Download ST110 Chemistry, Cellular Structure, and Function_BB

Chemistry, Cellular
Structure, and Function
Concorde Career College, Portland
ST110
Learning Objectives
• After you have completed this chapter, you should be
able to:
1. Define the terms atom, element, molecule,
and compound.
2. Describe the structure of an atom.
3. Compare and contrast ionic and covalent
types of chemical bonding.
4. Distinguish between organic and inorganic
chemical compounds.
Learning Objectives
5. Discuss the chemical characteristics of water.
6. Explain the concept of pH.
7. Discuss the structure and function of the
following types of organic molecules:
carbohydrate, lipid, protein, and nucleic acid.
What is chemistry and why is it important?
• Chemistry
– The science that deals with the composition and
properties of matter and applies to the studies of:
• Physiology – study of function
• Microbiology – study of microscopic plants and animals
• Pharmacology - study of drugs and their actions
Elements
• Elements are the substances that make up
matter.
– Matter is anything that takes up space
• Elements are identified on the Periodic Table
and include:
– Gasses
– Liquids
– Solids
Structure of Matter
A.
Elements and Atoms:
1. Matter is anything that has mass
(Weight) and occupies space.
2. All matter is composed of elements,
92 of which occur naturally.
* Oxygen, carbon, hydrogen, and
nitrogen make up 96% of the human
body.
* Elements are composed of atoms;
atoms of different elements vary in
size and in how they interact.
Periodic Table of Elements
• Periodic Table of Elements – Chart that
arranges the elements by atomic number and
by property
– Arranged by atomic number – Which is the
number of protons and electrons in an element
• O=8
• H=1
• C=6
Atoms
Atomic Structure
1. An atom consists of a
nucleus containing
protons and neutrons,
with electrons in orbit
around the nucleus in
shells.
2. Protons, with a positive
charge, are about equal
in size to neutrons, which
have no charge.
3.
4.
5.
Electrons are much smaller and bear
a negative charge.
An electrically neutral atom has equal
numbers of protons and electrons.
The number of protons denotes the
atomic number of an element; the
number of protons plus the number of
neutrons equals the atomic weight.
Molecules and Compounds
1.
A molecule is formed when two or more atoms
combine.
2.
If atoms of different elements combine, the
molecule can also be called a compound.
3.
Compounds always have a definite kind and
number of atoms.
Molecule Formation
• Molecules form when
electrons in the outer
energy levels (valences)
combine
Water
• The most abundant substance in living cells
• Participates in key cellular reactions
– Universal solvent
– Functions in:
•
•
•
•
Respiration
Temperature control
Protects fetus, brain and spinal cord
Body lubricant
Chemical Bonding
• Chemical bonds form to make atoms more
stable
1 .Atoms form bonds by gaining, losing, or sharing
electrons.
2. Electrons are found in shells around the nucleus.
a. The first energy shell holds two electrons; the other
energy shells each hold up to eight electrons when
on the outside.
(unpaired electrons can become stable by: sharing and
donating electrons)
Bonds and Energy
• Atoms combine by bonding together and
sharing electrons
• When atoms combine and bond together a
molecule or a compound is formed (CO2 or
H2O)
Types of Bonds
• Ionic bonds – One atom gains electrons while
another atom loses electrons (positive and negative
ions bond together)
– Ions – positively or negatively charged atoms
• Sodium – Na+ is a positively charged ion (cation)
• Chlorine – Cl- is a negatively charged ion (anion)
• What are electrolytes?
– Ions in solution
– Ionic molecules dissolve (dissociate/break apart)
in water.
– Water molecules wedge between the ions to force
them apart.
* Electrolyte —molecule that dissociates
(breaks apart) in water to form individual
ions.
Ionic Bonds
Types of Bonds
• What are electrolytes?
– Ions in solution
• What is the importance of electrolytes in the body?
– Blood clotting
– Muscle contraction
– Acid/base balance (pH)
• What type of diagnostic testing is performed using
ions (electrolytes) in the body?
Types of Bonds
• Covalent Bonds – Electrons are shared between
atoms of the molecule
– Electrons in the outer energy levels (valences) of the atom
bind together
– Covalent bonds exist between atoms that are the same or
different
– Nonpolar covalent bond – charges are equally distributed
– Polar covalent bond – one part of the bond is more
positive or more negative at a given time
Nonpolar Covalent Bond
Polar Covalent Bond
Types of Bonds
• Hydrogen bonds – hold molecules (rather than
atoms) together
– Weak in comparison to ionic or covalent bonds
– Positive hydrogen atoms attract negative
molecules
– Hydrogen bonds hold water molecules together in
the liquid form
Hydrogen Bond
Water molecules held
together with a
hydrogen bond
Types of Bonds
• Time permitting, view this animation from the
UC Davis Bioscience Department
http://www.youtube.com/watch?v=QqjcCvzWw
ww
Donors and Acceptors
Electron terminology
• Electron donor-donates an electron
• Electron acceptor-accepts an electron
• Electron carriers-accepts electrons for a short
time then loses them
Formulas
1. A molecular formula represents the numbers and
types of atoms in a molecule.
2. Various representations, called structural
formulas, can be used to illustrate molecules.
Inorganic Chemistry
• Organic molecules contain carbon– carbon
covalent bonds and/or carbon hydrogen covalent
bonds; inorganic molecules do not
• Examples of inorganic molecules: water and
some acids, bases, and salts
Inorganic Chemistry
• Water
– Water is a solvent (liquid into which solutes
are dissolved), forming aqueous solutions in
the body
– Water is involved in chemical reactions
– Dehydration synthesis — chemical reaction in
which water is removed from small molecules
so they can be strung together to form a
larger molecule
Hydrolysis —chemical reaction in which
water is added to the subunits of a large
molecule to break it apart into smaller
molecules
• Oxygen
Oxygen is needed to release energy from
nutrients and is used to drive the cell's
metabolism.
• Carbon Dioxide
Carbon dioxide is released as a
waste product during energy-releasing
metabolic reactions.
• Chemical reactions always involve energy
transfers, as when energy is used to build
ATP molecules
• Chemical equations show how reactants
interact to form products; arrows separate
the reactants from the products
Acids and Bases
1.
Substances that release ions in water
are called electrolytes.
2.
Electrolytes that release hydrogen
ions in water are called acids.
3.
Electrolytes that release hydroxide ions in water
are called bases.
pH scale
• Measures acidity
• Acids are compounds that
produce an excess of H+ ions
(less than 7)
• Bases (alkaline) are
compounds that produce an
excess of OH- ions
pH scale
4. The concentrations of H+ & OH- in the body is
very important to physiology.
5. pH represents the concentration of hydrogen
ions [H+] in solution.
6.
A pH of 7 indicates a neutral solution with
equal numbers of hydrogen ions and hydroxide
(OH-) ions.
a.
A pH of zero to less than 7 indicates the
presence of more hydrogen ions, and thus the
solution is more acidic; a pH greater than 7 to 14
indicates more hydroxide ions, or a basic
solution.
b.
Between each whole number of the pH scale
there is a tenfold difference in hydrogen ion
concentration.
Buffers
Buffer
• “Any substance or mixture of compounds that, added
to a solution, is capable of neutralizing both acids
and bases without appreciably changing the original
acidity or alkalinity of the solution.”
buffer. (n.d.). Dictionary.com Unabridged (v 1.1).
Retrieved November 10, 2007, from Dictionary.com
website:
http://dictionary.reference.com/browse/buffer
Buffers
Why is aspirin buffered?
Salts
Strong acids mixed with strong Bases can
neutralize each other.
When this happens usually a salt and
water remains.
Buffers prevent sudden changes in
concentration of hydrogen ions.
Chemical Constituents of Cells
A. Compounds that contain carbon are called
organic, the others are inorganic
Organic Chemistry
• More complex than inorganic compounds
• Larger than organic compounds
• Four type of major organic compounds
– Carbohydrates
– Lipids
– Proteins
– Nucleic Acids
Organic Chemistry
1. Carbohydrates
a. Carbohydrates provide energy for cellular
activities and are composed of carbon,
hydrogen, and oxygen.
Organic Chemistry
• Carbohydrates —sugars and complex
carbohydrates
– Contain carbon (C), hydrogen (H), oxygen (O)
– Made up of six carbon subunits called
monosaccharides or single sugars (e.g.,
glucose)
– Disaccharide —double sugar made up of two
monosaccharide units (e.g., sucrose, lactose)
Organic Chemistry
– Polysaccharide —complex carbohydrate made
up of many monosaccharide units (e.g.,
glycogen made up of many glucose units)
– Function of carbohydrates is to store energy
for later use
•
Humans synthesize the polysaccharide
glycogen.
Organic Chemistry
• Lipids —fats and oils
– Trigylcerides
• Made up of one glycerol unit and three
fatty acids
• Store energy for later use
Organic Chemistry
– Cholesterol
• Molecules have a steroid structure made up
of multiple rings
• Cholesterol stabilizes the phospholipid tails
in cellular membranes
• Makes steroid hormones such as estrogen,
testosterone and corisone
Proteins:
Made of amino acids held together by peptide bonds
creating a polypeptide chain.
2 types:
Structural Proteins – forms essential structures
Collagen – holds body tissues together
Keratin – forms outer layer of skin
Functional Proteins – play a part in chemical
processes within body.
Examples: hormones, cell membrane
channels and receptors, enzymes.
c.
Nucleic acids are of two major types: DNA (with
deoxyribose) and RNA (with ribose).
d.
RNA (ribonucleic acid) functions in protein
synthesis; DNA (deoxyribonucleic acid) stores
the molecular code in genes.
Organic Chemistry
– RNA (ribonucleic acid)
• Used as temporary “working copy” of a
gene
• Uses ribose as the sugar and A, U (not T),
and G as bases
• Forms a single strand
Organic Chemistry
– DNA (deoxyribonucleic acid)
• Used as the cell’s “master code” for
assembling proteins
• Uses deoxyribose as the sugar and A, T
(not U), and G as bases
• Forms a double helix
ATP
ATP
• Active Transport requires ATP
• ATP is the fuel/energy needed for Active
Transport
*just like a vehicle needs fuel to transport*
Pg. 25 AP4ST
Cell and Tissues
ST110
Concorde Career College, Portland
Learning Objectives
• After you have completed this chapter, you should be
able to:
1. Identify and discuss the basic structure and function of the three major
components of a cell.
2. List and briefly discuss the functions of the primary cellular organelles.
3. Compare the major passive and active transport processes that act to move
substances through cell membranes.
4. Compare and discuss DNA and RNA and
their function in protein synthesis.
5. Discuss the stages of mitosis and explain the importance of cellular
reproduction.
6. Explain how epithelial tissue is grouped according to shape and
arrangement of cells.
7. List and briefly discuss the major types of connective and muscle tissue.
8. List the three structural components of a neuron.
Composition
– Cytoplasm containing specialized organelles
surrounded by a plasma membrane
– Organization of cytoplasmic substances important
for life
Structure of a typical cell
Structure of a typical cell
Three Main Parts of the Cell
• Plasma membrane
• Cytoplasm
• Nucleus
(all parts are called
Organelles)
Parts of cell
• Organelle – “little organ” like structure. Highly
specialized cellular structure that carries out a
specific cellular activity. Pg. 22 AP4ST
Structural Parts
– Plasma membrane
• Forms outer boundary of cell
• Thin two-layered membrane of
phospholipids containing proteins
• Is selectively permeable
• Separates the inside from the outside pg. 27
AP4ST Table 2-1
Structure of Plasma Membrane
– Cytoplasm-materials that lie within the
boundary of the cell.
• Organelles (part with a specific
function; a cell organ)
–Ribosomes
»May attach to rough ER or lie
free in cytoplasm
»Manufacture proteins
»Often called protein factories
Structural Parts
– Endoplasmic reticulum (ER)
• Network of connecting sacs and
canals
• Carry substances through cytoplasm
• Types are rough and smooth
• Rough ER collects and transports
proteins by ribosomes
• Smooth ER synthesizes chemicals;
makes new membrane
Structural Parts
– Mitochondria
• Composed of inner and outer
membranes
• Involved with energy-releasing
chemical reactions
• Often called power plants of the cell
• Contain one DNA molecule
Mitochondria
Structural Parts
– Golgi apparatus
• Group of flattened sacs near nucleus
• Collect chemicals that move from the
smooth ER in vesicles
• Called the chemical processing and
packaging center
Structural Parts
– Lysosomes
• Membranous-walled organelles
• Contain digestive enzymes
• Have protective function (eat
microbes)
• Formerly thought to be responsible
for apoptosis (programmed cell
death)
Structural Parts
– Centrioles
• Paired organelles
• Lie at right angles to each other near
the nucleus
• Function in cell reproduction
Centrioles
Structural Parts
– Cilia
• Fine hairlike extensions found on free
or exposed surfaces of some cells
• Capable of moving in unison in a
wavelike fashion
Cilia
Structural Parts
– Flagella
• Single projections extending from cell
surfaces
• Much larger than cilia
• “Tails” of sperm cells are the only
example of flagella in humans
Flagella
Structural Parts
– Nucleus
• Controls cell because it contain the
genetic code—instructions for making
proteins, which in turn determine cell
structure and function
• Component structures include nuclear
envelope, nucleoplasm, and
chromatin granules
• 46 chromosomes contain DNA, which
contains the genetic code
Nucleus
Modes of Transportation
Plasma Membrane
• Separates: The inside from the outside of the cell.
• Selectively permeable, allows certain substances
in, keeps other substances out. Keeps cytoplasm
in, lets waste out, lets nutrients in.
• Molecules of water
• Foods
• Gases
• Waste
Transportation
• Passive transport
• Active transport
Passive Transport
Tonicity
• Isotonic
• Hypertonic
• Hypotonic
– EX
• 0.9% NaCl=isotonic to RBC
• Sterile water=hypotonic to RBC
Active Transport
Active Transport
• “Phago”• “Pino”
• Ion pumps-uses ATP to move ions across the
membrane against the concentration gradient
• Phago - permits a cell to engulf foreign material
• Pino - used to incorporated fluids or dissolved
substances
(Requires cell energy in the form of ATP)
Click for Animation
Mitosis and Meiosis
5 Stages of Mitosis
• Interphase
• Prophase
• Metaphase
• Anaphase
• Telophase
Stages of Mitosis
Interphase
• DNA replicate
• Process by which each half of a DNA molecule becomes a whole molecule
identical to the original DNA molecule; precedes mitosis
Centrioles
• Two rod-shaped organelles that migrate and
participate in cell division.
Stages of Mitosis
• Prophase—first stage
– Chromatin granules become organized
– Chromosomes (pairs of linked
chromatids) appear
– Centrioles move away from nucleus
– Nuclear envelope disappears, freeing
genetic material
– Spindle fibers appear
Stages of Mitosis
Stages of Mitosis
• Metaphase—second stage
– Chromosomes align across center of cell
– Spindle fibers attach themselves to each
chromatid
Metaphase
Stages of Mitosis
• Anaphase—third phase
– Centromeres break apart
– Separated chromatids now called
chromosomes
– Chromosomes are pulled to opposite
ends of cell
– Cleavage furrow develops at end of
anaphase
Anaphase
Stages of Mitosis
• Telophase—fourth stage
– Cell division is completed
– Nuclei appear in daughter cells
– Nuclear envelope and nucleoli appear
– Cytoplasm is divided (cytokinesis)
– Daughter cells become fully functional
Telophase
Types of Cells
Interactive Cell
• http://www.wisconline.com/objects/ViewObject.aspx?ID=ap11
403
• http://www.cellsalive.com/cells/cell_model.ht
m
• http://learn.genetics.utah.edu/content/begin/
cells/insideacell/
Cellular Metabolism
ST110
Concorde Career College
Objective
• Describe the process of cellular metabolism.
Cellular Metabolism Terminology
• Metabolism
– Total chemical changes that happen inside a cell
• Anabolism-builds larger molecules from smaller onesrequires energy
• Catabolism-breaks down large molecules to smaller
ones-releases energy
Cellular Metabolism Terminology
• Aerobic
– Needing oxygen to produce energy
• Anaerobic
– Without oxygen
• Calories
– Measurement of the energy in food
• Specifically, a calorie is the amount of energy, or heat, it takes to
raise the temperature of 1 gram of water 1 degree Celsius (1.8
degrees Fahrenheit). One calorie is equal to 4.184 joules, a
common unit of energy used in the physical sciences.
A Gallon of Gas contains 31,000,000
calories
Calories Defined
• Most of us think of calories in relation to food, as in "This can
of soda has 200 calories." It turns out that the calories on a
food package are actually kilocalories (1,000 calories = 1
kilocalorie). The word is sometimes capitalized to show the
difference, but usually not. A food calorie contains 4,184
joules. A can of soda containing 200 food calories contains
200,000 regular calories, or 200 kilocalories. A gallon of
gasoline contains 31,000 kilocalories.
• The same applies to exercise -- when a fitness chart says you
burn about 100 calories for every mile you jog, it means 100
kilocalories.
What do Calories do?
• Our bodies "burn" the calories in food through metabolic
processes, by which enzymes break the carbohydrates into
glucose and other sugars, the fats into glycerol and fatty acids
and the proteins into amino acids. These molecules are then
transported through the bloodstream to the cells, where they
are either absorbed for immediate use or sent on to the final
stage of metabolism in which they are reacted with oxygen to
release their stored energy.
Cellular Metabolism
• Energy created in the Mitochondria
– Post Glycolysis
– Contain their own DNA
– Thought to be
prehistoric symbiotic
bacteria
Cellular Respiration!
Cellular Respiration
• Oxidative Metabolism
• Basic Steps:
– Food Breakdown
• Catabolism
– Glycolysis
– Kreb’s Cycle
– Electron Transport System
Glycolysis-aerobic process
•
•
•
•
Glucose is transformed to pyruvic acid
Requires ATP
Phosphorylation-1st step of glycolysis
Glucose + 2xADP + 2xNAD+ -> 2xPyruvate +
2xATP + 2xNADH
Glycolysis
• Glycolysis- All in all the purpose of glycolysis is to break down
one molecule glucose into two molecules of pyruvate. The
pyruvate molecules are then individually sent to the transition
reactions. Glycolysis has two Products, H20 and NADH. Overall
Glycolysis makes four ATP but its net gain is two ATP due to
the fact that it uses two ATP in the process.
Transition Reactions
• Transition Reactions- The purpose of the
transition reactions is to take two hydrogen
electrons and one carbon dioxide away from
the pyruvate and add a coenzyme called
Coenzyme A. The new acetyl Co-A is ready to
be sent to the Krebs Cycle.
The Kreb’s Citric Acid Cycle-aerobic
• Next process in metabolism or respiration
• Pyruvic acid
Citric and Oxaloacetic
Acid
• Glycolysis and Kreb’s is for the purpose of
forming ATP
Kreb’s Cycle
• Krebs Cycle- The purpose of the Krebs Cycle is
basically to produce NADH+H and FADH2. Pyruvate
enters the Krebs Cycle than goes through a series of
reactions and the final product is six NADH+H and
two FADH2. These energy carriers are than sent to
the electron transport chain. The Krebs cycle Goes
around twice for every molecule of acetyl Co-A.
Electron Transport Chain
• Electron Transport Chain- The purpose of the electron transport chain is
to make the majority of ATP created in cellular respiration. The NADH and
FADH2 from the Krebs Cycle drop their electrons at the starting of the
electron transport chain. As the electrons move along the electron
transport chain they give it power to pump hydrogen across the
membrane from the matrix into the intermediate space. This creates a
concentration gradient forcing the hydrogen through ATP synthase
bounding ADP with Pi ( inorganic Phosphate). As the electrons move along
the transport chain they lose their energy and at the end are picked up by
oxygen and bonding with hydrogen making the bi-product H20.
• Yields about 32 ATP!
Fermentation-anaerobic
•
•
•
•
Used by yeast and muscles
Less efficient process
Produces ATP
Produces Lactic acid and causes muscle
soreness