- join end to end
- continuous fibres
> pic looks like coral reefs
What are the 4 types of plants tissues?
- Meristematic tissue
- Dermal tissue
- Ground tissue
- Vascular tissue
Describe meristematic tissue? What are the two parts made of meristematic tissue?
- Undifferentiated embryonic plant tissue, matures into specialized cells
- Regions of constant rapid division of cells (meristems)
- Gives length and width
Apical meristems
- At root and shoot tips
- Elongates plant (primary growth)
Lateral meristems
- Other locations, form cylinders of tissue
- Mitosis in lateral meristems causes increase in diameter of root and stems (secondary growth)
Describe dermal tissue?
- Coats external surface of roots, stems, leaves
- Epidermis: single dermal layer that makes up plants protective covering
- Periderm: secondary growth on older woody plants
- Cuticle: waxy coating secreted on the surface of leaves (minimize water loss)
Specialized epidermal cells
- Guard cells
> Regulates opening of stomata
> Prevents water loss
+ Stomata: allows gas exchange and transpiration on the undersurface of the leaf
- Trichomes
> Tiny growth on epidermis surface
> Fuzzy appearance (sticky)
> Keep leaves cool, decrease evaporation
- Root hairs
> Hairlike structures, extensions of epidermal cells
> Increase surface area, absorption of water and nutrients at roots
Describe ground tissue?
- All living tissue in epidermal layers (NOT VASCULAR OF MERISTEMATIC)
- Consists of all 3 types of cells
- Functions for photosynthesis, nutrient storage, regeneration and support
Describe vascular tissue? What are the two structures made of vascular tissue?
- Internal tubular system in stem, connects roots and leaves
- Connects water to move up towards leaves, and sugars downwards
- Two types:
> xylem
> phloem
Describe the xylem? What are the two types of cells?
- Transports water and minerals one-way up
- 2 chief types
> Tracheids
= Tapered cells, overlapping
ends (gymno and angio)
> Vessel elements
= Long tubes (angio only)
> Both dead at maturity, remains are lignified cell walls
Describe the phloem? What are the two types of cells?
- Living at maturity, food conducting cells (2 way)
- 2 chief types
> Sieve tube elements
= Anucleated (no nucleus) cells
with perforations at either end
> Companion cells
= Nucleated cells, maintain
vital functions of both types of
cells, direct activities of sieve
tubes
What are the functions of the roots? Why are they necessary?
- Roots have 3 main functions
> Anchor plants
> Absorb and transport water and minerals
> Store food, water and other nutrients - Limited water access
> Elongated root systems reach underground water
> Horizontal growing roots can collect from water sources during rainfall
