Complementary Base Pairs
-Cytosine pairs with Guanine
-Adenine pairs with Thymine
-Connected with Hydrogen bonds
The primary function of DNA in cells is to:
-Store information that tells the cells which proteins to make
During DNA replication, the enzyme DNA polymerase:
-Constructs new nucleotide chains that are complementary to the chains in the original DNA molecule
If the sequence of nucleotides in one chain of a DNA molecules is TCAAGC, a new nucleotide chain will be produced during replication with the complementary sequence:
What are the three parts of a DNA nucleotide, and how are they connected to each other?
-Deoxyribose sugar molecule, phosphate group, & Nitrogenous bases
-Sugar & phosphate have a covalent bond
-Bases have Hydrogen bons
If 15% of the nucleotides in a DNA molecule contain guanine, what percentage of the nucleotides contain each of the other three bases?
Why is it important that exact copies of DNA are produced during replication?
-The RNA will be different and lead to mutations
-Amino acids won't be the same
-There won't be daughter cells
Why is it advantageous to have weak hydrogen bonds between complementary base pairs and strong covalent bonds between phosphate and deoxyribose groups in a DNA molecule?
-Bases need to be separated for replication, so they need to easily break
-Backbone needs to remain whole and intact to form the shape and structure of DNA
-DNA genetic info to ribosomes
-Translated into amino acid sequences
-Nucleus to cytoplasm
-Functions as interpreter in translation
-Has a specific anticodon
-Picks up specific amino acids
-Conveys amino acid into codon on mRNA
-Synthesis of RNA on a DNA template
-DNA to RNA
-Makes 3 RNA's (messenger, transfer, ribosome)
-Nucleotide sequence at the start of the gene where transcription begins
-Binding site for RNA polymerase
Describe three ways that RNA differs from DNA:
-RNA has an -OH group on the C atom
-Ribose rather than deoxyribose
-Uracil rather than Thymine
-Single stranded structure
-RNA polymers read 3' to 5', not 5' to 3'
Describe the shapes of the three types of RNA:
-mRNA: single-uncoiled chain/strand
-tRNA: t shaped
-rRNA: part of ribosome; globular
How is information about making proteins transmitted from the DNA to the site of protein synthesis?
-mRNA is transcribed then travels to cytoplasm (tNRA), which has the code for amino acids
What would be the nucleotide sequence of the NRA that is transcribed from DNA with a nucleotide sequence of GCTAATCCG?
How would the transcription of a eukaryotic gene be affected if a replication error changed the nucleotide sequence of the termination signal for that gene?
-RNA wouldn't fully replicate
-May not be any stop codons, or a change in them
-Difference in amino acids
Step 5 of Transcription
-RNA polymerase reaches the termination signal and releases the DNA and RNA molecules
-3 nucleotide sequence in mRNA
-Specifies a particular amino acid or polypeptide termination signal
-Basic unit of genetic code
-mRNA to amino acid
-Synthesis of polypeptide using genetic information encoded in mRNA molecule
-On a tRNA molecule
-Specific sequence of 3 nucleotides that's complementary to codon triplet on RNA
*Pair with codon on RNA
The genetic code specifies the correlation between
-An RNA nucleotide sequence and an amino acid sequence
One binding site on a ribosome holds an mRNA molecule, and the other two binding sites hold:
Two amino acids are linked by a peptide bond when:
-Two tRNAs pair with neighboring codons on an mRNA transcript
List, in order, the tRNA anticodons that are complementary to the mRNA sequence AUGCAUGCAAGUUAG
How many amino acids will be in the polypeptide that is initially formed when this mRNA sequence is translated?
Explain why methionine is the first amino acid in every growing polypeptide
-It tells the polypeptide to start protein synthesis