#5 DNA/RNA

37問 • 1年前

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Genes in the DNA of eukaryotes contain ______ that code for proteins along with ______ that do not

exons, introns

Because the initial mRNA, called a ______, includes the noncoding introns, it must be processed before it can be read by the tRNA

pre-RNA

While the mRNA is still in the nucleus, the _____ are removed from the pre-RNA

introns

The ___ that remain are joined to form the mRNA that leaves the nucleus with the information for the synthesis of protein

exons

Several steps occur during transcription: 1. - a section of DNA containing the gene ______ 2 - one strand of DNA is copied starting at the ________, which has the sequence TATAAA 3. - an mRNA is synthesized using _________ with uracil (U) replacing thymine (T) 4. - the newly formed mRNA moves out of the nucleus to ribosomes in the cytoplasm and the _____

1. unwinds 2. initiation point 3.complementary base pairing 4.DNA re-winds

A specific mRNA is synthesized when the cell requires a _______ The synthesis is regulated at the transcription level: feedback control, enzyme induction

particular protein

______, where the end products speed up or slow the synthesis of mRNA -

feedback control

______, where a high level of a reactant induces the transcription process to provide the necessary enzymes for that reactant

enzyme induction

The _______ is found in the sequence of nucleotides in mRNA that is translated from the DNA

genetic code

A ______ is a triplet of bases along the mRNA that codes for a particular amino acid

codon

Each of the 20 amino acids needed to build a protein has at least _____

2 codons

There are also codons that signal the “start” and “end” of a ______

polypeptide chain

The amino acid sequence of a protein can be determined by reading the ______ in the DNA sequence that are complementary to the codons of the mRNA, or directly from the mRNA sequence

triplets

The entire DNA sequence of several organisms, including humans, have been determined, however, - only _______ can be determined this way - doesn’t give tertiary structure or protein function

primary structure

The sequence of bases in DNA forms the

Genetic Code

controls the production of a particular amino acid in the cytoplasm of the cell

triplet

The different amino acids and the order in which they are joined up do not determine the sort of protein being produced

FALSE

RNA AND tRNA ACTIVATION 1. Once the DNA has been transcribed to mRNA, the _____ must be translated to the amino acid sequence of the protein 2. The first step in translation is _______ 3.Each tRNA has a triplet called an ______ that complements a codon on mRNA 4. A ______ uses ATP hydrolysis to attach an amino acid to a specific tRNA

1. codons 2. activation of the tRNA 3. anticodon 4.synthetase

Initiation and Translocation 1. Initiation of _______ occurs when a mRNA attaches to a ribosome 2. On the mRNA, the start codon (AUG) binds to a tRNA with _______ 3. The second codon attaches to a tRNA with the ________ 4. A ______ forms between the adjacent amino acids at the first and second codons 5. The first tRNA detaches from the ribosome and the ribosome shifts to the adjacent codon on the mRNA (this process is called ______) 6. A ______can now attach where the second one was before translocation

1. protein synthesis 2. methionine 3. next amino acid 4. peptide bond 5. translocation 6. third codon

TERMINATION 1. After a polypeptide with all the amino acids for a protein is synthesized, the ribosome reaches the the _________; UGA, UAA, or UAG 2. There is no ______ with an anticodon for the “stop” codons 3. Therefore, protein synthesis ends (______) 4. The ______ is released from the ribosome and the protein can take on it’s 3-D structure (some proteins begin folding while still being synthesized, while others do not fold up until after being released from the ribosome)

1. “stop” codon 2. tRNA 3. termination 4. polypeptide

DNA and ENZYMES 1. The ______ build the cell structures 2. They also make ________ 3. The ______ controls which enzymes are made and the enzymes determine what reactions take place 4. The _______ in the cell determine what sort of a cell it is and what its function is 5.So DNA exerts its control through the _______

1. proteins 2. enzyme 3. DNA 4. structures and reactions 5. enzymes

A sequence of triplets in the DNA molecule may code for a complete protein Such a sequence forms a _______ There may be a thousand or more bases in one ______

gene

CONFORMATION AROUND N-GLYCOSIDIC BOND 1. Relatively free rotation can occur around the _______ in free nucleotides 2. The _______ about the N-glycosidic bond (N-C1') is denoted by the symbol x 3. The sequence of atoms chosen to define this angle is _______ for purine, 4. and ________ for pyrimidine derivatives 5. Angle near 0° corresponds to ________ 6. Angle near 180° corresponds to ________ 7. Anti conformation is found in _______

1. N-glycosidic bond 2. torsion angle 3. O4'-C1'-N9-C4 4. O4'-C1'-N1-C2 5. syn conformation 6. anti conformation 7. normal B-DNA

REPLICATION OF GENETIC CODE 1. _________ occurs first 2. Each strand serves as a ______ for the synthesis of a new strand 3. Synthesis is catalyzed by enzymes known as ___________ 4. Newly made DNA molecule has ______

1. Strand separation 2. template 3. DNA polymerases 4. one daughter strand and one parent strand.

Messenger RNA: Code Carrier for the Sequence of Proteins 1. Is synthesized using ______ 2. Contains ______ instead of deoxyribose 3. contains ______ instead of thymine 4. One mRNA may code for more than one ______

1. DNA template 2. ribose 3. uracil 4. protein

1 Gene

monocistronic

2 or more gene

polycistronic

Factors Affecting DNA Denaturation 1. The midpoint of melting (Tm) depends on __________ -high _____ increases Tm 2. Tm depends on ______ -_____ DNA has higher Tm -Important for _____ DNA 3. Tm depends on ________ -______ increases Tm

1. base composition, CG 2. DNA length , Longer, short 3. pH and ionic strength , High salt

3 Stages of Processing of mRNA

Splicing, Capping, Tailing

removing of introns and joining exons

splicing

complex protein and small RNAs that remove introns

spliceosome

RNA molecule that function as enzymes

ribozyme

modified guanine nucleotide is attached to the 5' end—5 cap

Capping

attachment of Poly-A-Tail at the 3' end

Tailing

sequence of 50-250 adenine nucleotide

Poly-a-tail

signals the addition of poly-a-tail AAUAAA

polyadenylation signal

Once the polyadenylation signal is recognized, mRNA is cleaved and _______ is added, which stabilizes the mRNA for translation, and protection from degradation

Poly-A-Tail

CH 1

OBILLO, MIKAELA T. · 78問 · 1年前

CH 1