Biology Flashcards
Describe the types of bacteria shapes?
Cocci, Bacilli, Spirill
Cocci:
spherical shaped bacteria
Bacilli:
rod shaped bacteria
Spirilli:
spiral shaped bacteria
Describe the difference between an anaerobe and aerobes?
The main difference between anaerobe and aerobe is that aerobes require oxygen to metabolize thus the name aerobe where as anaerobes do not require oxygen to metabolize thus the name anaerobe.
Gram positive:
the cell has a thick layer of peptidoglycan which is made from sugars and AA, it will also contain lipoteichoic acid which can create an immune system response.
Gram negative:
the cell wall contain peptidoglycan but only in small amounts and contain lipidsccarides which have a more triggering immune system response.
what is the unique function of a plasmid?
in prokaryotic cells a plasmid carries DNA that is not important for fundamental life and development and they are not considered as part of the genome however plasmids might be the key to antibiotic resistance.
What is Binary fission?
form of asexual reproduction of prokaryotes that results from DNA replication and split into two daughter cells from the prokaryote.
Describe the concept of genetic recombination and the methods by which bacteria can diversify themselves?
Genetic recombination is the process in which bacteria integrate DNA from episomes into their DNA and become more diversified bacteria and helps the evolution of the species over time these happen through three mechanisms
- transfromation
- Conjugation
- Transduction
Transformation:
integration of forgegin genetic material into the host genome and the foreign genetic material most frequently comes from bacteria
Conjugation:
bacterial form of mating (sexual reproduction) two cells from a conjugation bridge that facilitates the transfer of genetic material from a donor male to a recipient female and this is a UNIDIRECTIOAL transfer
> bacteria must contain sex factors that are plasmids that contain the necessary genes, this allows for genetic recombination and gaining anit-biotic resistant factors
Transduction:
ONLY genetic recombination process that requires a vector which is virus that carries genetic information from one bacterium to the other
What are transposons?
genetic elements that are capable of inserting and removing themselves from the genome
What happens if a patient is given an antibiotic and does not fully fish the treatment?
if a patient fails to complete the antibiotic treatment often discontinuing the treatment because they feel fine the creates antibiotic resistance and kills off the bacteria that are non resistant and leaving bacteria that is more resistance to reproduce resulting in a recurring infection
What is a virus?
genetic material that is composed of a protein coat and sometimes an envelope containing lips this genetic info can be DNA, RNA single or Double stranded
What is the protective case around a virus called?
capsid is the protein coat around a virus, these coats are very sensitive to heat, detergent etc.
Can virus reproduce independently or live on their own?
NO, they must express and replicate genetic information within a host cell because they lack the ribosome to carry out protein synthesis
What is a bacteriophage, is it bacteria or a virus?
bacteriophage is a virus that specifically targets bacteria, however they do not enter the bacteria they simply inject genetic material
What is the difference between positive sense and negative sense in viral genomes?
Positive Sense: genome my be directly translated to functional proteins by the ribosomes of the host cell just like mRNA, RNA virus stay in cytoplasm and are directly translated into proteins by host cell ribosome
Negative Sense: RNA virus that the RNA acts a template for synthesis of a complementary strand which can be used as a template fro protein synth and contain RNA replicase which ensure that the complementary strand is synthesized. Require the synthesis of a complementary RNA strand through RNA replicase that is translated and formed into protein
What are Retroviruses?
single stranded RNA virus that contain two identical RNA molecules that carry an enzyme called reverse transcriptase which synthesizes DNA from a single strand of RNA this DNA integrates into the host genome and replicated as its own host genome (like in HIV)
How can the concept of retroviruses be important in gene therapy?
retoerovisus and transduction are potentially going to be used in gene therapy, it can give functional version of a gene so that correct proteins can be synth for certain disease
Lytic:
Bacteriophage maximizes the use of the cells own machinery to replicate which no regard to the host cell, lysing the host genome
Lysogenic cycle:
virus becomes part of the host genome and my integrate into the host genome indef. however environmental factors can cause viruses to revert to the lytic pathway.
What are the stages of the cell cycle?
- Interphase
- G0
- G1
- G2
- M1
Interphase:
first three stages of the cell cycle, and the longest part of the cell cycle where the cells are not actively dividing and spend 90% of their life.
G0:
cell is simply living can carrying out its functions without any preparation for division.
G1:
the cell creates organelles fro energy and proteins for the production of mitochondria, ribosomes, and ER and the cell also increases its size .
S:
cell replicates its own genetic material so that each daughter cell will have identical copies and each chromosome consist of two identical chromatid that are bound by the centromere
he polyploidy of the cell does not change even if the number of chromosomes have doubled, in other words humans in this stage sill only have 46 chromosomes even though 92 chromatids are present.
G2:
cells pass through a quality control checkpoint that the DNA has been dubplicated and their are enough organelles and cytoplasm for two daughter cells.
M:
Mitosis along with Cytokinesis
G1/S checkpoint:
the cell determines if the condition of DNA is good enough for synthesis
> restriction point: if their is damage to the DNA the cell goes in to arrest until the DNA has been repaired and the main protein is controlled of P53.
G2/M checkpoint
ensures cells have the proper number of organelles
What happens if a cell does not have any transcription factors?
> they promote transcription of genes that are required for the next stage of the cell cycle
How is cancer related to the cell cycle?
> the cell cycle controls if cells divide or not, cancer causing genes called oncogene and tumor surpassing genes can effect the cell grown.
> oncogenes: genes that when mutated promote cell growth
> Tumor suppression genes: mutated, lose their ability to regulate or arrest the cell cycle
What is Cytokinesis and when does it occur in a cell?
occurs at the end of telophase this is when the cytoplasm separates giving each daughter cell enough material to survive on their own.
Explain what can happen if chromosome in Anaphase 1 or II of meiosis fail to separate properly?
if homologus chromosomes in anaphase 1 or sister chromatids in anaphase II fail to separate on of the resulting gametes will have two copies of a particular chromosome and the other gamete will have none. If this gamete gets to fertilization the resulting zygote may have too many copies or too few copies of the chromosome causing trisomy 21 which is downs or klinfelters/ turner syndrome for sex chromosomes.
What are the different pathway a cell can become determined?
- during cleavage where the existing mRNA and proteins in the parent cell has been asymmetrically distributed between daughter cells and the presence of specific mRNA and protein molecules
- secretion of specific molecules from nearby cells, called Morphogens may cause neighboring cells to follow particular developmental pathways
Inducers:
how cells become a specific cell type (often called growth factors, that promote differentiation and mitosis in certain tissues)
Responder:
the cell that is induced ( responsive cell)
Competent:
able to respond to inducing a signal
what are the four methods of cell to cell communication?
- Autocirne
- Paracrine
- Juxtacrine:
- endocrine
Autocirne:
acts on the same cell that screwed the signal in the first place
Paracrine:
signal acts on cells in the local area
Juxtacrine:
signals do not usually involve diffusion bu involve a cell directly stimulating receptors of an adj cell
endocrine:
signals involve the secretion of hormones that travel through the bloodstream to some distant target
Astrocytes:
nourish the nerouons in the blood brain barring which functions to control the transmission of solutes from the bloodstream to the nervous system
Ependymal cells
line the ventricle of the brain and produces CSF and physically sports the brain and serves as a shock absorber
Microglia
phagocytic that ingest and break down waste products and pathogens in the CNS
Oligidendrocytes and Schwann cells:
myelin sheets around axons
What happens with potassium leak channels?
Potassium leak channel facilitate outward movement of potassium which allows the slow leak of potassium outside of the cell making the outside of the cell positive and the inside of the cell negative.
What is Saltaory conduction?
the signal hops from node to node
With an action potential within the same neuron that have the same potential difference during depolarization do you want to increase the intensity or the frequency?
you want to increase the freq. because it is an all or none response!
What is Saltaory conduction?
the signal hops from node to node
With an action potential within the same neuron that have the same potential difference during depolarization do you want to increase the intensity or the frequency?
you want to increase the freq. because it is an all or none response!
What is the difference between electrical and chemical transmissions?
> electric uses to pass signals down the length of the axon
> Chemical is between neurons seen in NT and the transmission of glands and muscles.