Organismal

Introduction to Biology and the Cell

I. The Formation of the Universe: The Big Bang

A. The Big Bang 1. The Big Bang theory is the prevailing cosmological model that describes the early development of the Universe 2. According to the Big Bang theory, the Universe was once in an extremely hot, dense, and less than the size of an atom 3. It expanded rapidly causing the Universe to cool and expand 4. The Big Bang occurred approximately 13.7 billion years ago……this is the age of the universe 5. After its initial expansion from a singularity, the Universe cooled sufficiently to allow energy to be converted into protons, neutrons, and electrons 6. The first element produced was hydrogen, along with traces of helium and lithium 7. Giant clouds of these primordial elements would, in time, coalesce through gravity to form galaxies

B. Milky Way Galaxy 1. Our galaxy, called the Milky Way, Galaxy is one of 100 billion galaxies in the universe, each with about 200 billion stars 2. Our solar system is located on one of the spiral arms near the edge

----- solar system

C. Formation of the Solar System 1. Condensation Theory 1. Solar System consists of the sun, planets and the astronomical objects gravitationally bound in orbit around 2. It formed approximately 4.6 billion years ago

E. The Formation of the Earth 1. The young Earth was very hot, was showered with the sun’s UV radiation and had a poisonous atmosphere 2. Debris left over from the solar system constantly bombarded the premordial Earth 3. As time passed an “organic soup” developed that was teaming with carbon based compounds

F. Life Begins 1. As more and more life’s building blocks were formed, these materials reacted with each other to form new compounds 2. Eventually, a chance combinations gave rise to proteins, carbohydrates, lipids, and DNA 3. Life is believed to have come about 3.8 billion years ago

II. Chemical Evolution Hypothesis A. Alexander Oparin 1924 1. Was a Russian biochemist who proposed a theory for the origin of life on Earth 2. Oparin suggested that organic compounds could have undergone a series of reactions leading to more and more complex molecules 3. He proposed that the molecules formed colloid aggregates in an aqueous environment that were able to absorb and assimilate organic compounds 4. They would have taken part in evolutionary processes, eventually leading to the first life forms

B. Stanley Miller and the Spark-Discharge Apparatus 1950’s 1. Proposed that the Earth’s early atmosphere could have given rise to the molecules of life 2. He proposed that the organic soup was composed of methane, water vapor, ammonia, and hydrogen- all gases 3. He built a Spark-Discharge Apparatus to simulate the Earth’s early atmosphere 4. After a few days Stanley noticed the liquid had turned reddish in color 5. Upon analysis, the reddish liquid was teaming with amino acids…..the building blocks of all life 6. His conclusion: “given enough time, anything could happen”

Miller’s Spark-Discharge Apparatus

III. How Life is Classified A. Binomial Nomenclature System 1. Carolus Linnaeus devised the binomial nomenclature system of classification 2. Based on a two name system- genus and species 3. Format: capitalize first letter in the genus name; italicize both words Homo sapiens; Homo = man; sapiens = wise Escherichia coli; Escherichia = Theodor Escherich; coli = colon

B. The Five Kingdom System of Robert Whittaker 1. Monera 2. Protista 3. Fungi 4. Plantae 5. Animalia

IV. Characteristics of Living Things A. All Living Things are: 1. Composed of cells 2. Obtain and use energy 3. Grow and develop 4. Reproduce 5. Respond to their environment 6. Adapt to their environment

V. The Discovery of Cells- The Cell Theory A. Robert Hooke 1665 1. Observed microorganisms for the first time with a microscope 2. Coined the term “cell” B. Anton van Leeuwenhoek 1670’s 1. Microscope lens grinder who accidentally discovers microorganisms in a drop of water 2. Using his own microscopes, he observed sperm cells, bacteria, and red blood cells

C. Robert Brown 1831 1. Discovered the cell nucleus

D. Theodor Schwann 1839 1. Zoologist 2. All animals are composed of cells

E. Matthias Schleiden 1839 1. Botanist 2. All plants are composed of cells

F. Rudolf Virchow 1858

1. Proposed an important extension of the cell theory that “all living cells

arise from pre-existing cells"

VI. Life comes From Life- The Spontaneous Generation Controversy A. Jean Baptiste van Helmont 1. Recipe for “making mice” B. Francesco Redi-1688 1. Used the scientific method to prove that flies give rise to flie

C. John Needham (1748) 1. Stated that microorganisms arise spontaneously

E. Louis Pasteur (1860’s) 1. Performed the “swan-neck” experiment to disproved spontaneous generation of microorganisms

Pasteur’s “swan-neck” experiment

VII. Prokaryotic Verses the Eukaryotic Cell Types A. Prokaryotic Cell Characteristics

1. Found in bacteria and archaea 2. Evolved about 3.8 billion years ago

3. Very primitive cell- no nucleus or membrane-bound organelles

Prokaryotic cell

B. Eukaryotic Cell Characteristics 1. Evolved about 1.5 billion years ago 2. Well-defined nucleus 3. Numerous membrane bound organelles 4. Displays compartmentalization

VIII. Eukaryotic Cell Structures A. Nucleus 1. Nuclear membrane 2. Nuclear pores 3. Nucleolus 4. Chromatin

B. Plasma Membrane 1. Singer model of the membrane -Phospholipid bilayer -Proteins -Cholesterol

C. Transport Across the Membrane 1. Simple diffusion 2. Osmosis 3. Solutions

4. Facilitated Diffusion

Simple and facilitated diffusion

5. Active Transport a. transport against a concentration gradient b. requires energy c. sodium-potassium pump

Facilitated diffusion and active transport compared

D. Ribosomes

1. Protein factories 2. Composed of proteins and ribosomal RNA

E. Endomembrane System

F. Endoplasmic reticulum (ER) 1. Smooth ER The smooth endoplasmic has functions in several metabolic processes including synthesis of lipids and steroids, metabolism of carbohydrates, regulation of calcium concentration, drug detoxification, attachment of receptors on cell membrane proteins, and steroid metabolism 2. Rough ER Rough ER has numerous ribosomes attached to its surface membrane Serves as a roadway for proteins

G. Golgi Structure 1. Fate of transport vesicles after they leave the Golgi structure

Secretion of proteins from a cell

H. Lysosomes 1. Contains hydrolytic enzymes 2. Merge with phagosome to form a phagolysosome 3. Lysosomes play a major role in phagocytosis and autophagy

Autophagy of a “worn out” mitochondrion by a lysosome

I. Mitochondria

1. Site of true respiration 2. Structural features a. outer membrane b. inner membrane cristae c. intramembrane space d. matrix

J. Vacuoles

Animal vacuole Plant vacuole

K. Plastids 1. Chloroplasts a. site of photosynthesis b. pigments -chlorophylls -xanthophylls -carotenoids c. structural features -outer membrane -inner membrane -internal membrane granum thylakoid stroma

2. Amyloplasts in potato cells a. starch storage plastids

3. Chromoplasts in pepper cells a. pigments storage plastids

1. It’s a tough, usually flexible but sometimes fairly rigid layer that surrounds the plant cell 2. Provides these cells with structural support and protection, in addition to acting as a filtering mechanism 3. A major function of the cell wall is to act as a pressure vessel, preventing over-expansion when water enters the cell

4. Most plant cell walls are composed of three layers: middle lamella, primary cell wall, and the secondary cell wall 5. The middle lamella contains a layer rich in pectins which forms the interface between adjacent plant cells and glues them together 6. The primary cell wall, generally a thin, flexible and extensible layer is formed while the cell is growing 7. The primary plant cell wall is composed of cellulose, hemicellulose, and pectin 8. The secondary cell wall, a thick layer formed inside the primary cell wall after the cell is fully grown 9. It composed three layers in itself and it is not found in all cell types 10. The secondary cell wall contains cellulose, hemicellulose, and lignin

L. Cell Wall

M. Cytoplasm A. Cytoplasmic Streaming (Cyclosis)

Amoeba Elodea

IX. The Cytoskeleton: Microtubules, Microfilaments, and Intermediate Fibers

A. Microtubules 1. Are hollow cylinders about 23 nm in diameter 2. Are polymers of alpha and beta tubulin 3. They play key roles in: -intracellular transport (associated with dyneins and kinesins, they transport organelles like mitochondria or vesicles -compose the mitotic spindle -help in the synthesis of the cell wall in plants -compose flagella and cilia

4. Microtubules compose spindle fibers during mitosis and meiosis

5. Microtubules compose flagella and cilia

Euglena with flagella Paramecium with cilia

Flagellum or cilium structure with the 9 plus 2 arrangement microtubules

6. Centrioles -consist of nine triplet sets of microtubules that are star-shaped

.

7. Tracks used to move transport vesicles

B. Intermediate fibers 1. Provide structure to the cell

2. Microfilaments reinforce the microvilli of the intestine

3. Intermediate filaments attached to plasma membrane

C. Microfilaments 1. Smallest components of the cytoskeleton 2. Functioning in cytokinesis, amoeboid movement, and changes in cell shape

X. Cell Junctions

XI. Endosymbiotic Hypothesis A. Lynn Margulis 1. Ancestrial prokaryotes gave rise to mitochondria and chloroplasts in eukaryotic cells