chromosomes and mitosis Flashcards
what organelle does most cells in our body have?
nucleus
what does the nucleus contain? in what form?
the nucleus contains genetic material in forms of chromosomes.
what are chromosomes?
coiled up packets of DNA
what do chromosomes carry?
each chromosome carries a large number of different genes.
what do genes control?
genes control the development of different characteristics.
give 3 examples of characteristics a gene controls.
hair colour
eye colour
height
how many numbers of chromosomes do normal human body cells have?
23 pairs
how many copies of each chromosome do human body cells have? where do they get each one from?
body cells normally have 2 copies of each chromosome, one from the mother and one from the father.
what is the cell cycle?
a series of stages where a cell divides into 2 identical daughter cells.
why is the cell cycle needed?
it produces cells for: GROWTH, DEVELOPMENT, REPAIR.
How do cells divide?
through a series of stages known as the cell cycle
what happens during the cell cycle? give a brief explanation.
During the cell cycle genetic material is doubled and then divided into two identical cells
what stage is known for division?
mitosis
What is cell division by mitosis important in?
The growth and development of tissues in multicellular organisms
Repair of tissues in multi-cellular organisms
Asexual reproduction in multicellular organisms and binary fission in unicellular organisms
what are the 2 main stages of the cell cycle?
Growth + DNA replication and Mitosis
explain thoroughly the Growth + DNA replication stage.
- Before division occurs, DNA is spread out into long strings.
- The cell becomes larger and increases the number of subcellular structures, specifically mitochondria and ribosomes.
- DNA then duplicates, ensuring one copy for each new cell, forming X shape chromosomes. Each arm of the chromosome is genetically identical to the other.
explain thoroughly the mitosis stage.
- The chromosomes line up at the centre of the cell and cell fibres from each pole pull the arms of the chromosomes into opposite ends of the cell.
- Membranes build around each set of the chromosomes, dividing the nucleus into 2 nuclei for each new cell.
- Finally, the cytoplasm and cell membrane divide.
YOU NOW HAVE 2 DAUGHTER CELLS READY FOR:
GROWTH
REPAIR
DEVELOPMENT.
what is formed at the end of the cell cycle?
2 new cells, identical to the og cell sharing the exact number of chromosomes - 2 DAUGHTER CELLS
what is the scientific term for the division of the cytoplasm?
cytokinesis
what’s the name of the 23rd pair of chromosomes?
the sex chromosomes, these are the X and Y chromosomes
what do the daughter cells contain?
exact same DNA, identical to each other and the parent cell.
what happens to the daughter cells immediately after they’re formed?
they have a temporary cell resting period before undergoing the process of the cell cycle later on.
what the deinition of a gene?
a small section of DNA that codes for a particular protein.
