UNIT 1 - AOS 2 Flashcards
What is a eukaryotic cell?
Any cell or organism that possesses a clearly defined nucleus (they have membrane-bound organelles).
What is a prokaryotic cell?
Any cell or organism that lacks a distinct nucleus (they do not have membrane-bound organelles).
What is a nucleotide?
It contains phosphate, sugar, and a nitrogen-containing base.
What does it mean by complementary?
Having opposite shapes and changes, so that they pair together.
What does it mean by antiparallel?
Running side by side in the opposite direction.
What is binary fission?
One parent cell produces 2 identical daughter cells.
What are the steps of binary fission?
- A prokaryotic cell before cell replication.
- The circular chromosome is uncoiled and the DNA is replicated. Plasmids also replicate.
- The cell elongates as it prepares to separate into two new cells and the duplicated circular chromosomes migrate to opposite ends.
- The cell undergoes cytokinesis, this is the process of separating into two new cells – by pinching inwards and creating a septum.
- A new cell wall and membrane are formed down the centre of the cell.
- Finally, two new genetically identical cells are formed.
What are the stages of interphase?
G1, Synthesis, G2, Cytokinesis
What are the stages of mitosis?
Prophase
Metaphase
Anaphase
Telophase
What is interphase - G1?
This is the phase when the contractile ring has constricted to its fullest extent, membrane vesicles move to the constriction and fuse with the membrane, creating 2 separate cells. Cytokinesis is complete.
What is interphase - Synthesis?
Is the phase when DNA is packaged into chromosomes, DNA is replicated.
What is interphase - G2?
The cell grows more, makes proteins and organelles and begins to reorganise its contents in its preparation for mitosis.
What is interphase - Cytokinesis?
The nuclear membrane is fully formed, the chromosomes have decondensed and the nucleolus has reappeared. The contractile ring contracts, deepening the cleavage furrow.
What is prophase?
The nucleolus disappears and the chromatin starts to condense and become visible.
The chromatin starts to condense and the nuclear membrane starts to break down.
What is metaphase?
The nuclear membrane is gone. The chromosomes assemble along the equator and the kinetochore at each chromosome centromere extends kinetochore fibres attach spindle fibres.
What is anaphase?
The spindle fibres shorten and the chromatids of. each chromosome is dragged to opposite poles of the cell by its kinetochores.
What is telophase?
The chromosomes begin to decondensed back into expanded chromatin. The nuclear membrane starts to reform around each nucleus. A contractile ring of the fibres and motor proteins start forming, creating a cleavage furrow in the cell membrane