Topic 2.2 - Methods of studying cells Flashcards
All cells arise from other cells
Why is mitosis important?
This is important for growth
replacement of old cells to repair body tissue
asexual reproduction
To make 2 new genetically identical daughter cells (with the same DNA as the parent cell)
What are the different stages of the cell cycle ?
Interphase
Mitosis
Cytokinesis
What are the 4 stages of mitosis ?
prophase
metaphase
anaphase
telophase
Explain what happens during each stage of the cell cycle
Interphase:
Replication of organelles
Protein synthesis
DNA replicates
DNA decondensed
Prophase:
DNA coils up (condenses) – becomes more visible
Nuclear envelope breaks down
Centrioles migrate to opposite poles of the cell and produce spindle fibres which attach to the centromeres of the chromsomes
Metaphase:
Spindle fibres move the chromosomes so that they line up along the equator of the cell
Anaphase:
Spindle fibres shorten
This separates sister chromatids so that they are pulled to opposite poles of the cell
Telophase:
Nuclear envelopes reform
Chromosomes decondense
Cytokinesis:
cytoplasm divides so two separate cells are formed
Why do we take cells from the root tip?
The root tip is the region where mitosis/cell division occurs
Why do we squash the root tip? And why is important?
We squash the root tip to make the tissue layer thin. This allows light through.
Why is a stain used?
To distinguish chromosomes
What equation do we use to calculate the mitotic index?
Mitotic index = Number of cell in mitosis/ total number of cells
What is cancer?
Uncontrollable cell division.
Describe the replication process of bacterial cells
Binary Fission
Circular DNA and plasmids replicate
Circular DNA attaches to opposite ends of cell membrane
Bacterial cell grows
The cell membrane pinches inwards in the middle of the cell
cytoplasm divides to form two daughter cells (each has a variable number of plasmids)
A cell wall is formed around each daughter cell.
Label the structures of a virus
Capsid
genetic material
attachment protein
How does a Virus Replicate?
Virus attaches to a host cell
Virus injects its genetic material into the host cell
The host cell transcribes and translates the viral genes
These proteins form new virus particles
The virus particles burst out of the host cell, so the host cell is destroyed
