Biol 189 Quiz 3

Front 1

signal transduction pathway

Back 1

-sequence of molar events and chemical reactions that lead to a cellular response, following the receptor's activation by a signal.
-signal, receptor, response
-may produce short or long term responses

Front 2

autocrine

Back 2

-signals affect the same cells that release them
-only in cell

Front 3

paracrine

Back 3

-signals diffuse to and affect nearby cells

Front 4

hormones

Back 4

-travel to distant cells

Front 5

allosteric regulation

Back 5

-common mechanism of signal transduction
-change shape in protein as a result of a molecule binding to it

Front 6

ligands

Back 6

-not metabolized, their binding may expose an an active site on a receptor
-binding is reversible

Front 7

inhibitor

Back 7

-aka antagonist
-can bind in place of normal ligand
-closes active site

Front 8

cell receptors classified by activity
3 receptors

Back 8

-ion receptors
-dimensional receptors
-g protein-linked receptors

Front 9

ion channel receptors

Back 9

-aka gated ion channels
-change their 3-dimensional shape when a ligand binds (acetylcholine receptor)
-ie. nervous system

Front 10

protein kinase receptors

Back 10

-change their shape when ligand bonds
-new shape exposes or activates cytoplasmic domain that has catalytic

Front 11

g protein receptors

Back 11

-ligands binding to g protein-linked receptors expose a site that can bind to a membrane protein
-signal attaches to receptor transmembrane
-changes shape and gets phosphorylated
-will activate effector protein and all reactions will happen by phosphorelation

Front 12

signal transduction

Back 12

-initiates a cascade of protein interactions-signal can amplified and distributed to cause different responses

Front 13

second messages

Back 13

-intermediary between the receptor and cascade responses
-fight of flight response, epinephrine activates the liver enzyme glycogen phosphorylase
-breakdown of glycogen to provide quick energy

Front 14

signal cascade

Back 14

-enzymes may be either activated or inhibited by other enzymes
-in liver cells, signal cascade begins when epinephrine stimulates g protein-mediated protein kinase pathway

Front 15

signal transduction ends

Back 15

-after cell responds
-enzymes convert each transducer back to its inactive precursor
-balance between regulating enzymes and signal enzymes determines cell's response

Front 16

metabolic pathways

Back 16

-energy is stored in chemical bonds and can be released and transformed

Front 17

free energy

Back 17

chemical energy available to do work

Front 18

5 principles governing metabolic pathways

Back 18

1. Chemical transformations occur in a series of intermediate reactions that form a metabolic pathway.
2. Each reaction is catalyzed by a specific enzyme.
3. Most metabolic pathways are similar in all organisms.
4. In eukaryotes, many metabolic pathways occur inside specific organelles.
5. Each metabolic pathway is controlled by enzymes that can be inhibited or activated.

Front 19

exergonic reaction

Back 19

-release energy
-cell respiration
-catabolism
- (+)
- hydrolysis of ATP
- ATP + H20 -> ADP + Pi + free energy

Front 20

endergonic reaction

Back 20

-requires energy
-active transport
-cell movements
-anabolism
- (-)

Front 21

redox reactions

Back 21

-can also be transferred by transfer of electrons in oxidation-reduction
-Na + Cl (becomes oxidized loses electrons)-> Na+ + Cl- (becomes reduced gains electrons)
-transfers of hydrogen atoms involve transfers of electrons
-when a molecule loses a hydrogen atom it becomes oxidized
-more reduced a molecule is, the more energy is stored in its bonds
-coenzyme NAD+ (oxidized) is key electron carrier in redox reactions. NADH (reduced form)

Front 22

reduction

Back 22

-gain of 1 or more electons

Front 23

oxidation

Back 23

-loss of 1 or more electons

Front 24

endoplasmic reticulum

Back 24

-network of interconnected membranes in cytoplasm with large surface area
- 2 distinct regions
1. smooth ER- lack ribosomes
2. rough ER- has ribosomes studding its surface

Front 25

smooth er

Back 25

-synthesizes lipids and steroids for hormonal reproduction
-metabolizes carbohydrates for energy
-detoxifies poisons
-stores calcium for electronegativity exchange
-glycogen degradation site for energy in liver and muscles

Front 26

rough er

Back 26

-has bound ribosomes with secrete glycoproteins (-proteins and cho's)
-distributes transport vesicles, proteins surrounded by membranes
-membrane factory for the cell

Front 27

golgi apparatus

Back 27

-consists of flattened membranous sacs called cristernae
-shipping and receiving center

Front 28

fuctions of golgi appartus

Back 28

-modifies products of er
-manufactures certain macromolecules (polysaccharides in plants) for energy and structure
-sorts and packages materials into transport vesicles

Front 29

lysosomes

Back 29

-primary lysosomes originate from golgi apparatus
-contain digestive enzymes and are the site where macromolecules are hydrolyzed into monomers for energy
-carry waste out

Front 30

mitrochondria

Back 30

-in eukaryotes, molecules are first broken down in cytosol
-partially digested molecules enter mitochondria, here chemical energy is converted to energy rich ATP
-cells that require a lot of energy often has more mitochondria ie. heart
-2 membranes: outer-porous and inner-extensive folds called cristae to increase surface area for energy production
-fluid filled matrix inside the inner membrane contains enzymes, dna and ribosmes

Front 31

vacuoles

Back 31

-in eukaryotic cells
-in plants and fungi

Front 32

function of vacuole

Back 32

1. storage of waste products and toxic compounds; some may deter herbivores
2.structure for plant cells-water enters vacuole by osmosis, creating turgor pressure
3. reproduction: vacuoles in flowers and fruits contain pigments whose colors attract pollinators and aid seed dispersal
4. catabolism-digestive enzymes in seeds' vacuoles hydrolyze stored food for early growth