Chapter 25 DNA Flashcards
DNA is the “_____” for all proteins
Written instructions
These “written instructions” include:
- Letters (bases)
- Words (codons)
- Sentences (gene)
- Punctuation (promoters, stop codons)
Who built a double helix model to demonstrate the concept of DNA?
James WATSON and Francis CRICK
mRNA
Messenger RNA
-takes message from DNA to the ribosomes
rRNA
Ribosomal RNA
Translates the information in mRNA.
tRNA
Transfer RNA
Carry amino acids to the ribosomes to make proteins
Gene
a segment of DNA that specifies the amino acid sequence of a protein (or RNA)
Gene Expression
Making a protein from the gene
What are the stems in protein synthesis? (multi-step process…4 steps)
- DNA (master building plans)
- mRNA (blueprints)
- rRNA (construction site)
- tRNA (construction worker)
What 2 steps are required in gene expression?
- Transcription
2. Translation
Transcription (gene expression)
- making a readable copy of gene from DNA
- “transcribe” = to make a written copy
- happens inside the nucleus
Translation (gene expression)
- Using the gene’s instructions to construction protein
- “translate” = to turn from one language to another
- happens at ribosome on E.R. or in cytoplasm
Gene Mutation
A change in the sequence of bases within a gene
Gene mutations can lead to ____ ____ in cells
Malfunctioning protein
What causes mutations? (3 causes)
- Errors in replication
- DNA polymerase “proofreads” new strands, error rare - Mutagens
- Radiation, UV light, chemicals
- Rate is low, DNA repair enzymes monitor and repair - Transposons
- “jumping genes”
- can move to new locations and disrupt sequences
