4.1-4.3

Question 1

selective permeability

Answer 1

regulation of substances across membrane

Question 2

cell junctions

Answer 2

directly connect cytoplasms of adjacent cells (gap/plasmodesmata)

Question 3

synaptic signaling

Answer 3

nervous system, electrical signal moving along nerve cell triggers secretion of neurotransmitters across a synapse

Question 4

hormones

Answer 4

long distance signaling, secreted chemicals formed in specialized cells, travel in body fluids, act on target cells changing cells functioning, 3 steps: reception, transduction, response

Question 5

reception

Answer 5

target cells detection of signaling molecule outside the cell, detected when signaling molecule binds to receptor protein

Question 6

transduction

Answer 6

converts signal to form that can bring about cellular response- signal transduction pathway

Question 7

signal transduction pathway

Answer 7

series of steps linking mechanical, chemical, or electrical stimulus to specific cellular response

Question 8

response

Answer 8

cellular activity

Question 9

ligand

Answer 9

fits in receptor protein (signal molecule)< molecule that binds specifically to another molecule

Question 10

G protein- coupled receptor (GPCR)

Answer 10

responds to binding of signaling molecule by activating G protein (used by epinephrine, hormones, neurotransmitters)

Question 11

G protein

Answer 11

relays signals from GPCR to other signal transduction proteins in cell, binds to energy rich GTP, similar to ATP, many diseases from caused by bacterial toxins interfering with G protein function

Question 12

ligand-gated ion channel

Answer 12

transmembrane protein containing pore that opens and closes as it changes shape in response to signaling molecule (ligand)

Question 13

how do neurotransmitters work in the ligand-gated ion channel

Answer 13

neurotransmitter molecules released at a synapse between 2 nerve cells and bind as ligands to ion channels on receiving cell, causing channels to open

Question 14

how molecules reach a receptor

Answer 14

signaling molecule passes through plasma membrane, steroid and thyroid hormones can do this because they are hydrophobic

Question 15

transcription factors

Answer 15

special proteins that control which genes turn on, when receptors are activated, they act as transcription factor to turn on specific genes

Question 16

what happens if a receptor is a cell membrane protein instead of inside the cell

Answer 16

transduction stage is multi step, amplifying response

Question 17

protein kinase

Answer 17

enzyme that transfers phosphate groups from ATP to a protein thus phosphorylating the protein

Question 18

phosphorylation cascade

Answer 18

series of chemical reactions during cell signaling mediated by enzymes (kinases), in which each kinase phosphorylates and activates another, leading to phosphorylation of many proteins

Question 19

protein phosphatases

Answer 19

enzymes that can rapidly remove phosphate groups from proteins (dephosphorylation)

Question 20

2nd messengers

Answer 20

small, nonprotein, water soluble or ion, relays a signal to cell’s interior in response to signaling molecule bound by signal receptor protein, example: cyclic AMP

Question 21

signal transduction

Answer 21

process in which a chemical signal is converted to a cellular response

Question 22

phosphorylation cascades

Answer 22

involve series of protein kinases- enzymes that transfer phosphate groups from ATP to a protein, one way to activate pathway

Question 23

how does a cell turn off a pathway

Answer 23

cell uses protein phosphatases- enzymes that can rapidly remove P groups in dephosphorylation

Question 24

why do protein modifications occur in signal transduction

Answer 24

signaling pathway involves activating/deactivating proteins, which usually involves a change in shape of protein molecule

Question 25

programmed cell death

Answer 25

prevents self-fertilization, reproductive development, cell death releases nutrients and polen

Question 26

cell specializaition

Answer 26

during embryonic development, cells increase in number and undergo cell differentiation become specialized in structure and function

Question 27

morphogenesis

Answer 27

development of the form of an organism and its structures

Question 28

cytoplasmic determinant

Answer 28

maternal substance, such as proteinor RNA< that when placed into an egg, influences the course of early development by regulating expression of genes that effect developmental fate of cells

Question 29

induction

Answer 29

process in which one group of embryonic cells influences development of another, usually by causing changes in gene expression

Question 30

determination

Answer 30

point at which an embryonic cells is irreversibly committed to becoming a particular cell type

Question 31

apoptosis

Answer 31

programmed cell death brought about by activation of enzymes that break down many chemical components in the cell, occurs in infected/damaged cells and protects neighboring cells from damage (leaked digestive enzymes)

Question 32

how is apoptosis triggered

Answer 32

by signal transduction pathways which activate cascade of apoptotic “suicide” proteins in cels destined to die

Question 33

pattern formation

Answer 33

development of multi cellular organism’s spacial organization, arrangements of organs and tissues

Question 34

positional information

Answer 34

molecular cues that control pattern formation by indicating cell’s location relative to organism[’s body axes

Question 35

embryonic lethals

Answer 35

mutations with phenotypes causing death at embryonic or larval stage

Question 36

maternal effect gene

Answer 36

when mutant in mother, results in mutant phenotype in offspring regardless of offspring’s genotype

Question 37

morphogen

Answer 37

establishes embryo’s axis

Question 38

single celled signal transduction pathways

Answer 38

influence how the cell responds to its environment

Question 39

multi celled signal transduction pathways

Answer 39

coordinate activities within individual cells that support function (epinephrine)

Question 40

gene expression

Answer 40

signal transduction pathways can result in regulation of protein synthesis by activation/deactivation of a gene

Question 41

cytokines

Answer 41

small protein molecules used in intercellular signaling mediate protein synthesis, some are growth factors stimulating growth while others are inhibitory/signal for cell death

Question 42

gebberellins

Answer 42

group of chemicals that affect protein synthesis in plants

Question 43

signal transmission between cells

Answer 43

can mediate cell function example change in metabolism

Question 44

diabetes

Answer 44

cells have signaling pathway beginning with insulin receptor and resulting in cell taking in glucose, in type I diabetes, no insulin (signaling molecule) to bind to receptor