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Cells: The Unity of Life in Biology - Study Guide | BIOL 121, Study notes of Biology

test 1 Material Type: Notes; Professor: Buckalew; Class: The Unity of Life; Subject: Biology; University: Longwood University; Term: Fall 2010;

Typology: Study notes

2009/2010

Uploaded on 12/07/2010

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Chapter 1
Biology is defined as the study of life
Characteristics of living things
- Cellular organization
- Order
- Sensitivity
- Growth, development, reproduction
- Energy utilization
- Evolutionary adaptation
- Homeostatis
1) Cells surrounded by cell membrane, all cells come from preexisting cells cell theory
2) Order membranes organelles (mitochondria- energy generation)(endoplasmic reticulum-
protein and fat synthesis) fuel energy for the cell. Organs make organ systems which regulate
the activity of the cell
3) Sensitivity reacting to environment can lead to adaptation
4) Growth, Development, reproduction guidance of DNA inheritance coordination of mitosis
and meiosis
5) Energy utilization energy usage begins @ cell level
a. Autotrophs
b. Heterotrophs- carbohydrates+ other carbon sources (proteins, lipids, nucleic acids)
ATP
6) Evolutionary adaptation producers dictate consumers
7) Homeostasis maintenance of a stable internal environment (tonicity-- concentration), (ph),
[H2O] protein/enzyme function
Heirarchy of Life biosphere
a. Cellular level atoms- molecules- macromolecules- organelles
b. @organism level- cells tissue organsorgan systems organism
c. @population level (ecosystem level) populationspecies community (all plants &
animals) biotic and a-biotic ecosystems
Relative to life on Earth, the entire planet can be viewed can viewed as one large ecosystem called the
biosphere
The biosphere is approximately 25 miles thick. Approximately 19 miles into the air and 6 miles below
the ocean’s surface (diameter of earth at equator 7,926.41 miles only about 50 miles contains life)
At each level of hierarchy, emergent properties emerge
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Chapter 1 Biology is defined as the study of life Characteristics of living things

  • Cellular organization
  • Order
  • Sensitivity
  • Growth, development, reproduction
  • Energy utilization
  • Evolutionary adaptation
  • Homeostatis
  1. Cells surrounded by cell membrane, all cells come from preexisting cells cell theory
  2. Order membranes  organelles (mitochondria- energy generation)(endoplasmic reticulum- protein and fat synthesis) fuel energy for the cell. Organs make organ systems which regulate the activity of the cell
  3. Sensitivity reacting to environment can lead to adaptation
  4. Growth, Development, reproduction guidance of DNA inheritance coordination of mitosis and meiosis
  5. Energy utilization energy usage begins @ cell level a. Autotrophs b. Heterotrophs- carbohydrates+ other carbon sources (proteins, lipids, nucleic acids)  ATP
  6. Evolutionary adaptation producers dictate consumers
  7. Homeostasis maintenance of a stable internal environment (tonicity-- concentration), (ph), [H2O] protein/enzyme function Heirarchy of Life biosphere a. Cellular level atoms- molecules- macromolecules- organelles b. @organism level- cells tissue organsorgan systems organism c. @population level (ecosystem level) populationspecies community (all plants & animals) biotic and a-biotic ecosystems Relative to life on Earth, the entire planet can be viewed can viewed as one large ecosystem called the biosphere The biosphere is approximately 25 miles thick. Approximately 19 miles into the air and 6 miles below the ocean’s surface (diameter of earth at equator 7,926.41 miles only about 50 miles contains life) At each level of hierarchy, emergent properties emerge

Interactions hierarchy, emergent properties emerge Interactions between molecules, cells, organisms, etc result in a system beyond the sum of its parts This makes the process of life difficult to define Science= Latin for “to know” Charles Darwin- sought natural rather than supernatural causes for the unity/diversity of nature and in doing so revolutionized biology. Published the then controversial book on the origin of species... etc in 1859 Aeolian

  • Charles Lyell (1830) geology Darwin traveled 5yrs on the Beagle 1830’s -South America
  • Australia
  • Galapagos islands *** The Process of Science
  • Science seeks answers to natural phenomena o Activities that can be observed and measure o Activities that can verified through testing Ex: Cell theory, molecular theory (DNA RNA Protein), evolutionary theory Science uses two ways to approach problem solving
  • Inductive reasoning- generalization that summarizes many observations
  • Deductive reasoning- hypothesis testing and “if=then logic” reasoning flows from general to specific Does spontaneous generation occur?
  • Sg= belief that some life forms (usually lower life forms) could arise spontaneously from nonliving matter ex: toads, snakes, and mice come from soil, and old rags. Larvae after you because you are sweaty

Molecular theory- “Central Dogma of molecular biology”

  • DNA is molecule of inheritance
  • DNA encodes genes which make- up and control living organisms
  • DNARNA Protein Evolutionary Change
  • Over time, life-forms have evolved varying characteristics to adapt to varied environment Evolutionary Conservation
  • Some characteristics of earlier organisms are preserved and passed on to future generations Fossil evidence for evolution: geochronology
  • Eons of biological change shown in successive layers of rack strata
  • Earliest organisms found in pre-Cambrian rock
  • Simplest life form fossils at lowest depth and more advanced forms in shallower depths Fossil evidence for evolution: similar life in similar habitats
  • Similarity in cell components
  • Plant cells and animal cells
  • Exemplifies extreme conservation of cellular components across biotic realm although heterotrophy/ autotrophy is biologically ancient
  • Animal cells have golgi, plants have dictyosomes
  • Homology among vertebrate limbs
  • Similarities due to common ancestors or genetic lineage Molecular evidence for evolution:
  • Rhesus monkey, being primates and closely related to humans have fewer differences in the amino acid sequence of hemoglobin protein than more distantly related species
  • Non mammalian vertebrates differ to a greater extent Chain of amino acids in hemoglobin “polypeptide” 300AA’s bond between amino acids are peptide bonds CHAPTER 2 Water: an absolute necessity for life
  • Approximately three quarters of the planet is covered by water
  • Life existed in water two billion years prior to adapting to land
  • 60 percent of human weight is from water
  • 83 percent of human blood composition
  • Where water exists, life may be found
  • Water is critical to cell biochemistry
  • Water is critical for photosynthesis
  • Water is the “universal solvent” Water’s structure:
  • Covalent molecule that shows polarity (positive side, negative side)
  • Simple molecular structure with oxygen bound to two hydrogen atoms by single covalent bonds
  • Electro negativity of 0 is much greater that H so the bonds between these atoms are “polar” H2O molecules: covalent bonds + Polarity of molecule

Carbon’s bonding capacity is high (valence of 4) and forms covalent bonds A lot of energy in covalent bonds, when covalent bonds are broken, some energy is trapped between ADP+P yielding ATP Carbon linkages:

  • single chains
  • rings carbon bonds to more than just hydrogen OH hydroxyl group (tends to be polar) Amino Acid:
  • NH2= amine
  • COOH= carboxyl + carbon, hydrogen and R Group Carbon binds to:
  • OH groups in sugars
  • NH2 groups in amino acids
  • H2PO4 groups in nucleotides of DNA, RNA, ATP Functional groups:
  • Hydroxyl
  • Carbonyl
  • Carboxyl
  • Amine
  • Sulfhydryl
  • Phosphate
  • Methyl Isomers have the same molecular formulas but different structures
  • Structural isomer= difference in the C skeleton structure
  • Stereoisomers= difference in location of functional groups o Enantiomers= mirror images of each other “right hand”, “left hand” C bounded to 4 different atoms is called a chiral molecule. Chiral molecules rotate polarized light to the right (d form) or to the left (L form) Monomers are made into polymers via dehydration reactions Polymers are broken down into monomers via hydrolysis reactions

Carbohydrates (sugars)

  • Most abundant biomolecules on earth
  • Simple sugars, double sugars, or chains of sugars
  • Exist in a ring structure within the solution of the cell sugar monomers:
  • Carbons are counted in ring structure starting from right and moving clockwise Double sugars- disaccharides
  • Two six C chains or rings bonded together Glucose+ fructose= sucrose (table sugar) Alpha bond shows the covalent bond below the plain of the sugars (easy to break down) Beta bond shows the covalent bond above the plain of the sugars (very, very hard to break- cant be broken by any human enzymes) Complex Carbohydrates (polysaccharides):
  • Starch (amylose)
  • Cellulose
  • Glycogen
  • Chitin (in cell wall of some fungi and exoskeleton of insects) Proteins (polypeptides)
  • Composed of chains (polymers) of amino acids
  • 20 amino acids exist
  • Amino acids contain: o Central carbon o Amine group o Carboxyl group o R group The twenty amino acids all differ with respect to their R group Genetic Code: 3x3 combinations of AUGC (important for translation of protein synthesis)
  • Code for 20 amino acids 64 possible combinations

Antiparallelism affects DNA replication, protein synthesis and cell division DNA/ RNA polymerase reads DNA from 3’ to 5’ direction but only replicates in the 5’ to 3’ direction RNA= single chain of polymers and neucleotides (RNA has ribose- 1 oxygen added) AUGC 3 forms of RNA:

  • Messenger RNA (mRNA)
  • Transfer RNA (tRNA)
  • Ribosomal RNA (rRNA)

Lipids:

  • Large energy storing compounds
  • Contain a core molecule of glycerol (3 carbon sugar)
  • Fatty acids bind to OH groups creating triglycerides
  • Fatty acid chain has 14-20 carbons
  • Saturated fats- carbon to carbon bonds are single convalent, and each carbon has the maximum

    of hydrogens binding to it or “saturating” it. Higher melting point, solids at room temperature

  • Unsaturated fats- less # of hydrogens per each carbon, at least one double covalent bond between each carbon. Lower melting point, liquids at room temp, mobile in blood, “healthier fats”
  • Trans fats- hard to move in the body
  • Omega three fatty acids- in walnuts, almonds, salmon Water is released in bond between triglycerides and fatty acid chains

Pro (before)karyotic cells- bacteria (no nucleus) Eu(true)karyotic cells- plants, animals, algae, fungi Karyon= kernel or nucleus Prokaryotic cells are about 1-10 um in length (1 millionth meter) Eukaryotic cells are about 10-100 um in length Most cells are microscopic although vertebrate egg cells are large enough to be seen with the naked eye. Limitation to cell size limited by surface area 100um is about the limit PRO:

  • No nucleus
  • 1 chromosome (haploid)
  • Circular chromosome
  • No organelles
  • “small ribosomes” 70 S EU:
  • Nucleus (membrane bound)
  • At least two chromosomes (diploid)
  • Linear chromosomes
  • Organelles (organs of cells)
  • “large ribosomes” 80 S S= Svedberg how quickly they sediment or spin out in a centrifuge Eukaryotic cell structures
  1. Nucleus
  1. Ribosomes
  2. Endoplasmic reticulum