Chapter 7 - Mitosis Flashcards
- Define growth.
- What is a fertilised egg called?
- How long do cells continue to divide in animals?
- What do we call the life of a cell?
- What happens to a new cell once it has been made by division of an existing cell into two?
- Growth is defined as an increase in the number and/or size of cells in the organism.
- A zygote
- Animal cells continue to divide for growth until the organism reaches adulthood. In the adult some cells continue to divide in order to make new cells to replace ones that are damaged or worn out.
- The stages in the life of an individual cell are referred to as the cell cycle.
- It will increase in size and create more organelles such as mitochondria.
- Do all cells divide multiple times?
- What must cells do before they can divide?
- Once cells have made an exact copy of their DNA, which shape do the two chromosome copies make?
- No. Some cells divide repeatedly; other cells divide only once.
- Before they can divide they must make a copy of all their chromosomes so that a full set can go into each of the two new cells.
- The two copies stay attached to each other joined at the centre forming X shapes.
- Describe what happens during interphase.
- Describe what happens during prophase.
- Describe what happens during metaphase.
- Describe what happens during anaphase.
- Describe what happens during telophase.
- Describe what happens during cytokinesis.
- The DNA of the cell is copied (making X-shapes, each containing a chromosome and its copy). Sub-cellular parts (such as Mitochondria) are also copied.
- The membrane around the nucleus breaks down.
- The chromosomes line up at the equator of the cell, and spindle fibres from each pole attach to each side of the chromosome.
- Each of the chromosomes X-shapes splits to form two single chromosomes. The single chromosomes move away from each other.
- The single chromosomes arrive at opposite ends of the cell. The membranes around each nucleus start to form again.
- The cytoplasm of the cell is separated as a cell membrane divides the cell into 2 daughter cells.
- What is cancer?
2. What do carcinogens do to DNA?
- A broad term used to describe medical problems caused by uncontrolled cell division.
- Mutate it.
In which stage of pre-mitosis do MOST adult cells permanently remain?
Interphase.
What is responsible for tearing apart replicated chromosomes?
Spindle fibres
How is growth of an organism most easily measured?
By mass or length
The process of becoming a specific type of cell with a particular function is called……….
Differentiation.
What is different about red blood cells?
They are the only animal cell that does not have a nucleus, however they are still considered to be eukaryotic as they are present in eukaryotic organisms.
What is different about plant growth and why?
Plants continue to grow throughout their entire lifetime, because they have meristems. Meristems contain cells which continually divide by mitosis.
Where are meristems found?
At the tips of roots and shoots, and also other points along the plant.
Once a new plant cell is made, it will undergo a lengthening process called…….
Elongation
Give 2 examples of specialised plant cells.
- Root hair cell.
2. Xylem cells (transport water)
Cells that continue to produce new cells throughout the adult life of an organism are called……….
Stem cells.
In humans, cell-producing cells that produce cells which can differentiate into any cell are called…..
Embryonic stem cells.
