Lesson Six Flashcards
Protein synthesis
Uses DNA to produce proteins
DNA’s role in the production of proteins
Being the template/master copy
Does DNA ever leave the nucleus?
No
Proteins are put together in the….
Cytoplasm
What is the copy of DNA that transfers the message?
mRNA
The process of making mRNA from a DNA template is called…
Transcription
The newly synthesized mRNA travels to the cytoplasm where is then ______ into proteins
Translated
How many bases are needed to code for one amino acid?
3
Amino acids make up a…
Protein
Nitrogenous bases in the DNA contain the instructions to…
Make protein
Each set of 3 bases on the mRNA strand is called a….
Codon
How many possible combinations of codons are there vs how many amino acids?
64 vs 20
The duplication of codons is called…
Degeneracy
AUG is…
Methionine which is a start codon
UAA and UAF are…
Stop codons
At the end of each mRNA strand there are…
Long chains of adenine bases
Why are there long chains of adenine bases?
So the body can detect that the mRNA is still functional, then the tail falls off which tells the body this particular mRNA is not needed to produce the protein
Transcription short form:
- DNA is uncoiled by helicase and bass pairs are broken, DNA template ready.
- Free-floating nucleotides join complementary to the selected gene, RNA polymerase helps. (Uracil joins with Adenine) Ligase glues the backbone together.
- Enzymes break down temporary bond between mRNA and DNA template, then the mRNA is released.
- DNA molecule joins back together and the mRNA passes through the nuclear envelope through the nuclear pores into the cytoplasm.
Translation
First step:
Initiation:
mRNA associates with ribosome in the cytoplasm. The ribosomal subunits trap the mRNA and large subunit attaches to it. The first tRNA anticodon compliments and binds to the mRNA. Once both subunits attach the unit is functional.
Each tRNA carries…
An amino acid that is determined based on its anticodon
Anticodon
A set of 3 nucleotides at the base of the tRNA that will bind to a complimentary mRNA codon
Translation
Step 2
Elongation
A second tRNA comes in and compliments and binds to the second mRNA codon. The ribosome helps transfer the a.a from the 1st tRNA to the 2nd. The ribosome then moves down the mRNA by one codon. The first (empty) tRNA is recycled so it can bind to another mRNA codon. Peptide binds form between amino acids during the process.
Translation
Step 3
Termination
Ribosome continues to translate the mRNA strand and a polypeptide chain grows until a stop codon is reached. Once the terminator codon is reached, the finished protein is released.
Germ mutation
Occurs in gametes
Somatic mutation
Occur in body cells
Chromosomal mutations:
Deletion, Inversion, Translocation (broken piece attaches to a non homologous chromosome), nondisjunction (pair of chromosomes fail to separate during cell division
Point mutation
A change in a single nitrogen base in DNA
Frame shift mutation
The addition or deletion of a nitrogen base, causing the gene sequence to read out of sequence
Down syndrome
Chromosomal translocation, 21 joins with another chromosome and they have 2 normal 21
Sickle cell anemia
Substitution of a base to produce another amino acids 1 chromosome is normal the other is sickle
Cancer
Somatic mutation of uncontrollable growth of body cells
Hemophilia
Germ cell mutation, passed on to individual from multiple generations
