Bio 1023- chap 25

Open stomata during the day allow for all of these EXCEPT :

water conservation .

Xylem moves ________ a plant .

water up to the leaves of

Explain how plants protect themselves from predation . Using Infographic 25.10 and the internet , find examples of defenses used by plants and describe them .

1. Some plants grow in a location that is not easily accessible to herbivores . This avoids predation by staying out of reach . 2. Some plants grow mechanical defenses , such as thorns or sticky hairs , to discourage herbivory . 3. By mimicking insect predators , plants can prevent herbivory by scaring away potential threats . 4. Some plants shed their leaves if they detect insect pests , a mechanical defense .

List four items that are necessary for plants to grow and describe where they are found in the environment :

1. Water : soil 2. Carbon : air 3. Nitrogen : soil ; first must be processed by nitrogen - fixing bacteria such as Rhizobium 4. Sunlight : atmosphere

The production of a seed in plants requires _______ sperm , a process called _______ fertilization .

2 ; double

What is the drawback to plants of having stomata open during the day in a dry climate ?

A drawback of having the stomata open during the day in a dry climate is that rapid water loss through transpiration can be a problem for the plant .

What is one major function of the plant hormone auxin ?

Auxin causes cells to elongate .

Does auxin always make stems and roots bend ? Why ?

Auxin does not always make stems and roots bend . If auxin is found in equal concentrations on both sides of the stem or root , both sides of the stem or root will elongate , and no bend will be produced .

How does carbon dioxide enter the leaves ?

Carbon dioxide enters the leaves through stomata .

Why is it good for a plant to have its stomata open during the day ?

Carbon dioxide is an integral part of photosynthesis , because it provides the carbon used in the final product , glucose . Water and sunlight are also needed for photosynthesis , so having the stomata open during the day allows for all three of these elements to come together and perform photosynthesis .

How do carnivorous plants obtain nitrogen from the environment ?

Carnivorous plants obtain nitrogen by trapping and dissolving insects .

Explain why leaves change color in the autumn in temperate regions .

During spring and summer , plants produce high levels of three pigments : chlorophylls and red and yellow carotenoids . As daylight shortens and temperatures cool , much less chlorophyll is produced , but the red and yellow carotenoids are still produced . Thus , leaves change from green to red or yellow based on the most common pigment in the leaf .

Describe the uses of ethylene and gibberellins in agriculture .

Ethylene is commonly used to ripen fruits that are picked and shipped green . Picking and shipping the fruits when unripe prevents spoilage of the fruit . The fruit is sprayed at the warehouse with ethylene , which causes it to ripen . Gibberellins are used in agriculture to increase the size of fruit . Gibberellins cause growth of the stem ; growth of the stem results in larger fruits .

Describe the various tropisms ( phototropism , goetropism and thigmotropism ) and how plants respond to their environment .

Light : The plant hormone auxin promotes cell elongation and facilitates the ability of plants to grow toward light referred to as phototropism . Gravity : Plants respond to gravity , with the roots growing down toward the force of gravity , and the shoots growing up away from the force of gravity referred to as gravitropism . Touch : Some plants have the ability to grow up by winding themselves around nearby taller structures ( trees , fence posts ) . Again , auxin is important in this ability , causing cell elongation on the opposite side of the touched object , resulting in lopsided growth that results in coiling around the object known as thigmotropism .

Discuss three strategies plants use to conserve water .

Physical measures : waxy , thick leaves ( again , think of a cactus ) . Ability to use low levels of carbon dioxide : Some plants keep their stomata closed for most of the day but are still able to use minute levels of carbon dioxide trapped in the plant's internal air pockets to feed photosynthesis . Splitting the process of photosynthesis : Some plants that thrive in the desert keep their stomata closed during the day and collect carbon dioxide at night . The nocturnally collected carbon dioxide is stored in the leaves of the plant until the next morning , when sunlight drives photosynthesis .

Describe some dispersal mechanisms for seeds .

Seeds can be dispersed by the wind , water , or animals . Seeds dispersed by the wind are either very light and / or have adaptations to help them float relatively long distances , such as dandelions . Seeds dispersed by water float , and often have a hard , protective seed coat to protect them from predation in the water and from rotting . An example is a coconut . Animals can disperse seeds in a variety of ways . Seeds often have structures that stick to the fur ( or feathers ) of an animal ; as the animal travels , so does the seed , and when the animal grooms , the seeds drop off Some seeds also rely on animals eating them for dispersal . They can travel through the animal's digestive tract without being harmed and are dispersed in feces .

Why would placing an unripe avocado in a paper bag with an apple cause the avocado to ripen ?

The apple will emit the gas ethylene , causing the avocado to ripen .

What are the benefits and drawbacks of keeping stomata closed during the day in a hot climate such as by the desert's plant ?

The benefit of keeping stomata closed during the day is water conservation . The drawback is that no carbon dioxide would enter the leaf and photosynthesis would not occur ( i.c. , no sugar produced ) .

What force draws water from a plant's roots to its leaves ?

The strength of cohesion between water molecules draws water from a plant's root to its leaves .

Which part of the vascular system allows transpiration to occur ?

The xylem enables transpiration.

How does water leave the leaves ?

Water molecules leave the leaves through stomata as water vapor .

What is the wood of a tree , and how does a tree grow wider ?

Wood is formed from growth in the secondary meristem cells , allowing trees to grow out as well as up . Wood is actually hardened secondary xylem tissue .

Compare and contrast the structure and function of xylem and phloem .

Xylem : Plant vascular tissue ( made up of thick walled dead cells ) that transports water from the roots to the shoots ( upper parts of the plant). Phloem : Plant vascular tissue ( made up of thin walled live tissues ) that transports sugars from leaf to throughout the plant .

The tip of the growing shoot contains a tissue named :

apical meristem .

Eutrophication at the deltas of major rivers , such as the Mississippi , has led to areas called _____ zones .

dead

More auxin accumulation in root cells will result in which of the following ?

less elongation

What do plants obtain through digestion of insects ?

nitrogen

What is the most common gas in the atmosphere ?

nitrogen

The pathway water takes during transpiration includes the following EXCEPT :

phloem .