Bio Viruses and prokatyotes, Cell And Reproduction Flashcards
Binary fission is
Unicellular organisms such as bacteria reproduce asexually where parental bacterial cell doubles in size and then divided into two identical daughter cells. Then each of them divides into two and so on. Type of growth - exponential where rate of reproduction increases over time.
Circular chromosome replicates and attaches to the cell wall; plasma membrane and cell wall along the midline forming daughter cells.
Generation time is time needed for a bacteria to double or for a single bacterium to divide into two.
Original number of cell * 2^n = number of cells after reproduction where n is a number of generations
Phases : lag - before dividing when they become used to local conditions and synthesize compounds required for metabolism (RNA, enzymes), log phase - growth exponentially, stationary phase and death phase.
Difference between eukaryotic and prokaryotic cell is that eukaryotic has …
Membrane bound organelles (endomembrane system) such as peroxisome that contains hydrogen peroxide ( collect and break down material, oxidation reduction reactions and metabolism of specific lipids, site of beta oxidation of very long chain fatty acids, detoxification of harmful substances), nucleus (storage of DNA, DNA replication and transcription), nuclear pores ( transfer mRNA to cytoplasm for translation, transfer of proteins), cytoskeleton (filaments with micro tubules- actin to provide shake and internal structure of the cell and transport of cargo via motor proteins), double stranded DNA genome ( single stranded in viruses).
Eukaryotic cell composition
Telomeres are
Regions of repetitive nucleotide sequences at the ends of eukaryotic chromosomes that shorten each round of cell division ( only in eukaryotes because it has linear chromosome!)
Characteristics of prokaryotes and eukaryotes
Table below
Fungi and protozoa are eukaryotic with phospholipid bilayer (cell membrane)
Viruses characteristics
Obligate intercellular organisms that cannot reproduce outside of a host cell. The genetic material either DNA or RNA that single stranded or double stranded and is surrounded by a protective coat called a capsid.
Viruses can be either enveloped or nonenveloped. Enveloped have a membrane, phospholipid bilayer ( cell membrane) derived from the cell membrane of the host. This surrounds the capsid and contains proteins to help to entry into the host cell. Nonenveloped viruses lack the phospholipid bilayer.
Nucleus contains
All the genetic info necessary to replication of the cell
Blood cells do not contain nucleus
Mitochondrion function
Location of many metabolic processes ( citric acid cycle, pyruvate dehydrogenase, electron transport chain, oxidative phosphorylation, beta oxidation, some of gluconeogenesis, urea cycle and ATP production), replicated independently via binary fission
Lysosome function
Contains hydrologic enzymes that can break down many different substance, made by Golgi, single membrane.
Rough endoplasmic reticulum function
Synthesis of proteins by accepting mRNA destined for insertion into a membrane or secretion
Smooth endoplasmic reticulum
Lipid synthesis and detoxification
Golgi apparatus function
Post-translational modification and distribution of proteins occurs. Only in eukaryotes.
Vesicular transport: COP2 -> forward. COP1<- return.
Cisternal maturation: vesicles travel in retrograde, new Cis made, Cis/ Medial/ Trans/ Exit
Fluid mosaic model and membrane traffic characteristics
Phospholipid bilayer with cholesterol and embedded proteins
Exterior : hydrophilic phosphate head groups
Interior : hydrophobic fatty acids
Cells theory 3 statements:
All living organisms are composed of cells
The cell is the basic functional unit of life
Cells arise only from preexisting cells
Prokaryotes characteristics
By shape: spherical - cocci, rod shaped - bacilli, spiral shaped - spirilli.
Have cell wall ( peptidoglycan - violet, iodide) surround the plasma membrane (phospholipid layer) form the envelope. Composition of the cell wall classifies bacteria into gram positive ( purple, thick have large portion of peptidoglycan/ lipoteichoic acid in the cell wall) and gram negative ( pink-red, thin small quantities of peptidoglycan cell wall with lipopolysaccharides).
Prokaryotic flagella is different from the eukaryotic because it contains a basal body connected to filament by hook that serves for motion.
Divide by binary fusion.
Nucleoid Region function
DNA region in prokaryotes
Nucleolus function
Makes ribosomes, sits in nucleus, no membrane, rRNA is made in
Centrioles function
9 groups of microtubules, pull chromosomes apart.
Plasmids characteristics
In prokaryotes, carry DNA not necessary for survival
Cytoskeleton characteristics
Microfilaments: actin for protection and movement (cleavage furrow)
Microtubules: Tubulin (9+2), motor protein pathways, cilia/flagella, centrioles
Intermediate filaments : keratin = vimentin, desmin = lamin , cell cell adhesion
Obligate aerobe
Requires O2
Obligate anaerobe
Dies in O2
Facultative anaerobe
Toggle between aerobic/ anaerobic
Aerotolerant anaerobe
Does not use O2 but tolerates it
Eukaryotes vs prokaryotes
Prokaryotes have 30S/ 50S ribosome = 70 S, no mitochondria, no nucleus, single chromosome (haploid), DNA is naked, no introns.
Eukaryotes have 60S and 40S = 80S ribosome, chromosomes paired ( diploid or more), DNA bound to protein, has introns.
Prions characteristics
Infectious proteins. Trigger misfolding. Alpha helical -> beta pleated sheet. Decreased solubility
Viroid is
Plant pathogens
Retrovirus definition
Single stranded RNA. Carries reverse transcriptase needed to make DNA and its integrated into host genome
Bacteriophage life cycles characteristics
Lytic : virions made until cell lyses.
Lysogenic : virus integrates into genome as provirus or prophage. Goes dormant until stress activates it.
Bacteriophage is
Bacteria virus. Tail sheath objects DNA / RNA
Viral genome characteristics
May be DNA or RNA. Single or double stranded.
If single stranded: positive sense - can be translated by ribosomes of host cell, rna genomes can directly translate their genetic material into viral proteins upon infection of a host cell with no need of transcription.
Negative sense- rna replicase must synthesize a complimentary strand, which can then be translated.
Lacks ribosomes, membrane bound organelles
Virion is
Individual virus particles
Transformation in genetic recombination is
Gets genetic info from environment, integration of foreign genetic material into host genome
Conjugation is
Sexual, Transfer of genetic info between bacteria via conjugation bridge by a connecting tube called a pilus. F+ donor ( contain plasmid)-> pilus-> F-( lacks a plasmid) or Hfr -> recipient , use definite factor from donor +
Transduction is
Transfer using bacteriophage to carry genetic info from one bacterium to another
Transposons is
Genetic info that can insert/ remove themselves
Tissues can be
Epithelia: parenchyma (functional parts of organ), simple - one layer, stratified - multiple layers, pseudostratified - one layer, cuboidal - cube shape, columnar - long and narrow, squamous - flat, scale like.
Connective : stroma ( support, extracellular matrix). Bone, cartilage, tendon, blood
Operator is where …. but promoter …
Repressor binds,
RNA binds
Plasmids that can integrated is
Episomes
Phenotypic ratio for AaBb
9:3:3:1
Inducible system needs …, repressible needs
Inducer for transcription,
Depressor to stop tran
Virus is
Not considered living organism, they contain genetic material but cannot reproduce by their own, replicate by using RNA of other organism when invading
DNA to proteins steps
DNA -> RNA ( transcription in nucleus) then RNA -> protein (translation int ribosome and cytoplasm)
Northern blotting technique
To detect and measure the concentration of specific RNA molecules within a cell it tissue sample.
Southern blotting is a technique to
Detect and measure the concentration of DNA in a cell
DNA sequencing is used to
Determine the specific nucleotide order of a DNA molecule
Three elements of operon
1) promoter ( or the upstream region of DNA to which RNA polymerase and other transcriptional modulators binds). Transcription factor bind to the promoter region of the genre they regulate.
2) operator (nucleotide sequence either within the promoter or between the promoter and the downstream genes regulated by the promoter to which a repressor binds
3) genes controlled by the operon
Operon consists of set of genes whose expression is correlated due to regulation by the same promoter and operator
If the mRNA transcript levels of one gene in the opening increases then mRNA levels for other genes in the operon should also …
Increases and vice versa
Genetic variation in bacteria happens by ..
Recombination (mixing DNA from different sources) by three mechanisms : transduction, conjugation and transformation ( simple uptake of a DNA, either a liner fragment of a plasmid) from a recipient bacterium’s extra cellular fluid through membrane pores or transport proteins without joining a donor or a virus).
What is virus?
Small infectious agents containing genetic material (DNA or RNA) that can only be replicated within a living host cell
What is phagocytosis?
Certain immune cells like macrophages engulf pathogens inside a vesicle ( lysosome)
Antibiotic resistance is
A state in which a higher antibiotic concentration ( or a different type of antibiotic) is required to treat a bacterial infection
Each chromosome had a condensed region of repetitive non coding DNA called
Centromere which is a structure that facilitates spindle fiber attachment during mitosis and meiosis
