Larry M. Frolich, Ph.D. Biology Department, Yavapai College The Molecules of Life Molecules of lifeMolecules of life Origins of lifeOrigins of life Hierarchy

Larry M. Frolich, Ph.D.Biology Department, Yavapai College

The Molecules of Life

• Molecules of lifeMolecules of life

• Origins of lifeOrigins of life

• Hierarchy of living systemsHierarchy of living systems

• Role of DifusionRole of Difusion

• HomeostasisHomeostasis


Molecules of Life

C-chain Component Main Functions


Carbohydrates• Components are

simple sugars• Used for energy

storage in complex form

• Broken down to simple sugars to fuel cellular metabolism in mitochondria

• So, why are simple sugars bad for us? And why do we love them so much? (p. 29 in text)


Proteins• Components are

amino acids• Very complicated• Amino acid chain

folds up to give complex form

• Complex form allows for catalyzing very specific chemical reactino

• GenBlue


Fats/Lipids• Fundamental to life and

origins—separate cell interior from environment as cell membrane

• Mammals and other vertebrates—long-term energy storage

• Role in diet=big controversy!


DNA/RNA (Nucleic Acids)

• DNA and RNA store and use information• Components are nucleotides or “bases” (A,C,T/U,G)• One DNA molecule can be very long and complex—millions of bases

long• DNA duplicates to pass on information• Transcription to mRNA to be translated into protein’s amino acid chain• What do proteins do?


Evolutionary History and Origins of Life [link to John Kyrk]


Miller-Urey Experiments [link]

Interview with Stanley Miller [link]


The Hierarchy of Living SystemsMolecules

Cells

Tissues

Organs/Structures

Organ Systems

Organisms

Environment


Levels of Organization within Human Body


Levels of Organization• Chemical Level (Organic Chemistry and Biochemistry

• Cellular Level (Intro. Or Cell Biology): organelles, genes, mitosis, meiosis

• Tissue Level (Histology): groups of cells with common function—classes of tissues, epithelia (covering), connective tissues (support, protection)

• Organ Level (Anatomy): how tissues combine to form structures in body—lungs, bones, blood vessels, etc.

• Organ System level (Physiology) How organs and structures work together to accomplish specific functions: e.g., circulatory system, nervous system, skeletal system, etc.

• Organism: Entire body working together (Ecology or physiology in environment)


The importance of Diffusion• Diffusion versus Osmosis (diffusion across a membrane)• Diffusion fast and effective across microscopic distance• Virtually all living processes involve diffusion and/or osmosis• Cell membranes control diffusion and allow for life chemical reactions

to take place• Diffusion lets tissues do job and permits organ systems to function• Examples:

– Oxygen in circulatory system– Food in digestive system– Calcium in muscular function– Nerve impulses

Cell membranes and Diffusion


What does selectively permeable mean?

• The membrane allows some things in while keeping other substances out

cell membrane


How do things move across the plasma membrane?

1. Diffusion

2. Osmosis

3. Facilitated transport

4. Active transport

5. Endocytosis and exocytosis

cell membrane


What are diffusion and osmosis?

• 1. Diffusion is the random movement of molecules from a higher concentration to a lower concentration

• 2. Osmosis is the diffusion of water molecules

cell membrane


How does tonicity change a cell?

• Hypertonic solutions have more solute than the insideof the cell and lead to lysis (bursting)

• Hypotonic solutions have less solute than the inside of the cell and lead to crenation (shriveling)

• Isotonic solutions have equal amounts of solute inside and outside the cell and thus does not affect the cell

cell membrane


What are facilitated diffusion and active transport?

• 3. Facilitated transport is the transport of molecules across the plasma membrane from higher concentration to lower concentration via a protein carrier

• 4. Active transport is the movement of molecules from a lower to higher concentration using ATP as energy; requires a protein carrier

cell membrane


Body Systems and Diffusion

Understand path through body of:• Food/Nutrients (glucose)• Oxygen• Carbon Dioxide• Nitrogen


Homeostasis“…the ability to maintain relatively constant internal conditions even though the outside world changes continuously…”

• Within cells• Within body

Documents

Larry M. Frolich, Ph.D. Biology Department, Yavapai College The Molecules of Life Molecules of lifeMolecules of life Origins of lifeOrigins of life Hierarchy