Lab 2
Chemistry Comes Alive
Matter
• The “stuff” of the universe
• Anything that has mass and takes up space
• States of matter– Solid – has definite shape and volume– Liquid – has definite volume, changeable
shape– Gas – has changeable shape and volume
Energy
• The capacity to do work (put matter into motion)
• Types of energy– Kinetic – energy in action– Potential – energy of position; stored
(inactive) energy
Energy ConceptsPLAYPLAY
Major Elements of the Human Body
• Carbon (C)
• Hydrogen (H)
• Oxygen (O)
• Nitrogen (N)
Lesser and Trace Elements of the Human Body
• Lesser elements make up 3.9% of the body and include:– Calcium (Ca), phosphorus (P), potassium (K),
sulfur (S), sodium (Na), chlorine (Cl), magnesium (Mg), iodine (I), and iron (Fe)
• Trace elements make up less than 0.01% of the body– They are required in minute amounts, and
are found as part of enzymes
Atomic Structure
• The nucleus consists of neutrons and protons– Neutrons – have no charge and a mass of one
atomic mass unit (amu)– Protons – have a positive charge and a mass of
1 amu
• Electrons are found orbiting the nucleus– Electrons – have a negative charge and 1/2000
the mass of a proton (0 amu)
Models of the Atom
• Planetary Model – electrons move around the nucleus in fixed, circular orbits
• Orbital Model – regions around the nucleus in which electrons are most likely to be found (like a cloud)
Models of the Atom
Figure 2.1
Molecules and Compounds
• Molecule – two or more atoms held together by chemical bonds
• Compound – two or more different kinds of atoms chemically bonded together
Types of Chemical Bonds
• Ionic
• Covalent
• Hydrogen
Figure 2.8
Comparison of Ionic, Polar Covalent, and Nonpolar Covalent Bonds
Formation of an Ionic Bond
Figure 2.5a
Single Covalent Bonds
Figure 2.6a
Cells: The Living Units
THE CELL
Cell Theory
• The cell is the basic structural and functional unit of life (Schleiden & Schwann)
• Organismal activity depends on individual and collective activity of cells
• Biochemical activities of cells are dictated by subcellular structure
• Continuity of life has a cellular basis
• Virchow expanded on the cell theory and concluded “one living cell could only originate from another living cell”
Human cells are microscopic in size , but they vary considerably in size and differ even more in shape. For example : flat, brick shaped, threadlike, and irregular shapes.
Composition of the CELL
• Plasma membrane
• Cytoplasma• Organelles
• Nucleus
Part of the Cell
• Plasma membrane: surrounds the entire cell, forming its outer boundary
• Cytoplasma: living material inside the cell (except the nucleus)
• Nucleus: this structure contains the genetic code
Plasma membrane
• It is the membrane that encloses the cytoplasm and form the outer boundary of the cell.
• This membrane is compose by two layers of phospolipids, also a fat molecule called cholesterol (help to stabilize) and proteins (as receptor)
Plasma Membrane
Figure 3.3
Functions of Membrane Proteins
• Transport
• Enzymatic activity
• Receptors for signal transduction
Figure 3.4.1
Functions of Membrane Proteins
Figure 3.4.2
• Intercellular adhesion
• Cell-cell recognition
• Attachment to cytoskeleton and extracellular matrix
Passive Membrane Transport: Diffusion
• Simple diffusion – nonpolar and lipid-soluble substances – Diffuse directly through the lipid bilayer
– Diffuse through channel proteins
• Facilitated diffusion – Transport of glucose, amino acids, and ions
– Transported substances bind carrier proteins or pass through protein channels
Carriers
• Are integral transmembrane proteins
• Show specificity for certain polar molecules including sugars and amino acids
Diffusion Through the Plasma Membrane
Figure 3.7
Effect of Membrane Permeability on Diffusion and Osmosis
Figure 3.8a
Effects of Solutions of Varying Tonicity
• Isotonic – solutions with the same solute concentration as that of the cytosol
• Hypertonic – solutions having greater solute concentration than that of the cytosol
• Hypotonic – solutions having lesser solute concentration than that of the cytosol
Active Transport
• Uses ATP to move solutes across a membrane
• Requires carrier proteins
Active TransportPLAYPLAY
Types of Active Transport
Figure 3.11
Cytoplasma
• It is the specialized living material of cells
• It lies between the plasma membrane and the nucleus
• Numerous small structure (organelles) are part of the cytoplasma, along with the fluid that serves as the interior
environment of each cell
Cytoplasmic Organelles
• Specialized cellular compartments
• Membranous
– Mitochondria, lysosomes, endoplasmic reticulum, and Golgi apparatus
• Nonmembranous
– Cytoskeleton, centrioles, and ribosomes
Organelles
• Ribosomes
• Endoplasmic reticulum
• Golgi apparatus
• Mitocondria
• Lysosomes
• Centrioles
CELL PART STRUCTURE FUNCTION(S)
Plasma Membrane
Phospholipid bilayer studded with proteins
Serves as the boundary of the cell. P and C (outer surface) perform various functions (Ex. markers and receptor)
Ribosomes Tiny particles each made up of rRNA subunits
Synthesize proteins; a cell’s “protein factories”
Endoplasmic
Reticulum
(ER)
Membranous network of interconnected canals and sacs, some with ribosome (rough ER) and some without (smooth ER)
Rough ER receives and transports synthesized proteins
Smooth ER synthesizes lipids and carbohydrates
CELL PART STRUCTURE FUNCTION(S)
Golgi apparatus
Stack of flattened, membranous sacs
Chemically processes, then packages substances from ER
Mitochondria Membranous capsule containing a large, folded membrane encrusted with enzyme
ATP synthesis; a cell’s “powerhouse”
Lysosomes “Bubble” of enzymes encased by membrane
A cell’s “digestive system”
CELL PART STRUCTURE FUNCTION(S)
Nucleus Double-membraned, spherical envelope containing DNA strands
Dictates protein synthesis, thereby playing and essential role in other cell activities, namely active transport, metabolism, growth and heredity
Nucleolus Dense region of the nucleus
Plays an essential role in the formation of ribosomes
Mitochondria
Figure 3.17
Endoplasmic Reticulum (ER)
Figure 3.18a and c
Golgi Apparatus
Figure 3.20a
Nucleus
• Contains nuclear envelope, nucleoli, chromatin, and distinct compartments rich in specific protein sets
• Gene-containing control center of the cell
• Contains the genetic library with blueprints for nearly all cellular proteins
• Dictates the kinds and amounts of proteins to be synthesized
Nucleoli
• Dark-staining spherical bodies within the nucleus
• Site of ribosome production
Nucleus
Figure 3.28a
Cell Cycle
• Interphase– Growth (G1),
synthesis (S), growth (G2)
• Mitotic phase– Mitosis and
cytokinesis
Figure 3.30
Mitosis
Cell Division
• Essential for body growth and tissue repair
• Mitosis – nuclear division
• Cytokinesis – division of the cytoplasm
Mitosis
• The phases of mitosis are:– Prophase– Metaphase– Anaphase– Telophase
Cytokinesis
• Cleavage furrow formed in late anaphase by contractile ring
• Cytoplasm is pinched into two parts after mitosis ends
Early and Late Prophase
• Asters are seen as chromatin condenses into chromosomes
• Nucleoli disappear
• Centriole pairs separate and the mitotic spindle is formed
Early prophase
Early mitotic spindle
Pair of centrioles
Centromere
Aster
Chromosome, consisting of two sister chromatids
Late prophase
Fragments of nuclear envelope
Polar microtubules
Kinetochore
Kinetochore microtubule
Spindle pole
Metaphase• Chromosomes cluster
at the middle of the cell with their centromeres aligned at the exact center, or equator, of the cell
• This arrangement of chromosomes along a plane midway between the poles is called the metaphase plate
Metaphase
Metaphase plate
Spindle
Anaphase
• Centromeres of the chromosomes split
• Motor proteins in kinetochores pull chromosomes toward poles
Daughter chromosomes
Anaphase
Telophase and Cytokinesis• New sets of
chromosomes extend into chromatin
• New nuclear membrane is formed from the rough ER
• Nucleoli reappear
• Generally cytokinesis completes cell division
Telophase and cytokinesis
Nucleolus forming
Contractile ring at cleavage furrow
Nuclear envelope forming
THE MICROSCOPE
PROCEDURES
• 1- Turn on the illuminator using the on/off switch• 2- Turn the nosepiece to bring the 4X objective (scanner) into
position• 3- Raise the stage into its highest position• 4- Place a slide of the letter “e” in the slide clamp on the stage• 5- Turn the coarse adjustment knob to bring the “e” into focus• 6- Measure the field (the brightly lighted circle that you see
when you look through the ocular lens)• 7- Center the ”e” in your field of view and then rotate the
nosepiece to 10X• 8- Use the fine adjustment knob to focus until the image is
sharp. Draw the image. Do not use the coarse adjustment• 10- Rotate the nosepiece until the 40X. Draw the image
CARES OF THE MICROSCOPE
• When moving the microscope, carry it with 2 hands (one hand to grip the arm and the other under the base
• Lenses have to be clean with lens paper (to keep them free of oil and dust).
• Do not use the coarse adjustment when focusing with the higher power objectives
THE END