How do organisms obtain energy?

Transformation of Energy

Many chemical reactions and processes in your cells are ongoing, even when it seems like you aren't using any energy. Macromolecules are assembled and broken down, substances are transported across cell membranes, and genetic instructions are transmitted. All of these cellular activities require energy (the ability to do work).

Thermodynamics: The study of the flow and transformation of energy in the universe.

There are 2 laws that define thermodynamics.

1st:The Law of Conservation of Energy --> states that energy can be converted from one from to another, but it cannot be created or destroyed.

2nd: Law of Entropy --> states that energy cannot be converted without the loss of usable energy.

Autotrophs & Heterotrophs

All organisms need energy to live. Directly or indirectly, nearly all the energy for life comes from the sun. Some organisms make their own food, while others must obtain it from other organisms. Autotrophs are organisms that make their own food. Some autotrophs, called chemoautotrophs, use inorganic substances such as hydrogen sulfide as a source of energy. Other autotrophs, such as plants, convert light energy from the sun into chemical energy. Autotrophs that convert energy from the sun are called photoautotrophs.

Heterotrophs such as aphids and ladybugs, are organisms that need to ingest food to obtain energy. Plants are the main source of food for aphids, while aphids are the main source of food for ladybugs.

1

Which option describes the first law of thermodynamics?

Energy cannot be converted without the loss of usable energy.

Energy can be converted from one form to another, but it cannot be created or destroyed.

The energy of a system approaches a constant value at the temperature approaches absolute zero.

Energy cannot be converted from one form to another without a net gain of usable energy.

1

What describes the second law of thermodynamics?

Energy can be converted from one form to another, but it cannot be created or destroyed.

The energy of a system approaches a constant value as the temperature approaches absolute zero.

Energy cannot be converted without the loss of usable energy.

Energy cannot be converted from one form to another without a net gain of usable energy.

1

3

Stavka koja se može prevući		Odgovarajuća stavka
2nd Law of Thermodynamics		study of the flow & transformation of energy in the universe
Heterotrophs		Energy can be converted from one form to another, but it cannot be created or destroyed
Autotrophs		Energy cannot be converted without the loss of usable energy
1st Law of Thermodynamics		Organisms that make their own food
Thermodynamics		Organisms that need to ingest food to

Metabolism

All of the chemical reactions in a cell are referred to as the cell's metabolism. A series of chemical reactions in which the product of one reaction is the substrate for the next reaction--> this is called a metabolic pathway.

Metabolic pathways include 2 broad types: catabolic pathways & anabolic pathways. The relationship of anabolic and catabolic pathways results in the continual flow of energy within an organism.

Photosynthesis is the anabolic pathway in which light energy from the sun in converted to chemical energy for use by the cell. Cellular respiration is the catabolic pathway in which organic molecules are broken down to release energy for use by a cell.

2

Which of the following are characteristics of an anabolic pathway? Select all that apply.

Cellular respiration is an example

Energy is used to build larger molecules from smaller molecules

Photosynthesis is an example

Energy is released by breaking down larger molecules into smaller molecules

It is used by autotrophs

It is used by autotrophs & heterotrophs

2

Which of the following are characteristics of a catabolic pathway? Select all that apply.

Cellular respiration is an example

It is used by heterotrophs

Energy is used to build larger molecules from smaller molecules

Photosynthesis is an example

It is used by autotrophs

Energy is released by breaking down larger molecules into smaller molecules

1

Which of the following defines metabolic pathways?

a series of chemical reactions in which the product of one reaction is the substrate for the next reaction

a series of chemical reactions in which mechanical energy converts into chemical energy

a series of chemical reactions in which organic molecules are broken down to release energy

a series of chemical reactions in which light energy converts into chemical energy

4

Categorize each item as an anabolic pathway or a catabolic pathway. NOTE: some descriptions may fit both pathways

Cellular Respiration
chemical reactions in a cell
Photosynthesis
used by autotrophs
build-up of large molecules from smaller molecules
used by autotrophs & heterotrophs
metabolic pathway
breakdown of large molecules into smaller molecules

Catabolic Pathway
Anabolic Pathway

How do organisms obtain energy?

Which option describes the first law of thermodynamics?

What describes the second law of thermodynamics?

Which of the following are characteristics of an anabolic pathway? Select all that apply.

Which of the following are characteristics of a catabolic pathway? Select all that apply.

Which of the following defines metabolic pathways?

Categorize each item as an anabolic pathway or a catabolic pathway. **NOTE: some descriptions may fit both pathways**

Which option describes the first law of thermodynamics?

What describes the second law of thermodynamics?

Which of the following are characteristics of an anabolic pathway? Select all that apply.

Which of the following are characteristics of a catabolic pathway? Select all that apply.

Which of the following defines metabolic pathways?

Categorize each item as an anabolic pathway or a catabolic pathway. **NOTE: some descriptions may fit both pathways**

Categorize each item as an anabolic pathway or a catabolic pathway. NOTE: some descriptions may fit both pathways

Categorize each item as an anabolic pathway or a catabolic pathway. NOTE: some descriptions may fit both pathways