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Unit 2
Living vs. Non-Living,
Cells, and Life Functions
What does a
Biologist study???
Biologists study living
and once-living things.
Is it Alive??!!
What does it
mean to be
ALIVE???
Chick embryo
• Ebola Virus
What is it?! Is it Alive???!!!
What is it?!
Seawater!!!
Magnified 15 times!!!
• Hair and feathers
Part 1
• There is no single definition of life. However,
there is a list of characteristics by which we
determine if something is living or not.
Here are some characteristics of living things…
What Makes Something Living?
– 1. Nutrition: Ability to obtain and process
food.
• Autotrophic – Plants use energy from
sunlight to make glucose (sugar)
• Heterotrophic – Organisms need to ingest
(take-in food).
What Makes Something Living?
• 2. Transport:
–Movement of materials into, out of, and
throughout an organism
What Makes Something Living?
• 3. Carry out metabolic reactions:
–Metabolism = All the chemical reactions
that occur in living things to maintain life.
What Makes Something Living?
• 4. Respiration:
–Creating energy (ATP) from glucose
What Makes Something Living?
• 5. Excretion:
–Removal of cellular wastes (wastes of
metabolism) from an organism.
What Makes Something Living?
• 6. Regulation:
–Controlling and coordinating life
functions and body systems
What Makes Something Living?
• 7. They are able to grow
–Increase in cell size and number of
cells.
–Results from the assimilation of
materials and synthesis of new
materials.
–Materials come from nutrients (you are
what you eat!)
What Makes Something Living?
• 8. They Are able to reproduce:
– 1. Asexual Reproduction: 1 parent cell divides and
results in 2 new identical cells.
– 2. Sexual Reproduction: 2 cells combine to create
a new offspring.
– Note: Reproduction is NOT necessary for survival
of an individual organism but is for survival of a
species.
What makes something living?
9. Respond to changes in the environment
(stimuli):
–Examples:
• Shivering when cold
• Pulling hand away from something hot
• Pupils changing size based on
amount of light
What Makes Something Living?
• 10. Have a common genetic code:
– The code is found in the DNA of each organism,
which is found in the form of chromosomes in the
nucleus.
– The DNA is a code for proteins!!!
What makes something living?
• 11. Groups of organisms change over time
(evolve)
– Based on favorable adaptations (traits that aid in
an organism’s ability to survive and reproduce in
current environment).
– Example:
– Camouflage of frogs to blend in with
environment and avoid predators.
What Makes Something Living?
• 12. Maintain homeostasis
– Homeostasis – Ability of an organism to maintain
internal stability
– Example: Sweating during exercise to reduce body
temperature.
Homeostasis
Pushing Human Limits:
Disrupting Homeostasis!!!
Homeostasis
Homeostasis
Homeostasis
What makes something living?
• 13. Made up of 1 or more cells
a. cell = basic unit of life
Part 2:
Cells
Cells
• Unicellular – Made of one cell
– Examples: bacteria, ameba, paramecium
• Multicellular – made of several or many cells
– Examples: Most plants and animals!
• Cells can be organized into more complex
levels:
Organelles
Cells
Tissues
Organs
Organ Systems
Whole Organism
Cells
The Cell Theory:
1. All living things are made up of one or more
cells.
2. All cells carry on life functions.
3. All cells come from other cells.
Cells
Exceptions / Questions Regarding the Cell
Theory:
• Since all cells came from pre-existing cells,
what produced the 1st cell?
• Viruses are not considered to be a cell, yet
they contain genetic material that takes
over the activities of the host cell.
Cells
Cell Parts
• Define:
Organelle – Cell structures that perform certain
functions.
Cells
1. Cell Membrane
•Made of proteins, lipids, and
carbohydrates.
•Controls movement of materials
into and out of cell.
•Has receptors- allow cells to
communicate with one another
through chemicals
Receptors
*Molecules have a certain shape that fit with the
receptors to cause a response.
Cell Membrane Videos
• http://www.brightstorm.com/science/biology/parts-of-acell/cell-membrane-cell-wall/
Cells
2. Nucleus
•Control center for cell.
•Contains chromosomes
– hereditary material
Cells
3. Ribosomes
•Where proteins are
made (synthesized).
Ribosomes: Continued
• Ribosomes get the code
to make proteins from
DNA in nucleus.
• Each gene on the
chromosomes codes to
make one protein
Cells
4. Vacuole
•Storage sites for materials
and wastes.
•Plant cells have large
vacuoles for storing water
Cells
5. Mitochondria
•Where energy (ATP) is
produced from glucose
(called cellular respiration)
Cells
6. Cytoplasm
•Jelly-like material
within cell membrane.
•Molecules can move
throughout
Cells
7. Chloroplast
•Only in plant cells.
•Site of photosynthesis –
where glucose (sugar) is
made from water, carbon
dioxide and sunlight
Cells
8. Cell Wall
•Surrounds plant cells
•Gives cells shape and
protection (rigid).
9. Cilia and Flagella
• Used for
movement
Websites
• http://www.cellsalive.com/cells/3dcell.htm
Question:
• How are plant and animal cells similar and
different???
Plant
Animal
How are Plant and Animal Cells
Similar
• In middle:
– Many similar organelles
– Living
– On Left Under Plant:
•
•
•
•
Cell Wall
Chloroplasts
Boxy shape
Larger vacuole
– On right Under Animal:
• Have smaller vacuoles
• Rounder shape
Cells
• All of these organelles need to work together to
maintain homeostasis.
– Select 2 organelles and explain how they work
together to maintain homeostasis.
Maintaining Homeostasis
• Nucleus and Ribosome:
The nucleus instructs the ribosome on which
proteins to make.
• Chloroplast and Vacuole:
The vacuole stores the water that is needed
to perform photosynthesis.
Maintaining Homeostasis
• Mitochondria and Chloroplast:
– The chloroplast makes glucose that the
mitochondria needs to make energy.