Chapter 6- Protein Synthesis Flashcards
DNA replication produces..
An identical DNA strand
Protein synthesis uses what to produce proteins?
DNA
DNA never leaves what organelle?
The nucleus
What is the abbreviation for messenger RNA?
mRNA
DNA contains the instructions for what?
Production of proteins
What is the function of mRNA?
Sends the instructions of the DNA from the nucleus to the site of protein synthesis in the cytoplasm
What is the process of making the mRNA from a DNA template called?
Transcription
What is the process of mRNA being used to direct the synthesis of proteins called?
Translation
How many bases in a DNA strand code for one amino acid?
3
What is a codon?
Each set of 3 bases on the mRNA, once the code for protein synthesis is transcribed
How many possible codons are there?
64
How many amino acids are there?
About 20
What is the duplication of codons called?
Degeneracy
What do duplicate codons may have a way of doing?
Producing/reducing the effects of mutations
What does the fact that the genetic code is basically universal suggest?
That all living things came from a common ancestor
How does the body detect that the mRNA is still functional?
An adenine tail (long chains of adenine based at the end of an mRNA strand)
What does the body do with no longer functional mRNA?
The cell will digest it, with the help of the lysosomes
What happens to the adenine tail when enough protein is created?
It falls off
What are the steps of transcription?
- The gene in DNA is selected, isolated, and uncoiled by Helicase (enzyme). The hydrogen bonds between bases are broken
- Nucleotides join to the exposed bases with the help of Polymerase
- Backbone is joined together by Ligase
- Enzymes break the hydrogen bond between DNA and the mRNA strand
- DNA molecule joins together again, mRNA passes through nuclear envelope and cytoplasm
- DNA recoils into double helix shape
What are the steps of translation?
- Initiation: mRNA travels to cytoplasm, where it is joined to a ribosome. The larger subunit of ribosomes, either rRNA or proteins, attached to the mRNA. Both subunits must become attached.
- Elongation: a second tRNA comes in, and binds with the second mRNA codon. The amino acid from the first tRNA is transferred to the second tRNA with the help of the ribosome. The ribosome then moves down the mRNA by one codon. The first tRNA is recycled, and this whole process is repeated to continue the chain.
- Termination: the process of elongation is continued until a terminator is reached, which releases a polypeptide (protein). The mRNA can be read by many ribosomes.
What are the types of mutations?
- Germ mutation: occurs in gametes
- Somatic mutation: occur in body cells
- Chromosomal mutations: occurs in chromosomes
- Gene mutations: occurs in genes
What are the 4 types of chromosomal mutations?
- Deletion: piece of chromosome breaks off
- Inversion: piece of chromosome breaks off and reattaches in reverse order
- Translocation: broken piece attaches to a homologous chromosome
- Nondisjunction: pair of chromosomes fail to separate during cell division
What are the two types of gene mutations?
- Point mutations: change in single nitrogenous base in DNA
* Frame-shift mutation: addition or deletion of nitrogenous base
What are the causes of mutations?
- Occur randomly
* Caused by agent
What is a factor that increased the chance of a mutation called?
A mutagen
What are the two environmental mutagens?
- Chemical-food additives: hallucinogenic drugs, pesticides/fertilizers, industrial chemicals
- Radiation: non-visible short wavelength from electromagnetic spectrum
What are mutagens that can lead to an increased risk of cancer called?
Carcinogens
