Soriano Notes~Chapter 3~Anatomy & Physiology

Front 1

CELL THEORY

Back 1

~The cell is the basic structural and functional unit of life

~Organismal activity depends on individual and collective activity of cells

~Biochemical activities of cells are dictated by sub-cellular structure

~Continuity of life has a cellular basis

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PLASMA MEMBRANE

Back 2

~Separates intracellular fluids from extracellular fluids

~Plays a dynamic role in cellular activity

~Glycocalyx is a glycoprotein area abutting the cell that provides highly specific biological markers by which cells recognize one another

Front 3

FLUID MOSAIC MODEL

Back 3

~Double bilayer of lipids with imbedded, dispersed proteins

~Bilayer consists of phospholipids, cholesterol, and glycolipids

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GLYCOLIPIDS

Back 4

Lipids with bound carbohydrate

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PHOSPHOLIPIDS

Back 5

Have hydrophobic & hydrophilic bipoles

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FUNCTIONS OF MEMBRANE PROTEINS (6)

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1~Transport

2~Enzymatic activity

3~Receptors for signal transduction

4~Intercellular adhesion

5~Cell-cell recognition

6~Attachment to cytoskeleton and extracellular matrix

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PLASMA MEMBRANE SURFACES

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~Differ in the kind and amount of lipids they contain

~Glycolipids are found only in the outer membrane surface

~20% of all membrane lipid is cholesterol

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LIPID RAFTS

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~Make up 20% of the outer membrane surface

~Composed of sphingolipids and cholesterol

~Are concentrating platforms for cell-signaling molecules

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MEMBRANE JUNCTIONS TYPES (3)

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1~Tight junction

2~Desmosome

3~Gap Junction

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TIGHT JUNCTION

Back 10

Impermeable junction that encircles the cell

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DESMOSOME

Back 11

Anchoring junction scattered along the sides of cells

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GAP JUNCTION

Back 12

A nexus that allows chemical substances to pass between cells

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EXAMPLES OF PASSIVE MEMBRANE TRANSPORT

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1~SIMPLE DIFFUSION

2~FACILITATED DIFFUSION

3~OSMOSIS

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SIMPLE DIFFUSION

Back 14

Nonpolar and lipid-soluble substances

~Diffuse directly through the lipid bilayer

~Diffuse through channel proteins

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FACILITATED DIFFUSION

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~Transport of glucose, amino acids, and ions

~Transported substances bind carrier proteins or pass through protein channels

Front 16

CARRIER PROTEINS

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~Are integral transmembrane proteins

~Show specificity for certain polar molecules including sugars and amino acids

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OSMOSIS

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~Occurs when the concentration of a solvent is different on opposite sides of a membrane

~Diffusion of water across a semipermeable membrane

~Osmolarity – total concentration of solute particles in a solution

~Tonicity – how a solution affects cell volume

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EFFECT OF MEMBRANE PERMEABILITY ON DIFFUSION & OSMOSIS -PASSIVE MEMBRANE TRANSPORT: FILTRATION

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~The passage of water and solutes through a membrane by hydrostatic pressure

~Pressure gradient pushes solute-containing fluid from a higher-pressure area to a lower-pressure area

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EXAMPLES OF SOLUTIONS OF VARYING TONICITY:

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1~ISOTONIC

2~HYPERTONIC

3~HYPOTONIC

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ISOTONIC

Back 20

Solutions with the same solute concentration as that of the cytosol

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HYPERTONIC

Back 21

Solutions having greater solute concentration than that of the cytosol

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HYPOTONIC

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Solutions having lesser solute concentration than that of the cytosol

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ACTIVE TRANSPORT

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~Uses ATP to move solutes across a membrane

~Requires carrier proteins

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TYPES OF ACTIVE TRANSPORT

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1~SYMPORT SYSTEM

2~ANTIPORT SYSTEM

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SYMPORT SYSTEM

Back 25

Two substances are moved across a membrane in the same direction

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ANTIPORT SYSTEM

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Two substances are moved across a membrane in opposite directions

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TYPES OF ACTIVE TRANSPORT

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1~PRIMARY ACTIVE TRANSPORT

2~SECONDARY ACTIVE TRANSPORT

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PRIMARY ACTIVE TRANSPORT

Back 28

Hydrolysis of ATP phosphorylates the transport protein causing conformational change

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SECONDARY ACTIVE TRANSPORT

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Use of an exchange pump (such as the Na+-K+ pump) indirectly to drive the transport of other solutes

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TYPES OF VESICULAR TRANSPORT (5)

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1~Transport of large particles and macromolecules across plasma membranes via EXOCYTOSIS & ENDOCYTOSIS

2~TRANSCYTOSIS

3~VESICULAR TRAFFICKING

4~PHAGOCYTOSIS

5~FLUID-PHASE ENDOCYTOSIS

6~RECEPTOR-MEDIATED ENDOCYTOSIS

7~NON-CLATHRIN-COATED VESICLES

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EXOCYTOSIS

Back 31

Moves substance from the cell interior to the extracellular space

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ENDOCYTOSIS

Back 32

Enables large particles and macromolecules to enter the cell

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TRANSCYTOSIS

Back 33

Moving substances into, across, and then out of a cell

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VESICULAR TRAFFICKING

Back 34

Moving substances from one area in the cell to another

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PHAGOCYTOSIS

Back 35

Pseudopods engulf solids and bring them into the cell’s interior

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FLUID-PHASE ENDOCYTOSIS

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Plasma membrane infolds, bringing extracellular fluid and solutes into the interior of the cell

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RECEPTOR-MEDIATED ENDOCYTOSIS

Back 37

Clathrin-coated pits provide the main route for endocytosis and transcytosis

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NON-CLATHRIN-COATED VESICLES

Back 38

Caveolae that are platforms for a variety of signaling molecules

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MEMBRANE POTENTIAL

Back 39

~Voltage across a membrane

~Resting membrane potential – the point where K+ potential is balanced by the membrane potential
a) Ranges from –20 to –200 mV
b) Results from Na+ and K+ concentration gradients across the membrane
c) Differential permeability of the plasma membrane to Na+ and K+

~Steady state – potential maintained by active transport of ions

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GENERATION & MAINTENANCE OF MEMBRANE POTENTIAL CELL ADHESION MOLECULES (CAMs)

Back 40

~Anchor cells to extracellular matrix

~Assist in movement of cells past one another

~Rally protective white blood cells to injured or infected areas

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ROLES OF MEMBRANE RECEPTORS (4)

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1~CONTACT SIGNALING

2~ELECTRICAL SIGNALING

3~CHEMICAL SIGNALING

4~G PROTEIN-LINKED RECEPTORS

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CONTACT SIGNALING

Back 42

Important in normal development & immunity

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ELECTRICAL SIGNALING

Back 43

Voltage-regulated "ion gates" in nerve & muscle tissue

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CHEMICAL SIGNALING

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Neurotransmitters bind to chemically gated channel-linked receptors in nerve & muscle tissue

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G PROTEIN-LINKED

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Ligands bind to a receptor which activates a G protein, causing the erlease of a second messenger, such as cyclic AMP

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OPERATION OF A G PROTEIN:

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1~An extracellular ligand (first messenger), binds to a specific plasma membrane protein

2~The receptor activates a G protein that relays the message to an effector protein

3~The effector is an enzyme that produces a second messenger inside the cell

4~The second messenger activates a kinase

5~The activated kinase can trigger a variety of cellular responses

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CYTOPLASM

Back 47

~Material between plasma membrane and the nucleus

~Includes Cytosol, Cytoplasmic organelles & Inclusions

Front 48

CYTOSOL

Back 48

Largely water with dissolved protein, salts, sugars, and other solutes

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CYTOPLASMIC ORGANELLES

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Metabolic machinery of the cell

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INCLUSIONS

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Chemical substances such as glycosomes, glycogen granules & pigment

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CYTOPLASMIC ORGANELLES & TYPES (2)

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~Specialized cellular compartments

1~MEMBRANOUS

2~NONMEMBRANOUS

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MEMBRANOUS (Cytoplasmic organelles) (5)

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~MITOCHONDRIA, PEROXISOMES, LYSOSOMES, ENDOPLASMIC RETICULUM & GOLGI APPARATUS

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NON-MEMBRANOUS (Cytoplasmic organelles) (3)

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~CYTOSKELETON, CENTRIOLES & RIBOSOMES

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MITOCHONDRIA

Back 54

~Double membrane structure w shelf-like cristae

~Provide most of cell’s ATP via aerobic cellular respiration

~Contain their own DNA and RNA

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PEROXISOMES

Back 55

~Membranous sacs containing oxidases & catalases

~Detoxify harmful or toxic substances

~Neutralize dangerous free radicals

~Free radicals((Highly reactive chemicals w unpaired electrons (i.e., O2–))

Front 56

LYSOSOMES

Back 56

~Spherical membranous bags containing digestive enzymes

~Digest ingested bacteria, viruses & toxins

~Degrade nonfunctional organelles

~Breakdown glycogen & release thyroid hormone

~Breakdown non-useful tissue

~Breakdown bone to release Ca2+

~Secretory lysosomes are found in white blood cells, immune cells & melanocytes

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ENDOPLASMIC RETICULUM (ER) & TYPES (2)

Back 57

~Interconnected tubes & parallel membranes enclosing cisternae

~Continuous with nuclear membrane

1~Rough ER

2~Smooth ER

Front 58

GOLGI APPARATUS

Back 58

~Stacked & flattened membranous sacs

~Functions in modification, concentration & packaging of proteins

~Transport vessels from ER fuse with cis face of Golgi apparatus

~Proteins then pass through Golgi apparatus to trans face

~Secretory vesicles leave trans face of Golgi stack & move to designated parts of cell

Front 59

CYTOSKELETON & (3) PARTS

Back 59

~The “skeleton” of cell

~Dynamic, elaborate series of rods running through cytosol

~Consists of:
a) MICROTUBULES
b) MICROFILAMENTS
c) INTERMEDIATE FILAMENTS

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CENTRIOLES

Back 60

~Small barrel-shaped organelles located in the centrosome near the nucleus

~Pinwheel array of nine triplets of microtubules

~Organize mitotic spindle during mitosis

~Form the bases of cilia and flagella

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RIBOSOMES

Back 61

~Granules containing protein and rRNA

~Site of protein synthesis

~Free ribosomes synthesize soluble proteins

~Membrane-bound ribosomes synthesize proteins to be incorporated into membranes

Front 62

ENDOMEMBRANE SYSTEM & (2) FUNCTIONS & PARTS (8)

Back 62

~System of organelles that function to:

1~Produce, store, and export biological molecules

2~Degrade potentially harmful substances

Parts:
1~Nuclear envelope
2~Smooth E.R.
3~Rough E.R.
4~Lysosomes
5~Vacuoles
6~Transport vesicles
7~Golgi apparatus
8~Plasma membrane

Front 63

ROUGH E.R.

Back 63

~External surface studded with ribosomes

~Manufactures all secreted proteins

~Responsible for the synthesis of integral membrane proteins and phospholipids for cell membranes

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SMOOTH E.R.

Back 64

~Tubules arranged in a looping network

~Catalyzes the following reactions in various organs of the body:

a) In the liver – lipid and cholesterol metabolism, breakdown of glycogen and, along with the kidneys, detoxification of drugs

b) In the testes – synthesis of steroid-based hormones

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MICROTUBULES

Back 65

~Dynamic, hollow tubes made of the spherical protein tubulin

~Determine the overall shape of the cell and distribution of organelles

Front 66

MICROFILAMENTS

Back 66

~Dynamic strands of the protein actin

~Attached to the cytoplasmic side of the plasma membrane

~Braces and strengthens the cell surface

~Attach to CAMs and function in endocytosis and exocytosis

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INTERMEDIATE FILAMENTS

Back 67

~Tough, insoluble protein fibers with high tensile strength

~Resist pulling forces on the cell and help form desmosomes

Front 68

SIGNAL MECHANISM OF PROTEIN SYNTHESIS (5)

Back 68

1~mRNA – ribosome complex is directed to rough ER by a signal-recognition particle (SRP)

2~SRP is released & polypeptide grows into cisternae

3~The protein is released into cisternae & sugar groups are added

4~The protein folds into a three-dimensional conformation

5~The protein is enclosed in a transport vesicle & moves toward Golgi apparatus

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MOTOR MOLECULES

Back 69

~Protein complexes that function in motility

~Powered by ATP

~Attach to receptors on organelles

Front 70

CILIA

Back 70

~Whip-like, motile cellular extensions on exposed surfaces of certain cells

~Move substances in one direction across cell surfaces

Front 71

NUCLEUS

Back 71

~Contains nuclear envelope, nucleoli, chromatin & 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

Front 72

NUCLEAR ENVELOPE

Back 72

~Selectively permeable double membrane barrier containing pores

~Encloses jellylike nucleoplasm, which contains essential solutes

~Outer membrane is continuous with Rough ER & is studded with ribosomes

~Inner membrane is lined w nuclear lamina, which maintains shape of nucleus

~Pore complex regulates transport of large molecules into & out of nucleus

Front 73

NUCLEOLI

Back 73

~Dark-staining spherical bodies within nucleus

~Site of ribosome production

Front 74

CHROMATIN

Back 74

~Threadlike strands of DNA & histones

~Arranged in fundamental units called nucleosomes

~Form condensed, barlike bodies of chromosomes when nucleus starts to divide

Front 75

CELL CYCLE (2)

Back 75

1~Interphase
a) Growth (G1)
b) Synthesis (S)
c) Growth (G2)

2~Mitotic phase
a) Mitosis
b) Cytokinesis

Front 76

INTERPHASE (4)

Back 76

1~G1 (gap 1) –Metabolic activity & vigorous growth

2~G0 –Cells that permanently cease dividing

3~S (synthetic) –DNA replication

4~G2 (gap 2) –Preparation for division

Front 77

DNA REPLICATION

Back 77

1~DNA helices begin unwinding from nucleosomes

2~Helicase untwists double helix & exposes complementary strands

3~The site of replication is replication bubble

4~Each nucleotide strand serves as a template for building a new complementary strand

5~The replisome uses RNA primers to begin DNA synthesis

6~DNA polymerase III continues from primer & covalently adds complementary nucleotides to template

7~Since DNA polymerase only works in one direction:
a)A continuous leading strand is synthesized
b)A discontinuous lagging strand is synthesized

8~DNA ligase splices together short segments of the discontinuous strand & 2 new telomeres are also synthesized.
This process is called semi conservative replication

Front 78

CELL DIVISION (2)

Back 78

~Essential for body growth & tissue repair

~PHASES:

1~MITOSIS

2~CYTOKINESIS

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MITOSIS (4)

Back 79

~Nuclear division

~PHASES:

1~PROPHASE

2~METAPHASE

3~ANAPHASE

4~TELOPHASE

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CYTOKINESIS

Back 80

~Division of cytoplasm

~Cleavage furrow formed in late anaphase by contractile ring

~Cytoplasm is pinched into two parts after mitosis ends

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EARLY & LATE PROPHASE

Back 81

~Asters are seen as chromatin condenses into chromosomes

~Nucleoli disappear

~Centriole pairs separate & the mitotic spindle is formed

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METAPHASE

Back 82

~Chromosomes cluster at middle of cell with their centromeres aligned at exact center or equator of the cell

~This arrangement of chromosomes along a plane midway between poles is called metaphase plate

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ANAPHASE

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~Centromeres of chromosomes split

~Motor proteins in kinetochores pull chromosomes toward poles

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TELOPHASE & CYTOKINESIS

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~New sets of chromosomes extend into chromatin

~New nuclear membrane is formed from Rough ER

~Nucleoli reappear

~Generally cytokinesis completes cell division

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CONTROL OF CELL DIVISION

Back 85

~Surface-to-volume ratio of cells

~Chemical signals such as growth factors & hormones

~Contact inhibition

~Cyclins & cyclin-dependent kinases (Cdks) complexes

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PROTEIN SYNTHESIS

Back 86

~DNA serves as master blueprint for protein synthesis

~Genes are segments of DNA carrying instructions for a polypeptide chain

~Triplets of nucleotide bases form genetic library

~Each triplet specifies coding for an amino acid

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FROM DNA TO PROTEIN ROLES OF THE (3) TYPES OF RNA:

Back 87

1~Messenger RNA (mRNA) –Carries genetic information from DNA in nucleus to ribosomes in cytoplasm

2~Transfer RNAs (tRNAs) –Bound to amino acids base pair with codons of mRNA at ribosome to begin process of protein synthesis

3~Ribosomal RNA (rRNA) –A structural component of ribosomes

Front 88

TRANSCRIPTION

Back 88

~Transfer of information from sense strand of DNA to RNA

~Transcription factor:
a) Loosens histones from DNA in area to be transcribed
b) Binds to promoter, a DNA sequence specifying start site of RNA synthesis
c) Mediates binding of RNA polymerase to promoter

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TRANSCRIPTION: RNA POLYMERASE

Back 89

~An enzyme that oversees synthesis of RNA

~Unwinds DNA template

~Adds complementary ribonucleoside triphosphates on DNA template

~Joins these RNA nucleotides together

~Encodes a termination signal to stop transcription

Front 90

INITIATION OF TRANSLATION

Back 90

~A leader sequence on mRNA attaches to small subunit of ribosome

~Methionine-charged initiator tRNA binds to small subunit

~Large ribosomal unit now binds to this complex forming a functional ribosome

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GENETIC CODE

Back 91

RNA codons code for amino acids according to a genetic code

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INFO TRANSFER FROM DNA TO RNA

Back 92

~DNA triplets are transcribed into mRNA codons by RNA polymerase

~Codons base pair w tRNA anticodons at ribosomes

~Amino acids are peptide bonded at ribosomes to form polypeptide chains

~Start & stop codons are used in initiating & ending translation

Front 93

OTHER ROLES OF RNA (3)

Back 93

1~Antisense RNA – prevents protein-coding RNA from being translated

2~MicroRNA – small RNAs that interfere w mRNAs made by certain exons

3~Riboswitches – mRNAs that act as switches regulating protein synthesis in response to environmental conditions

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CYTOSOLIC PROTEIN DEGRADATION

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~Nonfunctional organelle proteins are degraded by lysosomes

~Ubiquitin attaches to soluble proteins & they are degraded in proteasomes

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EXTRACELLULAR MATERIALS

Back 95

~Body fluids & cellular secretions

~Extracellular matrix

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DEVELOPMENTAL ASPECTS OF CELLS

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~All cells of body contain same DNA but develop into all specialized cells of body

~Cells in various parts of embryo are exposed to different chemical signals that channel them into specific developmental pathways

~Genes of specific cells are turned on or off (i.e., by methylation of their DNA)

~Cell specialization is determined by kind of proteins that are made in that cell

~Development of specific & distinctive features in cells is called cell differentiation

~Cell aging
a) Wear & tear theory attributes aging to little chemical insults & formation of free radicals that have cumulative effects throughout life
b) Genetic theory attributes aging to cessation of mitosis that is programmed into our genes