Exam review Flashcards
What are the characteristics common to all land plants?
- multicellular, eukaryotic
- photosynthetic (using chlorophyll a and b, synthesize simple sugars to create more complex compounds including starch as the main storage molecule)
- have cellulosic cell walls
Which phylum contains the closest relative to land plants?
Charophyta
What surrounds a plant cell?
- Primary cell wall (sits outside of plasma membrane)
2. May also haave a secondary cell wall (found between primary wall and plasma membrane
Most abundant carbohydrate polymer on earth
Cellulose
What makes up a cell wall?
Cellulose, hemicellulose, pectin
What is the role plasmodesmata
- cytoplasmic chanel between cell walls that allows for comunication between adjacent cells
- all for rapid and regulated exchange of molecules betwen cells
Describe the structure of a chloroplast
- surrounded by two membranes
- have their own circular DNA
- contain thylakoid membranes organized into grana
- within thylakoid membranes are photosystems containing chlorophyll a and b
- fluid within the membranes is the stroma where the Calvin-Benson cycle takes place
Name the specialized chloroplasts
- chromoplasts (yellow, orange or red, contain carotenoids)
- leucoplasts (synthesize starch and oils)
(can all interconvert)
Summarize endosymbiotic theory
primitive eukaryotic cell engulfed a photosynthetic bacterium (prokaryote)
Evidence for endosymbiotic theory
chloroplasts and mitochondria
- have their own circular DNA
- are surrounded by two membranes
Describe the role of vacuoles
- stores cell metabolites and waste products
- maintains cell pressure and pH
- may contain anthocyanins
Name the main evolutionary milestones in the evolution of land plants
- developent of the cuticle (protection from UV rays, limits water loss)
- Epidermal pores allowed for gas exchange
- Development of Vasculature (lignification)
- Dominant sporophyte (first observed in seed plants)
- Flowers
State the main characteristics defining bryophytes
- non-vascular
- rely upon water for survival and reproduction (flagellated sperm)
- no true roots (instead use rhizoids)
- no leaves or stems
- dominant gametophyte
Name the bryophyta phyla
Hepaticophyta: the liverworts
Anthocerophyta: the hornworts
Bryophyta: the mosses
State the main charcteristics of the Seedless Vascular Plants (SVPs)
- first lignified plants (lignin reinforces cell walls, allows for upwards growth)
- developed megaphylls (leaves)
- developed sporophylls
- heterosporous
- endosportic development
Name the phyla of the SVPs
Psilorophyta: whisk ferns
Lycophyta: club mosses and quillworts
Equisetophyta: horsetails
Polypodiophyta: ferns
Whisk Ferns characteristics
- no true leaves or roots
- simple branching patter
- associated with mycorrhizal fungi which gametophyte cannot grow without
- homosporous
Lycophyta: Club mosses and quillworts characteristics
- heterosporous
- endosporic development
Equisetophyta: Horsetails
- contain silica deposits in their epidermal cell walls
Polypodiophyta: Ferns
- leaves with sporangia (sporophylls) and large leaves (megaphylls)
Name the phyla of gymnosperms
Pinophyta: Conifers
Ginkophyta: Ginkgos
Cycadophyta: Cycads
Gnetophyta: Gnetophytes
Characteristics of Pinophyta
- create seed cones
- have needle-like leaves (very well suited for cold, dry environments)
- use wind as the primary mechanism for seed dispersal
- some produce resin with antiseptic properties that deter insect attack
Characteristics of Ginkophyta
- only one living species remains
- male and female reproductive structures occur on separate trees
- male gametophyte produces flagellated sperm
Characteristics of cycadophyta
- cone bearing (only have one cone)
- male and female cones occur on separate plants
- male gametophyte produces flagellated sperm
Welwitschia mirabilis
- gnetophyte
- only one of its genera
- only opens stomata at night
How do gemnosperms promote outcrossing?
- ovulate and pollen cones that develop on the same plant can be at different locations
- male and female reproductive structures can be produced on separate treens
- wind pollinations is common, aiding the dispersal of gametes
Name the dominant phases of different plant groups
Bryophytes: gametophyte
SVPs: sporophyte
Seed Plants: sporophyte
Name the dependent phase of differerent plant groups
Bryophytes: sporophyte
SVPs: Independent sporophytes and gametophytes
Seed plants: gametophyte and young sporophyte
Identify the relative sizes of the different plant groups
Bryphytes: small and similar is size
SVPs: sporophyte size varies but generally large, gametophyte is relatively small
Seed plants: large sporophytes, gametophyte greatly reduced
Why are angiosperms so successful?
- Flowers (attract polinators and have become specialized due to co-evolution)
- Fruits (help in seed dispersal and help ensure daughter plants do not compete with the parent)
- they have competitive advantage
Describe the evolutionary history of flowers
- sporophylls with microsporangia evolved into stamens and megasporangia evolved into carpels (sepals and petal are sterile modified leaves)
- Stamens and carpels become less leaf-like
- Carpels fuse to form compound pistils
- Sepals and petals evolving to become more dissimilar (less alike)
- Floral parts progressing from a spiral arrangement on the central axis to that of whorls (three or more organs attached at one node)
- The number of whorls eventually decreasing from four to three, two and one
- Radial symmetry giving way to bilateral symmetry
Name the components of the carpels
produce ovules and contain
- a stigma
- a style
- an ovary
Name the components of the stamen
- the anther
- the filament
What is unique about Angiosperm sexual reproduction?
- both male and female gametophytes are microscopic
- the femal gametophyte does not produce archgonia
- sperm are not flagellated
- embryo obtains nutrients from a tissue that is the product of fertilization and is triploid (the endosperm) because of double fertilization
Name the sequence of primary tissues that arise from the apical meristem.
- Protoderm = dermal tissue
- Ground meristem = ground tissue
- Procambium = vascular tissues
Name the three cell types that make up ground tissue.
- parenchyma
- collenchyma
- sclerenchyma
What are some characteristics of parenchyma cells?
- most abundant, least specilized plant cell
- have thin primary cell walls therefore ‘space filling’
- functions include
- photosynthesis
- storage
- structure
- wound healing
What are some characteristics of collenchyma cells?
- main function is flexible support
- have thickened primary cell walls
- elongated cells, alive at maturity
What are some characteristics of sclerenchyma cells?
- two types (fibers and sclereids)
- have secondary walls often containing lignin
- main function is rigid support (key for upwards growth)
- dead at maturity
Name the components of xylem tissue
- parenchyma cells
- fibers
- vessels (conduct water)
- tracheids (conduct water)
- ray cells
Which water conducting structure in the xylem has better conducting capacity?
Vessel elements
- largest diameter of all conducting cells
- can conduct 100X as much water and minerals as tracheids
- open at each end and can stack on top of one another
What is the draw back of vessel elements?
- flow is more prone to blockage by air bubbles and ice crystals
- water column is not as wel supported by secondary walls
- if blocked, water flow in the entire column is impacted
Name the conducting components of the phloem
- sieve-tube members
2. companion cells
What cell types make up the phloem?
- conducting cells
- parenchyma
- fiber
- ray cells
How does the phloem prevent infection from a pathogen?
Sieve-tube members prodce callose and a special p-protein that plugs the memrane lined pores (sieve plates) which prevents pathogens from spreading through the phloem to uninfected areas.