bio final review

  1. what is cellular respiration?
    The transfer of energy from various molecules to produce ATP; occurs in the mitochondria of eukaryotes, the cytoplasm of prokaryotes. In the process, oxygen is consumed and carbon dioxide is generated.
  2. How does circulatory system help cellular respiration?
    circulatory system transports oxygen, carbon dioxide, nutrients, and waste products between cells and the respiratory system and carries chemical signals from the endocrine system; consists of the blood, heart, and blood vessels.
  3. transport in Cnidarians
    Cnidarians, such as Hydra, have a fluid filled internal gastrovascular cavity, this cavity serve both a digestive& circulatory system. this cavity supplies nutrients for all body sells lining the cavity, obtains oxygen from the water in the cavity, and releases carbon dioxide and other wastes into it by diffusion.
  4. transport in Platyhelminthes
    In the planarian, branches penetrate to all parts of the body. Diffusion distances for nutrients, gases, and wastes are small. Body movement helps distribute materials to various parts of the body. have to keep moving, because they have a gastrovascular cavity therefore no need for a circulatory system since digestive system is branch out and all over, cells are close to nutrients. they don't need a circulatory system. However, one disadvantage of this system is that it limits these animals to relatively small sizes or to shapes that maintain low diffusion distances.
  5. transport in Nematodes (round worm)
    • Body cavity is a pseudocoel, body fluid under high pressure.Has no circulatory system (no blood system)
    • Fluid in psuedocoelom with contracting longitudinal muscle. digestive tract can serve as a circulatory system too because they are thin enough
  6. transport in Annelids
    A closed circulatory system is present in most polychaetes. Characteristics of the circulatory system vary within the phylum. The blood usually contains hemoglobin, a red oxygen-carrying pigment; some annelids have a green oxygen-carrying pigment, and others have unpigmented blood. The circulatory system is usually closed, i.e., confined within well-developed blood vessels; in some polychaetes and leeches the circulatory system is partly open, with blood and coelomic fluid mixing directly in the sinuses of the body cavity. Blood flows toward the head through a contractile vessel above the gut and returns to the terminal region through vessels below the gut; it is distributed to each body compartment by lateral vessels. Some of the lateral vessels are contractile and serve as hearts, i.e., pumping organs for driving the blood.
  7. (Circulatory system) transport in Arthropods
    • have open circulatory system. This type of system has a heart and a few major arteries veins. There are very few capillaries connecting the arteries and veins. The blood spills into the body cavity where it is picked up and taken back to the heart. Arthropods are limited in size because of this inefficient circulatory system.
    • The insects, who have no need for an efficient circulatory system, have what is called an open circulatory system. They have a heart which pumps the blood into open-ended arteries and the "blood" sloshes around to reach the cells of the body. It is passively recollected by open-ended veins to be returned to the heart.
  8. open and close circulatory system
    • Arthropods, like insects and spiders, have an open circulatory system, in which the blood is pumped forward by the heart, but then flows through the body cavity, directly bathing the internal organs.
    • Vertebrates, like humans, have a closed circulatory system in which the blood stays in the circulatory system as it circulates, and chemicals are exchanged by diffusion.
    • In a closed system, blood is always contained within vessels (arteries, veins, capillaries, or the heart itself). In an open system, blood (usually called hemolymph) spends much of its time flowing freely within body cavities where it makes direct contact with all internal tissues and organs.
    • evolutionary advantage for a closed system: allow to walk on land will need strong muscle
  9. functions of arteries
    Thick-walled vessels that carry blood away from the heart. The wall of the arterioles, contains less elastic fibers but more smooth muscle cells than that of the aorta. The arterioles represent the major site of the resistance to blood flow and small changes in their caliber cause large changes in total peripheral resistance.
  10. function of veins
    Thin-walled vessels that carry blood to the heart. Units of the circulatory system that carry blood to the heart.
  11. function of capillaries
    Small, thin-walled blood vessels that allow oxygen to diffuse from the blood into the cells and carbon dioxide to diffuse from the cells into the blood.
  12. circulatory systems in fish
  13. In fish, the system has only one circuit, with the blood being pumped through the capillaries of the gills and on to the capillaries of the body tissues. This is known as single cycle circulation. The heart of fish is therefore only a single pump. Blood collected from throughout the fish's body enters a thin-walled receiving chamber, the atrium.
    • As the heart relaxes, the blood passes through a valve into the thick-walled, muscular ventricle.
    • Contraction of the ventricle forces the blood into the capillary networks of the gills where gas exchange occurs.
    • The blood then passes on to the capillary networks that supply the rest of the body where exchanges with the tissues occur.
    • Then the blood returns to the atrium.
  14. circulatory systems in amphibians
    two atria and a single ventricle. The atrium receives deoxygenated blood from the blood vessels (veins) that drain the various organs of the body. The left atrium receives oxygenated blood from the lungs and skin (which also serves as a gas exchange organ in most amphibians). when the ventricle contracts, oxygenated blood from the left atrium is sent, relatively pure, into the carotid arteries taking blood to the head (and brain); deoxygenated blood from the right atrium is sent, relatively pure, to the pulmocutaneous arteries taking blood to the skin and lungs where fresh oxygen can be picked up. Only the blood passing into the aortic arches has been thoroughly mixed, but even so it contains enough oxygen to supply the needs of the rest of the body. in contrast to the fish, both the gas exchange organs and the interior tissues of the body get their blood under full pressure.
  15. circulatory systems in reptile
    have a muscular septum which partially divides the ventricle. When the ventricle contracts, the opening in the septum closes and the ventricle is momentarily divided into two separate chambers. This prevents mixing of the two bloods. The left half of the ventricle pumps oxygenated blood (received from the left atrium) to the body. The right half pumps deoxygenated blood (received from the right atrium) to the lungs. amphibians and reptile have double circuit.
  16. circulatory system in mammals
    • mammals show complete separation of the heart into two pumps, for a total of four heart chambers.
    • pulmonary for gas exchange with the environment and
    • systemic for gas exchange (and all other exchange needs) of the rest of the body.
    • The efficiency that results makes possible the high rate of metabolism on which the endothermy ("warm-bloodedness") of birds and mammals depends.
  17. function of vertebrate circulatory system
    The circulatory system is made up of the vessels and the muscles that help and control the flow of the blood. primary function is the of transport: transport of gases, nutrients, hormones, toxic, and excess molecules. Maintains a stable and narrow internal body environment (homeostasis). Transport H2 O and nutrients from the intestine to the cells or to a storage site. O2 from the respiratory organ to the cells and CO2 from the cells back to the respiratory organ. hormones from endocrine glands. toxic or waste molecules to the excretory organ. Protection of the organism from foreign invaders (immune system) of itself from loss of blood (clotting mechanism)
  18. why do endothermic animals need a more efficient circulatory system?
    endothermic animal regulate their body temperature thru metabolism. A more efficient circulatory system will support the high metabolic rate required for maintance of internal body temperature.
  19. external environment in gas exchange is always aqueous, why?
    A respiratory surface is covered with thin, moist epithelial cells that allow oxygen and carbon dioxide to exchange. Those gases can only cross cell membranes when they are dissolved in water or an aqueous solution, thus respiratory surfaces must be moist.
  20. why can't larger animals rely on diffusion of oxygen from the external environment for all their oxygen requirement?
    [[i] surface area per unit volume, or surface-are to volume ratio, not just surface area because that the need for exchange is proportional to the amount of active tissue. [ii] very small animals can rely on diffusion across body surfaces alone [iii] large animals have a larger volume per unit exterior surface area, and the consequent need for exchange is not adequately met by body surface and diffusion alone; gas exchange is dealt with by having proliferated and specialised exchange surfaces and circulatory systems
  21. 3 ways that natural selection can optimize the rate of oxygen diffusion
    • they increase pressure difference, organisms create a water current by beating cilia, because this continuous replenishment of water, the external oxygen concentration does not decrease along the diffusion pathway. increase area, posses respiratory organs: gills, tracheae, lungs
    • and decrease distance.
  22. explain how bony fishes keep water moving over their gills
    Respiration occurs in 2 stages. The oral valve in the mouth is opened and the jaw is depressed, drawing water into the mouth cavity while the opercular cavity is closed. the oral valve is closed and the operculum is opened, drawing water through the gills to the outside
  23. countercurrent gas exchange in fish gills
    water passes from the gill arch over the filaments in a direction opposite to the direction of blood flow through the lamellae. It maximize the oxygenation of the blood by increasing the concentration gradient of oxygen along the pathway for diffusion. At everypoint, the oxygen concentration is higher in the water, so that diffusion continues.
  24. Explain how tracheae in insects function
    Insects have tracheoles that carry oxygen directly to the cells.tracheoles are in direct contact with individual cells, osygen directly diffuses across the plasma membranes. Air passes into the trachea by way of specialized openings in exocskeleton- spiracles. It uses internal tubes to minimize evaporation
  25. Evolution of the vertebrate lung
  26. Gills were replaced in terrestrial animals because 1) air is less supportive than water, 2) water evaporates. Gas moves in and out of lungs by 2-way- flow system.
    • Lungs of amphibians and reptiles are specialized outgrowths of the gut.
    • Mammalian lungs have greatly increased surface area
    • Birds have highly efficient flow-through system
  27. Gas exchange in amphibians and reptiles
  28. Amphibians force air into lungs- positive pressure breathing. Not very much surface area. Does cutaneous respiration.
    Reptile pull in air rather than push in- negative pressure breathing. They expand rib cages by muscular contraction. This creates a lower pressure inside the lungs, air diffuse in. more efficient than amphibians because have more surface area. Less cutaneous respiration but some do.
  29. Positive pressure v.s. negative pressure breathing
  30. In positive pressre breathing- they fill oral cavity with air, close their mouth and nostrils then elevate the floor of their oral cavity. In negative pressure beathing- They expand rib cages by muscular contraction. This creates a lower pressure inside the lungs, air diffuse in.
  31. Basics of gas exchange in humans
  32. The evolution of more efficient respiratory systems accommodate the increased demands on cellular respiration of endothermy.millions of alveoli provides each lung with an enormous surface area for gas exchange, alveoli cluster at the ends of the bronchioles. All gas exchange between air and blood takes place across the walls of the alveoli. Larynx--> trachea--> bronchi--> lung--> bronchioles--> alveoli
  33. Gas exchange in birds
    • Mammal lung ends in alveoli, bird lung end further in parabronchi. Air flow through parabronchi in one direction only, similar to unidirectional flow of water through a fish gill. Only fresh air enters the parabronchi, old air exits the lung by a different route.
    • Breathing occurs in two cycles: 1) inhaled air is drawn from trachea into posterior air sacs and then is exhales into the lungs. 2) air is drawn from the lungs into the anterior air sacs and then is exhaled through the trachea.
    • Air always flow from posterior to anterior.
  34. Gas exchange in cnidarians, flatworms, nematodes, echinoderms, sponges
  35. They all do gas exchange directly across body surface
  36. Structure and function of xylem and phloem
  37. Xylem are dead, hollow. They conducts water and dissolved minerals, xylem supplies support for the plant body.
    phloem cells are alive, conducts carbohydrates, hormones, amino acids, and other substances that are necessary for plant growth.
  38. Concept of water potential
  39. Water move from a cell or solution with higher water potential to lower water potential. Water potential is determine by 1) solute potential of pure water = zero. 2) solution containing solutes have negative solute potential. Water goes in by osmosis. Lowest water potential is at stomata. Water potential is higher in soil and roots because water evaporating from the leaves thru stomata causes additional water to move upward in the xylem and also to enter the plant thru the roots. Water potential drops substantially in leaves due to transpiration.
  40. Cohesion-tension theory of xylem transport- detail how water is transported from soil to leaves
  41. Movement of water from soil to roots- need high water potential in soil, root make sure its’ lower by pumping ions and mineral thru active transport to root hair cell, this way its lower than the soil in water potential, water move into root by osmosis. Movement of water from root hair to xylem. Transpiration of water from leaves- leaf cell has higher water potential than air, water moves from leaf cell to air spaces, veins have higher water potential than mesophyll cells, water moves from veins to cells. Transport water from root xylem to leaf xylem- water column in xylem has tensile strength due to cohesion of water molecule. Loss of water molecule from xylem in leaves create “pull” on the column of water in xylem.
  42. Explain how stomata function
  43. When ions from surrounding cells are pumped into guard cells, the guard cell turgor pressure increases as water enters by osmosis. The increased turgor pressure causes the guard cells to bulge, with the thick walls on the inner side causing each guard cell to bow outward, thereby opening the stoma. Turgor pressure of the guard cells causes the stomata to open and close. As the guard cells actively take up solutes their water potential decreases and water enters by osmosis. When the guard cells become turgid the stomata open. at night sucrose is pumped out of the guard cells, and they become flaccid and close. For stomata to open, guard cell has to be fill with water.
  44. Describe guttation
    Guttation- when root pressure is very high, it can force water up to the leaves, where it may be lost in a liquid form through a procces of guttation. Guttation is the appearance of drops of xylem sap on the tips or edges of leaves of some vascular plants. Guttation does not take place in stomata.
  45. Describe adaptations of plants to flooding
  46. Plants can respond to flooded conditions by forming larger lenticels (facilitate gas exchange) and adventitious roots that reach above flood level for gas exchange. Some form arenchyma.
  47. Pressure-flow hypothesis of phloem transport- detail how sugars are transported from the source to the sink in a plant.
  48. Source= leaf, storage, where glucose being produce. Sink = the growing part of a plant, any metabolically active, storage site.
    • Sugar transported into phloem at source. Decrease water potential of phloem so water moves from xylem(higher water potential) into phloem, pressure of water moving in pushes sugar to next cell. Sugar transported out of phloem at sink. Increase water potential of phloem so water moves into xylem (lower water potential) and back up to the leaves.
    • At the source active transport of sugars into phloem causes a reduction in water potential. As water moves into the phloem, turgor pressure drives the contents to the sink where the sugar is actively transported into the cells. Water diffuses back into the xylem to be reused.
  49. Shared characteristics of fungi, including structure
  50. All are heterotrophs.
    • Have hyphae
    • Have cell walls that include chitin
    • Some have a dikaryon (2 nuclei)
    • Undergo nuclear mitosis that also found in protist. Nuclear envelope does not break down and reform. Mitosis takes place within the nucleus.
  51. How fungi obtain nutrients
  52. Fungi obtain their food by secreting digestive enzymes into substrates, which may include anything from fallen
  53. homeostasis Definition; why is it necessary
  54. Homeostasis- maintenance of a relatively stable internal physiological environment in an organism. It is necessary because enzyme won’t function properly if not right.
  55. Sexual vs. asexual reproduction
  56. Sexual reproduction requires a specialized form of cell division, meiosis, to produce haploid gametes. Most animals reproduce sexually.
    Bacteria, archaea, protist, cnidarians and tunicates reproduce asexually. In asexual reproduction, genetially identical cells are produced from a single parent cell through mitosis.
  57. Advantages of sexual and asexual reproduction
  58. Asexual- asexual is faster and easier than sexual reproduction, because another partner is not needed. animal or pollen grains doesn't have to travel in order to propagate the species, which means it can conserve energy and be more discreet. Asexual reproduction is more reliable than sexual, because there are less steps to follow and therefore less can go wrong
    Sexual- sexual reproduction offers the opportunity to produce recombinant types that can make the population better able to keep up with changes in the environment. species with recombination can bunch harmful mutations together and eliminate several in a single "genetic death. More energy is required.
  59. Types of asexual reproduction
  60. Fission- individual organism divides and then each part becomes separate but identical.
    • Budding- a part of parent’s body becomes separated from the rest. Cnidarian.
    • Parthenogenesis- female produce offspring from unfertilized eggs. Arthropods.
  61. Different strategies for sexual reproduction
  62. External fertilization- male release their sperm into water containing eggs, then union.
    Internal fertilization- sperm directly into female reproductive tract
  63. Fish and amphibian reproduction
  64. Fish and amphibians have external fertilization. Fish eggs contain only enough yolk to sustain the developing embryo for a short time. Few grow to maturity. Amphibians gametes from both male and females are released through the cloaca. Process of development divides into embryonic, larval, and adult stages.
  65. Reptiles & birds – amniotic egg – know the functions of all the membranes
  66. Leathery shell- protection
    • Chorion- allows gas exchange but retain water
    • Allantois- surround a cavity into waste products from the embryo are excreted
    • Amnion- encases developing embryo within a fluid-filled cavity
    • Yolk sac -provides food from yolk for the embryo via blood vessels connecting to embryo’s sac
  67. Function of a cloaca – animals that have them
    cloaca is the posterior opening that serves as the only such opening for the intestinal, urinary, and genital tracts of certain animal species. For amphibians, reptiles and birds. It is a chamber where the products of the reproductive system (eggs-sperm), excretory-urinary wastes and digestive wastes (feces) are stored and then released.
  68. the structures, and functions of the structures in males
  69. seminiferous tubule- sites of sperm production
    • -->epididymis- deliver sperm
    • -->vas deferens- passes sperm into abdominal cavity via the inguinal canal.
    • Seminal vesicles- produce fructose fluid ‘
    • Prostate gland- ejaculatory duct merges with the urethra from urinary bladder.
    • Bulbourethral glands- secretes fluid that lines the urethra andn lubricates the tip of the penis prior to sexual intercourse.
  70. Spermatogenesis
    Spermatogenesis occurs in seminiferous tubules. The first meiotic division separates homologous chromosomes, forming two haploid secondary spermatocytes. Second meiotic division separates sister chromatids to form 4 haploid spermatids, which are converted into spermatozoa.
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bio final review