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Regents Biology Homework Packet

Unit 11: Nutrition and Digestion

Use your Biology by Miller & Levine textbook to complete and help with the following homework assignments.

(1) Read the assigned pages, (2) Define the vocabulary, and (3) Answer the questions.

Neatness counts. Number the definitions. Write the page and number of the questions. Do your work in ink or even type the homework. Staple the definitions and questions to the HW packet.

The homework assignment is due the day before the test. We will use the HW packet as a test review. The completed and corrected HW packet will be collected on the day of the test. Late homework assignments receive no credit (0). If the assignment is not turned in by the last day of the quarter the zero grade (0) will change to -5.

Ch 30: Digestive and Excretory Systems

Read pgs. 860 – 881; 889 – 893

Vocabulary p. 862 (6)p. 868 (6)p. 875 (11)

p. 867 #2a, 2bp. 873 #1a, 2a, 2b p. 881 #1b, 2a, 3a, 3b, 4

Regents Review891 – 893#1, 3, 5, 6, 8, 10 – 20, 23 – 25

TEST DATE: __________

Food IrradiationFor months, Jill and Laura had been planning their camping trip to a remote

region of South America. It was going to be a serious trip - everything they might

need for the entire four weeks would be carried by them in backpacks. They chose

their equipment carefully, picking out just the right tent, clothes, shoes, and

cooking equipment. But, by far the most preparation went into selecting the food

they would bring. "We must make sure our meals are well balanced," said Laura.

"We need to include food from each of the major food groups."

After numerous trips to supermarkets, camping stores, and health food stores, Jill and Laura realized

that it was not easy to find nutritious food that would not spoil without refrigeration.

"l guess we just can't have fresh fruits, vegetables, meats, and dairy products during our trip," Jill said.

"Wouldn't it be great if there was a way to treat these foods so they wouldn't spoil so quickly?"

"Yes," replied Laura, "l hear there actually is a method that may accomplish just that. Some scientists

are now experimenting with a process known as irradiation, which they say increases the shelf life of many

products. But, others are very skeptical about it because they feel it may introduce dangerous new substances

into the food."

The Food Irradiation Process

In the 1940s, the United States Army began experimenting

with food irradiation as a possible solution to the problem of

feeding its troops in the field. Interest in this new process grew

rapidly. These early studies showed that irradiation was an

effective, economical, and relatively simple process to perform.

To irradiate a food, the food is placed inside a closed

chamber containing radioactive forms of the elements cesium

and cobalt. These elements emit radioactive gamma rays, most of

which pass through the food. Some of the rays are absorbed by

the food. It is this absorbed energy that slows down the aging

process and kills insects and some microorganisms present in the

food.

The amount of radiation a food receives is determined by the amount of time the food is exposed to

the radioactive elements. High levels of radiation will preserve some foods indefinitely; somewhat lower levels

A Proposed Food Irradiation Unit. Boxed food would move through a chamber enclosed by thick concrete walls. Inside the chamber, food would be exposed to cobalt'60 or cesium-137.

will make it possible to keep items such as meats and poultry unrefrigerated for weeks. It is the role of the

Food and Drug Administration (FDA) to determine if irradiated food is safe for human consumption, and if so,

at what levels.

The FDA decided that irradiation is a safe process after about thirty years of research. Thus far, it has

approved irradiation of pork, fruits, vegetables, spices, teas, wheat and white flour, and white potatoes. A

major finding of the FDA's research was that this treatment does not make foods radioactive. But those who

oppose food irradiation claim this does not mean the food is safe. They are concerned about the chemical

changes that take place in food as a result of irradiation.

Scientists have identified various chemical substances that form in foods upon irradiation. Many of

these substances, called radiolytic products (RPs), now are known to exist also in foods that have been

canned, frozen, or dehydrated. While RPs are not believed to be harmful and some RPs are found in untreated

or cooled foods, irradiated foods contain some RPs that are not seen elsewhere. More than 40 of these

substances, which are known as Unique Radiolytic Products (URPs), have been found in irradiated foods thus

far. Many scientists claim that these URPs, like RPs, are not new substances. Other scientists are worried that

we know nothing about URPs, especially what effects they might have on humans who consume them over

long periods of time. They fear that URPs may trigger the development of cancer by damaging the body's

chromosomes

Scientific Studies

The FDA has evaluated hundreds of animal studies on food irradiation. In one extensive study done by

the U.S. Department of Agriculture, 300,000 pounds of irradiated chicken was fed to mice, rats, rabbits, and

beagles over a period of two years. The study evaluated effects on birth, reproduction, and the production of

toxic substances. It concluded that irradiation was a safe process.

Other scientific studies have led to very different conclusions. When ten human subjects were fed

irradiated wheat, some cells in their bodies developed abnormally. This condition gradually reversed itself

when this diet was stopped. Studies done on mice showed that groups fed irradiated foods had a higher death

rate and a higher incidence of tumors than did control groups. Fruit flies that were fed irradiated chicken

produced fewer offspring than the controls.

The FDA admits that the studies done so far have not been perfect. As one agency representative

remarked, "On the whole, you can find something wrong with every one of them." But, as the FDA also points

out, better studies are just not possible. In traditional animal feeding studies, high levels of the additive in

question are added to the food in order to exaggerate its effects. But with irradiation, the food and the

additive are essentially one and the same. To increase the amount, the animal would either have to be fed

more food than it ordinarily consumes or the dose of radiation would have to be increased so much that the

food's nutritional content would be destroyed.

Some scientists feel that animal studies, are simply not sufficient to resolve safety concerns. It is their

view that human epidemiological studies should be done. But as one scientist noted "Such a study is unlikely

to be done because it would require controlling the diets of at least 200,000 humans of various age groups for

at least 30 years, and following their health histories for at least 50 years." Without such a study, the FDA has

based its decisions on the studies that have been done.

Benefits of Food Irradiation

Those who favor food irradiation say it is the most important advance in dietary health since the

invention of pasteurization. Because currently 25 to 30 percent of the world's food supply is lost to spoilage

and pests, irradiation can help to fight global hunger. As of today, about twenty countries including Canada,

Japan, and the Netherlands allow the irradiation of a wide variety of foodstuffs.

The use of irradiation in the United States might enable us to expand the number of agricultural

products we export. Perishable foods could be shipped further distances without the risk of spoilage. By

providing more markets for their crops, irradiation might help alleviate many of the economic problems facing

the country's farmers today. At the same time, irradiation might make possible the exporting of perishable

foods to countries in need of them.

Another advantage of irradiation is its ability to protect human health by killing parasites like

salmonella, a bacterium that causes food poisoning, and the trichina worm in pork. It is believed that

trichinosis will soon be eradicated in the U.S. through the use of irradiation. In addition, food irradiation may

offer a safe alternative to many chemical pesticides, fumigants, and preservatives that are applied to stored

grains and fruits. One popular pesticide, ethylene dibromide (EDB), was banned recently by the FDA after it

was found to be carcinogenic. A few days after the ban on EDB, the Department of Health and Human Services

(which oversees the FDA) approved the use of low-dose radiation in its place.

Food irradiation also might provide a use for nuclear wastes. One of the byproducts of nuclear fuel

processing is radioactive cesium; currently, the disposal of nuclear wastes poses a major safety problem for

the world. By making use of this radioactive element in food processing, the risks and costs of nuclear wastes

disposal would be greatly reduced.

Drawbacks to Food Irradiation

There are many people who feel that the benefits of food irradiation do not outweigh its drawbacks.

Aside from the production of radiolytic products, they claim that irradiation alters the appearance, flavor,

texture, and nutritive value of many foods. Some nutritionists have noted that exposure to irradiation gives

milk a bad taste and causes soft foods, such as citrus fruits, to become mushy. In addition, they believe that

irradiation alters some amino acids and fats and destroys several vitamins, including A, some of the B group, C,

and E.

While irradiation may destroy many harmful pests, Clostridium botulinum (the bacterium responsible

for botulism) and aflatoxin (a poisonous substance produced by fungi) are resistant to irradiation. Some

scientists fear that if most of the organisms in a food sample are destroyed, the lack of microbial competition

might enable these resistant organisms to thrive. Alternatively, irradiation may produce dangerous variations

in some microorganisms, which then could be released into the environment.

Irradiation may not be the only alternative to many

pesticides, fumigants, and preservatives. Scientists currently are

testing aluminum phosphide, diatomaceous earth, and cold

storage of fruits as possible insecticides. In order to utilize nuclear

wastes in food irradiation, the wastes would have to be

transported great distances to and from irradiating facilities,

which are scheduled to be located in cities and farmlands. This

would greatly increase the risk of worker and public exposure to

these radioactive materials.

Public Acceptance

Even if food irradiation gains widespread approval by the FDA, public acceptance of the process may

lag far behind. Supermarkets have the go-ahead to sell irradiated fruits and vegetables, but few have these

items on their shelves. More than 50 percent of people surveyed would not even try irradiated meats, poultry,

or seafood. When the respondents were asked for their reasons, they voiced fears of exposure to radiation. As

one person explained, "Radiation is a scary word." The food industry has set public education as one of its

immediate goals. Industry representatives hope to prove to the public that this process is as safe as freezing

and canning.

Logo to be Used to Indicate that Food Has Been Irradiated.

1. What is food irradiation?

2. How are foods irradiated?

3. Why does irradiation extend the shelf life of some foods?

4. Why are some people concerned about the radiolytic products that form upon irradiation?

5. The essay states that when 300,000 pounds of chicken were fed to a large number of mice, rats, rabbits,

and beagles, it was determined that food irradiation was safe for humans. However, when 10 human subjects

were fed irradiated wheat, the opposite conclusion was reached. Which of these studies do you think was

more valid? Explain your reasoning.

6. Even though they have not yet been studied, the safety of Unique Radiolytic Products (URPs) found in

irradiated foods is assumed by some scientists. This is because other radiolytic products have been found to

be safe. Is this conclusion valid? How certain can the scientists be?

7. Has your food been irradiated? Research which are the most likely foods you have been eating that have

possibly been irradiated.

Adaptations for Digestion

Organism:

Organism:

Organism:

Organism: Organism:

Distinctive digestive feature(s):

Distinctive digestive feature(s):

Distinctive digestive feature(s):

Distinctive digestive feature(s):

Distinctive digestive feature(s):

Know the TermsMatch the definition to the word. Some words have more than one definition.

a. Produces gastric juiceb. The end of the digestive systemc. Emulsifies lipids

d. Digests carbohydrates in the mouth

e. Lower part of large intestinef. A measure of heat energy

g. Produces bile

h. Solid wastesi. Connects pharynx to stomach

j. Absorbs waterk. Eliminates wastesl. Stores wastesm. Finishes digestion and absorbs nutrients

n. Grinds food, temporarily stores food, and adds gastric juice

o. Part of the lymphatic system that absorbs the end products of lipid digestion.

p. Fingerlike projections in small intestine that absorbs nutrients

q. Digestive enzyme found in gastric juice

___ 1. amylase

___ 2. anus

___ 3. bile

___ 4. calorie

___ 5. esophagus

___ 6. feces

___ 7. lacteal

___ 8. large intestine

___ 9. liver

___ 10. mouth

___ 11. pepsin

___ 12. rectum

___ 13. small intestine

___ 14. stomach

___ 15. villi

Understand the Concepts

1. Types of NutritionThere are two basic ways that organisms obtain the organic nutrients they need. Some organisms are

capable of making, or synthesizing, these nutrients from simple inorganic substances. Such organisms are autotrophs (atr:t-uh-trohfs). Green plants and green algae and various other types of microorganisms are autotrophs. Most autotrophs are photosynthetic that is, they use energy from sunlight, and carbon dioxide and water from the environment to make their own organic nutrients. These organisms are called phototrophs. However, certain types of bacteria that are autotrophs do not use light as a source of energy. They are chemosynthetic, i.e., they obtain energy from special types of chemical reactions. Such organisms are called chemotrophs (kee-muh-trohfs).

Heterotrophs (het-uh-ruh-trohfs) are organisms that cannot synthesize their own organic nutrients. All animals and certain types of microorganisms are heterotrophs. Such organisms must take in, or ingest, food containing "ready-made" nutrients from other plants or animals.

Define:a. autotroph:

b. chemotroph:

c. heterotroph:

d. What is the difference between an autotroph and a heterotroph?

e. What is the relationship between autotrophs and heterotrophs?

2. DigestionFor a nutrient to be used by the cells of an organism, it must pass through the cell membranes. In

general, the nutrient molecules in food are too large to pass through cell membranes. Thus, to be used by the cells, most food molecules must be broken down into smaller, simpler forms. The process by which food molecules are broken down is called digestion (dyjes-chun).

The term digestion usually refers to the chemical breakdown of food substances into simple compounds. In many organisms, pieces of food are first cut, crushed, or broken into smaller particles without being changed chemically. This treatment results in the mechanical breakdown of the food. Mechanical breakdown increases the surface area of the food particles. Chemical digestion is carried out by digestive enzymes, which act only on the surface of food particles. Thus, mechanical breakdown prepares the food for more rapid chemical digestion by exposing more food surface to the action of the digestive enzymes. Chemical digestion, like mechanical breakdown, takes place in stages. Large molecules are broken down into smaller molecules, and these in turn are broken down into still simpler forms. The usable, simplest products of digestion are the end products of digestion

a. Define digestion:

b. What are the end products of digestion?

3. Trace the path of food through the alimentary canal of the grasshopper.

4. Why are nutrients needed by the body?

5. Where does digestion take place in protozoa?

6. List the human accessory glands, what each produces, and what the product does to food.GLAND PRODUCT EFFECT

7. How is a large surface area important in digestion and absorption?

8. What nutrients are required by living organisms? List them as organic and inorganic.

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Digestive ChemicalsChemical/ Enzyme Organ Made / Used Digestion

Salivary Amylase

Pepsin

Trypsin

Amylase

Lipase

Nuclease

Bile

Digestive System DisordersDisorder Description of

ProblemOrgan(s) affected Disruption of Homeostasis

Ulcer

Gall Stones

Diarrhea

Constipation

Appendicitis

Anorexia

Bulimia

Acid Reflux

Choose the best answer and write it on the blank.

Use the choices for questions 1 -5.1. digestion 2. pepsin 3. peristalsis 4. heterotroph

___ 1. digestive enzyme in gastric juice

___ 2. alternate waves of relaxation and contraction in the walls of the alimentary canal

___ 3. organism that cannot synthesize its own organic nutrients

___ 4. substance that breaks down large protein molecules into polypeptides

___ 5. process by which food molecules are broken down

___ 6. Organisms that use carbon dioxide and water from the environment and energy from sunlight to make their own organic nutrients are called1. phototrophs 2. chemotrophs 3. bacteria 4. heterotrophs

___ 7. A major difference in the digestive systems of the earthworm and the grasshopper is that1. only the earthworm has a tubular digestive system2. both have a crop but only the earthworm has a gizzard3. only the grasshopper has salivary glands4. only the grasshopper digests food mechanically

___ 8. A major difference in digestion between the hydra and the earthworm is that 13.1. the hydra is an autotroph and the earthworm is a heterotroph -2. wastes pass out the hydra's mouth and the earthworm's anus3. only the hydra has an alimentary canal4. the earthworm can ingest food only after previous food has been digested

Use the diagram to answer questions 9 -12.

___ 9. The sequence of food passing through the digestive system is

1. 2, 1, 3, 5, 9, 6, 7 2. 1, 3, 5, 9, 6, 73. 1, 3, 4, 9, 6, 7 4. 1, 3, 5, 6, 9, 7

___ 10. In which of the following does water reabsorption occur?1. 3 2. 83. 5 4. 9

___ 11. In which of the following does mechanical digestion occur? 1. 1, 2, and 11 only 2. 1, 3, and 5 only3. 3, 9, and 10 only 4. 4, 5, and 6 only

___ 12. Which organ produces lipase?1. 8 2. 53. 3 4. 4

___ 13. The amount of energy needed to raise the temperature of one gram of water 1’C is1. 1’C 2. 1 calorie3. 1 gram 4. 1 kilocalorie

___ 14. The human epiglottis1. closes during swallowing2. closes during breathing3. prevents food from passing through the esophagus4. allows food to pass through the windpipe

___ 15 Which of the following are coenzymes that participate with enzymes to catalyze reactions? 1. acids 2. mucus3. vitamins 4. amylases

___ 16. Which life process is classified as autotrophic in some organisms and heterotrophic in other organisms? 1. hormonal regulation 2. nutrition 3. anaerobic respiration 4. transport

___ 17. The diagram shown represents the cross section of an earthworm. Which letter indicates a structure that provides an increased surface area for the absorption of digestive end products?

1. A 2. B 3. C 4. D

___ 18. What does the process of photosynthesis produce? 1. starch, which is metabolized into less complex molecules by dehydration synthesis2. protein, which is metabolized into less complex molecules by dehydration synthesis3. glycerol, which is metabolized into more complex carbohydrates by dehydration synthesis4. glucose, which is metabolized into more complex carbohydrates by dehydration synthesis

___ 19. Which statement correctly describes one characteristic of the tube-like digestive system of an earthworm? 1. Various parts of the system perform different digestive functions.2. The shape of the system allows food to be processed by intracellular digestion.3. The shape of the system eliminates the need for egestion.4. Digestive enzymes are not used in the system.

___ 20. Which activity is illustrated in the diagram of an ameba?

1. egestion 2. synthesis3. respiration 4. ingestion

___ 21. A fungus is classified as a heterotroph rather than an autotroph because it1. grows by mitosis2. absorbs food from the environment3. manufactures its own food4. transforms light energy into chemical energy

___ 22. Which structure indicated in the diagram of a paramecium is used for the process of egestion?

1. A 2. B 3. C 4. D

___ 23. Which structures are adaptations for nutrition in the paramecium?1. pseudopodia and food vacuoles2. oral groove and cilia3. flagellum and eyespot4. contractile vacuoles and oral groove

___ 24. Two demonstrations were performed as described below. The two demonstrations were most likely used to illustrate the difference between

1. chemical and mechanical digestion2. photosynthesis and hydrolysis3. chemical digestion and hydrolysis4. mechanical digestion and synthesis

___ 25. The diagram below represents a protist. Structure X is most directly involved in the process of

1. extracellular digestion 2. enzymatic hydrolysis3. ingestion 4. transpiration

___ 26. The series of diagrams shown represents a process carried out by a unicellular organism.This process is known as

1. autotrophic nutrition 2. replication 3. sporulation 4. phagocytosis

___ 27. Because mushrooms absorb nutrients from decaying leaves, they are classified as1. autotrophs 2. anaerobes3. heterotrophs 4. protozoans

___ 28. The gizzard of an earthworm performs a digestive function similar to that of the1. small intestine in a human2. crop in a grasshopper3. anal pore of a paramecium4. teeth of a cow

___ 29. The function of the gastric caecum in a grasshopper is most similar to the function of the1. nephridium in an earthworm2. pancreas in a human3. anal pore in a paramecium4. nerve net in a hydra

___ 30. Which two organisms represented are heterotrophic?

1. A and B 2. B and C3. C and E 4. D and E

___ 31. Which chemical reaction is represented by the diagram?

1. dehydration synthesis of a dipeptide2. hydrolysis of a polypeptide3. dehydration synthesis of a lipid4. hydrolysis of a disaccharide

___ 32. Which food would provide the most roughage for the body? 1. baked fresh fish2. lettuce-and-tomato salad3. fried chicken breast4. milk shake

___ 33. Which three processes are indicated by the arrows in the accompanying diagram?

1. ingestion, diffusion, and excretion2. ingestion, digestion, and egestion3. cyclosis, meiosis, and mitosis4. diffusion, active transport, and cyclosis

Use the diagram to answer questions 34 – 36.

___ 34. From which structure are glucose and amino acids normally absorbed into the circulatory system? 1. F 2. H 3. C 4. E

___ 35. In which structure does extracellular chemical digestion of protein begin? 1. G 2. B 3. C 4. E

___ 36. In which structure does the initial hydrolysis of carbohydrates occur? 1. A 2. E 3. C 4. D

___ 37. Which substance is a nutrient in the human diet?1. oxygen 2. carbon dioxide3. water 4. roughage

___ 38. After food enters the small intestine, lipases, proteases, and amylases are secreted into the small intestine by the1. liver 2. gallbladder

3. salivary glands 4. pancreas

___ 39. In some regions of the world, children suffer from a protein deficiency known as kwashiorkor. This deficiency occurs when a child's diet is changed from high-protein breast milk to watery cereal. Even though the child is receiving calories, the child becomes sick and less active, and growth ceases. These symptoms are probably due to1. too many nucleic acids in the diet2. an overconsumption of complete protein foods3. not enough carbohydrates in the diet4. a lack of essential amino acids in the diet

___ 40. In humans, chemical digestion is accomplished by enzyme action that begins in the mouth and ends in the1. esophagus 2. stomach3. small intestine 4. gallbladder

___ 41. The graph shows the concentration of sugar (glucose) in the blood of a human over a 24-hour period after an injection of insulin. Which conclusion could be supported by these data?

1. Blood sugar concentration rises after the body uses up the injected insulin.2. Insulin raises blood sugar concentration in the liver.3. Blood sugar concentration remained constant in the blood throughout the 24-hour period.4. Insulin lowers blood sugar concentration in the muscle cells.

___ 42. The diagram shows a particle of food being moved along the human digestive tract by alternate waves of relaxation and contraction of the muscular walls of the esophagus. Which process causes the movement of the food down the esophagus?

1. circulation 2. active transport3. peristalsis 4. osmosis

___ 43. Which structures secrete chemicals utilized for the completion of digestion within the small intestine?1. liver and pancreas2. glomerulus and villi

3. esophagus and alveoli4. gallbladder and pharynx

Base your answers to questions 44 - 47 on the diagrams and on your knowledge of biology. The diagrams illustrate the pathway and the time frame for the digestion of a hamburger consisting of ground beef, ketchup, and a whole-wheat bun.

___ 44. An irritant can cause an erosion in the lining of structure C, leading to a disorder known as1. constipation 2. ulcers3. gout 4. appendicitis

___ 45. Chemical digestion of the whole-wheat bun begins after hydrolytic enzymes are secreted by structure1. A 2. B 3. C 4. D

___ 46. During which period does most of the digestive action of bile and pancreatic juice occur?1. 6:03 p.m. to 6:05 p.m.2. 6:05 p.m. to 6:08 p.m.3. 10:15 p.m. to 9:50 a.m.4. 9:50 a.m. to 1:00 p.m.

___ 47. Hydrolysis of the proteins present in the ground beef usually takes place in structures1. A and E 2. B and C3. C and D 4. A and D

___ 48. An accumulation of hardened cholesterol deposits is associated with the development of1. gout 2. gallstones3. constipation 4. appendicitis

___ 49. Which substance is normally absorbed by the large intestine?1. water 2. glycogen3. protein 4. cellulose

___ 50. Which type of digestion occurs in the mouth when an individual chews a piece of bread?1. mechanical digestion, only

2. chemical digestion, only3. both mechanical and chemical digestion4. neither mechanical nor chemical digestion