TEST

ONE

TERMINOLOGY

Anatomy Form of organism

Ana = up, Tome = to cut

Physiology

Physis = nature, Logia = to study Function

Iris – rainbow

Autopsy

Auto = self, opsis = to view

HOMEOSTASIS

Homeo = same, Stasis = Still Maintain a stable internal environment

e.g. Body temperature (98.6°), Heart rate (72beats/min), pH balance

Consumes most metabolic energy of all processes

REQUIRMENTS FOR HOMEOSTASIS 1. Receptors – Provide information about environment

Thermoreceptors –detect temperature

  2. Control Center with Set point

Control Center = sets the range at which the value is maintained Hypothalamus = Control Center

Set point = range of values 98.6°F = set point

  3. Effectors

Muscles or glands Responds to input from control center Alters conditions

e.g. Sweat glands secrete sweat to cool body

Example of Homeostatic Mechanism

EXAMPLES

Example of Homeostatic Mechanism Stimulus = hot environment → Body temperature increases →

Detected by thermoreceptors (receptors) → info into hypothalamus (control center) → Hypothalamus detects deviation from body temp (set point) →

output signal to sweat glands (effectors) → Sweat glands secrete sweat →

response = body temp cools → Stimulus decreases

HOMEOSTASIS

TWO TYPES OF FEEDBACK

Negative Feedback = response to decrease the deviation from a set point

Most homeostatic mechanisms rely on negative feedback

Positive Feedback = response to increase deviation from set point

Short lived and uncommon e.g. Child birth

CHARACTERISTICS OF LIFE

• Organized system

• 1 or more cells, humans have 50-100 Trillion cells

• Reproduction

• Consumes energy, usually ATP

• Maintains homeostasis

• Growth

REQUIREMENTS TO MAINTAIN LIFE

• Water (H2O) – Transportation & required for metabolic processes

• Food – energy & building blocks

• Oxygen – required to release energy from metabolic processes

• Heat – energy, regulates metabolic reactions

• Pressure – force, for breathing & circulation

LEVELS OF ORGANIZATION

Subatomic Particles Protons, Neutrons, Electrons

↓

Atom Hydrogen, Oxygen, Carbon

↓

Molecules H2O (water), C6H12O6 (Glucose)

↓

Macromolecules Proteins, Nucleic Acids, Polysaccharides

↓

Organelles Mitochondria, Golgi Apparatus

↓

Cell Neuron, Muscle Cell, Osteocyte

↓

Tissue Neural tissue, Epithelial Tissue, Bone tissue

↓

Organ Liver, Stomach, Brain

↓

Organ System Digestive, Skeletal, Cardiovascular

↓

Organism Human

CHEMISTRY

COMMON TERMS

Common Terms

Biochemistry = chemistry of living things

Matter = Anything that has mass and takes up space

Solids, Liquids, Gas

Element = Fundamental substance of matter

Groups of atoms of 1 type, e.g. Carbon, Oxygen, Hydrogen

Compund = Combination of 2 or more atoms, e.g. H2O, C6H12O6

Molecule = 2 or more atoms chemically bonded together May either be an element or may be a compound

BULK ELEMENTS

Carbon (C) Oxygen (O) Hydrogen (H)

Nitrogen (N) Magnesium (Mg) Sulfur (S)

Sodium (Na) Potassium (K) Calcium (Ca)

Chlorine (Cl)

TRACE ELEMENTS <0.1% OF ELEMENTS, BUT HAVE IMPORTANT FUNCTIONS

Cobalt (Co) Zinc (Zn) Copper (Cu)

Iron (Fe) Fluorine (F) Mangenese (Mn)

Iodine (I)

ATOMIC STRUCTURE

Nucleus Protons Neutrons

Electrons – Orbit nucleus

 

Subatomic Particle Atomic Weight (Daltons)Charge

Proton 1 +1

Neutron 1 0

Electron 0 -1

For most atoms, number of protons = number of electrons, and therefore are neutral

Number of neutrons may vary

Atomic Number (AN) = Number of protons in an atom Defines the identity of an atom Changing the atomic number changes the atom

Atomic Weight (AW) = Number of protons + number of neutrons

 

Examples:

Hydrogen = 1proton, 1 electron, 0 neutrons Atomic Number = 1, Atomic Weight = 1

 

Helium = 2 protons, 2 electrons, 2 neutrons Atomic Number = 2, Atomic Weight = 4

 

Lithium = 3 Protons, 4 Neutrons, 3 Electrons Atomic Number = 3, Atomic Weight = 7

ISOTOPESIsotopes Same atomic number, but different atomic mass Number of neutrons may vary

Example:

Isotope 1: Isotope 2

Oxygen (O) Oxygen (O)

8 protons 8 protons

8 electrons 8 electrons

8 neutrons 9 neutrons

Atomic Number: 8 8

Atomic Weight: 16 17

MOLECULAR FORMULA

Shorthand of molecules Water = H2O……2 Hydrogen + 1 Oxygen Molecule

Glucose = C6H12O6……6 Carbon + 12 Hydrogen + 6 Oxygen

BONDING ATOMS

Electron Orbit (Shell) Electrons orbit the nucleus in discrete orbits

Inner orbit = holds 2 electrons 2nd orbit = holds 8 electrons 3rd orbit = holds 8 electrons

Octet Rule Except for the 1st electron orbit, which holds 2 electrons, each

additional orbit holds 8 electrons

IONSIon = atom that gains or looses electrons Cation – Positively charged ion Anion – Negatively charged ion Example:

Sodium (Na) = 11 protons, 12 neutrons, 11 electrons 1 electron in outer orbit Outer lone electron is easily lost Na + = cation

Chlorine (Cl) = 17 protons, 18 neutrons, 17 electrons 7 electrons in outer orbit, which can hold 8 electrons 1 electron is easily gained Cl- = anion

IONIC BOND

IONIC BOND

BONDS CONT.

Ionic Bond Oppositely charged ions attract and form a bond Ionic bonds form arrays such as crystals, but do not form molecules

Covalent Bond Atoms share electrons

Hydrogen forms single bonds, H-H Carbon forms four bonds, Oxygen forms 2 bonds, O=C=O

COVALENT BONDS

NonPolar Covalent Bond Equal sharing of electrons, e.g. H2 (H-H)

  Polar Covalent Bond

Unequal sharing of electrons, e.g. H2O (H-O-H) Oxygen has stronger attraction to electrons & is slightly –

charged Hydrogen partially gives electrons to Oxygen & is + charged

HYDROGEN BOND

Attraction of + hydrogen end to – Oxygen end Weak bonds at body temperature

Forms crystals at lower temperatures, e.g. ice

CHEMICAL REACTIONS1. Synthesis

A + B → AB

 

2. Decomposition

AB → A + B

 

3. Exchange

AB + CD → AD + BC

 

4. Reversible

A + B ↔ AB

ELECTROLYTESElectrolytes = release ions in water

e.g. NaCl → Na⁺ + Cl⁻ (ions dissociate in water)

 

2. Acids – electrolytes that release H⁺ (protons) in water

e.g. HCl → H⁺ + Cl⁻

 

3. Base – electrolytes that release OH⁻(hydroxide ions) in water

e.g. NaOH → Na⁺ + OH⁻

 

 

4. Acid + Base → Salt + Water

e.g. HCl + NaOH → NaCl + H2O

PH

Neutral, pH = 7.0 number of protons = number of hydroxide ions (H⁺ = OH⁻)

e.g. Water H2O → H⁺ + OH⁻

Acids, pH < 7.0 Number of protons is greater than number of hydroxides (H⁺ > OH⁻)

Bases, pH> 7.0 Number of protons is less than number of hydroxides (H⁺ < OH⁻)

PH

average pH is 7.35-7.45 Acidosis = pH < 7.3 Alkalosis = pH > 7.5 Buffers = chemicals that resist changes in pH, stabilizes blood plasma

pH levels

INORGANICWater (H2O) 2/3 of weight in person Most metabolic reactions occur in water Transports gasses, nutrients, wastes, heat

Oxygen (O2)

Used to release energy from nutrients

 

Carbon Dioxide (CO2)

waste byproduct of metabolic reactions in animals

Inorganic Salts

Na⁺, Cl⁻, K⁺, Ca2⁺, HCO3⁻ (bicarbonate), PO42⁻ (Phosphate), ect.

Role in metabolism, pH, bone development, muscle contractions, clot formation

CELLS

Basic unit of life 50-100 Trillion cells in human body Size and shape vary

Size measured in micrometers (µm) 1 µm = 1/1000mm Red Blood Cell = 7.5 µm

Varieties 260 types of cells in body, all from 1 fertilized egg Differentiation = forming specialized cells from unspecialized cells Cells include neurons, skeletal muscle, osteocytes (bones), red blood cells,

ect.

CELL MEMBRANE

Maintains integrity of cell Fluid membrane

Flexible & elastic Selectively Permeable

Allows only selective substances into and out of cell Permits communication between cell and environment

Signal Transduction = cell interprets incoming messages

STRUCTURE

Bilayer of phospholipids Phosphate “Head”

Polar group Hydrophilic “water loving” = water soluble

Fatty Acid Chains “tail” Nonpolar groups Hydrophobic “water fearing” = insoluble in water Oily

Cholesterol Membrane Proteins

FORMATION OF MEMBRANE Phospholipids align in water

Expose polar heads to water = polar outside Hide nonpolar tails from water = oily inside

Nonpolar interior Allows nonpolar molecules to cross into and out of cell

e.g. O2,CO2, steroid hormones

Polar molecules cannot cross cell membrane

e.g. H2O, sugars, amino acids

 

 

Cholesterol Rigid steroid rings that add support to cell membrane

Membrane Proteins = Many types embedded in cell membrane

MEMBRANE PROTEINS Integral Proteins

Spans across membrane Forms channels and pores

e.g. aquaporins, Na+ channels Peripheral Proteins

Project from outer surface May be glycoprotein (protein + sugar) Does not penetrate hydrophobic portion of membrane Usually attach to integral proteins

Transmembrane Protein Spans from outside cell to inside cell Example 1 : Cellular Adhesion Molecules (CAM)

CAMs bind cells to other cells, or to proteins May anchor cell, or communicate with other cells

Example 2: Many receptors Transmits signals from extracellular environment into cell

NUCLEUS

Nuclear Envelope Double layered membrane Nuclear Pores

Channel proteins that allow specific molecules into and out of nucleus Messenger RNA leaves nucleus through pores Ribosomes leave nucleus through pores

Nucleolus “little nucleus” Dense body of RNA & Proteins Produces ribosomes

Chromatin “colored substance” DNA wrapped around proteins, called histones Tightly coil and condense during mitosis to form chromosomes “colored

body”

MOVEMENTSPassive = requires no energy from cell

Active = requires energy from cell in form of ATP

 

Passive Movements Diffusion

Random movement of molecules from higher to lower concentration Molecules tend to diffuse = become evenly distributed Requirements:

Cell membrane must be permeable to substance (small & nonpolar) e.g. CO2, O2, Steroids

A concentration gradient must exist across membrane One side of cell membrane must have a greater concentration than the other

  Facilitated Diffusion

Diffusion with the aid of a carrier protein Allows selective molecules to cross membrane

e.g. ions, sugars, proteins, amino acids Carrier protein changes conformation Substances move down concentration gradient Limited by number of carrier protein

  

 

Osmosis Diffusion of water across selectively permeable membrane

Water passes through channels, called aquaporins Large solutes (salts) cannot cross membrane Water follows salts

Osmotic pressure exerted on cell Isotonic = same solute concentration inside and outside cell Hypertonic = Greater solute concentration outside cell than

inside cell Water leaves cell & cell shrinks

Hypotonic = Greater solute concentration inside cell than outside Water enters cell and cell swells Cell may lyse “burst”

  Filtration

Fluid is pushed across a membrane that larger molecules cannot cross Separates solids from liquids

Force = hydrostatic pressure – derived from blood pressure

 

Active TransportMovement against a concentration gradientRequires ATP for energy (up to 40% of cell’s ATP)

Includes carrier proteins e.g. Na+/K+ pumps can pump sodium out of cell and potassium into cell

Establishes a concentration gradient

Endocytosis Cell membrane surrounds and engulfs particle Types include

Pinocytosis Cell takes up a fluid

Phagocytosis Cell takes up a solid Example: white blood cell engulfing a bacteria

Receptor mediated endocytosis Selective endocytosis Receptors on cell membrane bind to substance and

trigger endocytosis Provides specificity Removes substances in low concentrations

ExocytosisReverse of endocytosis

Transport substances out of cellVesicle merges with cell membrane and releases contentExample- neuron releasing neurotransmitters

Transcytosis Endocytosis & Exocytosis Allows passage through a cell

e.g. HIV enters body by transcytosis through epithelium of anus, mouth, or reproductive tract.

Cell CycleInterphaseMitosisCytokinesis = division of

cytoplasmDifferentiation

INTERPHASE

G1 (Gap) Phase Cell is active and grows Growth followed by a checkpoint that determines cell’s

fate. Cell May:

Continue to grow, then divide Remain active, but not divide Die

S phase (S = synthesis) DNA replicates

G2 phase Cell prepares for cell division

MITOSISMitosis occurs in somatic (non-sex) cellsSex cells divide by meiosis46 chromosomes –paired23 paternal & 23 maternal

Chromatin condenses to become chromosomeEach replicated chromosome consists of 2 sister chromatids

Chromatids held in place by centromeres

KNOW WHAT HAPPENS IN PMAT