1. Introduction to Life and Macromolecules
Unit 1 Notes
Introduction to Life and Macromolecules

2. Characterisitics of Life

3. All living things share some basic properties.
Cellular Organization—Made of Cells
Reproduction
Metabolism (Obtain and Use Energy)
Heredity
Responsiveness
Growth and Development
Adapt to the Environment
Homeostasis

4. All Living Things are Made Up of Cells
Smallest unit capable of all life functions
Unicellular Organisms
Entire organism is made up of one single cell
Bacteria and protists

5. Multicellular Organisms
The organism is made up of many cells
Cells have specialized functions within the organism

6. All Living Things Reproduce
Reproduction is the process of producing new organisms of the same type
Sexual Reproduction
Two different parent organisms contribute genetic information
Involves the combination of male and female sex cells
Asexual Reproduction
A single parent organism reproducing by itself

7. All Living Things Obtain and Use Energy
Living organisms need energy to grow, develop, repair damage, and reproduce
Metabolism is the sum of all chemical reactions in an organism

8. All Organisms Pass Along Hereditary Traits
Genes carry hereditary information
Genes are composed of DNA
Heredity is the reason children resemble their parents
Mutations change DNA code and can be passed from generation to generation

9. All Living Things Respond to Their Environment
An example is a plant’s leaves and stems growing toward light
Organisms react to stimuli:
Light
Temperature
Odor
Sound
Gravity
Heat
Water
Pressure

10. All Living Things Grow and Develop
Growth means to get bigger in size
Development involves a change in the physical form or physiological make-up of an organism

11. All Living Things Adapt to Their Environment
Adaptation-A process that enables organisms to become better suited to their environment
Desert plants have succulent waxy leaves and stems to store water and reduce water loss

12. All Organisms Maintain Homeostasis
A stable state of conditions in the body that are necessary for life
Body temperature
Blood volume
pH balance
Water balance

13. Levels of Organization

14. CELLS
The cell is the basic unit of structure and function of a living thing.
Cells are specialized by size and shape for the job they do.
Unicellular organisms have only one cell.
The amoeba above is made of only one cell and it must perform all the jobs of the organism.

15. T I S S U E S
Tissues are made of the same type of cells grouped together to do a specific job.
Examples: These ciliated lung cells work together to push mucous and debris out of the respiratory system.
The blue Man-o-war has tissues but no organs.

16. Organs
Organs are made up of different tissues that work together to do a job.
Example: a heart is an organ made of tissues such as connective, muscle, adipose, etc.
A leaf is a plant organ.

17. Organ Systems
An organ system is a group of organs working together for a specific function.

18. Organ Systems (Body Systems)

19. Organ Systems (Body Systems)

20. Organisms
An organism is a living thing. Sum of all cells, tissues, organs and organ systems makes an organism.

21. Homeostasis: maintaining a stable internal environment, despite internal and external change

22. Stimulus: a change to the level
Control center: gets the message from the receptor that the level is off, so the control center ‘designs a plan’ to fix the level
Ex: Brain (hint-the control center is usually the brain unless it is a reflex)
Receptor: usually part of your nervous system, senses that the level is ‘off’
Ex: your nervous system detects that your body temperature has dropped
Effector: receives a message from the brain to do something to change the level.
Ex: your muscles get a message from the brain to contract, which causes shivering and goosebumps because muscle contractions release heat
Stimulus: a change to the level
Ex: if you go outside in the cold your body temp drops
Factors stay within a ‘normal’ range due to homeostasis
Ex: Body temperature

23. This process is called a feedback loop
Most feedback loops are ‘negative feedback loops’, which means that the effector produces the opposite effect of the stimulus (ex: stimulus=lower body temp, effector=shivering to warm body)
Positive feedback loops cause an increase in the stimulus (ex: stimulus=a nursing baby, effector=hormones to increase milk production)

24. Cell Transport
Cells are constantly monitoring levels inside and outside of the cell and they let molecules move through the cell membrane in response to differences to try to ‘balance’ the solutions.

25. Solvent + Solute = Solution
Solutions
A solution is a solute dissolved in a solvent. In biology, the solvent is usually water and the solute is usually sugars, salts, etc.
Solvent + Solute = Solution
The more solute, the stronger the solution.
The less solute, the weaker the solution.

26. Movement of Molecules
The cell membrane does not allow most molecules to pass through, so to try to reach a balance, usually WATER (the solvent) is passed through the membrane.
Ask yourself: “Which solution has the most solute?”
Water moves toward that solution. If water moves into a cell, it will swell and if water moves out of a cell, it will shrink.

27. Passive Transport
Examples: diffusion and osmosis (which is the diffusion of water)
Molecules naturally move through the cell membrane to try to ‘balance’ with the external environment
Happens without any energy from the cell

28. Active Transport Requires energy from the cell
Sometimes goes against the cell’s natural effort to create a balance/homeostasis (makes the strong solution stronger)

29. Organic Macromolecules
There are four types of large molecules that are needed by all living things.
They all contain Carbon, Hydrogen, and Oxygen.
They are made of smaller molecules called monomers.

30. Rewind…. What are molecules? Why are they important?
Atoms bonded together (What are atoms?-those tiny particles made of protons, neutrons, and electrons—different types of atoms are called elements)
Why are they important?
They are used in all chemical reactions—things like your genetic code and the energy your body uses are stored in molecules. Your cells are built of lots of molecules working together.

31. Back to the organic macromolecules…
CARBOHYDRATES
Monomer: simple sugars (called monosaccharides—ex: glucose)
Function: Main energy source for cells. Also, structural molecule for plant cell wall.
Source in diet: plant products

32. LIPIDS Monomer: fatty acids Function: stored energy and cell membranes Source in diet: fats, oils

33. NUCLEIC ACIDS Monomer: nucleotides Function: genetic material (DNA/RNA) Source in diet: your body doesn’t get these molecules from eating—your cells make these molecules

34. PROTEINS Monomer: amino acids Function: structural molecule for animals, regulates cell and body processes, fight diseases Source in diet: meats, nuts/seeds, eggs, dairy