Chapter 8 (EXAM 2) Flashcards by El S

What are genes

Sequences of nucleotides, a protein, that codes for a protein

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What are proteins

Made of amino acids, connected by peptide bonds, structural and enzymatic

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Describe DNA

double helix
Alternating phosphate groups followed by sugar
Adenine-Thymine
Guanine-Cytosine

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What is a nucleotide

Sugar, phosphate and base together

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What is a nucleoside

Just a base and a sugar, no phosphate

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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

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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

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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

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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

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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

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What is insertion

Opposite of frameshift

A base will be thrown in instead of being kicked out

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What is translocation

Occurs in eukaryotes only

Non homologous chromosomes exchange genes

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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

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What is the leading strand

Light colored strand that is made continuously

Made of the original DNA strand, 5-3 direction

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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

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What does DNA gyrase do

Relaxes supercoiling of the replication fork

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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

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What are the stop codeons

UAA UGA UAG

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What is an exon

Segments that contain genes that will be expressed, transcribed and translated
Protein will be made from them

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What are Introns

Contain info that does not code for production, isn’t a recipe

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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