If all of your cells had a mutation in an important gene, why could that be bad?
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Transcript of If all of your cells had a mutation in an important gene, why could that be bad?
If all of your cells had a mutationin an important gene, whycould that be bad?
•
Chromosomes-• Each chromosome is made of many genes.
Genes-• Each gene holds a sequence to be transcribed and translated into a protein.
• A gene is an instruction for a protein to be made by your body.
• All cells in you have the SAME genetic code.• only read certain genes to tell them what that cell should do
• When a new cell is made…• these cells differentiate, turning on/off different parts of DNA to make them a specific type of cell
• DNA is the code of life
• BUT- it cannot leave the nucleus, AND it is written in the wrong language
• You need something to COPY and TRANSLATE it!
RNA (the copier)-• Single-stranded ribonucleic acid acts to bring the DNA’s message to the ribosome, telling it what protein to make.
Only two difference-• In RNA, no T. Instead, has U • Single-, not double-stranded
3 types• rRNA (ribosomal RNA)• makes up ribosomes
• *mRNA (messenger RNA)• brings DNA’s code to ribosome
• *tRNA (transfer RNA)• brings amino acids to ribosome for protein construction
• DNA used as a template• DNA opens in part, and each “gene” is used as a template for an mRNA strand to be constructed
• mRNA read in 3-letter sequences by the ribosome
Animation of Transcription
RNA goes to the Ribosome (the translatorRNA is “translated” into a protein
• each coded tRNA brings with it an amino acid to add to the protein
Animation of Translation
A change in a genetic sequence.
This can result in a change in the three-letter sequence, which results in differentamino acids being added, and the wrongprotein made
Point mutations-• A single DNA nucleotide is changed, resulting in one wrong codon being produced.
AAT AAG would add L instead of A to the amino acid chain.
Frame-shift mutations• Insertion or deletion• One nucleotide is either added or removed from the sequence, resulting in a change in all of the codons that result in the chain.
ATT GCC CTG GAT TAC
ATT CGC CCT GGA TTA C
Lac gene:• When glucose present, lac (lactose) gene is off (use glucose instead of lactose for energy
• When no glucose, lac gene turns back on to use other sugars (lactose) to | make energy
In many cases, the environment anorganism is in will change its geneticexpression.• Some will turn genes on, some will turn genes off
• **Your DNA doesn’t change, what does change is what genes are turned on and which are turned off
If a rabbit moves to a new locationand its fur color changes, has its DNA changed? Explain?