3.2 Mitosis/Bacterial & Viral RP Flashcards
What are chromosomes joined in the middle by?
A centromere.
What is a sister chromatid?
Two strands on the same chromosome.
What are centrioles?
Proteins which move to opposite ends of the cell and produce spindle fibres.
What don’t plants have regarding prophase?
Centrioles or spindle fibres.
What is binary fission?
A form of mitosis, the cell replicates its genetic material before splitting into 2 DC.
What do we grow colonies of bacteria on to observe BF?
Agar gel plates or in nutrient broth.
Why do we grow cultures of microorganisms?
To investigate the action of disinfectants and antibiotics.
What’s the difference between circular DNA and plasmids?
ODNA replicates once but plasmids can do many times.
How does a circular DNA replicate?
Cell englarges, circular moves to opposite poles of the cell & attach to the cell membrane.
Cytoplasm begins to divide and a new cell wall forms.
CP splits, two DC.
What are viruses?
Nucleic acids surrounded by protein.
What are 4 properties of viruses?
-Can only reproduce inside host cells.
-No cell surface membrane, RS and CP.
-Protein coat called a capsid, with attachment proteins sticking out.
-Attachment proteins bind to the host cell.
Why do different viruses require different receptor proteins?
They have different attachment proteins.
How do viruses replicate?
-Inject their DNA into a host cell.
-Incorporate their DNA into the host cell’s DNA.
-They then use the host cell’s reproductive DNA code to replicate nucleic acids, enzymes + structural proteins which are assembled into new viruses.
describe the events of prophase
chromosomes condense to become visible and fat
centrioles split and move to opposite ends of the cell, spanning spindle fibres from pole to pole to produce the spindle apparatus
the nuclear envelope disintegrates and chromosomes are freed into the cytoplasm
describe the events that occur in metaphase
spindle fibres attach to the chromosomes at their centromeres and chromosomes are pulled along the apparatus to line up along the equator of the cell
describe the events that occur during anaphase
centromeres divide into two and spindle fibres pull individual chromatids apart to opposite poles of the cell
describe the events in telophase
chromatids reach opposite poles of the cell
the nuclear envelope reforms around the chromosomes
the cell prepares to split its cytoplasm and contents
describe what happens in cytokinesis
the cytoplasm and cell membrane separate to form two identical daughter cells
describe the events in binary fission
circular DNA replicates and both copies attach to the cell membrane
the plasmids also replicate
cell membrane begins to grow between the two DNA molecules and pinches inward, dividing the cytoplasm into two
a new cell forms between the two molecules, dividing the original into two identical daughter cells, each with a singular copy of circular DNA
describe the events that occur in viral replication
the virus attaches glycoproteins to the complimentary receptors on their host cells
they inject their DNA/RNA into the host cell
the host cell divides as normal and the virus is replicated
describe the basic steps of the cell cycle
1- interphase occupies most of the cycle, the resting phase
2- nuclear division, either mitosis or meiosis
3- cytokinesis (cytoplasm divides)
chromosome non dysjunction
chromatids fail to separate during anaphase so both go to one pole of the spindle
human body cell chromosome number
46, diploid
sex cell cs number humans
23, haploid
consequence of offspring with uneven number of chromosomes
meiosis cannot occur so haploid cells are not produced
start and end of meiosis
one diploid cell, two haploid n daughter cells after meiosis 1, 4 haploid n daughter cells after meiosis 2
start and end of mitosis
two diploid daughter cells from one diploid body cells, genetically identical
diploid
two complete set of chromosomes
haploid
one complete set of chromosomes
