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Things To Know For The Chapter 12 Nucleic Acids & Protein Synthesis Test
KNOW THE FOLLOWING
Nucleotides are composed of a five carbon sugar, a phosphate group and a nitrogen containing base.
DNA Characteristics
- A strand of nucleotides that codes for the information to make/synthesize proteins in an
organism
- Contains the purines, adenine & guanine, and the pyrimidines, cytosine & thymine
- Watson & Crick determined that the DNA is a double helix
- DNA is a nucleic acid macromolecule
- Adenine bonds with thymine & guanine bonds with cytosine
- The backbone of DNA or the uprights of the DNA ladder are composed of phosphate groups &
deoxyribose (5 carbon sugar) sugar
- If the DNA molecule is seen as a ladder, the rungs would be nitrogen containing bases and the
uprights would be phosphate groups and 5 carbon sugars (deoxyribose)
RNA Characteristics
- A single strand of nucleotides that contains uracil instead of thymine
- RNA is a nucleic acid macromolecule
- RNA contains ribose sugar
Differences & Similarities between DNA and RNA
- DNA has deoxyribose sugars & RNA has ribose sugars
- DNA is double stranded & RNA is single stranded
- DNA contains thymine & RNA contains uracil
Mutations
- Mutations are changes in the DNA nucleotide sequence
- Mutations are caused by mutagens. Examples include x-rays, UV light, chemicals, etc.
- Point mutations are the change of one single nucleotide in the DNA
- Frameshift mutations are the addition/insertion or deletion of one side nucleotide pair in the
DNA strand. This causes the entire reading of the codons to be read incorrectly or messed up.
- DNA polymerase will proofread the DNA to find errors. If a wrong nucleotide is placed into the
strand a proofreading mechanism should find the error.
DNA Replication
- A new molecule of DNA is made through a process called replication.
- Know how to base pair to create the opposite strand of DNA.
- DNA replication results in two identical strands of DNA exactly like the original parent strand
Transcription
- Transcription is the process of copying DNA into mRNA (messenger RNA); This means the
instructions to make a protein encoded in a gene are copied into mRNA
- Transcription occurs in the nucleus
- mRNA carries the information contained in DNA to the ribosome for translation
Translation
- Translation is the process of converting mRNA (nucleotide sequence) to a protein (amino acid
sequence); converting RNA into amino acid sequence
- Amino acids are brought to the ribosome by tRNA (transfer RNA)
- Each amino acid is coded for by three nucleotides known as a CODON; codons can also code
for starts and stops
- tRNA contains an anticodon that briefly pairs with the codon on mRNA
- Translation occurs in the cytoplasm by ribosomes (ribosomes are made of rRNA)