Cell Replication Flashcards
As cells get older
- they grow in size
- Until it becomes more and more difficult for nutrients to get into the cell fast enough,
- and for the waste to leave fast enough.
- So the cell will either stop growing or divide into two smaller cells
Organisms reproduce either with
- Asexual Reproduction
* Sexual Reproduction
What is Asexual reproduction?
- Is a method of producing offspring that does NOT involve the fusion of different gametes (eggs or sperm)
- Instead it is a process called mitosis
- Where exactly everything inside the cell is copied exactly
- Then divided into two daughter cells
Why does MITOSIS Occur?
• Reproduction Single celled organisms, such as bacteria, divide to make new independent organisms. • Growth • Repair
6 stages of mitosis?
I nterphase P rophase M etaphase A naphase T elephase C ytokinesis
what is the cells life cycle?
- Cell reproduces
- Lives
- Dies – cell suicide or APOPTOSIS (cells have a certain life span – then they die. If they don’t die cancer)
What is apoptosis?
• Its function is to counter cell production and maintain an appropriate number of cells in the tissues.
What happens in apoptosis?
- Instructions come telling the cell’s lysosomes (enzyme containing organelles) to make chemicals to kill itself.
- The lysosome then empties its contents into the cell causing the cellular components to be broken down.
What do the enzymes do in cell replication?
- The enzymes slice up the DNA into tiny fragments.
* The enzymes make the cell change shape. It gradually shrinks and splits and repackages itself into smaller fragments.
what is necrosis?
- This is cell death by accident or poisoning, overheating or when starved of oxygen.
- The cell swells and the membrane splits, which makes it messy
What is the importance of cell death?
- Development changes in growing embryos
- Ridding tissues of old, infected or damaged cells
- Removing immune cells which attack “self” cells
- Removing cells which have sustained DNA damaged.
- However, too much apoptosis can have serious consequences
what does the cell cycle represent?
the time for a newly formed cell to mature and then give rise to two new cells through the process known as mitosis
What are the 3 events that the cell cycle consists of?
- Gap 1 (life)
- Synthesis (diving the chromosomes)
- Gap 2 (mitosis phases)
what happens in cytokinesis?
, the cytoplasm of the cell is divided to produce two daughter cells
what are the 2 types of cells in the body?
- Somatic cells
2. Gametes or sex cells – sperm and egg.
What are somatic cells?
body cells. Cell growth occurs by the process of MITOSIS and cytoplasmic division. Also repair of damaged or injured body tissues.
What are gametes or sex cells?
sperm and egg
sexual reproduction?
between a male and a female of the same species.
This results in GENETIC VARIATION
what happens in interphase?
no. of organelles and amount of cytoplasm increases as it wants to divide
what happens in prophase?
chromosomes shorten and thicken , spindle fibres form
what happens in metaphase?
chromosomes line up
what happens in anaphase
chromatids separate
what happens in telophase
chromosomes become visible ans nuclear membrane is made two new nuclei
what happens in cytokinesis
they separate and produce 2 new daughter cells
what is a centrometre?
strands that hold it all together
what is a chromatid?
two identical strands
