Exam 3, Good luck!

What is DNA?

deoxyribonucleic acid

What is RNA?

ribonucleic acid

What is DNA and RNA made of?

Nucleic Acids

What are nucleotides composed of?

phosphate group, sugar, nitrogenous base, OH group.

Structure of DNA

Double helix, Held together by hydrogen bonds

What are the base pairs for DNA?

AGTC

What are the base pairs is RNA?

UGTC

What is binary fission?

asexual reproduction done by DNA

Where does DNA replication take place?

Replication fork

Which direction does DNA replication take place?

5' to 3', Bidirectional

What are the enzymes involved in DNA replication?

DNA Helicase: Unwinds the DNA

LEADING STRAND:

DNA Polymerase: Connects the Leading strand to the "unzipped" other strand

LAGGING STRAND:

RNA polymerase: Makes RNA primer

DNA polymerase: Digests RNA primer and switches it to DNA

DNA Ligase: Ligates the Okazaki fragments

What is the central Dogma of molecular genetics?

DNA >>>(transcription)>>> RNA >>>(translation)>>> Protein

What is Transcription?

The process of making RNA from DNA

What direction does transcription take place?

5' to 3'

What enzymes are used in transcription?

RNA Polymerase

What is the start of transcription? End?

Promoter site, Termination site (Where MRNA gets released)

Be able to transcribe DNA into mRNA

ATGC>>>>>>>UACG

Know the differences between RNA and DNA

RNA:

Single Stranded

Ribose

U-A

DNA:

Double Stranded

Deoxyribose

T-A

What are the 3 major types of RNA in the cell?

mRNA: Contains the codons

rRNA: Ribosomes (70s)

tRNA: Transfer amino acids to ribosomes for protein synthesis, Anti- Codons

What is a codon?

a sequence of three nucleotides that together form a unit of genetic code in a DNA or RNA molecule.

What is an Anti-codon?

a sequence of three nucleotides forming a unit of genetic code in a transfer RNA molecule, corresponding to a complementary codon in messenger RNA.

What does it mean that genetic code is degenerative?

One amino acid can be coded by more than one codon, allows for silent mutations to be less harmful

What is the start codon?

AUG

remember that amino acids correspond to the codon on mRNA

.......

What does it mean that genetic code is universal?

All organisms on earth use the same genetic code

What are the 3 stages of translation?

initiation, elongation, termination

What happens during Initiation phase?

-mRNA attaches to the ribosome at the 5' end

- Small and large subunits come together

- Translation begins when ribosomes hits the start codon

What happens during elongation phase?

New amino acids are added

What happens during termination phase?

Translation of protein is completed when it hits a stop codon

What does mRNA do in translation?

Provides the template for which the order of amino acids

What does rRNA do in translation?

Forms the ribosomes that synthesize peptide bond between the amino acids.

Why do genes need to be regulated?

Because using all the would require to much energy from the cell, some are turned on all the time, others arent.

what are operons?

a series of structural genes under control of one regulatory gene.

What is a lac operon?

Series of genes that regulate lactose metabolism, usually turned off but turned on when lactose is present.

What is the trp operon?

repressible operon, encodes for the necessary enzymes for the cell to make tryptophan, always turned on. regulated by amount of tryptophan in the environment.

what is a point mutation?

a change in a single base pair in DNA, can be silent, nonsense or harmful.

What is a frame shift mutation?

When a base is inserted or deleted, Addition: One base aded by mistake, Deletion: On base is deleted by mistake.

Why is genetic transfer in bacteria important?

Results in genetic variation, needed for evolution

What is transformation in genetic transfer?

Genes are transferred from one bacterial to the next as naked pieces of DNA

What is conjugation in genetic transfer?

"passing plasmids", Cells must touch

What is Transduction in genetic transfer?

DNA is transferred through a virus, "Bacteriophage": A virus that only infects bacteria

How does gut microbiota develop early in life?

Development depends on the food and how it is delivered to us.

what is the role of gut microbiota in chronic diseases?

Various diseases can be linked to a unbalances intestinal microbiota, can lead to Dysibiosis, diabetes, allergies.

Characteristics of beneficial bacteria?

Anaerobic gram positive rods that ferment sugars with production of acid

Characteristics of probiotics? Role?

Consumed through fermented milk, pharmaceutical supplement, provides synergists effects, Reduces allergies, Detoxify some foods.

how are probiotics used outside the body?

vaccine carries, ex: Lactococcus lactis

What is the difference between probiotics, prebiotics, and synbiotics?

Probiotics: Upon ingestion exert health benefits beyond inherent general nutrition

prebiotics: Appropriate nutrients needed for supporting probiotic bacterial growth

synbiotics: are combined doses of probiotics and prebiotics

3 Domains of life?

Bacteria, Archaea, Eukarya

What is the 3rd domain based on?

Differences in morphology and physiology?

What has systematics of eukaryotes historically been based on; why can't microbial systematics be based on the same criteria?

Eukaryotes were based on differences in morphology and physiology, because microbes lack variability in morphological characteristics.

How were microbes classified until 1965?

biochemical test

how are microbes classified now?

Through their DNA sequences, much more accurate BECAUSE the material is much more abundant, looks and base pairs.

· What is the 'eocyte hypothesis'?

states that Eukaryotes originated within the archaea, they are not their own group.

Who discovered that the organisms formerly known as 'prokaryotes'? what gene was used?

Carl Woese in 1970, 16s because its found in every organism

What are Archaea?

Almost all are known as extremophiles. But most archaea are not extremophiles. Hyperthermophiles, Halophiles, Methanogens

which metabolic ability (ability to produce something) is only exhibited by archaea and never by bacteria?

Produce different flagellum, called archaellum

Know examples for characteristics that differentiate between archaea and bacteria?

Have irregular phospholipids (Sphingolipids), ether linkage rather than ester, Fatty acids are branched.

which common chemical compound is not utilized for energy production in archaea?

Glucose

How are archaea beneficial?

Methanogens produce biogas in landfills and waste water plants, methane is naturally used for heating