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Unit 1 Survival 101 Chapters 1-4

WHY WE EAT AND BREATHE

Objective I:

How is a human organized into organ systems, organs, tissues, cells, molecules, atoms and ions?

At the end of this Objective, you should also know:

A. How are the levels of organization related to each other?

B. What are examples of each level of organization?

C. What are four examples of organ systems in the body? What are they made of, and what do they do?

This figure attempts to show how each level of organization is part of the next largest level of organization.

Textbook: Anatomy review AND 7th edition: pages 2-4 or 6th edition: pages 2-5 or 5th edition: pages 2-3 or 4th edition: pages 2-3

Study Tip: (These study tips are included to give you ideas of how to think about the material at higher levels.) As you read these notes, prepare a visual representation of the levels of organization. For example, you might place each level into a box within a flow chart/concept map then make a connection to one side or below with examples of each level of organization.

Clinical Application:

Cystic fibrosis is a genetic disorder resulting from a mutation in the gene for a protein transporter. Protein transporters are molecules in the cell membrane that allow substances to cross cell membranes (see Unit 2). The protein transporter affected in cystic fibrosis allows chloride ions to cross cell membranes in epithelial tissues. The gene mutation changes the structure of the protein transporter which alters the function of this protein. This causes changes in cell function which changes tissue, organ, and organ system function. For example, altered chloride ion transport from changes in the protein transporter molecule in cells within epithelial tissue lining the trachea organ results in thick mucus, causing respiratory organ system problems.

Study Questions : (This question has you thinking about previous knowledge before discussing below. You do not need to turn these in, but they will help you answer exam questions. Do not spend time looking for the “right answer;” rather, use these to practice the type of thinking that will be required on the exams.)

(1) What do you already know about ecosystems and populations?

What is an ecosystem?

Biology is the study of life. In this field, we study organisms and their parts and how organisms interact with one another. The study of these interactions between organisms is the study of ecosystems and is the focus of fields such as ecology and environmental science. Ecosystems are the largest level of biological organization. An example from daily life is the impact of human actions such as fuel consumption on other species (such as polar bears and penguins) from the changing of environments through pollution and climate change.

How are populations related to ecosystems?

These fields as well as plant biology, animal biology, microbiology and others study populations, such as the study of genetically-modified crops, polar bears, or emerging pathogens. Populations are the next smallest level of biological organizations, and populations come together to make up ecosystems.

Study Questions : (This question attempts to apply/connect the material to everyday life.)

(2) What is another example of ecosystems or interactions between populations that has been discussed recently in the news?

How are organisms related to populations?

In human biology classes such as anatomy and physiology, we are mostly concerned with the next smallest level of organization, the organism. In these classes, we study the human organism, but we also sometimes study other organisms relevant to human biology such as the bacteria that live on the skin or in the digestive tract.

Study Questions : (These questions have you thinking about previous knowledge before discussing below.)

(3) What are organ systems that you learned about in anatomy?

(4) What are some examples of organs that you learned about previously?

(5) What are the four tissue types you learned about in anatomy?

How are organ systems related to organisms?

The human body is made up of organ systems which you learned about in anatomy. Examples include the digestive system, respiratory system, circulatory system, and nervous system.

How are organs related to organ systems?

An organ system is made up of organs. Examples are the heart and lungs.

How are tissues related to organs?

An organ is a collection of tissues. The four types of tissue are muscle, nervous, epithelial, and connective (e.g., bone, blood).

Study Questions : (Questions 6-8 attempt to get you to think about this material by making connections; questions 9-10 attempt to review material before discussing below)

(6) What are examples of the organs that are part of the digestive system?

(7) How are organs related to tissues?

(8) Think about your favorite organ. What is/are the function(s) of that organ? Which structures help that organ perform its function(s)? Which tissues are part of that organ? What are the functions of these tissues within that organ?

(9) How many chromosomes are in each human cell? How many chromosomes are in sperm and eggs? What cell division process produces sperm and eggs? Which cell division process produces all other human cells?

(10) What are examples of cells you remember from anatomy class? What are the functions of these cells? In which tissues, organs, and organ systems are they found?

How are cells related to tissues?

Tissues are made up of cells, the smallest functional unit of life. Some organisms such as bacteria are unicellular (one cell). Humans are multicellular and are made of trillions of specialized cells working together.

How does differentiation of stem cells result in different cell functions?

Remember that each human cell contains 46 chromosomes. Meiosis produces sperm and eggs with 23 chromosomes each. During fertilization, a sperm cell from a male fuses with an egg cell from a female to form an embryonic stem cell (with 46 chromosomes). Through mitosis , embryonic stem cells divide and specialize in a process called differentiation. For example, beta cells of the pancreas are specialized to make insulin and muscle cells express myosin , but other cells in the body do not make these proteins (see Unit 1, Objective IV).

Embryonic stem cells can develop into any cell in the body. This makes them attractive to research scientists. However, they are controversial since they are isolated from embryos.

Many tissues also contain stem cells. These stem cells can only differentiate into a sub-set of cell types. For example, the basal layer of the skin contains skin stem cells which divide and differentiate to continuously produce the layers of skin to protect us. The bone marrow contains stem cells to replace leukocytes (white blood cells, leuko means white), erythrocytes , and platelets .

Most cells become terminally differentiated, meaning they cannot develop into another type of cell. Neurons (nerve cells), muscle fibers (muscle cells), erythrocytes (red blood cells, erythro means red, cytes means cells), or keratinocytes (skin cells) are examples of terminally-differentiated cells.

Study Questions : (This question attempts to apply/connect the material to real-world issues.)

(11) What else do you know about stem cells and their role in political debates? What are your views on stem cell research?

How are molecules related to cells?

Cells are made up of molecules. In physiology, we will discuss small molecules such as water, glucose , and amino acids (the building blocks for proteins ). We will also examine the role of large biological macromolecules such as nucleic acids ( DNA and RNA ), proteins, carbohydrates such as glycogen (a storage molecule for glucose), and lipids such as cell membrane phospholipids and cholesterol (see Unit 1, Objective II).

How are atoms related to molecules?

Atoms are bonded together to form molecules. Atoms are the smallest level of biological organization. For example, there are covalent bonds between two atoms of hydrogen and one atom of oxygen to form water, the most common molecule in the human body.

How ions are related to atoms and molecules?

In physiology, we will often discuss charged atoms, or ions (charged particles), such as sodium, calcium, potassium, chloride, and hydrogen. A sodium ion and a chloride ion are joined together with an ionic bond to form another common molecule, table salt. In this example, sodium is a cation, a positively-charged ion since it has lost a negatively-charged electron [to help you remember: the word cation has a + sign (“t”) in the middle of it]. Chloride is an anion, a negatively-charged ion since it has gained an electron. When table salt is placed in a solvent such as water, it dissolves/dissociates into sodium and chloride ions. In Units 2, 3, and 5, we will begin to see how these two ions are important in many processes in physiology.

Study Questions : (This question attempts to connect the material to previous knowledge and has you applying this material by thinking about connections between molecules and atoms)

(12) What are examples of molecules you remember from previous classes? What are the functions of these molecules? Which atoms are a part of these molecules?

How are organelles related to cells?

Molecules within cells also come together into membrane-bound organelles (small organs). Examples of organelles include the nucleus and mitochondria . There are also other structures within cells which we will discuss in this class such as ribosomes and the cytoskeleton .

Study Questions : (These questions attempt to connect the material to previous knowledge)

(13) What are examples of organelles you remember from previous classes? What are the functions of these organelles?

(14) What is contained within the nucleus? Which cellular processes occur within this organelle?

(15) Which cellular reactions occur in the mitochondria? Why is it called the “power house” of the cell?

The Big Picture:

· Biology organizes life into many different levels from smallest to largest with each level having increasing complexity and being made up of the lower levels.

· Atoms (or ions) are bonded together to form molecules which interact to form subcellular structures (e.g., organelles) within cells. A collection of cells performing a similar function makes up a tissue, and tissues work together in organs within organ systems. Organ systems work together within a human organism which belongs to a population within an ecosystem.

Integration and Application:

(1) What are the levels of biological organization and examples for each level?

(2) Think about the digestive, respiratory, cardiovascular, and nervous systems you learned about in anatomy. Which organs are a part of these organ systems?

(a) Pick one organ from one of these systems. Which tissues make up this organ?

(b) Which cells make up these organ systems? What are their functions within these systems?

(c) Pick one cell from these systems. Which proteins are expressed in this cell?

(3) Re-read the Clinical Application at the start of this Objective. How did a change in a molecule alter the function of higher levels of organization? From this Clinical Application, provide an example for each level of organization (for example: molecule = protein transporter)

Study Activities:

(1) Write each level of organization on a separate note card. On the back of each note card, list:

(a) examples

(b) the level that is larger than it

(c) the level that is smaller than it

(2) Mix up the note cards and arrange the levels of organization from smallest to largest and then largest to smallest.

(3) Use the note cards to test your ability to think of examples, then look at the side with the examples, and see if you can determine the level of organization.

(4) Write some exam questions. For example, replace the bold words in questions such as:

Which levels of organization are larger than a tissue?

Which is larger, a cell or a molecule?

Which is smaller, glucose or a protein?

Name an example of a tissue found in the circulatory system.

Hemoglobin is an example of a(n) ______________.