Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

BI203 > Midterm #3 > Flashcards

Midterm #3 Flashcards

1
Q

what are codons

A

nucleotide sequence triplets

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what is the start codon/amino acid?

A

AUG - methionine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what are the stop codons

A

UAA, UAG, UGA - dont code for an amino acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what are the untranslated regions (UTR) of mRNA?

A

the 5’ and 3’ end of the mRNA that are not translated into proteins (5’ UTR and 3’ UTR)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what is tRNA?

A

transfer RNA - carries amino acid to ribosome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what is an open reading frame?

A

the region of mRNA that codes for amino acids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what are aminoacyl tRNA synthestases?

A

enzymes that attach amino acids to tRNA - specific to amino acids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what is a charged tRNA?

A

a tRNA with an amino acid attached

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what is the wobble hypothesis?

A

the idea that the base on the first position on the tRNA (5’ end) is usually an abnormal base like inosine, pseudouridine, tyrosine etc, which can pair with multiple nitrogenous bases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what is the function of the large subunit of the ribosome?

A

aids in the formation of peptide bonds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

which genes code for the large subunit of the ribosome?

A

28s, 18s, 5.8s genes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what is the gene that codes for the small subunit of the ribosome?

A

5s genes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what is the function of the small subunit of the ribosome?

A

recognition of the translation start site

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what are the differences between prokaryotic and eukaryotic mRNA in translation?

A

Prokaryotes:
- polycistronic = has multiple protein coding genes per mRNA transcript
- no mRNA transport out of nucleus
- has multiple translation start sites

Eukaryotes:
- monocistronic = has only one protein coding gene per mRNA transcript
- mRNA transport out of nucleus and into cytosol where translation occurs
- only has one translation start site

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what is initiation in translation?

A

when the ribosome binds at the 5’ UTR and initiates polypeptide synthesis at the start site

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

how do prokaryotes signal for translation initiation?

A

uses shine dalgarno sequence to signal translation start site - small subunit has a complementary sequence

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

how to eukaryotes signal for translation initiation?

A

ribosome scanning = small subunit of scans mRNA until it finds an AUG to initiate translation - requires ATP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what are eukaryotic initiation factors (eIFs)?

A

proteins that help aid and initiate translation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what are the different eIFs?

A

eIF2, eIF4E, and Poly-A binding protein (PABP)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what is the function of eIF2?

A

recognizes the tRNA for methionine (AUG) and binds the initiator methionyl-tRNA (translation cant start w/o methionine)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what is the function of eIF4E?

A

recognizes and binds to the 5’ methyl cap

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what is the function of the poly-A binding protein (PABP)?

A

binds to the poly-A tail

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

what are internal ribosome entry sites?

A

sites where translation can be initiated independent of the 5’ methyl cap - shortcut

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

what is elongation in translation?

A

the building of the polypeptide chain by the ribosome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

what are eukaryotic elongation factors (eEFs)?

A

proteins that aid in elongation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

what happens in the P(peptide) site of the ribosome?

A

where the amino aid chain is located and grows

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

what happens in the A (aminoacyl site) of the ribosome?

A

where the subsequent amino acids/tRNAs are brought in

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

what happens in the E (exit) site of the ribosome

A

where the tRNA exits the ribosome?

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

what are the different eEFs?

A

eEF1α and eEF2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

what is the function of eEF1α?

A

brings in the new tRNA/amino acids into the A site of the ribosome

31
Q

what is the function of eEF2?

A

moves the tRNA between the ribosome sites

32
Q

what is termination of translation?

A

the end of translation

33
Q

what happens during termination of translation?

A

release factors (proteins that release the polypeptide chain and mRNA from the ribosome) recognize the stop codon sequence and, releases the mRNA, and the ribosome dissociates

34
Q

what are chaperone proteins?

A

proteins that facilitate the folding of the proteins by recognizing hydrophobic residues

35
Q

what are chaperonins?

A

chaperone proteins that provide an isolated environment within which correct folding takes place

36
Q

what is protein disulfide isomerase (PDI)?

A

an enzyme that recognizes cystine residues and adds disulfide bonds

37
Q

what is peptidyl prolly isomerase?

A

an enzyme that recognizes proline residues and twists them into the trans conformation

38
Q

what is proteolytic processing?

A

removing sections of polypeptides in order to activate the protein

39
Q

what are glycoproteins?

A

proteins with carbs attached to them

40
Q

what is the function of glycoproteins?

A

protein folding in the ER, targeting proteins for transport, and cell-cell recognition

41
Q

what are GTPase activating proteins (GAP)?

A

activates the activity of GTPase - makes hydrolysis happen faster

42
Q

what are guanine exchange factors (GEF)?

A

protein that transforms GTP to GDP

43
Q

what are kinases?

A

enzymes that add a phosphate group

44
Q

what are phosphatases?

A

enzymes that remove phosphate groups

45
Q

what is the proteasome?

A

trash compactor that breaks down misfiled proteins

46
Q

what is the nuclear lamina?

A

a cytoskeletal structural complex composed of lamin proteins (intermediate filaments)

47
Q

what is the nuclear pore complex?

A

channels for all transport in and out of nucleus

48
Q

what are the two modes of passage in and out of the nuclear pore complex?

A
  1. Passive diffusion = fiddusion with no energy involved (goes down concentration gradient)
  2. energy dependent transport - mode of transport for most proteins and RNA
49
Q

what is a nuclear localization signal (NLS)?

A

signals that specific protein needs to be brought into the nucleus

50
Q

what are importins?

A

a family of receptors that bind to the NLS and transport proteins into the nucleus

51
Q

what is Ran?

A

GTP binding protein

52
Q

what are the steps of importing transport with Ran?

A
  1. importin binds to the NLS and transports the cargo protein through the nuclear pore complex
  2. Ran/GTP (activated Ran) binds to the importin and dislodges the cargo protein
  3. Ran/GTP transports importin out of the nucleus
  4. Conversion of Ran/GTP to Ran/GDP by RanGAP releases importin
53
Q

what is an exportin?

A

a family of receptors that binds to the NES (nuclear export signal) and transports proteins out of the nucleus

54
Q

what are the steps exporting proteins with Ran?

A
  1. NES of proteins bound for export is recognized by Ran/GTP
  2. binding of Ran/GTP stabilizes the complex and transports it out of the nucleus
  3. conversion of Ran/GTP to Ran/GDP by RanGAP releases cargo protein
55
Q

what are peroxisomes?

A

small membrane bound organelles present in nearly all eukaryotic cells

56
Q

what is a plasmalogen?

A

a specialized phospholipid

57
Q

what are the functions of plasmalogens?

A
  • contribute to structual integrity of cell membranes
  • acts as antioxidants protecting cells from oxidative stress
58
Q

what is the process of assembly of peroxisomes?

A

V1 and V2 vesicles fuse together
*these vesicles have distinct membrane proteins

59
Q

what is the process of importing peroxisomal matrix proteins?

A
  • protein that contains PTS1 targeting signal is recognized by Pex5
  • this complex binds to the docking complex on the peroxisomal membrane
  • Pex5 and Pex14 form a membrane pore
  • cargo protein is translocated into the peroxisome
  • Pex5 is recycled back to cytosol after translocation
60
Q

what are the two ways a peroxisome can be formed?

A
  • de novo formation - fusing of vesicles from ER
  • alternative formation - growth and divison of already existing peroxisomes
61
Q

what is the signficance of globular actin?

A

have binding sites that that mediate head to tail interaction

62
Q

what is the significance of filamentous actin?

A

can grow at both ends and has polarity

63
Q

actin is _ when bound to ATP and _ when bound to ADP

A

more stable; less stable and more likely to fall apart

64
Q

what is treadmilling?

A

when ATP actin is added at the barbed end while ADP-actin dissociates from the pointed end

65
Q

what is the function of formin in actin filament formation?

A

formin dimers bind to ATP-actin initiating the polymerization of long unbranched actin filaments

66
Q

what is the function of profilin in actin filament formation?

A

binds to actin monomers and stimulates the exchange of bound ADP for ATP, increasing the local concentration of ATP actin

67
Q

what is the function of Arp2/3 in actin formation?

A

makes the actin branches

68
Q

what is the function of tropomyosin?

A

stabilizes the actin filaments by binding lengthwise along the growth of the filament

69
Q

what is the function of capping proteins?

A

stabilize actin by binding to the barbed or pointed ends

70
Q

actin bundles are supported by _

A

crosslinking proteins

71
Q

actin networks are connected by _

A

large, flexible proteins that crosslink orthogonally (90°)

72
Q

actin bundles give rigidity and shape to cell protrusions for _ versus actin networks offer mechanical support and are involved in cellular activities such as _

A

interactions w/ the environment; mobility and shape changes

73
Q
A

BI203 (2 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions