deck_1403681 Flashcards
Types of plant tissue
- Vascular tissue2. Ground tissue3. Dermal tissue
The plant body has a hierarchy of ___, ___, and ___.
Organs, tissues, cells
Components of the plant cell
- Plasma membrane2. Cell wall - Primary cell wall - Secondary cell wall with lignin3. Plasmodesma(ta) - Channels that allow transport of food/hormones from cell to cell.
The three basic plant organs
- Leaves2. Stems3. Roots
Two plant organ systems
- Shoot system - Above ground2. Root system - Below ground
Plant cells store water in the ___ ___.
Central vacuole
Characteristic of secondary cell wall
Not permeable by water, causing cell death following maturation.
Root
- Anchors the vascular plant- Absorbs minerals and water- Often stores organic nutrients- May become photosynthetic + E.g., orchids
Root hairs
- Found in most plants- Occur at root tips where water/mineral absorption takes place- Increase surface area of root- Cannot absorb water if broken until they grow back
Modified roots
- Prop roots - Develop above ground to create new shoots2. Storage roots - Store food and water3. Strangling aerial4. Buttress roots - Very large above ground5. Pneumatophores - Stick out of water to breathe
Two root systems
- Fibrous roots - Monocotyledons2. Taproots - Dicotyledons
Stem
- Positions and supports leaf- May become modified to perform other functions
Anatomy of the stem
- Apical/terminal bud - Located near the shoot tip and causes elongation of a young shoot.2. Axillary/lateral bud - Located at each node. - Meristems - Structure with the potential to form a lateral shoot, or branch.
Apical dominance
- Apical shoots inhibit growth of lateral buds.- Lateral shoots will grow if apical bud is removed.
Node
Place where leaf meets stem
Internode
Space between nodes
Meristem
Undifferentiated plant cell
Modified shoot examples
Runner, strawberry, rhizomes, iris, tubers, potato, bulb, onion
If left out too long, potatoes will sprout ___ ___.
Lateral buds
Corm
Contain a solid, underground stem. - E.g., garlic
Leaf
- Main photosynthetic organ of most vascular plants.- Cuticle and stomata
Stomata opening formed by ___ cells.
Gaurd
Trichomes are also known as ___ ___.
Leaf hairs
Petiole
Joins the leaf to a node on the stem.
Most monocots have ___ veins.
Parallel
Most dicots have ___ veins.
Branching
Leaf types
- Simple- Compound + Pinnate + Bipinnate
Simple leaf
One continuous blade
Pinnate leaf
Blade is broken down into leaflets
Modified leaves
- Tendrils2. Spines3. Storage4. Bracts5. Reproductive
Modified leaves
- Tendrils2. Spines3. Storage4. Bracts5. Reproductive
Three tissue of plant organs
- Dermal tissue2. Vascular tissue3. Ground tissue
Dermal tissue system
- Consists of epidermis (in primary growth)- Covered in cuticle
Vascular tissue system
Carries out long distance transport of material between roots and shoots. - Consists of xylem tissue and phloem tissue.
Xylem tissue
Transports water and dissolved minerals upward from roots to shoots.- Dead at maturity.- Leave behind (yellow/red) lignin at death.- Two types of xylem cells + Tracheids + Vessel elements
Tracheids
- Long, narrow, tapered cells with pits on the cell walls.
Vessel elements
Short, wide cells with partially perforated walls.- Spiral-shaped
Phloem tissue
Transports organic nutrients (sugars) and hormones from where they are made to where they are needed.- Alive at maturity.- Sugars and hormones make up sap.Two types:- Sieve-tube members- Companion cells
Sieve-tube member
- No nucleus- Only have cytoplasm- Cannot undergo mitosis- Contain sieve plates at their ends- Run next to companion cells
Companion cell
Control metabolism in order to keep sieve-tube members alive.- Undergo mitotis- 1:1 ratio to sieve tube members- Run next to sieve tube members- Typically dyed blue
Phloem and xylem run ___ to one another.
Parallel
Ground tissue
Includes various cells that can be used for storage, photosynthesis, support, etc.- Three types + Parenchyma (most common) + Collenchyma + Sclerenchyma
Parenchyma cells
- Live at maturity with flexible primary cell wall- Metabolically active- Non-specialized and can divide to become other cells, but typically form xylem or phloem.- Common in vascular and ground tissue- Functions + Photosynthesis - Contain chloroplasts + Storage
Collenchyma cells
- Live at maturity with unevenly thickened cell wall- Common in ground tissues of stems and petioles- Also associated with phloem- Function + Flexible support which allows for plant growth
Sclerenchyma cells
- Dead at maturity with thickened cell wall containing lignin- Common in ground and vascular tissues- Cell types + Sclerids + Fibers - Long, tapered, non-digestible cells- Function + Support
Sclerids
Provide addition structure and support. - Variable shape
Fibers
Long, tapered cells that are non-digestible.
Tissue organization of leaves
- Epidermal barrier + Interrupted by stomata which allow for CO2 exchange.- Ground tissue + Sandwiched between upper and lower epidermis.- Vascular tissue + Continuous with vascular tissue of the stem.
Leaf structure (all leaves contain…)
- Upper and lower epidermis + Both contain cuticle with guard cells and stomata. + Epidermis does not contain chloroplasts and so it needs to be fed.- Mesophyll (composed of Parenchyma cells) + Monocots have one layer + Dicots contain palisade and spongy parenchyma- Vein
Vein
Vascular bundle containing xylem and phloem.
Meristems
Contain embryonic tissues that continuously generate cells for new organs. Work like stem cells.Types of meristems:- Shoot apical meristem + Elongate tips of shoots by primary growth.- Root apical meristem + Elongate tips of roots by primary growth.- Auxillary buds
Embryonic tissues leading to primary growth
- Protoderm- Ground tissue- Procambium
Protoderm
Gives rise to dermal tissue
Ground tissue
Gives rise to ground tissue
Procambium
Gives rise to vascular tissue
Primary growth
Growth in length of apical meristems at tips of roots and shoots.- Flexible- Eventually turns into secondary growth- Characteristic of all plants + Herbs only posses primary growth
Shoot apical meristems
Mass of dividing cells at the tip of the terminal bud.- Dome-shaped- Gives rise to the repetition of internodes and leaf-bearing nodes
Stem structure in primary growth
- Epidermis + One layer of cells and rarely more.- Cortex + Support tissues: - Collenchyma (live cells) - Sclerenchyma with fibers and sclerids (dead cells) - Parenchyma (live cells) + “Filler”- Vascular bundles + Xylem + Phloem + Procambium- Pith
Procambium
Undifferentiated cells that form xylem and phloem.
Pith
Composed of parenchyma cells - Compose the center of the stem in monocots and dicots. - Compose the center of the root in monocots only.
In gymnosperms and dicots, the vascular bundles are arranged in a ___ shape.
Ring- These rings separate the pith from the cortex.
Characteristics of monocot stems
- Vascular bundles scattered throughout the ground tissue.- Closed vascular bundle- No vascular cambium- No secondary growth + Due to vascular bundles being surrounded by sclerenchyma cells.
Root cap
Covers the root tip to protect the root apical meristem during primary growth. - Produce mucus to lubricate the root.
Root structure in primary growth
- Epidermis with root hairs- Cortex- Endodermis with Casparian strips- Stele + Vascular tissue- Movement of water and nutrients + Apoplastic pathway + Symplastic pathway
Cortex
Space between epidermis and endodermis composed of ground tissue.
Two types of plant epidermis
- Upper- Lower + Typically faces away from the sun
Annuals
Grow for one year and then die.
Biannuals
Grow for two years and then die.
Procambium
Gives rise to vascular tissue (primary) - Everything below is phloem - Everything above is xylem
Dicot roots have xylem in the shape of a ___.
Cross
Stele (a.k.a. vascular cylinder) composition
Center portion of the root.From outside in:- Endodermis + One cell thick- Pericycle + One or more cells thick- Sieve tubes in phloem- Trachieds and vessels in xylem
Pericyle
The only structure that gives rise to lateral roots that emerge from within. - Lateral roots are those that shoot off from the main root.
Secondary growth
Adds girth to stems and roots in woody plants.- Occurs in dicots but not in monocots- Occurs in stems and roots but not in leaves- Typically occurs after one year
Secondary plant body composition
Tissues produced by:- Vascular cambium- Cork cambiumVascular cambium and cork cambium are lateral meristems.
Apical meristems add ___ while lateral meristems add ___.
Length, growth
Vascular cambium
- Cylinder of meristematic cells- Phloem to outside, xylem to inside- One cell thick- Develops from original vascular cambium within the vascular bundles and some parenchyma cells within the cortex.- Mostly in stems and roots of dicots
Zone of division
Where mitosis occurs within the root.
Zone of elongation
Where root grow to potential size.
Zone of differentiation maturation
Where cells differentiate within the root to carry out particular functions.- Root hairs only occur at this zone.
Endodermis is ___ at maturity.
Alive
Root hairs
Act as capillaries to move water via capillary action.- Epidermal cells
Symplastic route
Water and minerals are moved through the cytoplasm from cell to cell from the root hair to the xylem.
Apoplastic route
Water and minerals do not travel through the cytoplasm of the cells until they reach the later cells. The cytoplasm is made to act as a filter, but the apoplastic route bypasses this to increase speed.
Secondary growth production
- Vascular cambium undergoes mitosis to produce xylem to the inside and phloem to the outside. + Xylem and phloem cells do not undergo mitosis.- Primary phloem is crushed as the secondary phloem expands.- Primary xylem is pushed into the pith by the secondary xylem until the pith is completely gone.- Secondary xylem continues to grow inwards, causing the stem to expand in width.
Determining age in plants
Xylem cells shrink with lack of water. This causes a small ring of xylem to form during the winter.
Cork cambium
Cylinder of meristematic cells.- One cell thick- Mostly in stems and roots of dicots- Develops from parenchyma cells in cortex- Forms cork to the outside until it ruptures the epidermis
Cork
- Contains lignin and suberin + Impenetrable by water or gasses- Dead at maturity- Contains lenticels
Lenticels
Breakages within the periderm which allow gases into the deeper layers of the plant tissue.
Periderm
Cork and cork cambium
Bark
Periderm and living (secondary) phloem
Sapwood
Conducting xylem
Heartwood
Non-conducting xylem
Wood
Secondary xylem- Consists of sapwood and heartwood- Forms annual rings
Girdling
Removal of ring of bark around the trunk of a tree to kill it. - Due to the removal of living phloem and so the roots do not receive food.
Gravitropism (gravity-positive)
Grow in the direction of gravity (down) - Characteristic of roots
Gravity-negative
Grow opposite the direction of gravity (up) - Characteristic of shoots
Statoliths
Starches that attach to root cells. Must be at the bottom of the root, so the root grows to ensure this placement. This is the cause of gravitropism in roots.
Grafting
Method of cutting and binding separate plants in order to form one hybrid plant.
Gas exchange mostly by these methods
- Stomata- Lenticles- Spaces between cells
Methods of fluid movement within xylem
- Adhesion- Cohesion- Evaporation- OsmosisPossibly due to capillary action, root pressure, or transpiration pull. Unidirectional from roots to tips.
Cohesion
Attraction between water molecules due to slight positive/negative charge.
Adhesion
Attraction between water molecules and the xylem walls.
Transpiration pull
Ultimately due to water rising upwards as a result of evaporation.
Guard cell
Open and close stomata. - Two per stomata, one on each side. - Contain chloroplasts.
Method of fluid movement within phloem
Fluids move by mass flow and is multidirectional.- Source vs. sink
Source vs. sink
Source may be a leaf, root, flower, etc. Active transport causes solutes to move to sieve-tubes. Water moves in to increase pressure, and bulk flow pushes solutes towards sink. Pressure and solute concentration decrease between source and sink, but solutes eventually reach the sink, lowering their water potential. Water enters the sink after the solutes.
Epidermis
- Undifferentiated cells.- Includes guard cells and other specialized cells- Present in primary growth but eliminated by secondary growth.
Kingdom Animalia
“Metazoa”- Eukaryotic- Multicellular- Heterotrophic- Lack cell walls- Only kingdom possessing nervous and muscle tissue.- Major groups: + Invertebrates + Vertebrates
Advantages of multicellularity
- Large size- Mobility- Stable internal environment- Relative independence from environment
Origin of Animalia
Derived from the “colonial choanoflagelate,” a prostist.- Monophletic
Evolution of Animalia
- Colonial protist is an aggregate of identical cells.- Forms to become a hollow sphere of unspecialized cell.- Cell specialization begins, and some cells become somatic cells while others become reproductive cells. + Somatic cells form the body.- Infolding + Hollow sphere of cells folds inward on one end.- Gastrula-like “protoanimal” is formed. + Cavity caused by infolding becomes the digestive cavity.
Eumetazoa possess ___ unlike Parazoa.
True tissues
Animal embryology
- Cleavage + Radial - Always indeterminate + Spiral - Always determinate- Cell fate + Indeterminate + Determinate
Cleavage
Series of rapid cell division by mitosis and cytokinesis.