Extentor

Question 1

True or false: After a protein moves through the protein translocator in the outer membrane of the
mitochondria, the protein diffuses in the lumen until it encounters a protein translocator in the
inner membrane.

Answer 1

False: It is always linked to the protein translocator during transport.

Question 2

True or false: Phosphatases remove the phosphate from GTP on GTP-binding proteins, turning them off.

Answer 2

False. It is hydrolysis that turns it off. Phophatase removes phosphate of kinases.

Question 3

True or false: In response to a nerve impulse, voltage gated Na+ channels in the presynaptic cell will open and
Na+ ions will enter the cell.

Answer 3

True. Nerve impulse (reached at threshold of – 40mV) will results in opening of Na channels and create
an action potential.

Question 4

True or false: When an action potential reaches a nerve terminal, it will open voltage-gated Na+ channels,
which will stimulate synaptic vesicles to fuse with the membrane and release their
neurotransmitter into the synaptic cleft.

Answer 4

False. It is a Ca2+ channel.

Question 5

True or false: In the S-phase of the cell cycle, cells check to determine whether the DNA is fully and correctly
replicated.

Answer 5

False. It is in the G phase.

Question 6

True or false: This happens in prometaphase of mitosis

• Breakdown of nuclear envelope
• Kinetochore microtubuli attach to kinetochores
• Interpolar microtubuli move the centrosome to opposite directions
• Chromosomes attach to the mitotic spindle via kinetochores + active movement

Answer 6

True

Question 7

True or false: The smell receptors use the same activation mechanism as the taste receptors for
umami, bitter and salty.

Answer 7

False. Sweet, bitter and umami has G protein coupled receptor. Like olifaction. Salty and sour use ion channels.

Question 8

Which of the following membrane lipids does not contain a fatty acid tail?

a. phosphatidylcholine
b. a glycolipid
c. phosphatidylserine
d. cholesterol

Answer 8

d. Cholesterol

Question 9

1. 11 Which of the following statements about the endoplasmic reticulum (ER) is false?
   a. the ER is the major site for new membrane synthesis in the cell
   b. proteins to be delivered to the ER lumen are synthesized on the smooth ER
   c. steroid hormones are synthesized on the smooth ER
   d. the ER membrane is contiguous with the outer nuclear membrane

Answer 9

B is false, proteins are synthesised in RER and lipids in SER.

Question 10

Which of the following choices best describes the role of the lysosome?

a. transport of material to the Golgi apparatus
b. sorting of transport vesicles
c. clean-up, recycling, and disposal of macromolecules
d. the storage of excess macromolecules

Answer 10

c. Disposal of macromolecules

Question 11

Progression through the cell cycle requires a cyclin to bind to a Cdk because

a. the cyclins are the molecules with the enzymatic activity in the complex
b. the binding of a cyclin to Cdk is required for Cdk enzymatic activity
c. cyclin binding inhibits Cdk activity until the appropriate time in the cell cycle
d. without cyclin binding, a cell-cycle checkpoint will be activated

Answer 11

b. the binding of a cyclin to Cdk is required for Cdk enzymatic activity

Question 12

1. 14 What is the immediate effect of a photon on the structure of 11-cis retinal?
   a. the molecule is released from the protein rhodopsin
   b. the molecule is converted to the all-trans retinal
   c. the molecule is converted from an aldehyde to an alcohol (retinol)
   d. the structure is not changed but accepts electrons

Answer 12

b. the molecule is converted to the all-trans retinal

Question 13

True or false: p53 is an example of an oncogene.

Answer 13

FALSE tumor suppressor gene: normally prevents cancer, recessive mutation creates
cancer – loss of function. P53 binds to p21 gene which encodes a CDK-inhibitor – cell goes
in arrest

Question 14

True or false: There are three major classes of membrane lipid molecules: phospholipids, sterols
and glycolipids.

Answer 14

TRUE membrane Is a bilayer composed of lipids and proteins.

Question 15

True or false: Second messengers are signalling molecules that bind to cell-surface receptor
proteins.

Answer 15

FALSE second mess are present in the cell (intracellular molecules) and can not bind on
the cell-surface receptor; example sec messengers: cAMP, IP3, DAG, Ca2+

Question 16

True or false: The capsaicin receptor is an ion channel that reacts both on heat and a mechanical
stimulus.

Answer 16

FALSE: activated by heat and chemical stimulus i.e. capsaicin

Question 17

True or false: Actin filaments are part of the cytoskeleton: they are rope like fibres that give
mechanical strength to the cell.

Answer 17

FALSE: intermediate filaments strengthen the cell and is distributing mechanical stress in
an epithelial tissue; actin filaments are like a twisted necklace, thinner than intermediate
filaments and important in forming bundles and networks (usually linked to other
structure; example muscle)

Question 18

What does the chromatin remodeling complex do?

Answer 18

multiprotein complexes that use the energy of ATP hydrolysis to mobilize and restructure nucleosomes.

Question 19

Vad använder man vid odling av mammalieceller för att:

a) få cellerna att lossna från en yta de växer på?
b) hålla miljön så ren som möjligt när cellerna hanteras?
c) få reda på andelen levande/döda celler?

Answer 19

a) Trypsin
b) sterile work
c) Tryptofan

Question 20

What is an operator?

Answer 20

An operator is a genetic sequence which allows proteins responsible for transcription to attach to the DNA sequence. The gene, or genes, which get transcribed when the operator is bound are known as the operon

Question 21

What is a mediator?

Answer 21

Mediator is a multiprotein complex that functions as a transcriptional coactivator in all eukaryotes
(combinatorial control, several transcription factors working at same time)

Question 22

Processen att få fram ett färdigt användbart mRNA skiljer sig mellan eukaryoter och prokaryoter. Ge två exempel på skillnader som normalt bara förekommer hos eukaryoter.

Question 23

Cellen kan laga brott på båda DNA-strängar med två olika metoder. Den ena metoden är
mer noggrann och ger en perfekt lagning, medan den andra metoden gör att vissa delar av DNA-
strängarna försvinner när lagningen är utförs. Varför använder inte cellen den mer noggranna
metoden hela tiden?

Question 24

What are the similarities and differences with G-protein and Ras-protein?

Question 25

What are the structurally and functionally differences of a tight junction and a gap
junction?

Question 26

Explain why nerve cell signalling is an active signalling mechanism. What happens at the
axon terminal when it gets a signal? Explain this process

Question 27

What is the function of exocytosis? Which cell organelles play a major role in this
mechanism? Describe the working mechanism of 2 different types of exocytosis pathways.

Question 28

The interphase of the cell-division cycle exists of three phases: G1, S and G2. What are the
main functions of G1 and G2 phases? How are these phases controlled?

Question 29

Name a concrete example of a mechanically gated ion channel and describe its working
mechanism.

Question 30

What is the biological reasoning behind designing scaffolds for tissue engineering with
mechanical properties similar to those of the host tissue?

Question 31

ou have been recruited to a bone implant biotech as a tissue engineer expert. Your new
company is moving into tissue engineering from their expertise in the fabrication of inert bone
implants. Your boss is, however, stubborn and thinks that you only need to seed some cells
on the strong and inert implant, put it in a static bioreactor, and after some time, you have a
piece of bone ready to be implanted. You urgently need to brief your team on why inert
implants are not suitable!
a. Why is your boss’s statement inaccurate (motivate your answer)? (2p)
b. Is an implant a scaffold? Describe at least four important (motivate) properties of the
implant/scaffold you think will help the company produce functional bone parts. (3p)

Question 32

Välj ut två olika celltyper inom det medfödda immunförsvaret och förklara vad deras
specifika funktion inom immunförsvaret är.

Question 33

Kroppen kan producera antikroppar med väldigt många olika specificiteter vilket gör att
kroppen har antikroppar som kan binda med hög affinitet till väldigt många olika antigen. Välj
en effektorfunktion som antikroppar har och förklara hur det möjliggör att en patogen som
angripit kroppen kan elimineras. (1 p)

Question 34

Majoriteten av kloroplastens protein är kärnkodade. Förklara hur dessa protein når
kloroplasten och hur importen in i stroma går till. (2p)

Question 35

Beskriv plasmodesmata och dess funktion i växten. (1p)

Question 36

Vilka är de egenskaper som definierar en stamcell? (2p)

Question 37

Vad är splicing, och var i cellen sker detta?

Question 38

För att den eukaryota transkriptionen ska kunna starta behövs många olika typer
av proteiner, utöver RNA-polymeras. Ge minst två exempel på olika proteiner, och
förklara kort deras uppgift.

Question 39

Tryptofan-operonet hos E. coli kodar för proteiner som behövs för syntes av
tryptofan, och ska uttryckas enbart när koncentrationen tryptofan är låg. Operonet regleras
med två olika mekanismer, förklara hur dessa fungerar.

Question 40

Cell memory innebär att celler bibehåller sin differentiering när de delar sig, och flera
olika typer av regleringsmekanismer kan användas för att uppnå detta, t ex positiv feedback
loop och epigenetiska mekanismer
a) Förklara principen för hur en positiv feedback loop kan kontrollera cell memory.
b) Ge ett exempel på en epigenetisk regleringsmekanism för cell memory, och förklara
kortfattat hur den går till.

Question 41

Vilka är de tre huvudsakliga typerna av T-celler (utöver minnes-T-celler)? Beskriv kortfattat
respektive T-cellstyps främsta funktion. (3p)

Question 42

4.2 Nämn två metoder för att inducera slumpmässiga mutationer, som inte regleras som GMO 
inom EU (1p). 
4.3 Vilka är de tre grundprinciperna för växtförädling (1p)?

Question 43

Är det primär eller sekundär cellvägg som har

a. har lignin som komponent?
b. är uppbyggd av cellulosa mikrofibriller?
c. Ligger intill “middle lamella” (mittlamell)?
d. kan expandera?

Question 44

You just graduated and joined a promising startup company dealing with cartilage repair. The
company is at a cross-road and uncertain of the next-generation technology in cartilage repair. The
CTO (chief technical officer) calls for a meeting and wants you to present the options. The starting
situation is a damaged cartilage, and the damage site has been removed to the bone. How do we
repair it?
(a) Fill the site with a cell-free scaffold and create some micro-fracture on the bone to release blood
and bone marrow.
(b) Fill the damaged site with ground native cartilage (from a healthy site) combined with fibrin glue.

6.1 Describe the two approaches carefully using keywords and concepts from the lectures. Illustrations
are welcome. (5p)
6.2 Which one of the approaches would you recommend? Motivate your answer. (2p)