Cells and Control Flashcards
What is mitosis?
- Mitosis is the stage of the cell cycle when the cell divides
- Mitosis is a type of cell division.
- Mitosis occurs wherever more cells are needed.
- It produces two new diploid cells that are identical to each other, and to the parent cell.
Importance of mitosis
uses
- For growth
- Repair damaged cells
- Asexual reproduction
Interphase
Cell prepares for mitosis by increasing amount of sub cellular structures and duplicating its dna
Phrophase
- Chromosomes condense
- Spindle fibres form and the nuclear membrane starts to break down
Metaphase
Chromosomes line up at the middle of the cell , attached to spindle fibres
Anaphase
The chromatids are pulled apart by cell fibres and move to opposite ends of the cell
Telephase
Nuclear membrane form around each set of chromosomes; these have become the nuclei of the 2 new cells
Cytokinesis
Cytoplasm and cell membrane divide to form 2 separate cells
What is cancer
Cancer is a result of uncontrolled mitosis; cancerous cells divide repeatedly and a tumor develops which is an irregular mass of cells
CELL DIFFERENTIATION
- Used in growth by both animals and plants
- The process by which cells become specialised to complete different tasks.
- There is one type of cell that can be used to make any cell.
CELL DIVISION
- Used in growth by both animals and plants
- cells need to divide in order to grow and repair themselves
CELL ELONGATION
- This is where a plant expands, making it bigger and so making it grow.
- ONLY in plants
Growth in animals
All growth in animals happens by division. They tend to grow whilst young, reach full growth and then stop, from then on most cell division is for repair.
Growth in plants
In plants, growth in height is mainly due to elongation. Cell division happens at the tips of roots and shoots. Plants grow continuously. Therefore plants continue to differentiate.
Importance of differentiation
Differentiation allows specialised cells to distinguish between each other, to perform specific functions and in turn, creates variation among and between species.
Percentile Charts
-They are used to define an overall pattern in development and to highlight potential problems
‘Percentile’- eg. a baby is in the 75th percentile of average mass this means that 75% of babies are lighter and 25% are heavier
-investigations may occur if results are above/below the top/bottom percentile line, or if it -increases/decreases over more than 2 percentiles, or if there is a general inconsistent pattern.
Stem cells
Stem cells are undifferentiated cells.
Embryonic stem cells
- Found in an early embryo
- Can differentiate into every type of cell in your body
- Important for growth
Adult stem cells
- Found in the body eg. bone marrow
- They aren’t as versatile as embryonic cells as they can only produce several types of specialised cell
- Used to replace damaged cells
Benefits of stem cells in medicine
- Scientists would be able to test millions of potential drugs without the use of humans or animals
- Provides great potential for discovering treatment/cures for a variety of diseases
- Benefits the study of development that can not be directly studied in a human embryo, therefore allowing prevention and treatment of abnormal human dvelopment