Academic Biology:
Midterm Review
Quarter #1
Chapter 1: The Science of
Biology
 Biology – the study of the living world
 Scientific Method
 Step 1: Observation
 Step 2: Forming a Question
 Step 3: Form a Hypothesis (suggested answer
based on evidence)
 Step 4: Experiment & Compile Data (should only
test ONE variable
 Step 5: Analyze Data
 Step 6: Draw Conclusion & Retest as needed
Chapter 1: The Science of
Biology
 Independent Variable
 The variable the scientist changes
 Dependent Variable
 The variable being measured
 Use the metric system
 When enough experimental data support a
hypothesis, it can become a theory.
 Theories change!
Chapter 1: The Science of
Biology
 8 Characteristics of Living Things:
1. Made up of cells (smallest unit of life)
2. Reproduce (sexually or asexually)
3. Based on universal genetic code (DNA)
4. Grow & develop
5. Obtain & use materials/energy (metabolism)
6. Respond to their environment (stimuli)
7. Maintain stable internal environment
(homeostasis)
8. Change over time (evolution)
Chapter 1: The Science of
Biology
 Tools for Observing Life:
 Compound Light Microscope – to observe small,
living samples
 Electron Microscope – higher magnification, but
can only observe dead, properly
preserved/prepared samples
 Robert Hooke coined the term “cell” looking at
cork through a simple light microscope
Chapter 2: The Chemistry
of Life
 4 Main Organic (Carbon) Compounds:
 Carbohydrates
 Main source of energy
 Made up of monosaccharides (sugars)
 Proteins
 Control reaction rates, allow molecules in and
out of cells, fight disease, make up muscles
 Made up of amino acids
Chapter 2: The Chemistry
of Life
 4 Main Organic (Carbon) Compounds:
 Lipids
 Comprise membranes, energy storage,
insulation
 Made up of glycerol & fatty acids
 Nucleic Acids
 Store and transmit genetic information
 Made up of nucleotides (sugar, phosphate
group & nitrogenous base)
Chapter 2: The Chemistry
of Life
 Chemical Reactions – rearranging of atoms
to form new compounds
 Activation Energy – E needed to start a rxn
 Catalyst – speeds up the rate of chemical
reactions
 Enzymes – naturally occurring, biological
catalysts; lower activation E needed
 Can only be used to speed up ONE specific
reaction!!!
Chapter 2: The Chemistry
of Life
 Water
 Polarity
 H’s and O don’t share e-’s evenly
 O side ends up slightly negative; H side is
slightly positive





Universal solvent
Ice floats!
Most abundant compound in living things
Hydrophilic – water loving
Hydrophobic – water fearing
Chapter 2: The Chemistry
of Life
 Acids
 Donates H+’s
 pH <7
 Bases
 Absorb H+’s
 pH >7
Quarter #2
Early Earth
 The Universe
 Formed by Big Bang
 14 BYA
 The Earth
 Formed 4.6 BYA
 First organisms were probably bacteria
(archaebacteria)
 Reducing atmosphere  oxidizing
atmosphere
 Cyanobacteria released O2
Early Earth
 Miller & Urey
 Recreated hypothesized conditions of
early Earth in lab
 Demonstrated how organic molecules
could have formed before life was
present
Chapter 16: Darwin’s
Theory of Evolution
 Evolution by Natural Selection – species
change over time
 Struggle for Existence
 Survival of the Fittest
 Natural Selection
 Evidence of Common Ancestry:
 Structural similarities (body parts), similar
genes, similar species in geographically
isolated areas
Chapter 16: Darwin’s
Theory of Evolution
 Published The Origin of Species
 Controversial for its time
 Fossil Record – collection of fossils over
time that illustrates ancestry commonalities
between species
 Shows that most organisms that have ever
lived on Earth are extinct!
Chapter 7: Cell Structure &
Function
 In multicellular organisms, cells specialize
to perform different functions.
 Cell Theory:
1. All living things are made of cells.
2. Cells are the basic unit of life.
3. All cells are produced by existing cells.
Chapter 7: Cell Structure &
Function
 Prokaryotic Cells – lack “true” nucleus and
membrane-bound organelles (bacteria)
 Eukaryotic Cells – contain a membrane-bound
nucleus as well as specialized organelles
 Plant Cell – square-ish; cell wall, large central
vacuole, chloroplasts & general organelles
 Animal Cell – round-ish; centrioles & general
organelles
(Do you remember the functions of each organelle?)
Chapter 7: Cell Structure &
Function
 Endosymbiotic theory
 Proposed by Lynn Margulis
 Bigger prokaryotes engulphed smaller prokaryotes
 organelles
 3 endosymbionts: chloroplast, mitchondria, and
centrioles
 Fluid Mosaic Model of the Cell Membrane:
 Phospholipids – main component
 Proteins channels and pumps – made from proteins; aid
materials in movement across cell membrane
 Cell Transport:
 Passive transport
 Diffusion – movement from an area of high
concentration to an area of low concentration
 Osmosis – movement of water from an area of high
concentration to an area of low concentration
 Facilitated Diffusion – Diffusion that gets “help”
from a protein
 Active Transport




Movement from LOW to HIGH concentration
Requires energy
Endocytosis: Pino- and phagocytosis
Exocytosis
 Water movement
 Hypertonic – water out; cell shrinks
 Hypotonic – water in; cell may burst
 Isotonic – water in and out; cell’s happy!
Energy Transfers & ATP
 ATP  ADP + Pi + E
 Energy is released when the bond
holding the end phosphate is broken
The ATP Cycle
ATP
Energy for cells
E from food
ADP
+ Pi
Energy Pyramid
E
4° con.
3° consumer
2° consumer
1° consumer
1° producer
% E/g decreases as you go up because
efficiency in E transfer is not 100%
E is lost - Metabolism, waste, cellular processes
Chapter 8: Photosynthesis
 6CO2 + 6H2O + Sunlight  C6H12O6 + 6O2
 Occurs in the chloroplast
 Thylakoid: membrane sacs; Chlorophyll (pigment)
found in membranes (reflects green light)
 Light-Dependent Reactions – produce high-energy
molecules (ATP & NADPH)
 Stroma: fluid surrounding thylakoid
 Calvin Cycle (Light-Independent Reactions) –
produce high-energy sugars
Chapter 9: Cellular
Respiration
 6O2 + C6H12O6  6CO2 + 6H2O + 36 ATP
 2 Types:
 Aerobic
 Anaerobic
Chapter 9: Cellular
Respiration
 Steps of Aerobic Respiration
 Glycolysis – occurs in cytoplasm, net gain 2
ATP, anaerobic (no O2 needed), if O2 is present
followed by Krebs Cycle
 Krebs Cycle - occurs in matrix (inner cavity of
mitochondria), aerobic (O2 needed), net gain 0
ATP
 Electron Transport Chain – occurs in cristae
(mitochondria), aerobic (O2 needed as the final
electron acceptor), net gain 34 ATP
Chapter 9: Cellular
Respiration
 Fermentation
 Alcoholic Fermentation
 Lactic Acid Fermentation – causes muscle soreness
during excessive physical activity
 Sources of Energy:
 Stored ATP (energy is released as bonds are
broken and phosphate groups are removed from
ATP)
 Cellular Respiration
 Lactic Acid Fermentation
Questions???