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Cell biology > Lecture 13 > Flashcards

Lecture 13 Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

membrane around nucleus

A

shares border w ER

  • nuclear lamina
  • nuclear pores
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2
Q

Nuclear pores

A
  • More than 50 different proteins (nucleoporins)
  • Octagonal arrangement
  • Aqueous channel - lined with fibrils
  • <5000 daltons freely diffuse
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3
Q

what other structure can less than 5000 daltons diffuse?

A

porins in mitochondria

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4
Q

nuclear localization signals

amino acid sequence of a protein determines?

A

its localization

  • regions w positive charge within protein sequence
  • can be transported fully folded
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5
Q

since proteins can be transported fully folded, this is

A

different from protein import into other organelles

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6
Q

NLS sequence (nuclear localization signals)

A

pro-pro-lys-lys-lys-arg-lys-val

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7
Q

nuclear import receptors

A
  • floating freely in cytosol
  • traffick through pore is bidirectional
  • have nuclear export receptors that help molecules leave nucleus
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8
Q

Molecules made in cytosol that are needed in the nucleus

A
  • DNA binding proteins - histones (for packaging)

- Transcription factors

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9
Q

Molecules that are made in nucleus but get used in cytosol (exported)

A
  • Ribosomal subunits made in nucleolus

- Exported for assembly into ribosomes

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10
Q

trafficking though unclear pore controlled by Ran

A
  • GTPase

- found in cytosol and nucleus

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11
Q

Ran GAP

A

is cytosolic

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12
Q

Ran GEF

A

is nuclear

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13
Q

Spatial separation of regulatory molecules important for

A

function

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14
Q

How does Ran regulate trafficking?

A
  • Nuclear import receptor binds to NLS on protein
  • Receptor binds to FG repeats on nucleoporins and enters nucleus
  • In nucleus, Ran-GTP binds to receptor - releasing cargo
  • Receptor with Ran-GTP exits nucleus
  • Ran-GAP hydrolyzes GTP to GDP causing release from receptor
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15
Q

NF cappa B

made up of what?

A

nuclear factor kappa B

p50 and p65. they are size.

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16
Q

what makes NF kappa B?

A

2 polypeptide chains that bind together. if you have one, you either have p50 or p65

17
Q

IKK

A

inhibitor kappa kinase

18
Q

ligand binding leads to activation of

A

IKK which activates more IKK’s.

19
Q

p50 and p65 are bound to IKB

A

inhibitor of NF cappa B.

20
Q

so IKB is blocking nls on NFcappaB. how can we fix this?

A

phosphorylate w kinase. it comes off NFkappaB.

21
Q

ANTI-MÜLLERIAN HORMONE (AMH)

A
  • hormonal control of sex differentiation in the male fetus (prevents the production of uterus and Fallopian tubes in male fetus)
22
Q

FSH

A

7 pass transmembrane protein. Called G protein coupled receptor (alpha beta gamma associated with it)

23
Q

structure of dna

A

Chromosomes
Genes - introns and exons
- Each cell has 2 meters of DNA

24
Q

DNA

RNA

A

no enzymatic activity

enzymatic activity

25
Q

dna folds up so

A

it fits more

26
Q

chromatin =

A

dna + proteins
extra dna called junk dna
-serve as spacer (not really junk)

27
Q

chromosomes

A

dna origin of replication

28
Q

centromere

A

kinetochore attaches

29
Q

telomere

A

repeated nucleotide sequences

30
Q

nucleosomes

A 
Histones and DNA
-H2A, H2B, H3, H4
-H1 (binds to spacer) 
-146 bp/nucelosome
-2-80 bp on linker
Beads on a string
31
Q

histones

A
  • highly positively charged

- Deacetylation and methylation

32
Q

for nucleosomes
primary structure is beads on a string
secondary structure is called 30 nm fiber
third level is called loops

A

2nd level of packaging

33
Q

heterochromain

A

highly condensed

34
Q

euchromatin

A

less condensed 30 nm fibers and loops

35
Q

telomeres and centromeres are

A

heterochromatin

36
Q

mitotic chromosomes

A

most condensed state

-allows for separation of sister chromatids

37
Q

condensin

used in third level of nucleosomes

A

proteins uses ATP to coil DNA into mitotic chromosome state

-cohesins 2 separate sister chromatids that are tightly bound to one another

Cell biology (15 decks)

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