Cell Metabolism (Biochem)

Question 1

ligands can be

Answer 1

hydrophilic or hydrophobic

Question 2

hydrophilic ligands

Answer 2

dont need a receptor to get in a cell

Question 3

hydrophobic ligands

Answer 3

need a receptor to get into cell and cross the membrane

Question 4

four types of cell signaling

Answer 4

Direct contact
Autocrine
Paracrine
Endocrine

Question 5

direct contact

Answer 5

cell target a cell connected by gap junctions( in direct contact)

Question 6

ex of direct contact

Answer 6

cardiac contractions+ depolarization of cells causing contractions=Na+ travelling cell by cell transferring energy causing contractions
how natural killer cell recognize healthy cells

Question 7

Autocrine Signaling

Answer 7

cell signals itself. Ligand binds to same or similar cells

Question 8

Physiological ex of autocrine signaling

Answer 8

liver regeneration ( release by cells)> TGF binds to liver cell> cause cell proliferation of liver tissue.
proliferation of antigen stimulated lymphocytes

Question 9

Pathological Autocrine ex

Answer 9

strategy used by cancer cells to upregulate growth/tumorigenesis
Ex. HER2 receptor> uncontrollable growth

Question 10

Paracrine signaling

Answer 10

adjacent cell communication but cells are DIFFERENT

Question 11

Ex of Paracrine Signaling

Answer 11

Connective tissue repair ( tissue macrophages stimulate fibroblast in wound repair)
Histamine released from mast cells act on nearby blood vessels (endothelial cells)
Neurotransmitters=secreted by neurons acts on cells (upregulate or downregulate cell)

Question 12

Endocrine signaling

Answer 12

ligands act on target cells distant from sender cell (via blood)
hormones, growth factors, cytokines(IL-1, TNFa > bs> fever)

Question 13

Ex of Endocrine Signaling

Answer 13

Hormones> secreted from endocrine cells> act on cells with correct receptors
HYpothalamus> anterior Pit> target organs
HYpothalamus> post pit> via neurohormones> trigger release of hormones (oxytocin> produce breast milk, and smooth muscle contraction during child birth, ADH>regulate BP)

Question 14

Which hormones work via G protein coupled receptors

Answer 14

Glucagon and Epinephrine

Question 15

how do GPCRs work

Answer 15

molecules binds g protein linked receptor> activated g protein>g protein turns on adenylyl cyclase> release atp> create cAMP>activates protein kinase A> phosphorylates other proteins

Question 16

what does epinephrine do

Answer 16

-increases glycogenolysis(breakdown glucagon) and gluconeogenesis(noncarb breakdown> create glucose)
-increase release of glucagon and cortisol (cortisol activates gluconeogenesis)
-stimulates B-oxidation of FA(breakdown of FA> increase ATP for energy

Question 17

when is epinephrine released

Answer 17

when glucose is low

Question 18

what cells do glucagon come from

Answer 18

alpha cells in the pancreas

Question 19

what else to epinephrine simulates

Answer 19

sympathetic system causing increase HR and sweating which are symptoms of HYPOGLYCEMIA

Question 20

what hormones work through tyrosine kinase receptors

Answer 20

insulin

Question 21

what does insulin do

Answer 21

it is released when glucose is high
-glycogen synthesis (putting glucose in storage)
-protein synthesis ( glucose> AA> use for energy or make proteins)
-Lipogenesis( make lipids)
-regulate genes

Question 22

what cells release insulin

Answer 22

Beta cells of the pancreas

Question 23

what is the process of insulin release

Answer 23

glucose enter cell> krebs cycle> atp binds ion channel> close ion channel> K+ stay inside cell > depolarization> Ca+ ion channel open> increase cAMP> secretory granules release insulin

Question 24

how does incretins work (GLP-1 or GIP)

Answer 24

stimulate insulin release/inhibit glucagon release> lower blood glucose

Question 25

why are DPP-4 enzymes not good for blood sugar

Answer 25

it inhibits incretins> causes high blood sugar *some pts have high DPP-4 *meds used to block this enzyme

Question 26

why do type2 diabetes need more insulin

Answer 26

body does produce enough -insulin produced dont work well

Question 27

how are receptors complex

Answer 27

specificity desensitization modularity integration

Question 28

specificity

Answer 28

-only binds specific ligands *mutation cause> other ligands to bind> cause problems

Question 29

desensitization

Answer 29

reduce responsiveness to ligand -alot more ligands are need to get the same response> receptors become tolerant -ex: substance abuse disorder

Question 30

Modularity

Answer 30

ligands bind> not a fast response Ex. GCPRs

Question 31

Integration

Answer 31

multiple cells delivering messages at a time -cross talk(insulin signal small but glucagon and epinephrine high because need to increase blood sugar)

Question 32

catabolism

Answer 32

extract energy from nutrients

Question 33

anabolism

Answer 33

uses energy to synthesize biomolecules(proteins, nucleic acids)

Question 34

what does c peptide do

Answer 34

cleave insulin (release) high c peptide high insulin low insulin low c peptide

Question 35

where is epinephrine released from

Answer 35

adrenal medulla (inner)

Question 36

what happens in the well feed state

Answer 36

blood glucose rises>. insulin release> takes up glucose in skeletal muscle, liver (glycogen prod. triglyceride synthesis (after glycogen stor.), adipose (which is why people gain weight)

Question 37

What happens during Starvation

Answer 37

glucagon(stimulated breakdown in the liver) and epinephrine release> increase glucose in the blood