15-16

Question 1

Hvar er myndunarstaður sterahormóna í innkirtilsfrumu?

Answer 1

Slétta frymisnetið - smooth endoplasmic reticulum

The endoplasmic reticulum (ER) is the location of synthesis for proteins (rough ER) and many lipids including steroid hormones (smooth ER).

Question 2

Hvar er myndunarstaður próteina í frumu?

Answer 2

Grófa frymisnetið - rough endoplasmic reticulum

The endoplasmic reticulum (ER) is the location of synthesis for proteins (rough ER) and many lipids including steroid hormones (smooth ER).

Question 3

Hvaða frumulíffæri eru umlukin einföldu lagi af lípíðhimnu?

Answer 3

• Golgikerfið
• Leysikorn
• Frymisnetið

The nucleus, mitochondria, and chloroplasts are each surrounded by a double membrane, and organelles like the Golgi apparatus, lysosomes, and the endoplasmic reticulum have a single membrane.

Question 4

Hvaða frumulíffæri eru umlukin einföldu lagi af lípíðhimnu?

Answer 4

• Kjarni
• Hvatberar og grænukorn

The nucleus, mitochondria, and chloroplasts are each surrounded by a double membrane, and organelles like the Golgi apparatus, lysosomes, and the endoplasmic reticulum have a single membrane.

Question 5

hvert er u.þ.b. rúmmálshlutfall frymisvökva í meðalfrumu?

Answer 5

50%

The volume of a typical eukaryotic cell is about 50% cytosol and the remaining 50% is occupied by membrane-bound organelles.

Question 6

Hvert eru próteinin sem eru flutt frá frymisvökvanum á leiðinni?

Answer 6

• í kjarnann
• í hvatbera
• í grænukorn
• í oxunarkorn

Proteins destined for the nucleus, mitochondrion, peroxisomes, and chloroplasts are transported from the cytosol.

Question 7

Hvernig eru próteinin sem eru að fara í golgikerfið, leysikornin og innfrumunarbólurnar flutt?

Answer 7

Þau eru flutt inn í frymisnetið á meðan það er verið að nýmynda þau. Síðan eru þau flutt á áfangastað með flutningsblöðrum.

Proteins destined for the Golgi, lysosomes, and endosomes are transported into the endoplasmic reticulum as they are being synthesized and are then transported via vesicles to their final destination.

Question 8

Hver væri lokastaðsetning próteins sem hefur kenniraðir fyrir bæði kjarna og frymisnet?

Answer 8

Frymisnetið

An endoplasmic reticulum sorting signal directs a protein to the ER while it is still being synthesized, thus an ER sorting signal would supersede a nuclear localization signal. A nuclear localization signal imports a completely synthesized protein from the cytosol to the nucleus.

Question 9

Fullmynduð og umbrotin prótein eru flutt inn í hvaða frumulíffæri?

Answer 9

Kjarna

Nuclear transport occurs on folded proteins.

Question 10

Flutningsprótein í hvaða himnum “unfolda” prótein á meðan flutningi stendur?

Answer 10

Flutningsprótein í hvatberum og grænukornum

Transporters in the membranes of mitochondria and chloroplasts unfold the protein during transfer.

Question 11

Prótein eru flutt á meðan þau eru nýmynduð. Hvert eru þau að fara?

Answer 11

Í frymisnetið

Proteins destined for the endoplasmic reticulum are transported as they are being synthesized, thus the proteins are unfolded.

Question 12

hvernig eru prótein flutt inn í innra hólf hvatbera?

Answer 12

þau eru þýdd í frymisvökvanum og með merkiröð sem sendir þau til hvatberans þar sem þau eru dregin inn á línulegu formi

Mitochondrial proteins that are encoded by genes in the nucleus are synthesized on free ribosomes in the cytosol. A signal sequence in the proteins is recognized by import machinery that transports the unfolded protein across both membranes at once.

Question 13

Hvernig velja clathrin-hjúpaðara blöðrur farm sinn?

Answer 13

Farmviðtakar tengjast bæði farmi OG clathrini

Vesicles destined for different compartments have different types of protein coats. The cargo for these vesicles is selected by specifically binding to cargo receptors that interact with a specific type of protein coat.

Question 14

Hvað eru Rab prótein?

Answer 14

Litlir GTPasar sem eru sértækir fyrir hverja tegund frumulíffæris og blöðru

Question 15

Hvað þekkir Rab prótein á blöðrum?

Answer 15

“Tethering protein” á markhimnu

Question 16

hvað gerir “Tethering protein” á markhimnu?

Answer 16

Fangar og festir blöðruna til að hún geti sameinast himnunni

Question 17

Í hvaða ferli í myndinni skiptir Rab máli?

Answer 17

vesicle tethering

Rab proteins are a family of small GTPases that are specific for each type of organelle and vesicle. Rab proteins on vesicles are recognized by tethering proteins on the target membrane and help capture and tether the vesicle for later docking and fusion.

Question 18

Leysikorn innihalda ____________ ensím sem brjóta niður fjölbreyttar stórsameindir, frumuhluta og örverur.

Answer 18

Vatnsrofs-

Lysosomes are a compartment in the cell where ingested cell particles, organelles, or macromolecules can be digested for recycling. The macromolecules from ingestion or from these cell parts are broken down into their building blocks by hydrolytic enzymes and are then exported out of the lysosome for reuse.

Question 19

Hvernig boð virkar yfir langar vegalengdir og nýtir hormón sem boðefni?

Answer 19

Endocrine

Endocrine signaling is a long-range type of cell–cell signaling that uses hormones secreted in the blood by specialized cells. This is distinguished from paracrine signaling, which also uses chemical signals that are secreted but over a shorter range.

Question 20

Hverskonar viðbragð frumu taka stuttann tíma?

Answer 20

• Viðbragð sem kallar á losun úr seytibólum
• Boð sem send eru með boðspennu eftir taugasíma

Question 21

Hverskonar viðbragð frumu taka langann tíma?

Answer 21

Boð sem kalla á breytingu í genatjáningu

Question 22

Fyrsta skref í boðflutningi sem hefst á sameind sem ekki kemst yfir frumuhimnu er

Answer 22

Binding boðefnisins við viðtaka

Signaling pathways that are activated in response to an extracellular signal must begin with the signal molecule binding to the receptor, often a membrane protein. Then the signal can be relayed and amplified inside the cell to produce cellular responses like activation of growth, gene expression, etc.

Question 23

neikvætt afturkast (negative feedback regulation)

Answer 23

**Einhver þáttur seint í boðferlinu hindrar virkni ensíms snemma í því. **

Negative feedback is when a product of a signaling pathway inhibits steps earlier in the pathway. This leads to a dampening of the response in response to strong activation. Hence, negative feedback can help a pathway switch rapidly between on and off states.

Question 24

Ensím sem bæta fosfati á prótein til að hafa áhrif á virkni þess (til að kveikja, eða slökkva) kallast

Answer 24

Kínasar

Enzymes called kinases add a phosphate to a protein; the phosphate could either activate or inactivate the protein, depending on the protein.

Question 25

Hvað gera fosfatasar?

Answer 25

Fjarlægja fosfat

Question 26

Virka form próteins sem bindur GTP er

Answer 26

GTP-bundna formið.

Monomeric GTP-binding proteins (also known as monomeric GTPases) are in their active form when bound to GTP. An enzyme called GEF helps activate the GTP-binding protein by promoting its binding to GTP.

Question 27

Hverskonar yfirborðsviðtakar hvata sjalfir efnahvarf innan frumunnar þegar þeir virkjast?

Answer 27

Ensímviðtakar - enzyme-coupled receptors

When bound to a signal, enzyme-coupled receptors become active enzymes that catalyze a reaction inside the cell.

Question 28

Hvað gera G-próteintengdir viðtakar - G-protein-coupled receptors?

Answer 28

Virkja G-protein, sem geta virkjað ensím en gera það á óbeinann hátt.

G-protein-coupled receptors activate G-proteins, which can activate enzymes but do so indirectly.

Question 29

Þegar það er virkjað, er G-Prótein með byggingu sem

Answer 29

Er tengt GTP

G-proteins are heterotrimers, made up of an alpha, a beta, and a gamma subunit. When activated, the alpha subunit binds to GTP and dissociates from the rest of complex.

Question 30

Hvað myndi vera sneggsta viðbragðið við G-prótein virkjun?

Answer 30

Opnun jónagangna

G-proteins can activate membrane-bound enzymes to produce second messenger molecules like cAMP and cGMP, or they can activate ion channels directly. Ion-channel activation is a rapid response that causes an immediate change in the cell, whereas small-molecule second messengers take longer to produce cellular outcomes.

Question 31

Hvað parar saman prótein sem er virkjað af g-próteini og annan boðbera (second messenger) sem það myndar?

Answer 31

phospholipase C -> diacylglycerol

G-proteins activate membrane-bound enzymes like phospholipase C, which cleaves inositol phospholipids to produce the second messengers inositol triphosphate and diacylglycerol. Other important enzymes are adenylyl cyclase and guanylyl cyclase, which produce cyclic AMP and cyclic GMP, respectively.

Question 32

Hvaða cAMP-miðluð boð myndi taka mínútur til klukkustundir að klárast, en ekki sekúndur?

Answer 32

Breyting á virkni umritunarþáttar

Question 33

Hvaða cAMP-miðluð boð myndi sekúndur að klárast?

Answer 33

Breytingar á próteinvirkni eða jónagangnavirkni

Signaling pathways that lead to changes in gene expression via transcriptional regulators are slower and take minutes to hours for an effect. This is in contrast to signaling pathways that change protein activity or ion channel activity, which elicit changes in seconds to minutes.

Question 34

Losun á kalsíumjónum virkjar

Answer 34

• Vöðvasamdrátt
• Viðbragð í frjóvguðu eggi
• Losun taugaboðefna

Calcium ion release is an important signal in muscle contraction, fertilized egg development, and secretion of neurotransmitters. Calcium ions do not lead to action potential transmission along an axon of a nerve.

Question 35

Hvernig virkjar binding boðefnis við RTK innanfrumuboðferla?

Answer 35

**RTK myndar tvennd (dimer) og fosfórýlerar sjálfan sig **

RTKs are single transmembrane proteins that dimerize upon signal binding. The dimerization brings the kinase domains in close proximity to each other, allowing the two monomers to phosphorylate each other in a crosswise manner.

Question 36

innanfrumuboðflutningsprótein sem eru virkjuð af RTK?

Answer 36

• Ras
• monomeric GTPase
• Π-3-kinase

Question 37

G-prótein eru virkjuð af

Answer 37

GPCR