Transcript Exploring Life and Chemical Context of Life

Exploring Life and Chemical
Context of Life
Chapters 1 and 2
1. Characteristics of
Life
1. Characteristics of Life
CHOGEERS
 Cells: compose all living things
 Homeostasis: regulation using positive and negative
feedback
 Order: levels of organization
 Growth & development: mitosis, meiosis, binary fission
 Energy: use and transfer; autotrophic or heterotrophic
 Evolution: adaptations – natural selection
 Reproduction: offspring
 Stimuli: response to environment
2. Levels of Organization – Emergent Properties
2. Levels of Organization – Emergent Properties
Atoms: PS CHON
Molecules : two or more atoms grouped together
– H2O, Carbohydrates, Lipids, Proteins, Nucleic Acids
Organelles: grouped molecules with specialized functions in
the cell
– Nucleus, plastid, mitochondria etc.
Cells: unicellular (colonial) or multi-cellular
– Prokaryotic: no nucleus or membrane bound organelles
– Eukaryotic: nucleus and membrane bound organelles
– Level of organization that performs all activities required for life
Tissues: group of cells with a similar structure and function
– Xylem, phloem, nervous, muscle, epithelial etc.
2. Levels of Organization – Emergent Properties
Organs: two or more tissue types perform a specific function
– Root, stem, leaf, kidney, brain, heart etc.
Organ Systems: organs grouped to perform a body task
– Water transport, digestion
Organism: individual living thing
– Bacteria, Protists, Ameoba, Fungi - unicellular microorganisms
– Plants, Animals, Fungi - multicellular
Population: a group of similar organisms in an area that can
interbreed and produce fertile offspring
– Species
2. Levels of Organization – Emergent Properties
Community: different populations inhabiting the same area
– Biotic Factors - living
Ecosystem: living organisms interacting with non-living
factors in an environment
– Biotic & abiotic (nonliving) factors: nutrient cycling
– Energy transfer: sunlight  producers (autotrophs)  consumers
(heterotrophs)
Biosphere: sum of all the planet’s ecosystems
– Land, water, atmosphere
– Globe
How does form fit function in a human hand?
Arrangement of fingers
Opposable thumb
Fingernails
Complex system of nerves and muscles
Allows hand to grasp and manipulate
objects with great dexterity.
3. Exploring Life
3. Exploring Life
Scientific Method
Inquiry (question) based
Hypothesis  Theory
over time
– Data
• quantitative
– Observations
Observations
Questions
Hypothesis # 1:
Dead batteries
Hypothesis # 2:
Burnt-out bulb
Prediction:
Replacing batteries
will fix problem
Prediction:
Replacing bulb
will fix problem
• qualitative
One Variable
Control group vs.
experimental groups
Test prediction
Test falsifies hypothesis
Test prediction
Test does not falsify hypothesis
4. Atom
4. Atom
Sub atomic Particles
– protons (+)
– neutrons (0)
– electrons (-)
Nucleus = protons +
neutrons
– Overall positive charge
5. Elements
Element: substance that cannot
be broken down by a chemical
reaction
Mass # = protons + neutrons
Atomic # = proton #
Mass # - Atomic # = Neutron #
6. Major Elements to Life
CHON: 96% of living
matter
P, S, Ca, and K: 4%
Trace elements : Na
and Cl found in small
amounts
7. Isotopes
Atom of an element that
contains a different # of
neutrons
# of protons always
determines the element
– 6 protons is ALWAYS
carbon
8. Radioactive Isotopes
8. Radioactive Isotopes
Unstable isotope will decay
giving off particles until it
becomes stable
– Alpha particle, beta particle,
or gamma ray
C –14 decays to N –14
Dangerous to living tissue
– Radiation
Biological Research Uses
– Dating fossils
– Trace atoms through a
metabolic process
– Diagnose medical disorders
• Inject known amount and monitor
amount excreted
– Used with imaging instruments
to monitor chemical processes
in the body
9. Bonds
9. Bonds
Covalent : electrons are shared
– Strongest bond: contains lots of
energy
– Polar: electrons not shared
equally
• H2 O
– Non-polar: electrons are shared
equally
• O2
9. Bonds
Ionic: electrons are transferred and
atoms are held together by
attraction of charge
–
–
–
–
Weak bond between ions
Cation (+)
Anion (-)
Salts NaCl
9. Bonds
Hydrogen Bond: formed when
(+) hydrogen atom covalently
bonded to an electronegative
atom is attracted to (-) end of
another electronegative atom
– Weak bond
• H–O
• H–N
9. Bonds
Van der Waals Interactions
– occurs between all molecules
• electrons are not stationary
• at times, atoms may have a slight
charge - dipole
– Weakest bond
– Gecko lizard
10. Molecular Shape and Function
10. Molecular Shape and Function
All molecules have a specific
shape and size
Molecular shape determines
function
Biological molecules
recognize and respond to
one another based on shape
and size
– endorphins and morphine
11. Chemical Reactions
Chemical reaction:
making and breaking of
chemical bonds
Cannot create or destroy
matter – only rearrange
– Reactants and products
must be balanced
Photosynthesis and
Cellular Respiration
Questions
The difference between the mass number and the
atomic number is equal to the number of
_____________.
To move to a shell farther from the nucleus, an
electron must ____________ energy; energy is
______________ when an electron moves closer to
the nucleus.
Non-polar or polar covalent bonds?
a.
b.
c.
d.
Write an equation that uses the products of photosynthesis as
reactants and the reactants of photosynthesis as products.
C6H12O6 + 6O2  6CO2 + 6H2O + 36ATP
• Glucose and oxygen react to form carbon
dioxide and water, releasing energy in the form
of ATP.
• We breathe in oxygen, a reactant for this
reaction (cellular respiration) and exhale carbon
dioxide which is a product