Chapter 33 AP Biology Flashcards

Questions and Answers

Ingested dietary substances must cross cell membranes to be used by the body, a process known as _____.

absorption

Animals that migrate great distances would obtain the greatest energetic benefit of storing chemical energy as what?

fats

Why are certain nutrients considered 'essential' in the diets of some animals?

These animals are not able to synthesize these nutrients

What is an advantage of a complete digestive system over a gastrovascular cavity?

It allows for specialized regions with specialized functions Signup and view all the answers

In what order does a fasting animal draw on its stored resources?

liver glycogen, then muscle glycogen, then fat Signup and view all the answers

What do earthworms, grasshoppers, and birds all have?

crop Signup and view all the answers

What is peristalsis in the digestive system?

Smooth muscle contractions that move food along the esophagus Signup and view all the answers

What happens upon activation by stomach acidity in the secretions of the parietal cells?

They initiate the digestion of protein in the stomach Signup and view all the answers

What can constipation result from?

The consumption of a substance that promotes water reabsorption in the large intestine Signup and view all the answers

After ingestion by humans, what is the first category of macromolecules to be chemically digested by enzymes in the mouth?

carbohydrates Signup and view all the answers

What pH level is characteristic of the stomach's digestive secretions?

2 Signup and view all the answers

What enzyme has high activity in an acidic environment?

pepsin Signup and view all the answers

What enables adult lampreys to achieve nutritional balance without a stomach?

They attach to the surface of large fish to feed on body fluids Signup and view all the answers

What would a hiatal hernia most likely increase the frequency of?

gastric reflux Signup and view all the answers

What is typical of rabbits, horses, and herbivorous bears?

An enlarged cecum Signup and view all the answers

What nutrients are required by cells and obtained through food?

essential nutrients Signup and view all the answers

What are the four classes of essential nutrients?

Essential amino acids, essential fatty acids, vitamins, minerals Signup and view all the answers

What does undernourishment refer to?

A diet deficient in calories Signup and view all the answers

What is malnourishment?

Missing one or more essential nutrients Signup and view all the answers

What are the four main stages of food processing?

Ingestion, digestion, absorption, elimination Signup and view all the answers

Define intracellular digestion.

Digestion of food inside cells by food vacuoles Signup and view all the answers

What is extracellular digestion?

Food broken down outside of cells Signup and view all the answers

What characterizes a gastrovascular cavity?

It is a simple digestive system with a single opening for both food intake and waste removal Signup and view all the answers

What is an alimentary canal?

A complete digestive system that begins at the mouth and ends at the anus Signup and view all the answers

What is peristalsis?

Muscular contractions that push food through the digestive tract Signup and view all the answers

What do sphincters do?

Regulate the movement of material between compartments Signup and view all the answers

What is the purpose of the oral cavity?

Mechanical and chemical digestion Signup and view all the answers

What is the role of salivary glands?

Saliva lubricates food Signup and view all the answers

What is the main function of teeth?

Chew food into smaller particles Signup and view all the answers

What does salivary amylase do?

Breaks down glucose polymers Signup and view all the answers

What is the pharynx?

The back of the throat Signup and view all the answers

What is the function of the epiglottis?

A flap of cartilage that covers the trachea when swallowing Signup and view all the answers

What is the esophagus?

The food tube that connects the pharynx to the stomach Signup and view all the answers

What is the role of the stomach?

The stomach stores food and secretes gastric juice, which converts a meal to acid chyme Signup and view all the answers

What is HCl (hydrochloric acid) and its role?

It has a pH of 2, kills bacteria, and denatures proteins Signup and view all the answers

What is pepsin?

An enzyme that hydrolyzes proteins into smaller peptides Signup and view all the answers

What protects the lining of the stomach from self-digestion?

Mucus Signup and view all the answers

What are gastric ulcers?

Lesions in the lining caused mainly by the bacterium Helicobacter pylori Signup and view all the answers

What is the major organ of digestion and absorption?

Small intestine Signup and view all the answers

What is the duodenum?

The first section of the small intestine for major chemical digestion Signup and view all the answers

What are the digestive juices produced by the pancreas?

Bicarbonate, trypsin, chymotrypsin, lipase, amylase, nuclease Signup and view all the answers

What is absorption?

The process where the animal's cells take up small molecules like amino acids and simple sugars Signup and view all the answers

What is elimination in the digestive context?

Undigested material passes out of the digestive system Signup and view all the answers

What is digestion?

The breakdown of food into molecules small enough for absorption Signup and view all the answers

What is ingestion?

The act of eating or feeding Signup and view all the answers

What is the difference between undernourishment and malnourishment?

Malnourishment is a failure to obtain adequate nutrition, whereas undernourishment is where the body fails to provide adequate sources of chemical energy Signup and view all the answers

What must vegetarians do to obtain essential amino acids?

They must eat a varied diet of plant protein Signup and view all the answers

Where is bile produced, and where is it stored?

Produced in the liver and stored in the gallbladder Signup and view all the answers

What are lacteals?

Vessels at the core of each villus, part of the lymphatic system Signup and view all the answers

What is bile's role in digestion?

Aids in the digestion and absorption of lipids Signup and view all the answers

What are non-enzyme digestive secretions?

Mucus, bile, bicarbonate, hydrochloric acid (HCl) Signup and view all the answers

What involves enzymes in digestion?

Chemical digestion Signup and view all the answers

What are the two types of digestion?

Chemical digestion and mechanical digestion Signup and view all the answers

What is the function of bile?

Aids in digestion and absorption of lipids, destroys old red blood cells Signup and view all the answers

Why does pepsin not function in the small intestine?

Pepsin only functions at very low pH levels, whereas the pH in the small intestine is around 6 or 7 Signup and view all the answers

Does stress cause ulcers?

False Signup and view all the answers

What do monosaccharides and amino acids do after moving into capillaries in the villi?

Travel to the liver via the hepatic portal vein Signup and view all the answers

How can dentition of a mammal's skull indicate its diet?

The skull has adaptations based on its diet, such as sharp teeth for carnivores and flat molars for herbivores Signup and view all the answers

What is a major function of the colon?

Recover water that has entered the alimentary canal Signup and view all the answers

What is the role of the cecum in grazing animals?

Fermenting ingested material, especially in animals that eat large amounts of plant material Signup and view all the answers

How are fats absorbed?

Fats are absorbed by epithelial cells, recombined into triglycerides, and coated with phospholipids Signup and view all the answers

What makes up feces?

Bacteria, undigested material including cellulose fiber, and gases Signup and view all the answers

What is digested by lipase and packed into chylomicrons?

Triglycerides Signup and view all the answers

What is the role of leptin?

Suppresses appetite Signup and view all the answers

What is leptin?

A hormone that suppresses appetite Signup and view all the answers

What is obesity?

The excess accumulation of fat Signup and view all the answers

What are the two functions of the small intestine?

Digest food and absorb nutrients Signup and view all the answers

What is the human appendix and what is its role?

It's a finger-like extension of the human cecum with a minor role in immunity Signup and view all the answers

What are essential amino acids?

Tryptophan, lysine, methionine, and histidine Signup and view all the answers

What do your symbiotic bacteria do for you?

Some produce vitamins that are absorbed into the blood Signup and view all the answers

Which category of vitamin is most likely to result in an overdose?

Fat-soluble; excess is stored in body fat, potentially leading to toxicity Signup and view all the answers

In humans, how is additional energy stored once liver and muscle cells are full?

Excess energy is stored in fat, in adipose cells Signup and view all the answers

What keeps food from entering the lungs when we swallow?

A flap of cartilage covers your vocal cords Signup and view all the answers

What health problems are related to obesity?

Type two diabetes, colon cancer, breast cancer, cardiovascular disease Signup and view all the answers

What was reported in the 2005 Nobel Prize about the cause of ulcers?

Infection by acid-tolerant bacterium Helicobacter pylori causes ulcers Signup and view all the answers

What is the pH of the stomach?

2 Signup and view all the answers

How does the structure of the villi of the small intestine fit its function?

The highly folded surface increases surface area for absorption of nutrients Signup and view all the answers

Why do herbivores have longer alimentary canals than carnivores?

Plants are more difficult to digest than meat, requiring more time and surface area Signup and view all the answers

What is the pH of the small intestine?

6 Signup and view all the answers

What must animals obtain from the food they eat?

Chemical energy for cellular processes, organic building blocks for macromolecules, essential nutrients Signup and view all the answers

What does bicarbonate do in the digestive system?

Neutralizes the acidity of chyme and acts as a buffer Signup and view all the answers

What does mechanical digestion involve?

Chomping of teeth and churning activity of the stomach Signup and view all the answers

Explain the role of insulin and glucagon in glucose homeostasis.

They maintain glucose homeostasis by tightly regulating the synthesis and breakdown of glycogen Signup and view all the answers

Study Notes

Digestive Process and Nutrient Absorption

Absorption is the process where ingested dietary substances cross cell membranes for body use.
Essential nutrients cannot be synthesized by certain animals and must be obtained through diet.
Fats are the most efficient way for animals that migrate long distances to store chemical energy.
A complete digestive system allows for specialized functions in different regions.

Energy Utilization

In fasting states, energy is drawn from stored resources in the order: liver glycogen, muscle glycogen, and then fat.
Undernourishment results from a calorie-deficient diet; malnourishment occurs when one or more essential nutrients are missing.

Digestive Anatomy and Physiology

Earthworms, grasshoppers, and birds possess a crop for food storage.
Peristalsis refers to smooth muscle contractions that push food through the digestive tract.
The stomach secretes gastric juices that initiate protein digestion and contain hydrochloric acid (pH 2), essential for pepsin activation.
The mucosal lining of the stomach is protected from self-digestion by mucus.

Digestive Disorders and Functions

Gastric ulcers can arise from infections by Helicobacter pylori.
The small intestine is the major organ for digestion and absorption, with its first section (duodenum) engaging in significant chemical digestion.

Nutrient Classes and Their Functions

Essential nutrients include essential amino acids, essential fatty acids, vitamins, and minerals that are crucial for cell function.
Chemical digestion utilizes enzymes, while mechanical digestion involves physical processes like chewing and stomach churning.

Nutrient Pathways and Energy Storage

Monosaccharides and amino acids are absorbed through the villi and travel to the liver via the hepatic portal vein for nutrient regulation and detoxification.
Chylomicrons carry triglycerides from the intestine, facilitating fat absorption.

Role of Gut Flora and Vitamins

Symbiotic bacteria produce vitamins in the gut that supplement dietary intake.
Fat-soluble vitamins can lead to toxicity due to storage in body fat, while water-soluble vitamins are excreted through urine.

Digestive Processes Across Species

Herbivores have longer alimentary canals compared to carnivores, providing more time for nutrient absorption due to the complexity of plant material.
The appendix in humans has a minor role in immunity and is a remnant of larger digestive structures in herbivorous ancestors.

Homeostasis and Hormonal Regulation

Insulin and glucagon from the pancreas regulate glucose levels and glycogen synthesis, ensuring glucose homeostasis.
Leptin is a hormone that regulates appetite, helping to maintain body fat levels.

Obesity arises from overnourishment and is associated with various health issues including type 2 diabetes, cardiovascular diseases, and certain cancers.
Dietary adaptations can be inferred from the dentation of mammals, indicating their feeding habits (carnivorous vs herbivorous).

Miscellaneous Facts

Digestive secretions include bile, bicarbonate, and non-enzyme substances, aiding in digestion and maintaining pH levels in the intestine.
The villi structure maximizes surface area for absorption in the small intestine, crucial for nutrient uptake.

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Test your knowledge on Chapter 33 of AP Biology with these flashcards. This chapter covers important concepts such as nutrient absorption, energy storage in animals, and essential nutrients. Perfect for reviewing key terms and definitions.