Download 1 BIOS 1300 SI SI WORKSHEET 8 (Chapter 3 Cont.) SI Leader

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BIOS 1300 SI
SI WORKSHEET 8 (Chapter 3 Cont.)
SI Leader: Merrin Jeffries (email:[email protected])
February 5, 2015
DNA Base Pairing
There are base pairing rules for writing complimentary DNA strands for
a given strand.
A pairs with T
C pairs with G
In RNA, A pairs with U, instead of T.
1. Write the complimentary DNA strand for each given strand of DNA.
a. CGTAAGCGCTAATTA
b. TCTTAAATGATCGATC
c. AATGAATAGCTAGCTT
d. GGCATTCGCGATCATG
e. CGTTAGCATGCTTCAT
f. ACTAACGGTAGCTAGC
2.Now write the mRNA strand for the given DNA strand.
a. ATGTCGCTGATACTGT
b. GAAGCGATCAGTTACG
c. AATGAATAGCTAGCTT
d. GGCATTCGCGATCATG e. CGTTAGCATGCTTCAT f. ACTAACGGTAGCTAGC 2
3. Write the tRNA sequence for the given strand of mRNA
a. AGGUCAUGCAUGGGCAUGCAU
b. AGAGAUUCAGCUAGCACGAUA
c. GUCAUCGAUCGAUCGGAUGCC
d. UUUCAGUCAGCUAGCGAUCGU
4. Now you will translate the amino acid sequence for the given tRNA
strand. Remember that codons are 3 base pairs long.
a. AUG CAC UGU CCU UUC GCU GAC b. GAG AUC UGG UUG GAA UCG c. AGC GUA UUA ACG UAU CAU d. AGU CGA UCG AUG CGG AUG AUA e. GUC GUC GAU AGC UAU CAU GCA 5. Transcribe the following DNA strand. Then translate the tRNA strand
you wrote.
a. TGAGTCGACTGGCTGACCGTAGAC b. CTTGGCTTATGGTGGTTCGCTCGC 6. The following are pieces of mRNA. Give the DNA strand from which it
was transcribed.
a. GAGAUCUGGUUGGAAUCG
b. AGCGUAUUAACGUAUCAU
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7. Complete the table below showing the sequences of DNA, mRNA
codons, tRNA anticodons and the amino acids. Remember the genetic
code is based on mRNA codons.
DNA
GAT
mRNA codon
UAU
tRNA anticodon
Amino Acid
UUC
Tryptophan
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8. Using the following piece of DNA, give the mRNA molecule and the
amino acid sequence for which it codes.
DNA- A T A T A A A C G A G G A A A T T C C G G G C G
mRNA:
tRNA:
Amino acids:
9. Use the mRNA sequence to find the DNA sequence and the amino acid
sequence.
DNA
mRNA- A U G C C U A C A U G U G G U G U A A C C U U A
tRNA
Amino acids
10. For each codon below, give the tRNA anticodon.
a. UUC _______
b. AUC _______
c. CCG _______
d. CGU _______
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Gene expression: The process by which DNA directs the synthesis of proteins
I. Transcription:
1. Initiation
- RNA polymerase attaches to the DNA at the promoter,
_____________________________________________________, and separates the 2 DNA
strands - In prokaryotes, RNA polymerase attaches directly to the promoter - In eukaryotes, RNA polymerase binds to a specific promoter sequence
called the __________________ with the help of _________________________________. 2. Elongation: RNA polymerase adds RNA nucleotides to the ______ end of the
growing mRNA chain
3. Termination
- In prokaryotes, transcription ends once a ___________________ sequence is
transcribed
- In eukaryotes, transcription ends 10-35 nucleotides after a
_________________________________ is transcribed
II. RNA processing: modifications to an mRNA transcript that occur only in
_____________________.
- Alteration of mRNA ends: the 5’ end receives a _____________ and the 3’ end receives
a ___________________ that have 3 important functions:
1. Facilitate export of mature mRNA from _____________________.
2. Protect mRNA from degradation by _____________________.
3. Help __________________ attach to the 5’ end of the mRNA in the cytoplasm
- RNA splicing: the removal of large portions of non-coding DNA, called
_______________, from pre-mRNA
- The remaining coding regions are called ________________.
- Introns are removed by a spliceosome complex, consisting of many snRNPs (made
of ______________________________________ )
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-Alternate RNA splicing allows 1 pre mRNA to code for multiple proteins
III. Translation:
1. Initiation: mRNA, a tRNA corresponding to the __________ codon, and 2 ribosomal
subunits unite to form a translation initiation complex with the help of
_________________ factors 2. Elongation: Amino acids are added one by one to the growing polypeptide chain
by tRNA’s with the help of ___________________ factors - Involves the recognition of mRNA codons by the ______codons of tRNA
- Translocation:
3. Termination: a _____________ codon in the mRNA is reached and translation stops
with the help of a ______________ factor
IV. Post-translational modifications:
Folding: A protein’s secondary and tertiary structures form automatically based
on ____-group interactions, but folding may be mediated by ____________________
protein Modifications:
Targeting: may be targeted for the ER (& ultimately secretion) by a
_______________________________.