Biology 1406 – Exam 1 Notes : The Scientific Study of Life
What are the three basic human instincts and drives. How does the third instinct relate to science?
Human brain recognizes patterns: What is the difference between a type I error and a type II error?
Which are we more likely to make?
What is science? A way of knowing based on observation and measurement
How does this compare with other ways of knowing? (theology and philosophy)
- only physical measurement evidence is accepted
:“factual”, natural causes, can be experimentally tested
- intuition (“common sense”) can be misleading.
1.8 - .9
some examples:
- statistical analysis to understand variation in nature
- supernatural explanation (beyond natural laws and therefore not measurable) not accepted;
cannot be experimentally tested
- no absolute truths - latest conclusions - allows
self-correction and more accurate conclusion
- no value judgments (morals, ethics)
Scientific Method
Recognize problem or question
recognize new problem
Inductive
Propose an answer = hypothesis
must be testable falsifiable
modify hypothesis
Design and perform an
experiment to test hypothesis
modify experiment
Deductive
Conclusion
- Hypothesis - proposed answer ; “educated guess”
- Theory - very well supported hypothesis
- Experiment must be repeatable and include controls to reduce bias
Brief history of science (ybp = years before the present)
100,000 ybp - fully modern humans
50,000 ybp - symbolic thought and language (the “great leap forward”)
11,000 ybp - agriculture
2,500 ybp - Greeks introduce naturalist thought- beginnings of science
2,000 ybp - Roman Empire
400 AD - “Dark Ages” - no science
Rebirth of Science
1543 AD - Nicolaus Copernicus, Andreas Vesalius
1632 AD - Galileo Galilei
Biology vs. “vital force”
1700’s AD - Industrial Revolution
- Sir Francis Bacon (hypothesis and experimentation)
1859 AD - Charles Darwin (“Origin of Species”,
natural selection is the force of change)
Adaptation is the central organizing principle
in biology – the “unifying concept”
Biology - scientific study of life - what is life?
- living organisms made of common elements – no unique elements
2.1
- working definition of life based on observations of what living organisms do
1.1
1. Order - structural complexity (levels of organization)
1.2
2. Metabolism - energy utilization to produce and
control chemical processes
3. Regulation of internal environment
4. Grow and develop through stages
5. Respond to environmental stimuli
6. Reproduce - production of offspring with similar
genetic information (DNA)
7. Ability to change - evolve and adapt
Which of these traits give the most basic definition of life?
1.7
Levels of organization in living organisms
1.1
Biosphere
Ecosystem
Community
What is reductionism and how is it important in studying life?
Population
Organism (individual)*
Organ system*
What are emergent properties and why are they important to the study
Organ*
of life?
1.2
Tissue*
Cell
Organelle
What very important property emerges at the cell level?
Molecule
Atom
* in multicellular organisms
•
•
•
Water
2.6, 2.8, 2.10 - .16
-What makes water essential to life?
- dipolar molecule
- properties of water (describe each of the following and give an example of why it is
important to life)
- good solvent
- evaporative coolant
- cohesive and adhesive
- high specific heat
- high boiling point
- good thermal conductor
- lower density as solid
- graph of heat energy vs. temperature / phase change
Biological Chemistry
- about 25 of 92 elements found in living organisms
- carbon, hydrogen, oxygen, nitrogen ≈ 96%
- carbon forms most organic molecules - why?
List four characteristics of carbon
- very large variety of organic molecules
- many polymers from few monomers
2.1
3.1
3.3
- four major groups of organic molecules:
3.4 - .16
(know these four groups, the monomer for each and the primary function(s) of each)
1. Carbohydrates – sugars, starches, cellulose
- monomers called monosaccharide
- fuel, energy storage, structural (cellulose)
2. Lipids - fats, oils, phospholipids
- monomers called fatty acids
- energy storage, insulation, metabolic activity, cell membranes
3. Proteins
- monomers called amino acids
- structural, regulating metabolic activity by controlling chemical reactions
(enzymes)
4. Nucleic acids - deoxyribonucleic acid (DNA) and ribonucleic acid (RNA)
- monomers called nucleotides
- storing and expressing genetic information
Cells
Ch 4 -5
- the cell theory:
- cells are the basic unit of life (how is this related to emergent properties?)
- all living organisms are made of cells
- all cells come from living cells [under present conditions on Earth]
- cells are very small - Why?
(v = 4/3 Π r3
compared to
A = 4 Π r2 )
4.2
Prokaryotic cells ( 1-10 μm diameter) - Bacteria and Archaea
4.3
Eukaryotic cells (10-100 μm diameter) - protists, fungi, plants, animals
[1meter = 1000 millimeter; 1mm = 1000 micrometer (μm) ]
Eukaryotic cells are similar with same basic structure
- specialize by exaggeration
- structure is related to function
- organisms increase in size by being multicellular
Basic Eukaryotic Cell Structure
Plasma membrane:
5.1 - .2
- phospholipid bilayer with isolated proteins (fluid mosaic design)
- Know five functions of plasma proteins.
- selectively permeability (semipermeable)
- all membranes in cell have similar structure
Cytoplasm:
4.3
Endomembrane system: (internal membranes)
- nuclear membrane (nucleus)
4.4 - .12
- endoplasmic reticulum (rough E.R., smooth E.R.)
- Golgi apparatus
- lysosomes
- vacuoles, vesicles, peroxisomes
Ribosomes:
4.6
- formed in nucleolus inside nucleus
- move to cytoplasm; either free or bound to membrane
- organize protein synthesis
Mitochondria (“power plant of the cell”):
4.13, 4.15
- site of cellular respiration and ATP production (Adenosine Triphosphate)
- composed of 2 membranes (smooth outer and a folded inner membrane)
- origin of mitochondria – the endosymbiotic hypothesis
- contains DNA, RNA and ribosomes
- resemble primitive bacteria structurally and chemically
- unique metabolism
Cytoskeleton (“cell skeleton”)
4.16 - .18
- protein microfilaments, intermediate filaments and microtubules
- dynamic framework – causes movement
- extend into cilia and flagella
Cells joined by junctions:
4.19 - .21
- plasmodesmata (plants)
- tight junctions, anchoring junctions, gap junctions (animals)
- extracellular matrix
Structures in plant cells only:
Cell wall
- cellulose, rigid “box” around cell
- support and protection for cell
- reduces mobility
chloroplasts
- photosynthesis
- contain DNA, RNA, ribosomes; self-replicating
- endosymbiotic hypothesis
4.21
4.14
Why do these structures affect the biology of plants?
Transport across membranes
Passive transport:
5.3 - .7
- no cell energy required, powered by concentration gradient
- examples:
- diffusion
- osmosis (selectively permeable membrane; hypotonic, isotonic,
hypertonic)
- facilitated diffusion
Active transport:
5.8 - .9
- cell energy (ATP) required
- examples:
- protein pumps (ion pumps)
- endocytosis (phagocytosis, pinocytosis, receptor-mediated
endocytosis
- exocytosis
Biology 1406
Review Exam 1
What is the “third” basic instinct in humans? What drives make us complete this instinct?
Describe a type I error and a type II error in understanding patterns in nature.
What is science? How is science different from philosophy and theology (type evidence used)?
Describe the steps in the scientific method. Why is the hypothesis the critical step? How can you
recognize a good scientific hypothesis?
How does a hypothesis differ from a theory? Why is it important that experiments be repeatable?
Why is it important that science does not accept absolute “truths”? Is science moral?
Trace the history of science. What group originated scientific (naturalistic) thought? What progress
was made in science during the dark ages? Why is the year 1543 important in the history of science?
Why did biology develop more slowly than physics after the rebirth of science in the 1600’s?
Describe 7 characteristics that all living things have in common (used to define life).
What element is unique to life?
List in order the levels of organization, from smallest to largest, that we recognize in living
organisms.
Define the term emergent property. What is the most important emergent property at the cell level?
Define the term “reductionism” and tell how this method has been useful in biology.
What small molecule is not an organic molecule but is absolutely essential for life? List 7 properties
of this substance that allow life to exist. Describe why each of these properties is important to life.
What are the 4 most common elements that, together, make up about 96% of living mass?
What element forms the backbone of all organic molecules. Give 4 reasons why this element can do
this.
How are the terms monomer and polymer used to describe the way organic molecules are made?
List the 4 major groups of organic molecules, then for each list the monomer that they are formed
from and the primary functions.
List the 3 parts of the cell theory. What is the difference between spontaneous generation and
biogenesis?
Explain the most important reason that cells cannot be large. How can organisms be large and still
have a large cell surface area to volume ratio?
How are prokaryotic cells different from eukaryotic cells? Which is smaller? Which is older?
Which type cell is found in each of the five kingdoms of living things (bacteria, protists, fungi, plants,
animals)?
What is an advantage of being multicellular?
List 11 parts that are common to all eukaryotic cells. Give the most important job of each part.
Describe the structure of the plasma membrane (and all cell membranes).
Describe 4 functions of the plasma proteins.
Which parts make up the endomembrane system?
Describe the endosymbiotic hypothesis. What 2 organelles (cell parts) may have originated this way?
Describe 2 structures that are found in plant cells but not animal cells and tell why they are important.
How is passive transport across a cell membrane different from active transport? List an example of
each.
Define the term “concentration gradient“. Why is this important?
Describe how osmosis occurs in different solutions (hypotonic, isotonic and hypertonic).
A cell that has cytoplasm that is 7% solute is placed in a solution that is 9% solute. Which (the
cytoplasm or the solution) is hypotonic and which is hypertonic?
Describe how osmosis will occur in this situation.