Chapter 8 (EXAM 2) Flashcards
What are genes
Sequences of nucleotides, a protein, that codes for a protein
What are proteins
Made of amino acids, connected by peptide bonds, structural and enzymatic
Describe DNA
double helix
Alternating phosphate groups followed by sugar
Adenine-Thymine
Guanine-Cytosine
What is a nucleotide
Sugar, phosphate and base together
What is a nucleoside
Just a base and a sugar, no phosphate
DNA vs RNA
Made of deoxyribose sugar
two strands, double helix
uses the base C, G, A, T, during replication A binds to T
Made of ribose sugar
3 types: messenger RNA, ribosomal RNA, transfer RNA single strand
has bases C, G, A, U, during production A binds to U
What is a mutation
A change in DNA, natural occurrence but environment can force a change
Most result in no change in the protien and no change in organism
Can occasionally be harmful to the environment, or beneficial
benefits includeL resistance to microbial agents, pathogenicity: generating disease
What is a mutagen
Something that causes mutations, example is UV, can lead to cancer
Causes 2 T to bind together and is cut out.
Too much UV can lead to major changes in DNA that the body can’t recover from leading two growths and cancers
What is a frameshift mutation
Is caused by aflatoxin
Is a change in DNA, gene code changes and it interferes with the proper protein being reproduced
If caused by random or a mutagen, one base will be kicked out and everything will be shifted over. Now making a whole different amino acid and a different amino acid means a different charge which means the protein will be shaped differently and is now nonfunctional to the enzyme
What is a base substitution
Instead of C followed by a C, it’s followed by T because the code was substituted.
Can occur by random mutation or mutagen.
The problem with this is that the amino acids have charges on them and the charge will cause it to change it’s shape so the protein won’t fit the enzyme
What is insertion
Opposite of frameshift
A base will be thrown in instead of being kicked out
What is translocation
Occurs in eukaryotes only
Non homologous chromosomes exchange genes
Replication
Helicase tears apart weak hydrogen bonds, helps with the unwinding for replication
Separates A from T and C from G
The new bases will be brought to the exposed unpaired by DNA polymerase enzyme to create new strands of DNA
What is the leading strand
Light colored strand that is made continuously
Made of the original DNA strand, 5-3 direction
What is the lagging strand
Made discontinuously and those spaces have to be filled in by chances of Okazaki fragments.
Takes longer than the leading strand and jot as fast
What does DNA gyrase do
Relaxes supercoiling of the replication fork
Transcription
Making a close copy of DNA
Template is used as the pattern to build mRNA, its one half of the DNA strand
RNA polymerase brings in the base pair and mRNA is built
The codes will make the recipe for the amino acids just like in DNA
What are the stop codeons
UAA UGA UAG
What is an exon
Segments that contain genes that will be expressed, transcribed and translated
Protein will be made from them
What are Introns
Contain info that does not code for production, isn’t a recipe
What are operons
Chunks of DNA that contain functional sections
Promoter, Operator and Structural genes
What is a promoter
Segments of DNA in which RNA polymerase binds
What is a operator
Next to promoter
What is a structural gene
Contains genetic encoded info
What is a repressive protein
Can attach to operator and repress function of the promoter. Will allow to not combine on/off switch of promoter
What is the inducible system
A way to control protein synthesis
Is a type of operon, lac operon that is not functioning, is normally off, repressor protein is stuck
Genes are turned on ONLY if particular substrate is in the environment, the lactose substrate
Glucose has to be absent bc it will only turn on if the only thing to eat is lactose!!
What is the repressible system
A way to control protein synthesis
Is on, repressor protein is not stuck.
Allows RNA polymerase to bind to promoter and transcription of structural genes to occur
Repressible system: Constitutive genes
Bacteria will spend the energy to constantly transcribe the proteins because those proteins are essential
What is eukaryotic regulation
microRNA binds to mRNA to degrade it
Gets cells to produce proteins of only certain kinds
The small interfering RNA will control which messenger RNA gets read by the ribosomes
Methylenated genes will be turned off temporarily
What is genetic transfer and its types
A way of getting genes that may enhance the life of an environmentally challenged bacteria for survival
It has to obtain genes to:
eat foods its never eaten, allow it to conjugate, are resistant, cause disease to have its needs met, make bacteriocins
The types include: transformation, transaction and conjugation
Describe transformation
A type of genetic transfer
When dying or desperate bacteria PICKS UP genes in its environment that will allow the bacteria to survive.
Will only pick the genes up of it has those recipes, if not it will drop them.
Will keep the genes as plasmids or recombines them to the host genome
* occurs only when there is some environmental challenge that is killing the bacteria there*
When the bacteria is no longer in danger it cleans house and discards any genes not used in a long time
Describe Transduction
A type of genetic transfer
INVOLVES A VIRAL, Fancy genes
1.Virus infects bacterial cell
2. chops up host DNA
3. Utilizes the cell to make more viruses. If those fancy genes are in cell it keeps them
4. When challenge disappears it gets rid of those genes
Same as transformation except it involves a viral to occur first
Describe conjugation
Occurs with gram- or gram+ bacteria when challenged
IS BACTERIAL SEX
If challenged they spend their energy to make a plus btwn the two cells
The f+ cell will share genes with the f- cell bc f+ is the one with the fancy genes so f- needs it to survive
What is feedback inhibition
Product serves as allosteric inhibitor
What enzyme dominates the process of transcription
RNA polymerse
DNA of TTA-GCT is what mRNA
AAU-CGA
DNA of TAT-GCT is what tRNA
AUA-CGA= UAU-GCU
Name the bonds that hold DNA bases together
hydrogen bonds
Name the bonds that holds amino acids together
peptide bonds
What are bacteriaphages
Virus that infects a bacterium and reproduces inside of it
What are the products of transcription
mRNA also tRNA,rRNA and microRNA
What does ionizing radiation do to bacterium
breaks up DNA, creates ions that stick to DNA so they’re unusable
transcription vs replication diagram
transcription has template and only one binded strand
replication has template and two binded strands
Tetracycline
binds to 30s ribosomes, prevents tRNA attachment
Chloramphenicol
binds to 50s ribosome, inhibits peptide bond formation
Streptomycin
binds to 30s ribosome, causing kink and read incorrectly
Erythromycin
blocks tunnel btwn large and small ribosomal pieces
narrow spectrum
What enzyme bonds adjacent nucleotide bases
DNA ligase
What enzyme cuts DNA at specific nucleotide sequence
restriction enzyme
The two strands of DNA run
antiparallel
What is found on plasmids
Double stranded DNA that replicated independently
carry genes, r factors with fancy genes
