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

E from food Energy for cells

ADP

+ Pi

Energy Pyramid

4° con.E 3° consumer

2° consumer1° consumer1° 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???