Microbiology Chapter 5, 6, 7

Genomes

Entire collection of genetic material in a cell

Humans have how many chromosomes pairs

23

Carcinogen examples

Birth control pills, new car smell, cancer killing drugs

Gene

Sequence of nucleotides that code for a trait

Allele

Complementary copy of a gene

Genotype

Genetic makeup

Phenotype

Physical trait

____ influences phenotype

Genotype

Genome size ___

Varies

Eukaryotic genomes are ___

Larger

Organisms with larger genomes are more ____

Complex

Chromosomes

Condensed strands of DNA

Organizational proteins

Histones (euk) and histone-like (prok)

Histone function

DNA weapons around to prevent it from getting tangled

Plasmids

Pieces of DNA outside that replicate independently

Plasmids are found in

Bacteria, yeast, and plants

Nucleic acid is built from

Nucleotides

Nucleotides are composed of

A phosphate group, sugar, and a nitrogenous base

Sugar in DNA nucleotides

Deoxyribose; 5 carbons

Phosphate group in nucleotides bind to

5 carbon of sugar

Nitrogen base in DNA nucleotides binds to

1 carbon of sugar

DNA nucleotides nitrogen base pairs

A/T and C/G

A

Adenine

G

Guanine

C

Cytosine

T

Thymine

DNA is built

5 to 3

RNA nucleotides

Ribonucleoties

RNA folded on itself

Helical and loop

Ribonucleoties are made of

Phosphate group, sugar, and a nitrogen base

Ribonucleoties sugar

Ribose

Ribonucleotied nitrogen base pairs

A/U and C/G

U

Uracil

Uracil is like ___ in DNA

Thymine

RNA types

mRNA, tRNA, and rRNA

DNA replication

DNA copying itself

Protein synthesis

Genetic info is read to create proteins

DNA replication order

1. Unwinding DNA

2. Copying DNA

3. Rewinding new DNA with parent DNA

DNA replication speed

Fast

DNA replication has ___ mutations

Few

Helicase

Unwinds DNA

Primase

Builds RNA primers; multiple are needed to build the lagging strand

DNA polymerase III

Main enzyme that copies DNA on leading and lagging strand

DNA polymerase I

Replaces RNA primers with DNA; has a role in DNA repair

Ligase

Forms bonds to seal nicks in DNA; important in replication and repair

Gyrase and topoisomerase

Relives tension and stress that develops ahead of helicase as DNA unwinds

Leading strand

New strand made in same direction as the helix unwind; replication goes towards the replication fork

Lagging strand

New strand made in the opposite direction as the helix unwind; replication is aways from the replication fork

DNA replication takes ___ and has __ protein factors

Longer; more

Protein synthesis creates

Proteins (gene products)

Transcription steps

1. Initiation

2. Elongation

3. Termination

Main enzyme in transcription

RNA polymerase

Transcription occurs in

Cytoplasm of prokaryotes and nucleus of prokaryotes

Initation

RNA polymerase bonds to promoter and DNA unwinds

Elongation

RNA is built from 5 to 3

Termination

A sequence ending the transcribed DNA causing the RNA polymerase to fall off and the DNA to release mRNA

Messenger RNA (mRNA)

Carries message in codons and is translated to build a protein

Transfer RNA (tRNA)

Ushers amino acids into the ribosome during translation

Ribosomal RNA (rRNA)

complex stem and loop structure that combines with proteins to build ribosomes

3 nucleotides make up a

Codon

Ribosomes have a large and small sunbit that combine to

Preform translation

RNA translation step 1

Initiation

RNA initiation

Ribosome attached to mRNA until it reached a start; initiator tRNA carried amino acids and enter ribosomes P site

RNA elongation step one

tRNA enters a site

RNA elongation step two

Peptide bond forms between amino acids giving protein to tRNA

RnA elongation step 3

Ribosome goes down mRNA: tRNA goes to exit and tRNA in A site goes to P site

RNA elongation step four

Cycle repeats until stop codon

RNA termination

Ribosome reaches stop codon and releases the protein and detaches from mRNA

Mutation

Change in genetic material of cell or virus

Mutations in unicellular organisms

Passed onto daughter cells with binary fission or mitosis

Mutations in multicellular organisms

Only mutations in germ line cells are passed on with meiosis

Spontaneous mutations

Naturally occurring

Induced mutations

Response to agents in environment that carnage DNA structure

Mutagens

Chemical, physical, biological agents increasing the rate of mutation

Carcinogens

Mutagens that promotes cancer development

Mutation: substitution

Incorrect nucleotide is added

Mutation: insertion

Cell adds one or more nucleons to its sequence

Mutation: deletion

One or more nucleotides are removed from sequence

Silent mutation

Resulting amino acid isn't changed

Reversion mutation

Base substitution mutation corrected by another base substitution

Missense mutation

New codon encodes wrong amino acid

Nonsense mutation

Change leads to a stop

Frameshift mutation

Bases are inserted or deleted

Vertical gene transfer

Cells pass genetic info to next generation bc of sexual or asexual division

Horizontal gene transfer

Passed genetic info through process independent of cell division

Horizontal gene transfer types

Conjugation, transformation, transduction, transposons

Conjugation

Plus acts as a bridge for transferring

Transformation

Bacteria takes up DNA from its environment

Transduction

Introduction of new genetic material into a bacterial cell by a virus

Pilus

Small hollow tube

Pilus

Small hollow tube

Conjugation steps

1. Attachment to bacterial cell w/o a fertility plasmid

2. Pilus acts as a bridge for giving copy of fertility plasmid onto the lacking cell

3. Pilus dismantles and the cell separates

4. Recombination can occur (plasmid combines w/ cromosome)

Exogenous

DNA crosses the cell wall through absorption

Bacteriophages

Viruses that infect bacteria

Generalized transduction

Page DNA immediately directs production of new phage particles

Specialized transduction

DNA integrated into host cells genome

Transposons

Jumping genes

Virus

Nonliving infectious agent with living and non living characteristics

Viruses can infect

Plants, animals, and other microorganisms

Nonliving

Can’t synthesize their own components