Biology Ch. 4

Front 1

Nucleus

Back 1

-Contains ALL DNA in an animal cell (except) for a small amount in the mitochondria.
-distinguishes eukaryotes from prokaryotes.
-Transcription can only take place in the nucleus! (b/c DNA can't leave the nucleus).

Front 2

Nuclear membrane

Back 2

-the nucleus is wrapped in a double phospholipid bilayer.

Front 3

Nuclear pores

Back 3

-The nuclear envelope is perforated with large holes.
-mRNA can leave exit the nucleus through nuclear pores, but DNA cannot.

Front 4

Phagocytosis

Back 4

-the cell membrane protrudes outward to envelope and engulf particulate matter.
-only a few specialized cells engage in this.
-impetus is the binding of proteins on particulate matter to protein receptors in the phagocytotic cell.

Front 5

Pinocytosis

Back 5

-extracellular fluid is engulfed by small invaginations of the cell membrane.
-process is performed by most cells, it is nonselective.

Front 6

Endoplasmic reticulum

Back 6

-a thick maze of mebranous walls seperating the cytosol from the ER luman or cisternal space (the extracellular fluid" side of the ER).

Front 7

ER lumen or cisternal space

Back 7

-the internal space of the ER

Front 8

Rough ER

Back 8

-has many ribosomes attached to it on the cytosolic side, giving it a granular appearance.
-translation on the rough ER propels proteins into the ER lumen as they are created.

Front 9

Golgi apparatus

Back 9

-A series of flattened, membrane bound sacs.
-small transport vesicles bud off from ER and carry the proteins across the cytosol to the Golgi.
-organizes and concentrates proteins as they are shuttled by transport vesicles progressively outward from one compartment of the Golgi to the next.
-the end product is a vesicle full of proteins, which may be expelled from the cell as secretory vesicles or mature to lysosomes

Front 10

secretory vesicles

Back 10

-vesicles that transport proteins from the Golgi and are then expelled from the cell
-may contain enzymes, growth factors, or extracellular matrix components.
-release contents through exocytosis
-vesicle incorporates into the cell membrane, thus acts as a vehicle with which to supply the cell membrane with integral proteins and lipids, and as a mechanism for membrane expansion.

Front 11

lysosomes

Back 11

-contain acid hydrolases that are capable of breaking down every major type of macromolecule within the cell.
-low interior pH (5)
-fuse with endocytotic vesicles and digest their contents, digest their contents.

Front 12

Smooth ER

Back 12

-ER that lacks ribosomes.
-tends to be tubular whereas rough ER tends to resemble sacs.
-important in lipid synthesis including steroids
-helps to detoxify drugs

Front 13

Cytoskeleton

Back 13

-A network of filaments that determine the structure and motility of a cell.
-anchors some membrane proteins and other cellular components, moves components within the cell, moves the cell itself.

Front 14

Microtubules vs. microfilaments

Back 14

-both are major types of filaments in the cytoskeleton.
-Microtubules are larger. They are rigid, hollow tubes made from a protein called tubulin. Involved in flagella and cilia constructure, and the spindle apparatus.
-Microfilaments squeeze the membrane together in phagocytosis and cytokinesis. The contractile force in microvilli and muscle.

Front 15

Tubulin

Back 15

-a globular protein that forms microtubules.

Front 16

flagella and cilia

Back 16

-specialized structures made from microtubules
-the major portion of each structure is called the axenome
-cross bridges made from a protein called dynein connect the outer pairs of microtubules to their neighbor.

Front 17

Axenome

Back 17

-the major portion of each flagellum and cilium.
-contains microtubules forming a circle around two loan microtubules in a 9 + 2 arrangement.

Front 18

Dynein

Back 18

-cross bridges between microtubules in a flagellum or cilium which connect outer pairs of microtubules to their neighbor.
-allow microtubules to slide laterally along their neighbors creating a whip-like action in cilia or a wiggle-like action in flagella.

Front 19

Centrosome

Back 19

-The major microtubule organizing center (MTOC) in animal cells.
-A microtubule grows away from the MTOC.

Front 20

Centrioles

Back 20

-function in the production of flagella and cilia

Front 21

microfilaments

Back 21

-smaller than microtubules
-a major component is polymerized protein actin
-squeeze the cell membrane together in phagocytosis and cytokinesis.
-produce the contracting force in muscle, active in cytoplasmic streaming.

Front 22

cytoplasmic streaming

Back 22

-responsible for amoeba-like movement in cells, produced by microfilaments.

Front 23

Eukaryotic flagella vs. prokaryotic flagella.

Back 23

-eukaryotic flagella are made from a 9 + 2 microtubule configuration, undergo a whip-like action
-a prokaryotic flagellum is a thin strand of a single protein called flagellin, rotate.

Front 24

Types of cellular junctions

Back 24

1. tight junction
2. desmosome
3. gap junction

Front 25

Tight junction

Back 25

-a type of cellular junction that forms a watertight seal from cell to cell that can block water, ions, and other molecules from moving around and past cells.

Front 26

Desmosome

Back 26

-joins two cells at a single point.
-Attach directly to the cytoskeleton of each cell.
-do not prevent water from circulating around all sides of the cell.
-found in tissues that experience a lot of stress (ex. skin)

Front 27

Gap junctions

Back 27

-small tunnels connecting cells.
-allow small molecules and ions to move between cells.
-found in cardiac muscle.

Front 28

Mitochondira

Back 28

-the 'powerhouse' of the eukaryotic cell.
-location of the Krebs cycle
-have their own circular DNA that replicates independently from the eukaryotic cell.
-know the parts and relate to cellular respiration!!!

Front 29

Endosymbiotic theory

Back 29

-mitochondria may have evolved form a symbiotic relationship between ancient prokaryotes and eukaryotes
-like prokaryotes, have their own circular DNA that replicates independently from the eukaryotic cell.
-DNA is passed maternally
-surrounded by two phospholipid bilayers

Front 30

Inner membrane of mitochondria

Back 30

-the inner phospholipid bilayer.
-holds the electron transport chain.

Front 31

Cristae

Back 31

-invaginations in the innermembrane of the mitochondria.

Front 32

Intermembrane space in mitochondria

Back 32

-the space between the inner and outer membrane.

Front 33

Extracellular matrix

Back 33

-a molecular network that holds tissue cells in place.
-the stuff that surrounds the cell and that is formed by the cell itself.

Front 34

Neuronal communication vs. hormone communication

Back 34

-neuronal tends to be rapid direct, and specific.
-hormonal tends to be slower, spread throughout the body, and affect many cells and tissues in many different ways.

Front 35

Intersitial fluid

Back 35

-the fluid between cells into which local mediators are released by a variety of cells

Front 36

Paracrine system

Back 36

-local mediators are released by a variety of cells into the interstitial fluid and act on neighboring cells a few millimeters away.

Front 37

Neuron

Back 37

-the functional unit of the nervous system.
-capable of transmitting an electrical signal from one cell to another via electrical or chemical means.
-consist of many dendrites, a single cell body, and usually one axon with many small branches.
-depends almost entirely on glucose for chemical energy
-highly specialized; has lost the capacity to divide

Front 38

Nervous system

Back 38

-includes the brain, spinal chord, nerves and neural support cells, certain sense organs such as eye and ear.

Front 39

dendrites

Back 39

-part of a neuron that receives a signal to be transmitted

Front 40

axon hillock

Back 40

-part of the neuron that connects the cell body to the axon.
-if an electrical stimulus is great enough, the axon hillock will generate an action potential in all directions, including down the axon.

Front 41

axon

Back 41

-part of a neuron that carries the action potential to the synapse, which passes the electrical signal to another cell.

Front 42

Resting potential

Back 42

-established by an equilibrium between passive diffusion of ions across the membrane and the Na/K pump.
-the Na/K pump moves 3 positively charged Na ions out of the cell while bringing two positively charged K ions into the cell.
-increases the positive charge on the outside of the cell, negative on inside.
-when all rates are at equilibrium, the inside of the membrane is negative = resting potential

Front 43

Voltage gated sodium channels

Back 43

-integral membrane proteins in the membrane of a neuron
-change configuration when the voltage across the membrane is disturbed.
-allow Na to flow through the membrane into the cell.
-as Na flows in, changes potential further causing more channels to open, K remains high in cell.
-the cell reverses polarity resulting in depolarization.

Front 44

Depolarization of a cell

Back 44

-when the membrane potential reverses from negative inside to positive inside due to influx of Na.

Front 45

Voltage gated potassium channels

Back 45

-Take longer to open than Na-gated channels.
-by the time they open, Na is flowing out of the cell. Make the inside more negative.
-results in repolarization

Front 46

Repolarization of the cell.

Back 46

K+ flows out of the cell when K+ channels are open during an action potential. The inside of the cell becomes more negative.

Front 47

Hyperpolarization.

Back 47

-potassium channels during depolarization are slow to close and the inside of the cell membrane becomes even more negative than its resting potential.

Front 48

Steps of depolarization in a neuron

Back 48

1. Membrane is at rest. Na and K potassium channels are clossed. 3 Na pumped out of cell, K pumped into cell by Na/K pump. Inside is negative, outside is positive.
2. Na channels open when a change in voltage occurs. The cell depolarizes as Na flows in.
3. K channels open as Na channels begin to deactivate. K flows out.
4. Na channels are inactivated. Open potassium channels repolarize the membrane.
5. Potassium channels close and the membrane equilibrates to its resting potential.

Front 49

Threshold stimulus

Back 49

-the stimulus to the membrane must be greater than the threshold stimulus in order to create an action potential.
-any stimulus greater than the threshold stimulus creates the same size action potential.

Front 50

Synapse

Back 50

-neural impulses are transmitted from one cell to another chemically or electrically via a synapse.
-slowest part of the process of nervous system cellular communication

Front 51

Electrical synapse

Back 51

-uncommon. composed of gap junctions between cells.
-transmit signals faster than chemical synapses in both directions.

Front 52

Chemical synapse, method of communication.

Back 52

-a more common synapse.
-unidirectional.
-a small vesicle filled with a neurotransmitter rests just inside the presynaptic membrane.
-membrane near the synapse contains large number of Ca voltage gated channels.
-When action potential arrives at synapse, Ca flows into cell.
-sudden influx of Ca triggers neurotransmitter vesicles to be released into synaptic cleft via exocytotic process.
-nuerotransmitter moves across synaptic cleft via Brownian motion
-postsynaptic membrane contains neurotransmitter receptor proteins. When neurotransmitter attaches to receptor proteins, postsynaptic membrane becomes more permeable to ions. Ions move across postsynaptic membrane completing transfer of neural impulse.
-the neurotransmitter may be recycled or destroyed by enzymes.

Front 53

Second messenger system.

Back 53

-A system of neural communication in which a neurotransmitter activates a another molecule inside the cell to make changes.
-good for prolonged change, such as memory.

Front 54

Myelin

Back 54

-electrically insulating sheaths which wrap around axons in the CNS.
-increases the rate at which an axon can transmit signals.

Front 55

Schwann cells

Back 55

-in the PNS, myelin is produced by these cells.

Front 56

White matter

Back 56

-myelinated axons appear white to the naked eye.

Front 57

Gray matter

Back 57

-the neuronal cell appears gray to the naked eye.

Front 58

nodes of Ranvier

Back 58

-tiny gaps between myelin

Front 59

Saltatory conduction.

Back 59

- an action potential jumps from one node of Ranvier to the next as quickly as the disturbance moves through the electric field between them.

Front 60

3 functions that a neuron may perform

Back 60

1. sensory (afferent) neurons
2. Interneurons
3. Motor (efferent) neurons.

Front 61

Sensory (afferent) neurons.

Back 61

-Receive signals from a receptor cell that interacts with the environment.
-located ventrally on the spinal chord.

Front 62

Interneuron

Back 62

-transfers signals form neuron to neuron.

Front 63

Motor (efferent) neurons

Back 63

-carry signals to a muscle or gland called the effector.
-located dorsally on the spinal chord.

Front 64

Nerves

Back 64

-Neural processes (axons and dendrites) are typically bundled together to form this structure.

Front 65

somatic nervous system

Back 65

-designed primarily to respond to the external environment.
-contains sensory and motor functions.
-part of the PNS

Front 66

autonomic nervous system

Back 66

-part of the PNS, deals with involuntary reactions.

Front 67

Sympathetic nervous system

Back 67

-part of the autonomic nervous system
-deals with the "fight or flight" response
-originates in neurons whose cell bodies are found in the spinal chord.

Front 68

Parasympathetic nervous system

Back 68

-deals with the "rest and digest" response.
-signals originate in neurons whose cell bodies can be found in both the brain and spinal chord.

Front 69

Acetylcholine

Back 69

-the neurotransmitter used in somatic and parasympathetic nervous system.

Front 70

Ganglion

Back 70

-an encapsulated neural structure consisting of a collection of cell bodies or neurons

Front 71

Preganglionic neuron

Back 71

-cell body is located in the brain or spinal cord.
-neurons that pass between the CNS and the ganglion; only in the ANS

Front 72

Postganglionic neuron

Back 72

-cell body is located outside the CNS
-pass between the ganglia and the effector cells; only in the ANS.
-connected to a preganglionic neuron before.

Front 73

Epinephrine and norepinephrine

Back 73

-used in the sympathetic nervous system.

Front 74

Structures and functions of the lower brain

Back 74

-medulla, hypothalamus, thalamus, cerebellum.
-integrates subconscious activites such as the respiratory system, arterial pressure, salivation, emotions, reactions to pain and pleasure

Front 75

Structures and functions of higher brain

Back 75

-cerberum and cerebral cortex.
-acts and stores memories, process thoughts.
-cannot function without lower brain.

Front 76

Cornea

Back 76

-when light reflects off an object in the external environment it first strikes the eye on the cornea.
-nonvascular, made largely from collagen.

Front 77

Ciliary muscle

Back 77

-a muscle that circles the lens of an eye. when it contracts, the opening of the circle decreases allowing the lens to become more like a sphere and bringing the focal point closer to the lens.

Front 78

retina

Back 78

-covers the inside back (distal portion) of the eye. Contains rods and cones.

Front 79

cones

Back 79

-sensitive cells that discern color
-located on the retina.

Front 80

rods

Back 80

-sensitive cells that do not distinguish color
-located on the retina.

Front 81

Iris

Back 81

-the colored portion of the eye that creates the opening called the pupil

Front 82

Pupil

Back 82

-the opening in the eye, surrounded by the iris.

Front 83

Parts of the ear

Back 83

1. outer ear
2. middle ear
3. inner ear

Front 84

tympanic membrane

Back 84

-the external auditory canal carries soundwaves to the tympanic mebrane or ear drum
-starts the middle ear.

Front 85

parts of the middle ear

Back 85

1. malleus
2. incus
3. stapes
-the three bones act as a lever system translating waves to the oval window.
-changes the combination of force and displacement from the inforce to the outforce.
-the displacement lessens, creating an increase in force.
-also an increase in pressure b/c smaller space.

Front 86

cochlea

Back 86

-a spiral in the inner ear, increase and decrease in pressure moves the vestibular membrane in and out.

Front 87

hair cells in ear

Back 87

-contain a specialized microvilli which detect movement.
-detect movement in the ear.

Front 88

organ of Corti

Back 88

-contain hair cells, where movement is detected and transduced into neural signals.

Front 89

semicircular canals

Back 89

-located in the inner ear
-responsible for balance.
-each canal has fluid and hair cells. when the body changes position with respect to gravity, the momentum of the fluid is changed impacting the hair cells, and the body senses motion.

Front 90

Peroxisome

Back 90

-vesicles in the cytosol.
-grow by incorporating lipids and proteins from the cytosol.
-involve the production and breakdown of hydrogen peroxide.
-inactivate toxic substances, regulate oxygen concentration, play a role in the synthesis and breakdown of lipids, metabolism of nitrogenous bases and carbohydrates.