bio 2 test 2 Final Exam Practice

negative feedback

-A homeostatic control mechanism whereby an increase in some substance or activity inhibits the process leading to the increase; also known as feedback inhibition. -When a deviation in a condition occurs, a message is sent to increase or decrease the activity of particular target organs, termed effectors. Effectors are generally muscles or glands, and their actions can change the value of the condition in question back toward the set point value. -Hypothalamus detects changes

Define the terms cleavage and blastula, describing the two major patterns of cleavage and what is responsible for each of them. Distinguish between the cleavage patterns and blastula formation in frogs, birds, mammals, and insects.

-Cleavage is a series of rapid cell divisions that trasorfm the zygote into the blastula-a hollow ball of cells. -The amount of yolk is the major determinant of cleavage pattern. Eggs with little yolk cleave completely (holoblastic cleavage); eggs with a large yolk cannot cleave completely (meroblastic cleavage). -In sea urchins, endoderm forms by invagination of the blastula; mesodermal cells form from other surface cells. In vertebrates with moderate to extensive amounts of yolk, surface cells move through a blastopore or a primitive streak, respectively. Mammalian gastrulation is similar to gastrulation in birds. -Insects have yolk-rich eggs -birds have almost all yolk in the egg so cleavage is incomplete

Describe how the nervous system regulates breathing.

-Each breath is initiated by neurons in a respiratory control center located in the medulla oblongata. -Breathing is automatic but can be voluntarily overridden -Neurons of the medulla oblongata must be responsive to changes in blood PO2 and PCO2 in order to maintain homeostasis.

Describe the events necessary for fertilization to occur, including the effects of sperm on eggs. List the different ways that polyspermy is blocked.

-Following penetration, fusion of sperm with the egg membrane initiates a series of events including egg activation, blocks to polyspermy, and major rearrangements of cytoplasm. Egg and sperm nuclei then fuse to create a diploid zygote. -Polyspermy is blocked by changes in membrane polarity, release of enzymes that remove sperm receptors, and a release of hyalin that lifts the vitelline envelope from the cell membrane.

Compare and contrast the advantages and disadvantages of gills, tracheal systems, cutaneous respiration, and lungs, relating these structures to the specific environments in which they are each used.

-Gills: fish, great increase in diffusion surface area that gills provide enables aquatic organisms to extract far more oxygen from water than would be possible from their body surface alone. Gills are specialized extensions of tissue that project into water -Tracheal systems: arthropods, respiratory system consists of small, branched cuticle-lined air ducts called tracheae, which branch into very small tracheoles, are a series of tubes that transmit gases throughout the body. Tracheoles are in direct contact with individual cells, and oxygen diffuses directly across the plasma membranes. -Cutaneous respiration: amphibians, some aquatic reptiles, The process of exchanging oxygen and carbon dioxide across the skin. -Lungs: mammals, terrestrial animals, The lung minimizes evaporation by moving air through a branched tubular passage.

List animals that have open and closed circulatory systems, as well as some that have none, comparing and contrasting the structure and function of each approach.

-Open circulatory systems: grasshopper, mollusks, arthropods -Closed circulatory systems: earthworm, all vertebrates -No circulatory system: sponge, hydra, nematode In the open circulation of an insect, hemolymph is pumped from a tubular heart into cavities in the insect's body; the hemolymph then returns to the blood vessels so that it can be recirculated. no distinction between the circulating fluid and the extracellular fluid of the body tissues. -In the closed circulation of the earthworm, blood pumped from the hearts remains within a system of vessels that returns it to the hearts. All vertebrates also have closed circulatory systems. the circulating fluid, blood, is always enclosed within blood vessels that transport it away from and back to the heart

Describe the cost of endothermy, and the effect of body size on metabolic rate and temperature homeostasis.

-Requires relatively constant and high rates of energy intake(food) -Changes in body mass have a large effect on metabolic rate, smaller animals consume much more energy per unit body mass than larger animals -For smaller animals with a high metabolic rate, surface area is also large relative to their volume which could be disastrous as they can't produce enough internal heat to balance conductive loss through their large surface area.

Describe the function of extraembryonic membranes and list the taxa that have them.

-The amniotic membrane and several other membranes form from embryonic cells, but they are located outside of the body of the embryo. For this reason, they are known as extraembryonic membranes. The extraembryonic membranes include the amnion, chorion, yolk sac, and allantois. -The amnion is the inner membrane that surrounds the embryo and suspends it in amniotic fluid, thereby mimicking the aquatic environments of fish and amphibian embryos. The chorion is located next to the eggshell and is separated from the other membranes by a cavity—the extraembryonic coelom.

Define how organisms can be categorized with respect to temperature regulation.

-We can make this temperature dependence quantitative by examining the rate of a reaction at two different temperatures. The ratio between the rates of a reaction at two temperatures that differ by 10°C is called the Q10 for the enzyme: -For most enzymes the Q10 value is around 2, which means for every 10°C increase in temperature, the rate of the reaction doubles. -eventually enzyme's structure denatures

Describe the different mechanisms by which plants reproduce asexually, and describe the advantages and disadvantages of asexual and sexual reproduction.

-asexual reproduction results in genetically identical individuals because only mitotic cell divisions occur. -In the absence of meiosis, individuals that are highly adapted to a relatively unchanging environment persist for the same reasons that self-pollination is favored. -Should conditions change dramatically, there will be less variation in the population for natural selection to act on, and the species may be less likely to survive. -Apomixis involves development of diploid embryos -vegetative reproduction, new plant individuals are simply cloned from parts of adults -The forms of vegetative reproduction in plants are many and varied: Runners or stolons, Rhizomes, Suckers, and Adventitious plantlets.

mechanisms of temperature regulation

-behavior -evaporative cooling -vasodialation/vasoconstriction -insulation -thermogenesis -regulated hypothermia -appendage size -counter-current heat exchange

Describe the classic experiment of Spemann and Mangold, explaining the role of the organizer.

-removed cells of the dorsal lip from one embryo and transplanted them to a different location on another embryo. The new location corresponded to that of the animal's future belly. They found that some of the embryos developed two notochords: a normal dorsal one, and a second one along the belly.

Define translocation, describing the substances that are translocated, where in the plant they are translocated to, and why the plant translocates them.

-translocation-(1) In plants, the long-distance transport of soluble food molecules (mostly sucrose), which occurs primarily in the sieve tubes of phloem tissue. (2) In genetics, the interchange of chromosome segments between nonhomologous chromosomes. -carbohydrates manufactured in leaves and other green parts are distributed through the phloem to the rest of the plant. -Phloem also transports plant hormones,, environmental signals can result in the rapid translocation of hormones in the plant. In addition, mRNA can move through the phloem, providing a mechanism for long distance communication among cells. Phloem also carries other molecules, such as sugars, amino acids, organic acids, proteins, and ions.

henson's node

A node, or primitive knot, is an enlarged group of cells located in the anterior portion of the primitive streak in a developing gastrula. The node is the site where gastrulation, the formation of the three germ layers, first begins.

Cuticle

A plant cuticle is a protecting film covering the epidermis of leaves, young shoots and other aerial plant organs without periderm. It consists of lipid and hydrocarbon polymers impregnated with wax, and is synthesized exclusively by the epidermal cells.

intercalary meristem

A type of meristem that arises in stem internodes in some plants, such as corn and horsetails; responsible for elongation of the internodes.

countercurrent gas exchange

Allows for constant supply of oxygen to diffuse into the blood

lung structure of birds

Birds: highly efficient flow-through system, most efficient respiration of all terrestrial vertebrates, the bird lung channels air through tiny air vessels called parabronchi, where gas exchange occurs. Air flows through the parabronchi in one direction only. This flow is similar to the unidirectional flow of water through a fish gill. only fresh air enters the parabronchi of the lung, and the "old" air exits the lung by a different route. The unidirectional flow of air is achieved through the action of anterior and posterior air sacs unique to birds. When these sacs are expanded during inhalation, they take in air, and when they are compressed during exhalation, they push air into and through the lungs.

Describe how cell movement and apoptosis are involved in animal development.

Cell movement allows for certain structures in an animal to form in certain areas. Like the backbone on the dorsal side. Apoptosis gets rid of mutated or bad cells to prevent detrimental things from happening to the animal

Draw a phylogenetic tree demonstrating the evolution of the multi-chambered heart in fish, amphibians, reptiles, mammals, and birds, listing the advantages of each type.

Fish-2 chamber, rue chamber- pump heart. The fish heart is, in essence, a tube with four structures arrayed one after the other to form two pumping chambers . The first two structures—the sinus venosus and atrium—form the first chamber; the second two, the ventricle and conus arteriosus, form the second chamber. Simple Amphibians- lungs require separate circulation, double circulation, amphibian heart has a single ventricle, the separation of the pulmonary and systemic circulations is incomplete. Cutaneous respiration -Reptiles- 3-chambers, in most, lungs require separate circulation, double circulation, reptiles have a septum that partially subdivides the ventricle. This separation is complete in crocodilians, which have two separate ventricles divided by a complete septum (discussed later in this section). -Mammals-four-chambered heart with two separate atria and two separate ventricles -Birds-four-chambered heart with two separate atria and two separate ventricles

lung structure of frogs

Frogs: lungs of amphibians are formed as saclike outpouchings of the gut, much less surface area is available for gas exchange in amphibian lungs than in the lungs of other terrestrial vertebrates. Each amphibian lung is connected to the rear of the oral cavity, or pharynx, and the opening to each lung is controlled by a valve, the glottis. positive pressure breathing- force air into their lungs, filling their oral cavity with air, closing their mouth and nostrils, and then elevating the floor of their oral cavity.

Describe the tissues and organs that originate from each of the three embryonic germ layers.

Gastrulation creates the three primary germ layers: endoderm, ectoderm, and mesoderm. The cells in each germ layer have very different developmental fates.

Describe how gills work, including both their advantages and disadvantages as respiratory surfaces.

Gills are specialized extensions of tissue that project into water. They can be simple, or complex. The great increase in diffusion surface area that gills provide enables aquatic organisms to extract far more oxygen from water than would be possible from their body surface alone. Advantages: countercurrent flow(between blood and water) Disadvantages: requires constant moisture

guard cells

Guard cells open and close the stomata

root hair

In plants, a tubular extension from an epidermal cell located just behind the root tip; root hairs greatly increase the surface area for absorption.

collenchyma cell

In plants, the cells that form a supporting tissue called collenchyma; often found in regions of primary growth in stems and in some leaves. sclerenchyma cell-Tough, thick-walled cells that strengthen plant tissues.

procambium

In vascular plants, a primary meristematic tissue that gives rise to primary vascular tissues.

xylem

In vascular plants, a specialized tissue, composed primarily of elongate, thick-walled conducting cells, which transports water and solutes through the plant body.

apical meristem

In vascular plants, the growing point at the tip of the root or stem.

lateral meristems

In vascular plants, the meristems that give rise to secondary tissue; the vascular cambium and cork cambium.

Draw a picture of an angiosperm flower, identifying the location and function of the key parts.

Male structures. Androecium is a collective term for all the stamens (male structures) of a flower. Stamens are specialized structures that bear the angiosperm microsporangia. Female structures. The gynoecium is a collective term for all the female parts of a flower. In most flowers, the gynoecium, which is unique to angiosperms, consists of a single carpel or two or more fused carpels. Single or fused carpels are often referred to as simple or compound pistils, respectively. Ovules (which develop into seeds) are produced in the pistil's swollen lower portion, the ovary, which usually narrows at the top into a slender, necklike style with a pollen-receptive stigma at its apex.

lung structure of mammals

Mammals: require more oxygen, The lungs of mammals are packed with millions of alveoli, tiny sacs clustered like grapes, Each alveolus is composed of an epithelium only one cell thick, and is surrounded by blood capillaries with walls that are also only one cell layer thick. Thus, the distance d across which gas must diffuse is very small. The term trachea is used both for the vertebrate windpipe and the respiratory tubes of arthropods, although the structures are obviously not homologous. The mammalian trachea bifurcates into right and left bronchi (singular, bronchus), which enter each lung and further subdivide into bronchioles that deliver the air into the alveoli.

Compare and contrast the different types of plant tissue, and the different dermal and ground system cells

Roots and shoots are composed of three different types of tissues: dermal, ground and vascular dermal tissue- primarily epidermis, In multicellular organisms, a type of tissue that forms the outer layer of the body and is in contact with the environment; it has a protective function. ground tissue-In plants, a type of tissue that performs many functions, including support, storage, secretion, and photosynthesis; may consist of many cell types. vascular tissue-Containing or concerning vessels that conduct fluid. Plant cell types can be distinguished by the size of their vacuoles, whether they are living or not at maturity, and by the thickness of their cellulose cell walls, a distinguishing feature of plant cells

Describe the advantages and disadvantages of self-pollination and outcrossing, detailing how self-pollination is prevented.

Self-pollination is favored in stable environments Self-pollination is ecologically advantageous under certain circumstances because self-pollinators do not need to be visited by animals to produce seed. self-pollination produces progenies that are more uniform than those that result from outcrossing. separate stamens and pistils. Another strategy involves self-incompatibility that prevents self-fertilization. . Self-incompatibility results when the pollen and stigma recognize each other as being genetically related, and pollen tube growth is blocked

endoderm

The cells that move into the embryo to form the tube of the primitive gut are endoderm; they give rise to the lining of the gut and its derivatives (pancreas, lungs, liver, etc.).

mesoderm

The cells that move into the space between the endoderm and ectoderm are mesoderm; they eventually form the notochord, bones, blood vessels, connective tissues, muscles and internal organs such as the kidneys and gonads

ectoderm

The cells that remain on the exterior are ectoderm, and their derivatives include the epidermis on the outside of the body and the nervous system.

neurulation

The development of the dorsal nerve cord is called neurulation.

blastoderm

The layer of cells formed by the cleavage of a fertilized mammalian egg, which later divides into the three germ layers from which the embryo develops. Also called germinal membrane, germ membrane.

parenchyma cell

The most common type of plant cell; characterized by large vacuoles, thin walls, and functional nuclei. They function in the storage of food and water, photosynthesis, and secretion.

blastopore

The opening of the archenteron in the gastrula that develops into the mouth in protostomes and the anus in deuterostomes.

protoderm

The primary meristem that gives rise to the dermal tissue.

ground meristem

The primary meristem, or meristematic tissue, that gives rise to the plant body (except for the epidermis and vascular tissues).

trichomes

Trichomes serve a variety of functions, depending on their location. As root hairs (and as leaf hairs in epiphytes), trichomes absorb water and minerals. As leaf hairs, they reflect radiation, lower plant temperature, and reduce water loss. They also provide defense against insects.

Compare and contrast xylem and phloem transport, in terms of the paths taken, the substances transported, the plant cells and tissues involved, and the forces acting along the way.

Water and minerals go up the xylem Glucose and amino acids go up and down the phloem Xylem goes up from the stem to the leaves, phloem goes back and forth Phloem is made up of living cells, xylem is made up of dead

blastula

a hollow sphere of cells, referred to as blastomeres, surrounding an inner fluid-filled cavity called the blastocoele formed during an early stage of embryonic development in animals.

heterotherms

a physiological term for animals that exhibit characteristics of both poikilothermy and homeothermy.

hemoglobin

a protein composed of four polypeptide chains and four organic compounds called heme groups. At the center of each heme group is an atom of iron, which can bind to a molecule of oxygen. Each hemoglobin molecule can carry up to four molecules of oxygen. Hemoglobin's affinity for oxygen is affected by pH and temperature

myoglobin

a protein composed of four polypeptide chains and four organic compounds called heme groups. At the center of each heme group is an atom of iron, which can bind to a molecule of oxygen. Each hemoglobin molecule can carry up to four molecules of oxygen. Hemoglobin's affinity for oxygen is affected by pH and temperature

blastocyst

a structure formed in the early development of mammals. It possesses an inner cell mass (ICM) which subsequently forms the embryo. The outer layer of the blastocyst consists of cells collectively called the trophoblast.

blastomere

a type of cell produced by cleavage (cell division) of the zygote after fertilization and is an essential part of blastula formation.

blastocoel

also termed the blastocyst cavity (or cleavage or segmentation cavity) is the name given to the fluid-filled cavity of the blastula (blastocyst) that results from cleavage of the oocyte (ovum) after fertilization.

ectotherms

an animal that is dependent on external sources of body heat. -counter-current heat exchange. This circulatory adaptation allows the cooler blood in the veins to be warmed through radiation of heat from the warmer blood in the arteries located close to the veins.

endotherms

an animal that is dependent on or capable of the internal generation of heat; a warm-blooded animal. -create internal metabolic heat for conservation or dissipation -Dilation vs constriction of blood vessels based on heat need

pokiolotherms

an organism that cannot regulate its body temperature except by behavioral means such as basking or burrowing.

homeotherms

an organism that maintains its body temperature at a constant level, usually above that of the environment, by its metabolic activity.

notocord

becomes discs between your vertebrae

deuterostomes

blastopore becomes anus

protosomes

blastopore becomes mouth

Describe the mechanisms of heat transfer relevant to animals.

body heat = heat produced + heat transferred the second law of thermodynamics indicates that no energy transaction is 100% efficient. Thus the reactions that make up metabolism are constantly producing heat as a result of this inefficiency. -Radiation. The transfer of heat by electromagnetic radiation, such as from the Sun, does not require direct contact. Heat is transferred from hotter bodies to colder bodies by radiation. -Conduction. The direct transfer of heat between two objects is called conduction. It is literally a direct transfer of kinetic energy between the molecules of the two objects in contact. Energy is transferred from hotter objects to colder ones. -Convection. Convection is the transfer of heat brought about by the movement of a gas or liquid. This movement may be externally caused (wind) or may be due to density differences related to heating and cooling—for example, heated air is less dense and rises; the same is true for water. -Evaporation. All substances have a heat of vaporization—that is, the amount of energy needed to change them from a liquid to a gas phase. the larger the surface area relative to overall mass, the greater the conduction of heat.

positive feedback

body uses positive feedback mechanisms, which push or accentuate a change further in the same direction. In a positive feedback loop, the effector drives the value of the controlled variable even farther from the set point. As a result, systems in which there is positive feedback are highly unstable, analogous to a spark that ignites an explosion. They do not help to maintain homeostasis.

trophoblast

contributes to placenta

Describe the structure and primary functions of plant shoots, with an emphasis with what is occurring at the apical meristem, vascular cambium, and cork cambium.

cork cambium-The lateral meristem that forms the periderm, producing cork (phellem) toward the surface (outside) of the plant and phelloderm toward the inside. vascular cambium-In vascular plants, a cylindrical sheath of meristematic cells, the division of which produces secondary phloem outwardly and secondary xylem inwardly; the activity of the vascular cambium increases stem or root diameter. shoot-In vascular plants, the aboveground portions, such as the stem and leaves. Stems serve as a scaffold for positioning the leaves, the principal sites of photosynthesis Flowers, other reproductive organs, and ultimately, fruits and seeds are also formed on the shoot

Define gastrulation, describing the germ layers that are formed and the mechanisms by which cells move during this process. Draw figures of gastrulation in sea urchins, frogs, birds, and mammals, comparing and contrasting the formation of the three germ layers and the effect of the amount of yolk.

forms the three primary germ layers and converts the blastula into a bilaterally symmetrical embryo with a central progenitor gut and visible anterior-posterior and dorsal-ventral axes. Gastrulation creates the three primary germ layers: endoderm, ectoderm, and mesoderm.

bud

itself is simply described as an undeveloped tip of the embryonic shoot, or the portion that grows up and holds the plant together. It can either develop immediately, or some buds will lay dormant.

List the characteristics, different types, location, and function of meristematic tissue in plants.

meristem-Undifferentiated plant tissue from which new cells arise. Found in root and shoot apices Meristems are clusters of small cells with dense cytoplasm and proportionately large nuclei that act as stem cells do in animals. That is, one cell divides to give rise to two cells, of which one remains meristematic, while the other undergoes differentiation and contributes to the plant body. In this way, the population of meristem cells is continually renewed. apical meristem lateral meristems ground meristem intercalary meristem Tissues formed from lateral meristems, which comprise most of the trunk, branches, and older roots of trees and shrubs, are known as secondary tissues and are collectively called the secondary plant body.

did gills evolve into lungs?

no they did not -lungfish had both lungs and gills, 3 chambered heart

morphogenesis

organization and spatial distribution of differentiated cells in multicellular body and its organ

Epidermis

outermost, protoderm-derived layer of cells covering the stem, root, leaf, flower, fruit, and seed parts of a plant. The epidermis and its waxy cuticle provide a protective barrier against mechanical injury, water loss, and infection.

neural crest cells

pinch off of neural plate (ectoderm), become neurons, pigment cels, nerve stuff

differentiation

process by which different cels arise

Explain the colonial flagellate hypothesis of metazoan origin and why it is currently favored.

proposes that multicellular organisms evolved from a single flagellated cell.

determination

sets developmental fate of cell

Sclerenchyma

support tissue composed of any of various kinds of hard woody cells. Mature sclerenchyma cells are usually dead cells that have heavily thickened secondary walls containing lignin.

somitogenesis

the division of the mesoderm and somites

Define homeostasis, and explain how feedback control is used to maintain it.

the dynamic constancy of the internal environment is called homeostasis. -controlled through positive and negative feedback

blastodisc

the embryo-forming portion of an egg with discoidal cleavage usually appearing as a small disc on the upper surface of the yolk mass — see egg illustration.

organogenesis

the formation of the organs in their proper locations—which occurs by interactions of cells within and between the three germ layers.

thermogenesis

the process of heat production in organisms.

Describe gas exchange across membranes, using Fick's laws to explain the properties of respiratory systems that affect gas exchange, and evolutionary strategies for maximizing gas diffusion.

the rate of diffusion between two regions is governed by a relationship known as Fick's Law of Diffusion. Fick's Law states that for a dissolved gas, the rate of diffusion (R) is directly proportional to the pressure difference (Δp), which results from differences in the concentration of the gas, between the two sides of the membrane and the area (A) over which the diffusion occurs. Furthermore, R is inversely proportional to the distance (d) across which the diffusion must occur. A molecule-specific diffusion constant, D, accounts for the size of molecule, membrane permeability, and temperature. Shown as a formula R= DA (change in)P/d - Increasing oxygen concentration difference and Increasing area and decreasing distance

meristatic tissue

totipotency, can make any part of the plant

Draw a labeled picture of the process of pollination in detail, and the different types.

two types of pollination, called self-pollination and cross-pollination. Self-pollination is the more basic type of pollination because it only involves one flower. This type of pollination occurs when pollen grains from the anther fall directly onto the stigma of the same flower.

Explain what is meant by tidal volume and anatomical dead space and explain their importance. Compare the amount of fresh air in bird and mammal lungs.

where no gas exchange occurs—termed the anatomical dead space. Tidal volume (symbol VT or TV) is the lung volume representing the normal volume of air displaced between normal inhalation and exhalation when extra effort is not applied. Birds have a constant supply of fresh air, mammals do not

Phloem

which is located toward the outer part of roots and stems, is the principal food-conducting tissue in vascular plants. Food conduction in phloem is carried out through two kinds of elongated cells: sieve cells and sieve-tube members.