Unit 4

Question 1

What are primary producers?

Answer 1

autotrophs, normally photosynthetic

Question 2

What are primary consumers?

Answer 2

herbivores (eat plants and other primary producers) (heterotrophs)

Question 3

What are secondary consumers?

Answer 3

carnivores that eat herbivores (heterotrophs)

Question 4

What are tertiary consumers?

Answer 4

carnivores that eat other carnivores (heterotrophs)

Question 5

What are decomposers?

Answer 5

consumers that get their energy from detritus (nonliving organic material) (heterotrophs)

Question 6

Define and apply the first law of thermodynamics.

Answer 6

“Energy cannot be created or destroyed but can be transferred or transformed”

Plants transform solar energy to usable ATP via photosynthesis. The energy that gets stored is transferred to herbivores and continues up the food pyramid. Some energy is also transformed to thermal energy and released as heat, which is unavailable for work. This is why only about 10% of energy from each trophic level is transferred to the next.

Question 7

Define and apply the second law of thermodynamics

Answer 7

“Every energy transfer or transformation increases the entropy of the universe”

The heat loss of animals adds to the universe’s entropy.

Question 8

Apply the concept of biomagnification in food webs.

Answer 8

Biomagnification is the concentration of toxins in an organism as a result of its ingesting other plants or animals in which the toxins are more widely disbursed. Animals further up the food web (secondary and tertiary consumers) are more likely to have a higher concentration of toxins since it is consuming the animals below it, who have also possibly ingested these toxins from other organisms it has consumed.

Question 9

How are animals organized from the smallest to the largest unit?

Answer 9

organelle, cell, tissue, organ, organ system, organism

Question 10

Describe the general characteristics and functions of epithelial tissues.

Answer 10

epithelia: cover the outside of the body and line organs and cavities within the body
- closely packed to function as barrier against mechanical injury, pathogens, and fluid loss
- all are polarized so one side faces the cavity (apical) that is outside the organ and the basal on the opposite side

Question 11

Describe the composition and functions of connective tissues.

Answer 11

connective tissue: sparse population of cells scattered through an extracellular matrix and holds many tissues a organs together and in place.
-the matric has fibers in a jelly-like liquid and has fibroblasts that secrete fiber proteins and macrophages

Question 12

What are the types of tissue fibers?

Answer 12

collagenous (provide strength/flexibility), reticular (join connective tissue to adjacent ones), elastic (make tissues elastic)

Question 13

What is loose connective tissue?

Answer 13

binds epithelia to underlying tissues and holds organs in place

Question 14

What is fibrous connective tissue?

Answer 14

dense with collagenous fibers in tendons and ligaments, bone, blood, and cartilage

Question 15

What is adipose connective tissue?

Answer 15

specialized connective tissue that stores fat in adipose cells (insulates the body and stores fuel as fat molecules)

Question 16

Compare and contrast smooth, skeletal, and cardiac muscle.

Answer 16

All are types of muscle tissues that are responsible for all body movement. Skeletal muscle is attached to bones by tendons and for voluntary movement. They consist of long cells (muscle fibers) in bundles. Smooth muscle is found in walls of the digestive tract, urinary bladder, arteries, and other internal organs. They are responsible for involuntary movement, and the cells are spindle shaped. Cardiac cells form the contractile wall of the heart and have branched fibers. Both the skeletal and cardiac muscle cells are striated while the smooth muscle cells are not.

Question 17

Explain how neurons and neuralgia interact to form a nerve.

Answer 17

Neurons generate and transmit nerve impulses. Neuralgia (glial cells) nourish insulate, and replenish neurons. Nervous tissue functions in the receipt, processing, and transmission of info.

Question 18

Explain the relationship between body weight, energy expenditure, and calorie intake.

Answer 18

As body size decreases, the energy cost per gram of tissue increases. This is related to surface area to volume ratio. As body size decreases, the SA:V ratio increases, which means the animal is more likely to lose heat to its environment. Therefore, it has to expend energy to maintain homeostasis. However, as body size increases more energy is needed for the exchange, support, and locomotion of more tissue, so the calorie intake would increase. As a whole, the metabolic rate is proportional to the body mass.

Question 19

Identify different sources of nutrients for humans.

Answer 19

Protein- meat, eggs, fish, dairy, beans, and nuts
Carbs- (sugars, fibers, and starches) rice, bread, pasta, etc
Fats- dairy products; meats, poultry, seafood, and eggs; and seeds, nuts, avocados, and coconuts
Vitamins and Minerals- milk, yogurt, cheese, whole and enriched grains, meat, fruits, and vegetables
Water

Question 20

Explain the importance of homeostasis.

Answer 20

Homeostasis is the maintenance of internal balance. Conditions in the body must be constantly controlled because cells depend on the body’s environment to live and function. The maintenance of the conditions by homeostasis is very important because in the wrong body conditions certain processes (osmosis) and proteins (enzymes) will not function properly.

Question 21

Define and provide an example of a negative feedback loop.

Answer 21

controls the mechanism that dampens the stimulus

Ex. sweating, pancreas secreting glucagon and insulin to maintain glucose levels

Question 22

Define and provide an example of a positive feedback loop.

Answer 22

controls the mechanism that amplifies the stimulus
Ex. when giving birth, the baby’s head pressure increases contractions, platelets increase when their is a cut to prevent blood loss

Question 23

Describe how glucose levels are maintained in humans by a hierarchal system of organs, tissues, cells, and hormones.

Answer 23

When there is a rise in glucose levels, the beta cells of the pancreas are stimulated to release the hormone insulin into the blood. Insulin attaches to receptors on cells which stimulates body cells to take up more glucose and the liver to take up glucose and store it as glycogen. As the blood glucose level declines to the set point, the stimulus for releasing insulin diminishes. When there is a drop in blood glucose levels, alpha cells of the pancreas are stimulated to release the hormone glucagon into the blood. Liver cells have glucagon receptors that prompts them to break down glycogen and release glucose into the blood. The blood glucose level rises to a set point, and the stimulus for glucagon release diminishes.

Question 24

Predict how glucose homeostasis can be disrupted in humans, and identify how it can be restored.

Answer 24

If after eating a carbohydrate-rich meal, it is likely that blood glucose levels will rise and insulin will be released. If a person skips a meal, then blood glucose levels will diminish, so glucagon will be released.

Question 25

Which organs are involved in the digestive system?

Answer 25

mouth, esophagus, stomach, pancreas, liver, gallbladder, small intestine, hepatic portal vein, large intestine, rectum, and anus

Question 26

What is the function of the mouth?

Answer 26

The teeth break down food via mechanical digestion to increase the food particles SA. The salivary glands also release mucous to lubricate food for swallowing and has amylase to start breaking down starch.

Question 27

What is the function of the esophagus?

Answer 27

It connects to the stomach. Food is pushed down along by smooth muscle contraction and the sphincter regulates passage of food to the stomach.

Question 28

What is the function of the stomach?

Answer 28

The stomach stores food and fluid and processes food into a liquid suspension. The stomach also secretes gastric juice and churns food to get chime. HCl disrupts the extracellular matric in plant/meat and exposes protein’s peptide bonds, which protease attacks. HCl also activates inactive pepsinogen to pepsin.

Question 29

What is the function of the small intestine?

Answer 29

Most enzymatic hydrolysis occurs here. The chyme mixes with digestive juices from the pancreas, liver, gallbladder, and small intestine. The arrival of chyme triggers secretin, causing the pancreas to secrete bicarbonate to neutralize the chyme’s acidity. Bile secreted by the liver and concentrated in the gallbladder breaks down fats. Villi aid in nutrient absorption.

Question 30

What is the hepatic portal vein for?

Answer 30

leads the nutrient rich blood to the liver and to the heart. This allows the liver to regulate nutrient distribution and remove toxins.

Question 31

What is the large intestine for?

Answer 31

It completes the recovery of water ad ends in the rectum where feces are stored before elimination.

Question 32

What is the function of the pancreas?

Answer 32

secreates enzymes for further breakdown in the small intestine, including bicarbonate ions, lipase, lactase, trypsin, amylase, chymotrypsin, etc.

Question 33

Describe the human microbiome and its role in human health.

Answer 33

The relationship between the microbiome of bacteria and the human digestive system is an example of mutualism. Intestinal bacteria produce Vitamin K, biotin, and folic acid and regulate intestinal epithelium development. The immune system in return gives a stable nutrient supply an host environment.

Question 34

Predict the consequences of interruption in digestive process.

Answer 34

This would result in the body not receiving the nutrients and energy it needs to function, causing it to collapse and die. Pancreatic cancer is one example of such a disruption since the pancreas plays a vital role in supplying the digestive system with enzymes for food breakdown and regulating glucose levels.