Author: Biology Junction Team

Unsegmented Worm

Unsegmented Worms

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Phylum Platyhelminthes
Characteristics

  • Called flatworms because bodies are flattened dorso-ventrally

  • Acoelomate – solid bodies without a lined body cavity
  • Have 3 body layers — outer ectoderm, middle mesoderm, & inner endoderm
  • Bilaterally symmetrical
  • Show cephalization (concentration of sensory organs at anterior or head end)
  • Body cells exchange oxygen & carbon dioxide directly with environment by diffusion
  • Single opening into gastrovascular cavity; two-way digestive tract
  • Some are parasites & others are free-living
  • Parasitic worms have thick cell layer called tegument covered with a nonliving cuticle covering their bodies as protection inside hosts
  • Includes 3 classes — Turbellaria (planarians), Trematoda (parasitic flukes), & Cestoda (parasitic tapeworms

Class Turbellaria

  • Most are marine but includes freshwater planarian (Dugesia)

Planarians

  • Spade-shaped at the anterior end & have two, light-sensitive eyespots
  • Can sense light, touch, taste, & small
  • Have 2 clusters of nerve cells or ganglia to form a simple brain
  • Nervous system composed of a nerve net
  • Capable of simple learning
  • Move by tiny hairs or cilia over a mucus layer that they secrete
  • Feed by scavenging or protozoans
  • Have a single opening or mouth located at the end of a muscular tube called the pharynx which can be extended when feeding
  • Flame cells help remove wastes to excretory pores

  • Hermaphrodites that cross-fertilize eggs that are then deposited into a capsule until hatching in 2-3 weeks
  • Reproduce asexually by fragmentation

Class Trematoda

  • Includes parasitic flukes
  • About 1 cm long & oval shaped

  • Require a host to live
  • Have both oral & ventral suckers to cling to host & suck blood, cells, & body fluids
  • Oral sucker around mouth at anterior end sucks blood
  • May be endoparasites (live inside a host) or ectoparasites (live on the outside of host
  • Covered in tough, unciliated tegument
  • Nervous & excretory systems like turbellarians
  • Hermaphrodites
  • Have a long, coiled uterus that stores & releases 10,000+ eggs
  • Eggs released through genital pore & develop into larva
  • Show complex life cycles
  • Life cycle of sheep liver fluke:
    * Adult liver flukes live in sheep liver & gall bladder where they mate & form eggs
    * Eggs enter intestines, pass out with feces, & hatch in water
    * Larva enter snails, asexually multiply, then leave snail & form cysts
    * Cysts (dormant larva with hard, protective covering) clings to grass
    * Sheep ingest cysts when they eat grass
    * Cysts hatch in digestive tract & bore through intestines into bloodstream
    * Mature & reproduce in the liver

  • Schistosomiasis (disease caused by parasitic blood flukes) infects people in Asia, Africa, & South America causing intestinal bleeding & tissue decay that can result in death

Class Cestoda

  • Includes tapeworms
  • Adapted for parasitic life
  • Tough outer tegument prevents being digested by host
  • Anterior end called scolex contains hooks & suckers for attachment to intestine of host

  • Long, ribbon-like bodies up to 12 m in length
  • Nervous system extends length of body but lacks sense organs
  • Lacks mouth & digestive tract but absorbs digested nutrients from host
  • Grows by making body segments called proglottids
  • Each proglottid produces eggs & sperm that cross-fertilize with other segments & also self-fertilize (hermaphrodites)
  • Oldest, mature proglottids containing eggs at posterior end break off & pass out with feces
  • Life cycle of beef tapeworm:
    * Cattle eat grass with proglottids containing fertilized eggs
    * Eggs hatch into larva & bore through cow’s intestine into bloodstream
    * Larva burrow into cow’s muscle & form cysts
    * Humans eat beef (muscle) & cysts travels to intestines
    * Cyst breaks open & adult beef tapeworm forms


BEEF TAPEWORM LIFE CYCLE

Phylum Nematoda
Characteristics

  • Called roundworms
  • Includes Ascaris, hookworms, Trichinella, & pinworms
  • Pseudocoelomates have fluid-filled body cavity partially lined with mesoderm
  • Pseudocoelom contains the body organs & provides hydrostatic skeletal support for muscles
  • Have long slender bodies that taper at both ends

  • Covered with flexible cuticle
  • Digestive tract with anterior mouth & posterior anus; called one-way digestive tract
  • Separate sexes in most species
  • Most are free living
  • Some are parasites on plants & animals
  • Ascaris is a parasitic roundworm living in the intestines of pigs, horses, & humans
  • Ascaris life cycle:
    * Enter body in contaminated food or water & hatch in intestines
    * Larva bore into bloodstream & carried to lungs & throat
    * Larva coughed up, swallowed, & return to intestines to mature & mate
    * Block the intestine causing death

  • Hookworm eggs hatch in moist soil & larva bore through bare feet of new host 
  • Trichinella are human parasites caused by eating undercooked pork containing the cysts
    * Cause disease called trichinosis
    * Cysts cause muscle pain & stiffness


 CYSTS IN CONTAMINATED PORK

Phylum Rotifera
Characteristics

  • Known as rotifers or wheel animals
  • Transparent, free-swimming microscopic animal
  • Freshwater & marine
  • Have a ring of cilia around mouth that rotates like a wheel to bring in food
  • Feed on unicellular algae, bacteria, & protozoa
  • Have a muscular organ called the mastax behind the pharynx to chop food
  • Nervous system composed of anterior ganglia & 2 long nerve cords
  • Show cephalization (head end)
  • Have 2 anterior, light-sensitive eyespots

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Unsegmented Worms Study Guide B1

Unsegmented Worm Study Guide

  • Describe the digestive tract of planarians
  • How are tapeworms able to get their food
  • What is the life style of most flatworms
  • What are the characteristics of rotifers
  • What are the general characteristics of all flatworms
  • Why do flatworms not need circulatory & respiratory systems
  • What causes schistosomiasis
  • To what kingdom & phylum do flatworms belong
  • Describe a pseudocoelom & give examples of worms that have this characteristic
  • Explain the life cycle of Ascaris
  • How do rotifers eliminate wastes
  • What is regeneration & give an example of an unsegmented worm that uses this process
  • What is the cuticle and what is its function
  • What are proglottids & what is their function
  • If a worm has a one-way digestive system, what must be true about the organism
  • Why are rotifers called “wheel animals”

Sucrose Hydolysis by Sucrase

 

Sucrose Hydrolysis Using Sucrase

INTRODUCTION:

In this lab, you will demonstrate the production of the enzyme sucrase (invertase) by yeast. The enzyme sucrase catalyzes the hydrolysis of the disaccharide sucrose to invert sugar. Invert sugar is a mixture of glucose and fructose, which are both monosaccharides. Yeast cannot directly metabolize (ferment) sucrose. For the yeast to utilize sucrose as an energy source, it must first convert it to the fermentable monosaccharides glucose and fructose.
Benedict’s solution is a test reagent that reacts positively with simple reducing sugars. All monosaccharides and most disaccharides are reducing sugars, possessing a free carbonyl group (=C=O). Sucrose is an exception in that it is not a reducing sugar. A positive Benedict’s test is observed as the formation of a brownish-red cuprous oxide precipitate. A weaker positive test will be yellow to orange. Both glucose and fructose test positive with benedict’s solution, sucrose does not.

MATERIALS NEEDED:

*Yeast filtrate solution
one 7 gram package active dry yeast per 80 mL distilled water
Ring stand and ring to hold funnel
Filtering funnel
Filter paper (fast speed)
**5% sucrose solution
5 grams sucrose per 95 mL distilled water
***5% glucose (dextrose) solution
5 grams dextrose per 95 mL distilled water
Benedict’s qualitative solution
Distilled water
Five 10-mL graduated cylinders (one for each solution)
7 test tubes 18 x 150 mm
Test tube holder
Test tube rack
2 400-mL beakers
Hot plate

PRE-LAB:

* To prepare a yeast filtrate solution, mix one package of active dry yeast with 80 mL of distilled water. Let stand for 20 minutes, stirring occasionally. Filter the resulting suspension and save the filtrate solution. This is your invertase extract. Refrigerate the extract if held overnight. Approximately enough for 8 labs.

**To prepare a 5% sucrose solution, dissolve 5 grams of sucrose in 95 mL of distilled water. This should be prepared shortly before use. Approximately enough for 4 labs.

***To prepare a 5% glucose solution, dissolve 5 grams of dextrose (this is the name used when dry) in 95 mL of distilled water. This should be prepared shortly before use. Approximately enough for 9 labs.

PROCEDURE:

1. Label 3 test tubes A1, A2, and A3, and place in the test tube rack. Place into the test tubes as follows:

    • Into tube

A1

    • , place

10 mL

    • of 5% sucrose solution.

Into tube A2, place 10 mL of 5% sucrose solution and 4 mL of invertase extract.

Into tube A3, place 10 mL distilled water and 4 mL of invertase extract.

Thump the tubes to mix.

2. Put approximately 250 mL of 30 to 35 oC water into a 400-mL beaker. Incubate the three tubes in this warm water bath for 35 minutes.

3. Label 4 test tubes B1, B2, B3 and B4, and place in the test tube rack. Place 5 mL of Benedict’s qualitative solution into each tube. Now transfer to the B tubes as follows:

    • Into tube

B1

    • , transfer the contents of tube

A1

    • .

Into tube B2, transfer the contents of tube A2.

Into tube B3, transfer the contents of tube A3.

Into tube B4, place 10 mL of 5% glucose solution.

Thump the tubes to mix.

4. Place tubes B1, B2, B3, and B4 into a boiling water bath. CAUTION: do not let the bath boil hard. Keep it just at the boiling point. After 3 or 4 minutes, remove the tubes and note whither any change is evident.

QUESTIONS AND OBSERVATIONS:

1. Did tube B1 test positive or negative?

2. What does this show?

 

3. Did tube B2 test positive or negative?

4. What does this show?

5. Did tube B3 test positive or negative?

6. What does this show?

 

7. Did tube B4 test positive or negative?

8. What does this show?

 

 

 

Successful AP Biology Student

 

The Successful Biology Student:
  1. Realizes this is a fast-paced course so they have excellent attendance.
  2. Is never late.
  3. Always has their textbook, notebook, lab book, pencil, … when they come to class.
  4. Let’s the teacher know ahead of time when they will miss for a doctor’s appointment or school trip.
  5. Makes certain that all assignments, labs, projects, and reports are completed on time.
  6. Schedules tests & labs to be made up after school when they return from an absence.
  7. Does not miss an excessive number of class periods for school trips.
  8. Keeps track of their grade.
  9. Always reads every lab before that lab day.
  10. Reads and recopies lecture notes and keeps them in an organized notebook.
  11. Reads all chapters before lecture.
  12. Reviews all chapters and notes each day.
  13. Asks questions in class.
  14. Utilizes the computer tutorials that supplement each unit of study.
  15. Pays attention in class.
  16. Keeps neat & accurate lab data to be organized in lab reports.
  17. Follows all instructions for projects & collections.
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Study of Biology pptQ

 

Study of Biology
ppt Questions

What is Biology?

1. Define biology.

 

2. What are organisms?

3. Name 5 groups of organisms.

 

4. Living things share common _______________.

5. What is the basic unit of life that makes up all organisms?

6. To survive, populations of organisms must be able to _____________ offspring.

7. All organisms have a _________ code carried in  a molecule called _______.

8. Organisms require ____________ such as food and need __________ for their activities.

9. Living things _________ to their environment.

10. Organisms must maintain what type of internal environments ?

11. What does evolve mean?

 

12. Do groups or individuals evolve?

Characteristics

13. All ____________ are made of cells.

14. Most cells are so __________, they can’t be seen without a microscope.

15. What is cytoplasm?

 

16. What surrounds all cells?

17. What is the function of the cell membrane?

 

18. Cells are complex and highly ___________.

19. What are organelles and give an example?

 

20. The simplest type of cells are known as ______________.

21. Describe prokaryotic cells.

 

22. Name one of the most common prokaryotes.

23. More complex cells are called ______________.

24. Eukaryotes have a true _________ and _________________ organelles.

25. Name 3 types of eukaryotic cells.

26. Organisms can be grouped by their __________ of cells.

27. Define unicellular organisms.

28. What are multicellular organisms?

 

Reproduction

29. When organisms reproduce they pass what on to their offspring?

30. Name 2 types of reproduction.

31. What type of reproduction involves 2 parents?

32. A fertilized egg is called a ___________.

33. Are sexually reproduce organisms genetically identical to their parents?

34. asexual reproduction involves a _____________ parent or _________.

35. In asexual reproduction, a single cell __________ to form two new cells.

36. How do asexually reproduced organisms genetically compare  to their parents?

Genetic Code

37. What carries the genetic code for all organisms?

38.DNA stands for ____________________ ___________.

39. Do all organisms have DNA?

40. What does DNA code for in a cell?

41. Why are proteins so important to cells?

 

Growth and Development 

42. Name the stages of development in the life of a frog.

 

43. Name two ways that organisms grow.

44. When organisms change into adults they ___________ and may change.

Requiring Food and Energy

45. What organisms can make their own food?

46. What is a photoautotroph and give an example.

 

47. What food making process is used by photoautotrophs?

48. What do chemoautotrophs use to get energy?

49. ___________ cannot make their own food.

50. How do heterotrophs meet their food requirements?

51. Name 3 groups of heterotrophs.

52. Explain the difference among herbivores, carnivores, and omnivores.

 

 

53. Define metabolism.

 

54. All metabolic processes require ____________.

55. What is the ultimate energy for all life on earth?

56. What metabolic process uses sunlight for energy?

57. Write the balanced overall equation for the photosynthesis process and label the reactants & products.

 

 

58. What metabolic process releases the chemical energy stored in food?

59. Write the balanced overall equation for cellular respiration .

 

60. Name several environmental factors that organisms respond to.

 

61. Give an example of an organism responding to their environment to promote survival.

 

62. Define homeostasis.

 

63. Give 3 examples of internal conditions in which organisms must maintain stability.

 

64. Why do populations evolve?

 

65. What record do we have that populations evolve?

Organization Levels

66. Name 3 nonliving levels into which life is organized.

67. At what level of organization does life begin?

68. Cells organize into ____________.

69. What makes up organs?

70. Organs working together become a ____________, and these working together make the entire _____________.

71. From simplest to most complex, list the levels of life above organism.

72. What is the most inclusive level of life?

 

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