Ch 2. - Cycles of Matter (AP Content)

Question 1

What is metabolism?

Answer 1

Sets of life-sustaining chemical reactions in organisms.

Question 2

What are the three main purposes of metabolism?

Answer 2

• The conversion of food to energy to run cellular processes;
• The conversion of food/fuel to building blocks for proteins, lipids, nucleic acids, and some carbohydrates;
• The elimination of metabolic wastes.

Question 3

What can the word metabolism also refer to?

Answer 3

To the sum of all chemical reactions that occur in living organisms, including digestion and the transport of substances into and between different cells.

Question 4

What are endotherms?

Answer 4

Because metabolism is inefficient and produces heat, endotherms use metabolic heat to keep a stable body temperature.

Question 5

What are ectotherms?

Answer 5

Metabolism is inefficient and produces heat, but ectotherms DO NOT use metabolic heat to keep a stable body temperature.

Question 6

What is the basal metabolic rate (BMR)?

Answer 6

The “baseline” metabolic rate of an animal, for endotherms.

Question 7

What is the standard metabolic rate (SMR)?

Answer 7

The “baseline” metabolic rate of an animal, for ectotherms.

Question 8

How does size influence basal BMR and SMR?

Answer 8

Among endotherms, smaller animals tend to have higher per-gram basal metabolic rates (a “hotter” metabolism) than larger animals. The same is true among ectotherms, though we can’t compare between the groups.

Question 9

How does activity level influence BMR and SMR?

Answer 9

Metabolic rate varies with activity level. More active animals have a higher metabolic rate than less active animals.

Question 10

What is torpor?

Answer 10

Some animals enter this state of torpor in which their metabolism slows.

Question 11

What are two examples of torpor?

Answer 11

Hibernation in the winter, and estivation in the summer.

Question 12

BMR and SMR in both endotherms and ectotherms are measures of metabolic rate in animals that are:

Answer 12

• At rest
• Calm/unstressed
• Not actively digesting food (fasting)

Question 13

Do endotherms or ectotherms (assuming the same size) have higher metabolic rates?

Answer 13

Endotherms tend to have basal high metabolic rates and high energy needs, thanks to their maintenance of a constant body temperature. Ectotherms of similar size tend to have much lower standard metabolic rates and energy requirements, sometimes 10% or less of those of comparable endotherms.

Ex: Mr. Willard has a BMR of 1980 calories! (roughly 2 large strawberry cheesecake Blizzards from DQ, or 5 McDoubles)
Ex: Mr. Glowinski has a BMR of 1780 calories!

Question 14

How does size affect metabolic rate? Why?

Answer 14

An elephant obviously has a higher total metabolic rate but looking at per-mass metabolic rate a gram of mouse tissue metabolizes 10x faster than a gram of elephant tissue.

Why? Full reasons unknown could have to do with Area-To-Volume Ratio.