Genetic Code Flashcards Preview

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Flashcards in Genetic Code Deck (13)
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1

Gene

a unit of DNA that encodes a specific protein or RNA molecule, and through transcription and translation, that gene can be expressed.

2

3 types of RNA found in cells

Messenger RNA (mRNA)
Transfer RNA (tRNA)
Ribosomal RNA (rRNA)

3

Messenger RNA (mRNA)

carries information from DNA by traveling from the nucleus (where it is transcribed) to the cytoplasm (where it is translated)

4

Transfer RNA (tRNA)

translates nucleic acids to amino acids by pairing its anticodon with mRNA codons; it is charged with an amino acid, where it can be added to the growing peptide

are charged and activated with an amino acid

5

Ribosomal RNA (rRNA)

forms much of the structural and catalytic component o the ribosome, and acts as a ribozyme to crease peptide bonds between amino acids

6

Central Dogma

DNA --> RNA --> Proteins

7

Start codon:

AUG

8

Stop codon:

UGA, UAA, UAG

9

Wobble position

Redundancy and wobble (third base in the codon) allows mutations to occur without effects in the protein

protects against mutations
usually found in the 3rd base in the codon

10

Point mutations can cause:

Silent mutations - with no effect on protein synthesis
Nonsense (truncation) mutations - that produce a premature stop codon (expressed mutation); a mutation were the codon now encodes for a premature stop codon
Missense mutations - that produce a codon that codes for a different amino acid (expressed mutation); a mutation where one amino acid substitutes for another

11

Frameshift mutations

result from nucleotide addition or deletion, and change the reading frame of subsequent codons

12

RNA is structurally similar to DNA except:

Substitution of a ribose sugar for deoxyribose
Substitution of uracil for thymine
It is single stranded instead of double stranded

13

The anticodon sequence allows the tRNA to pair with the codon in the

mRNA