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Flashcards in Molecular Biology Review Deck (32):
1

RNA polymerase moves in what direction?

5' → 3' (binds 3' end of template strand)

2

Which is more likely to have errors, replication or transcription?

Transcription

3

Coding strand

Always the same 3' → 5' strand, used to generate RNA strand (RNA sequence will be same as non-coding strand)

4

Uracil replaces what DNA nucleotide?

Thymine

5

RNA processing

Occurs in nucleus → results in mature RNA strand

5' end capped

Poly-A tail added to 3' end

6

Function of capping primary RNA

Ensure mRNA's stability during translation

7

Function of adding poly-A tail to primary RNA strand

1. Protects mRNA from degradation by exonucleases
2. Essential for transcription termination, export from nucleus and translation

8

Introns

Non-coding regions of gene (do not appear in mature RNA transcript → removed in nucleus)

9

Exons

Coding regions of a gene (can be spliced to form multiple proteins)

10

3 types of mature RNA

1. tRNA
2. rRNA
3. mRNA

11

tRNA

1. Binds 1 specific AA
2. Recognizes 1 or more mRNA sequence

12

rRNA

AKA:

Function:

Ribosomal RNA

ribosome = rRNA + protein

1. Orients mRNA & AA complex
2. Ensure accurate reading

13

mRNA contains information for?

Proteins (translation)

14

mRNA turnover rate

Very high (much less stable than tRNA and rRNA) → 1/2 life is hours to days

Allows for amplification of genetic message (multiple copies)

15

Translation

Conversion of mRNA into protein

16

AA sequence is determined by?

Nucleotide sequence

17

Ribosome

Location:

Function:

Cytoplasm

Protein synthesis

18

3 sites on ribosome

A site (aminoacyl): binds newly arriving tRNA

P site (peptidyl): tRNA carrying polypeptide chain residues

E site (exit): tRNA exits from ribosome

19

Codon

Ribosome reads mRNA sequence 3 nucleotides at a time → 64 possible

20

Start codon

AUG

21

Stop codon

1. UAG
2. UGA
3. UAA

22

2 posttranslational modifications and what is their function?

1. Amino acids removed (splicing)
2. Add sugars

→ makes protein active and directs protein to appropriate location

23

Endoplasmic reticulum mostly contains?

Glycoproteins (protein with carbohydrate grop)

24

How does protein attach to ER?

Protein is on ribosome → ER recognizes tag on protein

25

What happens to protein in ER?

Folding and further glycosylation

26

Channel network in ER

Directs protein to proper location in cell

27

Donor molecules and acceptor residues of glycosylation

Donor molecules: nucleotide sugars (ex: ADP-glucose)

Acceptor residues:
1. Asparagine (N)
2. Serine (S)
3. Threonine (T)

28

PCR

Does what:

Discovered by:

Exponentially amplify DNA segment in vitro

Kary Mullis, 1983

29

3 steps of PCR

1. Denaturation (separates DNA strands)
2. Annealing (primers bind DNA)
3. Extension (new DNA synthesized)

30

What is glycosylation directed by?

Enzyme-directed site-specific process (glycosyltranferases)

31

Where does glycosylation occur?

ER and Golgi apparatus

32

What is glycosylation?

Folding, targeting and function of protein