Flashcards in Test 2 Deck (77):
What is the significance of the charophytes?
a. Green algae called charophytes are the closest relatives of land plants
What is lignin?
a. Lignin or lignen is a complex chemical compound most commonly derived from wood, and an integral part of the secondary cell walls of plants
what is the significance of the Viridiplantae?
a. Viridiplantae includes the largest amount of genetic diversity among plant-like organisms.
What are the functions of secondary compounds?
a. The secondary compounds are primarily adaptations that inhibit herbivory (predators)
What feature of plants protects them from desiccation?
a. Cuticle. Plant cuticles are a protective waxy covering produced only by the epidermal cells of leaves, young shoots and all other aerial plant organs without periderm.
How do plants transport water, minerals, etc?
a. Transport of water and minerals into the xylem (goes up the plant)
Water and minerals can travel through a plant by three routes
- Transmembrane route: out of one cell, across a cell wall, and into another cell
- Symplastic route: via the continuum of cytoplasm ( the cytoplasm of neighboring cells is connected by channels called plasmodesmata * best one*
- Apoplastic Route: Via the cell wall and extra cellular spaces
Know the characteristics of bryophytes.
a. Non-vascular plants, flagellated sperm, non-woody, their life cycle is dominated by gametophytes.
Know characteristics of ferns
a. Ferns eventually become coal
b. Water must be present for flagellated sperm
What types of plants would have become part of the coal deposits?
a. Ferns WOULD have become part of the coal deposites.
b. Woody plants would NOT have become coal
Know which groups have flagellated sperm.
a. All early plants had flagellated sperm until angiosperms evolved.
b. Phylum Lycophyta includes club mosses, spike mosses, and quillworts.
c. Phylum Pterophyta includes ferns, horsetails, and whisk ferns and their relatives
What is the significance of the reduction of the gametophyte phase of a plant’s life cycle?
a. It indicates that there is ongoing evolution. Sporophytes are more complex and are more dominant in modern plants.
How do pine trees disperse their offspring?
a. By wind. They DO NOT have flagellated sperm.
Critical thinking question- Understand differences between angiosperms and gymnosperms in relation to ovules, flagellated sperm, and pollination by animals.
a. Angiosperms - The “vessel seed” plants, the flowering plants, and they are the most diverse group of land plants. They have flowers, beetles eat the pollen and spread it around when they poop.
b. Gymnosperms – The “naked seed” plants including the conifers. They don’t have flowers. The gymnosperms have “Naked” seeds not enclosed by ovaries. An example is pine cones, and there are four phyla:
- Cycadophyta (cycads) – even though cycads are eaten by beetles like angiosperms, they are still gymnosperms.
- Ginkgophyta (one living species: Ginkgo biloba)
- Gnetophyta (three genera: Gnetum, Ephedra, Welwitschia)
- Coniferophyta (conifer, such as pine, fir, and redwood)
Know characteristics of cycads.
a. They have flagellated sperm. They have large cones and palmlike leaves.
What are modified leaves?
• A flower is a specialized shoot with up to four types of modified leaves:
- Sepals which enclose the flower
- Petals, which are brightly colored and attract pollinators
- Stamens which produce pollen on their terminal anthers
- Carpels which produce ovules
a. Sporophylls – Are modified leaves with sporangia
b. Pine Cones
Know the characteristics of angiosperms.
a. They all have double fertilization. So one sperm will fertilize the egg cell to form a diploid zygote. The other sperm will form the endosperm which provides nutrient for the zygote.
b. They have flowers for reproduction and produce fruit.
Understand how seeds are dispersed, especially when they are eaten by animals
a. Frugivourous (fuit eating) animals have coevolved unique adaptations. Seed coats need to be protected going through the digestive track. Some seeds are resistant to digestive enzymes and some seed coats can also withstand low pH’s. Some seeds actually need disruption of the seed coat to germinate, whether it is acid or enzyme action or scarification (scratching the seed coat) to start the formation of the seeding.
What is unique about orchids?
a. Does NOT have an extensive endosperm, has the smallest seeds, and because they don’t have much endosperm to live on, they have to germinate soon after leaving the ovary.
19. How to fruits help angiosperms survive?
a. Fruit = The ovary. They help to disperse seeds. Te seeds of some flowering plants are contained within fruits that function like parachutes or propellers. Some fruits, like coconuts, are adapted to dispersal by water. Many angiosperms rely on animals to carry seeds. Some fruits are modified to be burrs that cling on to the fur coat of animals. Other angiosperms produce edible fruits, which are usually nutritious, sweet tasting, and vividly colored, advertising their ripeness. When an animal eats the fuit, it digests the fruit’s fleshy part, but the tough seeds usually pass unharmed through the animal’s digestive tract. Animals may deposit the seed, along with a supply of natural fertilizer, many kilometers away from where the fruit was eaten.
Be familiar with these flower parts:
a. Ovule – Seeds.
b. Ovary – The fruit.
c. Fruit – the ovary.
d. Style – The shaft that supports the stigma.
e. Stamen – The shaft that holds up the pollen.
f. Stigma – Sits on top of the style, and it collects pollen.
g. Micropyle - is small opening in the surface of an ovule, through which the pollen tube penetrates, often visible as a small pore in the ripe seed.
The shaft that supports the stigma.
The shaft that holds up the pollen.
Sits on top of the style, and it collects pollen.
is small opening in the surface of an ovule, through which the pollen tube penetrates, often visible as a small pore in the ripe seed.
What does the ovary of a plant develop into?
The ovary develops into the fruit.
How are nectar producing plants different from non-nectar producing plants?
a. They have brightly colored flowers to attract animals to disperse their seeds.
Know an overall brief understanding of how plants prevent herbivary (getting eaten).
a. They have physical and chemical barriers. Many mammals have skins and mucous membranes that are sensitive to phenolic secretions of plants like poison oak and ivy. The secondary compounds are primarily adaptations that inhibit herbivory (coevolution)
Familiarize yourself with the different types of land plant tissues.
a. Vascular Tissue – carries out long-distance transport of materials between the root and shoot systems. The two types of vascular tissue are called xylem (with tracheids) and phloem; they serve as the plumbing for the plant.
b. Epidermal Tissue – is the plant’s outer protective covering. It is usually a single tissue that is a layer of tightly packed cells. The cuticle is on the surface of the epidermal tissue
c. Meristem – 746-47
d. Ground Tissue – Tissue that is neither dermal dermal nor vascular are part of the ground tissue system. It is not just a filler, it includes various cells specialized for functions such as storage, photosynthesis, and support.
conducts water and dissolved minerals upward from roots into the shoots.
Transports sugars down the plant to where they are needed.
Sieve tubes are mainly to transport sugars and nutrients up and down the plant.
Thick cells, dead, and found in hollow xylem. Have a smaller diameter that can move water higher up plants.
Have a thicker diameter so they can’t move water as high up a plant, but they can move more water at the same time. They are thick cells that are dead. A vessel element is one of the cell types found in xylem, the water conducting tissue of plants. Vessel elements are typically found in the angiosperms but absent from most gymnosperms such as the conifers. Vessel elements are the building blocks of vessels, which constitute the major part of the water transporting system in the plants where they occur. Vessels form an efficient system for transporting water (including necessary minerals) from the root to the leaves and other parts of the plant
They are the least specialized cells. They perform most of the metabolic functions, and they can divide and differentiate. (white fleshy part of the apple).
They are structural cells. They are grouped into strings and they help support the young plant cells. They are thicker and have uneven cell walls. They provide flexible support without hindering growth. Example is the stringy stuff in celery.
they provide the plant with strength. They have rigid structure; they are thick secondary walls that are strengthened by lignin. They are dead when at full maturity.
What is the primary difference between the anatomy of roots and leaves?
A waxy cuticle covers the leaves, but not the roots.
How do plants grow?
They have indeterminate growth, because there is no set mature size, so they can just keep on growing.
Understand how a tree would reach its vertical height.
Apicol meristem tips are what helps the plant to grow vertically.
What are secondary tissues?
Lateral meristems add thickness to woody plants, a process called secondary growth. Tissue produced by a lateral meristem, such as secondary xylem and cork are called secondary tissues.
Primary xylem is the xylem that is formed during primary growth from procambium. It includes protoxylem and metaxylem. Metaxylem develops after the protoxylem but before secondary xylem. It is distinguished by wider vessels and tracheids. Xylem development occurs in a number of patterns, which vary in the relative position of the protoxylem and metaxylem, e.g. endarch in which the protoxylem is towards the centre of the stem or root, or exarch in which the metaxylem is towards the centre.
Secondary xylem is the xylem that is formed during secondary growth from vascular cambium. Although secondary xylem is also found in members of the "gymnosperm" groups Gnetophyta and.
The phloem originates, and grows outwards from, meristematic cells in the vascular cambium. Phloem is produced in phases. Primary phloem is laid down by the apical meristem and develops from the procambium. Secondary phloem is laid down by the vascular cambium to the inside of the established layer(s) of phloem.
Most of the interior of the leaf between the upper and lower layers of epidermis is a parenchyma (ground tissue) or chlorenchyma tissue called the mesophyll (Greek for "middle leaf"). This assimilation tissue is the primary location of photosynthesis in the plant. The products of photosynthesis are called "assimilates".
The vascular cambium is a lateral meristem in the vascular tissue of plants. The vascular cambium is the source of both the secondary xylem (inwards, towards the pith) and the secondary phloem (outwards), and is located between these
tissues in the stem and root. A few leaf types also have a vascular cambium. The vascular cambium adds layers of vascular tissue called secondary xylem (makes up most of the wood of a tree) and secondary phloem. The secondary plant body consists of the tissues produced by the vascular cambium and cork cambium.
What tissue makes up most of the tree?
f. Secondary Xylem.
What does heart wood and sap would have in common?
Secodary Xylem. As a tree or woody shrub ages, the older layers of secondary xylem in the heartwood, no longer transport water and minerals. The outer layers known as sapwood still transport materials through the xylem. They both have secondary xylem, but it’s no longer functioning in the heart wood.
Know which tissues is NOT part of an older tree’s bark.
Secondary Xylem. Bark consists of all the tissues external to the vascular cambium,
including secondary phloem and periderm. NOT xylem
What happens when you trim a plant by pulling off the outer-most flowers? Hint, what role would
apical meristems play if you did this?
If you cut the tops off of snap dragons, more flowers because removing the apicol meristems would cause lateral growth instead of vertical growth.
How would you measure the amount and direction of water movement in plants?
You would measure the water potential and the water activity. This would allow you to measure the flow of water in the plant.
Know the functions and characteristics of xylem.
It transports water and minerals up, it is made of dead-hollow tubes, and they do NOT use any energy in transporting water.
Know the significance of root hairs
They provide a greater surface area for nutrient absorption, much like the hyphae of fungus do.
Know the function of the casparian strip.
The waxy casparian strip of the endodermal wall blocks apoplastic transfer of minerals from the cortex to the vascular cylinder and filters material symplastically
The casparian strip ensure that all water and dissolved substances must pass through a cell membrane before entering the xylem in the stele.
Why do plants not grow as well in sterile soil?
Because there would be no mycohrizae, which helps nutrient uptake in plants, which in turn helps the plants to grow better.
What is guttation? When would it be likely to occur?
a. Guttation is the appearance of drops of xylem sap on the tips or edges of leaves of some vascular plants, such as grasses. Guttation is not to be confused with dew, which condenses from the atmosphere onto the plant surface.
b. At night, transpiration usually does not occur because most plants have their stomata closed. When there is a high soil moisture level, water will enter plant roots, because the water potential of the roots is lower than in the soil solution. The water will accumulate in the plant, creating a slight root pressure. The root pressure forces some water to exude through special leaf tip or edge structures, hydathodes, forming drops. Root pressure provides the impetus for this flow, rather than transpirational pull.
c. So at night the root pressure is high and it forces water out the leaves.
How does water move within the xylem vessels to the top of a tree?
Evaporation or transporation.
the relative water potentials of various plant structures.
a. Water potential is the combined pressure and osmotic gradient that determines the potential of water to move. The lower (more negative) the water potential, the more the water has the capacity to move. Water flows from high water potential areas to low water potential areas. (high pressure to low pressure) So the higher structures in the plant needs to have lower water potentials, to draw the water so high.
b. The leaves of the plant at the top would have the lowest water potential of all.
the requirements necessary for transpiration in a plant.
a. Transpiration is a process similar to evaporation. It is a part of the water cycle, and it is the loss of water vapor from parts of plants (similar to sweating), especially in leaves but also in stems, flowers and roots. Leaf surfaces are dotted with openings which are collectively called stomata, and in most plants they are more numerous on the undersides of the foliage. The stomata are bordered by guard cells that open and close the pore. Leaf transpiration occurs through stomata, and can be thought of as a necessary "cost" associated with the opening of the stomata to allow the diffusion of carbon dioxide gas from the air for photosynthesis. Transpiration also cools plants, changes cell's osmotic pressure, and enables mass flow of mineral nutrients and water from roots to shoots. Mass flow of liquid water from the roots to the leaves is driven in part by capillary action. In taller plants and trees however, the force of gravity can only be overcome by the decrease in hydrostatic (water) pressure in the upper parts of the plants due to the diffusion of water out of stomata into the atmosphere. Water is absorbed at the roots by osmosis, and any dissolved mineral nutrients travel with it through the xylem.
b. It occurs through xylem cells
Compare and contrast tracheids vs. vessels. Which would support transportation in taller trees and why?
a. Vessels have a larger diameter so they can move more water, but it can’t move it very high into the plant.
b. Tracheids have a smaller diameter, so they carry less water, but it means that they can transport water higher up in the plant than vessels can.
which adaptations help reduce water loss from a plant.
a. They have evolved closed stomata which prevent water from escaping out of the leaves during CO2/O2 exchange.
b. They have developed smaller leaves, or lost their leaves altogether.
c. Dormancy and C4 photosynthesis
If phloem transport of sucrose flows from “source to sink” what is a “source” and what is a “sink”?
- Movement from sugar sources to sugar sinks
a. A sugar sources is an organ that is a net producer of sugar, such as mature leaves
b. A sugar sink is an organ that is a net consumer or storer of sugar, such as a tuber or bulb, a fruit, a young growing leaf a growing root
c. A storage organ can be both a sugar sink in summer and sugar source in winter
Be able to account for each event in the mass flow of material in phloem.
- Movement of sugars, amino acids, hormones, etc. through the phloem is as follows:
a. Leaf produces the sugar
b. Sugar is transported from cell to cell in the leaf
c. Solutes are moved (actively transported) into the sieve tubes
d. Water diffuses into the sieve tubes
e. Sugar moves to a sink
What are the characteristics of good soil?
Good drainage and increased cation exchange
Why is it bad to over-water a plant?
It will kill the plant because it won’t be able to get enough oxygen.
What makes up most of a plant’s weight?
Why are oxygen, carbon, and hydrogen essential for plant growth?
Because they are the top 3 organic materials needed to survive. They make organic compounds like sugar.
What is nitrogen fixation?
It is where bacteria take nitrogen from the atmosphere as N2 and converted to NH3. N2 has a triple bond which can’t be used by plants, so the bacteria have to convert the nitrogen into NH3 which can be used by the plants.
What element requires bacteria to make it available to plants?
Nitrogen. Plants are only able to utilize nitrogen after the bacteria change N2 gas to NH3 so that it can be used by plants. The bonds of Nitrogen need to be rearranged and ultimately oxidized, which is unlike the other elements like Carbon, Oxygen, and Hydrogen which are readily usable in their natural form.
What is nitrogenase?
It is the enzyme that bacteria use to catalyze the reaction of Nitrogen from it’s diatomic gaseous state (N2) to ammonia (NH3). It is coded for by the rhizovium chromosome.
Why are Hyphae beneficial to roots?
They give the roots increased surface area for water and mineral absorption.
Distinguish between extomycorrhizae and endomycorrhizae.
a. Extomycorrhyzae are the fungus that live outside the cells
b. Endomycorrhyzae are the fungus that live inside the cells.
What are rhizomes? How did they absorb minerals and nutrients?
Rhyzomes are plants that are roots (like ginger, turmeric, galangal, and fingerroot). If you break a piece of the root off and plant it, the individual piece can grow into a whole new plant. It is an example of and vascular plant that existed earlier in evolutionary history. They are planted directly into the soil and have no stem that pokes above ground. So they are able to absorb water, minerals, and nutrients directly from the surrounding water.
What is a parasitic plant called?
a. Haustoria is a parasite. It has a haustorium which is a structure that one plant sticks inside the other to suck out nutrients.
b. Dwarf mistletoe is an example of a parasite.
What type of plant is commensalistic with other plants?
Epiphytes are non-parasitic; they grow on the plants and obtain water and minerals from the rain. An example of this is an orchid.