Final Bio Exam

What is guttation? Transpiration?

- The xylem sap is pushed through pores, hydathodes, at ends of veins. - loss of water from the leaf as water vapor. This loss can be significant. A large tree can lose 60 gallons of water an hour! Plants lose this much water because it evaporates though open stomata in the leaves. Transpiration occurs at high rates during the day as the plant is actively photosynthesizing.

a. NPK Fertilizer b. How does a plant use these nutrients?

-A macronutrient fertilizer containing Nitrogen, Phophorus and Potassium -House plants: need both macronutrients and micronutrients. These plants often become depleted for iron in our soil.

What is the function of the Xylem? The Phloem?

-The basic function is to transport water but it also transports some nutrients through the plant. -Phloem is the living tissue that carries organic nutrients in particular, sucrose to all parts of the plant where needed. In trees, the phloem is the innermost layer of the bark. The phloem is concerned mainly with the transport of soluble organic material made during photosynthesis.

How do sugars move through the plant? What is a source? a sink?

-Translocation...In the phloem, sugars move through sieve cells or sieve tube elements. These cells are alive but are missing many organelles, including the nucleus. - The movement of sucrose in the phloem is a tissue called the source to a tissue called the sink. A source is often a mature leaf that is actively photosynthesizing and produces more carbohydrate than it can use itself. A sink is another tissue in the plant that needs carbohydrates to meet its energy requirements. A sink may be a root, an apical meristem, a fruit or seed. Some sinks, like roots, act as storage organs. Notice that a sink may be positioned above or below a source.

Know the symptoms of nutrient deficiency.

-interveinal chlorosis, - Lack of iron results in loss of chlorophyll and chlorosis. In severe cases, new leaves may appear white. -Molybdenum (mo) is essential in nitrogen fixation so plants deficient for molybdenum look very similar to plants that lack nitrogen (lowest requirement)

What is pyrethrin ? What plants make this compound? why?

-the compound pyrethrin is made by plants in the chrysanthemum/daisy family. It acts as a neurotoxin in insects (acts as an insecticide) This compound is available commercially and is a safe and effective natural insecticide. It has relatively little effect on mammals and breaks down quickly in the environment.

Laticifer

A laticifer is a type of elongated secretory cell found in the leaves and/or stems of plants that produce latex and rubber as secondary metabolites

Differentiate radial symmetry from bilateral symmetry.

A regular flower is radially symmetrical.. No left or right, just top or bottom. An Irregular flower has bilateral symmetry. (pansies, lilies). R and L symmetry.

Know examples of animal pollinators and the characteristics of the flowers they pollinate.

About 80% of cross pollinating lpants rely on animals; insects account for all but 10% of that number (70%)- Bees are by far the most important insect pollinator.- Providing bees to growers is a big business. Without the aid of these bee hives, many farmers would not have an annual crop.- Some crops, like almonds, are completely dependent on bees for pollination.- 80% of the worlds almond production is in California. Over 600,000 acres of almond groves are pollinated in 3 weeks each February.- ½ of the bees in the United States are required to pollinate these almonds. Hives are imported from all over the country.- Plants have evolved different mechanisms to attract various animals that pollinate their flowers. Color, fragrance, and food are the most common.- Pollen itself is an energy rich food for some animals. Some flowers produce NECTAR, a sugary solution, to attract pollinators. It is stored in nectarines and is an energy rich food for pollinators.- Many flowers have markings that serve as nectar guides - The nectar guides on this iris direct a bumblebee down between the sepal and the style arm.- Insects also see ultraviolet light, which we cannot. Many flowers have special markings in this wavelength of light to indicate the center of the flower.- Some flowers have specialized shapes designed for a specific pollinator. The lower petal on this snapdragon serves as a landing platform for a bee. Its weight causes the flower to open.- The bee opens the flower and can reach the pollen. The tight fit ensures that much of thebee will get covered in pollen.- Butterflies have good vision, they can see red, but have a weak sense of smell. So butterfly pollinated flowers are brightly colored but odorless.- Butterflies are marching feeders. They walk around on flower clusters probing the blossoms with their tongues. Each flower has a tube that is the right length for the butterflys tongue.- Beetles also pollinate many flowers. Since they aren't agile flyers, they need broad, open, flowers.- Most moths are nocturnal and have a good sense of smell. They pollinate flowers that are white or pale colors so they are visible at night, many only open at night.- Typically, these flowers have a strong, sweet scent and deep tubes to match the length of the moth's tongue. The petals are flat or bent back so that the moth can get in.- Some moths are active by day. These hawk moths, or sphinx moths....- Sphinx moths hover above the fragrant flowers they visit. Very large moths, they are often mistaken for small hummingbirds.- Flies are attracted to rotting flesh. Flowers pollinated by flies may be nondescript or a brownish red color. They emit a strong, rotten smell as their main attractant.- Birds have no sense of smell. Red flowers that rely on birds for pollination often have no smell.- The flower is designed so that its pollinator must have a long tongue, like this hummingbird, to reach the nectarines.- Some flowers, like this columbine, are pollinated by both insects and birds. Its nectarines are at the base of the long spurs on the petals. Hummingbirds and sphinx moths have long tongues that can reach them.- Bats are also important pollinators. They feed at night and do not see well. Many of the flowers they visit have a strong smell similar to fermenting fruit.- In some parts of the world other animals also act as pollinators, like thei gecko and the lemur of Madagascar.- Some plants, like this yucca, have specifically COEVOLVED with a certain pollinator. The females of these yucca moths have special mouthparts for gathering pollen and pollinating the flower.- The caterpillar offspring of this moth, will feed on the seeds of the yucca plant.- There are orchids with flowers that look and smell like females of certain species of bee or wasp. The males emerge before the females (mimicry) - A male who smells a flower of this orchid, thinks the flower is a female wasp.- He will eventually give up in frustration, but not before he picks up a load of pollen. The pollen will be transferred to the next orchid he visits that smells like a female.- Plants that use wind for pollination usually have small, inconspicuous flowers that lack both odor and nectar.- Trees, like this oak, flower in the early Spring before new leaves emerge. This avoids problems with leaves that might interfere with pollination.- The stigma of a wind pollinated plant is often large and feathery to help capture pollen grains as they pass by.- The grasses are wind pollinated and have small flowers near the top of the plant

How do you know if a nutrient is essential?

All nutrients have been identified by culturing plants in the absence of soil using a simple solution or hydrophonic approach. è Using this approach they can grow plants in a solution that has all essential nutrients except the one to be tested. If the plant cannot complete its life cycle, the element may be essential. è The very nature of micronutrients makes it difficult to establish their importance to plants. At trace amounts, it is much easier to establish that an element is essential than that it is not essential. è Many plants are grown hydroponically for commercial purposes now. It reduces water costs in arid countries and allows growers to produce some crops year round in greenhouses.

Macronutrient

An essential element that is required in a fairly large amount for normal plant growth. the three primary macronutrients: nitrogen (N), phosphorus (P), and potassium (K). the three secondary macronutrients:calcium (Ca), sulfur (S), magnesium (Mg).

Micronutrient

An essential element that is required in very small amounts for normal plant growth. the micronutrients (trace minerals): boron (B), chlorine (Cl), manganese (Mn), iron (Fe), zinc (Zn), copper (Cu), molybdenum (Mo) and selenium (Se).

How do the flowers of a monocot and a dicot differ?

Angiosperms are divided into two groups; dicotyledons and monocotyledons. è Among the angiosperms, dicots make up the largest number of species. Many of the fruits we eat come from dicot.è In terms of their importance to humans, the monocots are the more important food source.è The seeds of monocots have a well developed endosperm. It is this feature that makes wheat, corn, rice and other monocots so important to us. The flower parts of dicots are in multiples of 4 and 5.è The flower parts of monocots are in groups of three.

What is a complete flower? incomplete flower? perfect flower? imperfect flower?

Any flower that is missing one or more of the four organs, is called an incomplete flower. Complete flower- has all 4 organs Perfect flower- Has both stamens and carpels. It may be complete or incomplete! Imperfect flower- has stamens or carpels but not both.

What is double fertilization? What is the eventual product of each fertilization event?

Each pollen grain has 2 cells: POLLEN TUBE cell and a GENERATIVE cell.- The generative cell will divide to form 2 sperm nuclei. Once pollination occurs, the tube cell grows a long, thin pollen tube down through the style to reach the ovules within the ovary. Each pollen tube is one, long, long cell.- There are signals within the style to direct the pollen tube to individual ovules.- Each ovule contains several cells. The ones that have a direct role in fertilization are the EGG CELL and a central cell that has 2 nuclei called the POLAR NUCLEI.- Plants undergo a unique fertilization that is very different from animals. 2 sperm nuclei are delivered to the ovule from a single pollen grain.- In a process known as DOUBLE FERTILIZATION, both of these sperm nuclei will fuse with nuclei within the ovule. One sperm nucleus will fuse with the egg cell. This produces a zygote that will develop into an EMBRYO. (and eventually a seed)- The second sperm nuclei fuses with the 2 polar nuclei. The cell resulting from the 3 fused nuclei develops into the ENDOSPERM.- The ENDOSPERM nourishes the developing embryo. In monocots, it also supports the young seedling just after germination. -

Know the components of soil and their characteristics.

Four distinct components compose soil: inorganic mineral particles, organic matter, water and air. Inorganic mineral particles (sand, silt, clay) come from weathered parent material and constitute most of what we call soil. Organic matter consists of litter, droppings, and the remains of dead plants, animals and microorganisms that are in various stages of decomposition. Pore spaces of different sizes around and among the soil particles are filled with varying proportions of soil air and soil water; plants and other soil-dwelling organisms need soil minerals, soil air an soil water.

Know drugs and plants that make them. Why do plants synthesize these compounds?

In the late 1700's a British physician realized that foxglove was an effective treatment for "dropsy" Foxglove is the source of digitalis, a drug used to treat heart disease. It restores regular heat beats and strengthens the contractions. Goes by the names Digoxin and Digitoxin. - Other plants also make cardenolides. Milkweed produces it in its latex. The cardenolide is toxic to most insects and protects the plant. Very poisonous to insects/animals. - Taxol was discovered. It is purified from the bark of the Pacific Yew tree (Tacus brevifolia). And is very effective. Taxol works by inhibiting the cell cycle at the G2-M phase (most anti-cancer drugs act on the G1-S phase). It blocks progression through mitosis by stabilizing microtubules. - Work on this plant, the English yew, provided an answer. It contains a precursor to taxol in the needles, a renewable source. This is harvested and used by chemists to synthesize taxol. - Rosy periwinkle, is also a source of cancer-fighting drugs. It is originally from Madagascar, and came to the attention of Western scientists during WWII. - Coumarin is a mildly toxic compound that gives newly-mown hay its distinctive, sweet smell. Derivatives of coumarin are highly toxic. The derivative is called dicoumarol , has a structure that is very similar to Vitamin K and interferes with Vitamin K activity. Vitamin K acticates the process that makes blood clot in wounds. Cattle fed contaminated hay develop a "bleeding disease." They suffer from internal bleeding and often die. Warfarin is a synthetic coumarin that is used as rat poison. It causes intestinal bleeding in rodents. It has been described as a "terrible drug." It has a very narrow range, meaning that the minimal useful dose is very close to the maximal safe dose. Patients must be monitored very closely. -One of the most common stimulants used by humans is coffee. It is the fruit of the coffea Arabica tree. Coffee is the most widely used drug in the world. Coffee contains the stimulant caffeine, an alkaloid compound that is very bitter. Humans are one of the few animals that like bitter tasting alkaloids. -Some of the world's oldest medicines are alkaloids. The opium poppy, papaver somniferum, contains more than 20 compounds. -The drug opium, codeine, morphine, and heroin are all made from the opium poppy. Codeine is used to treat mild pain and to relieve coughs. It treats the symptoms, not the cause of the symptoms. In pain treatment, it changes the way the brain perceives pain. Laudanum is opium dissolved in alcohol and its consumption became very popular with Victorian ladies. -Morphine was isolated from opium in 1805. It was the first alkaloid to be isolated from any plant. Morphine is ten times as strong as opium and was first thought to be non-addictive. - Heroin, which is a derivative of morphine, was also thought to be non-addictive at one time. It was used widely for medicinal purposes in the early 1900's. Heroin is however, highly addictive and very deadly.

Long-day plant? short-day plant? day-neutral plant?

Long-day plant-Flowers with a short night. day longer than 12 hrs A short-day plant-Flowers with a long night. day shorter than 12 hrs. A day-neutral plant-Flowers regardless of night length.

What essential oils are and be able to name plants that make essential oils. How do they function? How are they stored?

Many plants, like basil, synthesize essential oils These oils act as insect repellants and are highly volatile. This accounts for the smell and taste we associate with these plants. Many of the herbs we use to season our food come from plants that synthesize essential oils. We use the leaves of those plants as herbs. These oils are stored in a specialized trichome, modified epidermal cells, leaf hairs. These specialized trichomes are glandular trichomes. They have a cap-like structure. The cap is a very prominent feature and advertises the toxic nature of the stored chemicals so insects learn to avoid these caps. Some other plants that make their own unique essential oils include: Cedarwood, geranium, lemongrass, mints, sage, and tea tree. Not all plants that make essential oils store them in trichomes, some secrete these oils in ducts. Citrus fruits have fragrant essential oils in their skins that deter insects from feeding on them. Pine trees defend against pine beetles by secreting resin that contains turpentine. Resin is secreted when a beetle makes a hole in the tree and the beetle is killed.

What is pollination? What is the difference between self-pollination and cross-pollination?

POLLINATION occurs when pollen grains are transferred from the anther to the stigma. - SELF-POLLINATION occurs if: Pollination is within the same flower or a different flower on the same plant. Cross pollination occurs when pollen is transferred from a flower on one plant to a flower on another plant of the same species

How does a flower that relies on wind pollination differ from a flower that relies on animal pollination? example:

Plants that use wind for pollination usually have small, inconspicuous flowers that lack both odor and nectar. Trees, like this oak, flower in the early Spring before new leaves emerge. This avoids problems with leaves that might interfere with pollination. The stigma of a wind pollinated plant is often large and feathery to help capture pollen grains as they pass by. The grasses are wind pollinated and have small flowers near the top of the plant d.

What plants has been the traditional source of rubber and what plants may be alternative sources in the future?

Rubber is harvested from the Brazilian rubber tree. It occurs as a latex emulsion secreted in special phloem cells called laticifers. The Russian dandelion produces latex in its root. The FDA recently approved the first medical product made from guayule, the Yulex natural rubber examination glove.

Different ways a plant can differentiate between the spring and the fall.

Some measure the change in day length and require long days before the critical short day length. - Another mechanism is VERNALIZATION to distinguish fall from spring. Vernalization is the requirement of a cold period before a plant will flower.

difference between a Herb and a Spice.

Spices are bar, roots, seeds or fruits of plants. Herbs-the leaves of those plants that produce essential oils.

Know the parts of a flower and their functions.

The flower parts of dicots are in multiples of 4 and 5.è The flower parts of monocots are in groups of three. (example: Lily)è Flowers are made up of four whorls or rings of organs. From the outside to the inside, the order of these organs is: sepals, petals, stamens, carpels. The outer two whorls, the sepals and the petals are sterile. Theinner two whorls, the stamens and the carpels, are the reproductive parts of the flower. Sepals: are often green and leaf-like in shape. They cover and protect the flower bud. As the flower opens, the sepals fold back to reveal the petals. The collective term for all of the sepals is calyx. Not all sepals are green. In this daylily the sepals and petals are both colored yellow. It makes the flower more conspicuous. Petals: of flowers are often brightly colored to attract pollinators. In some flowers, the petals fuse to form a long tube. The collective term for all the petals is corolla. Just inside the petals are the stamens, the male reproductive organ. Stamen: made of a long filament, or stalk, on top of which is the anther. Pollen grains develop in the anthers. Carpels: inside the stamens, the female reproductive organs. Flowers may have one or more carpels. Carpels may be separated or fused into a single structure. Complex organ Have three sections: the stigma, where the pollen grains land, the style, a structure though which the pollen grain grows and the ovary. The ovary contains one or more ovules, or eggs. The eggs will develop into seeds; the ovary will develop into a fruit.

How can some animals use toxic plant compounds for their own defense?

The monarch butterfly. These caterpillars dine exclusively on milkweed! They have evolved to use the toxins for own protection they are stored in its body. The bright colors of both the adult and the caterpillar advertize that they are toxic. If a bird eats one, it is very bitter and the bird vomits. Birds quickly learn to avoid these insects.

What cell types are in the xylem? The Phloem? Know the characteristics of these diff cell types.

Xylem-(dead cells)- tracheids. vessel elements and parenchyma. Phleom cells- The sieve-tube cells lack a nucleus, have very few vacuoles, but contain other organelles such as ribosomes. The sieve tube is an elongated rank of individual cells, called sieve-tube members, arranged end to end. The endoplasmic reticulum is concentrated at the lateral walls. Sieve-tube members are joined end to end to form a tube that conducts food materials throughout the plant. The end walls of these cells have many small pores and are called sieve plates and have enlarged plasmodesmata. The survival of sieve-tube members depends on a close association with the companion cells. All of the cellular functions of a sieve-tube element are carried out by the (much smaller) companion cell, a typical plant cell, except the companion cell usually has a larger number of ribosomes and mitochondria. This is because the companion cell is more metabolically active than a 'typical' plant cell. The cytoplasm of a companion cell is connected to the sieve-tube element by plasmodesmata.

Know the role of phytochrome in flowering time? What are the different forms of phytochrome?

a pale blue pigment found in very small amounts. Phytochrome acts as a photoreceptor. - Absorbs light energy. - Phytochrome exists in two forms: Pr: (for red-absorbing phytochrome) strongly absorbs red light with a relatively short wave-length. Pfr: (for far red-absorbing phytochrome) - Absorption of red light changes the shape of phytochrome and converts it the pfr form pfr is the active form of phytochrome absorption of far red light bypfr converts it back to pr - It is believed that phytochrome triggers the formation of florigen when the appropriate critical night length is reached.

Theories of water movement: a- Capillarity b- Root Pressure c- Cohesion-tension Which explains how water moves to the very top of trees?

a- capillarity, is the ability of liquid to flow against gravity where liquid spontaneously rises in a narrow space such as a thin tube, or in porous materials such as paper or in some non-porous materials such as liquified carbon fibre. This effect can cause liquids to flow against the force of gravity or the magnetic field induction. It occurs because of inter-molecular attractive forces between the liquid and solid surrounding surfaces; If the diameter of the tube is sufficiently small, then the combination of surface tension (which is caused by cohesion within the liquid) and forces of adhesion between the liquid and container act to lift the liquid b-Water that enters a plant's roots is pushed up through the xylem. This is known as Root Pressure. You can see root pressure when the stem of a wall- watered plant is cut off above the soil line and xylem sap oozes out. Root pressure is often seen in small plants when the soil is wet. The "dewdrops" on leaf margins, often seen in the early morning, are the result of positive root pressure. c-cohesion-tension water is pulled up the xylem. This explains how water moves to the very top of trees

Photoperiodism

any response a plant has to the relative length of the day and the nightgdt. This includes growth, development and flowering.

What is florigen? Where is it made? Where does it act?

hypothesized hormone-like molecules responsible for controlling and/or triggering flowering in plants. Florigen is produced in the leaves and acts in the shoot apical meristem of buds and growing tips