✅1.1 Cell Division Flashcards
What does the nucleus of a cell contain?
The nucleus of a cell contains chromosomes
What are chromosomes made up of?
Chromosomes are made up of DNA molecules
What do chromosomes carry?
Chromosomes carry a large number of genes
Explain the function of genes
Genes contain the instructions for making proteins
How are chromosomes normally found?
Chromosomes are normally found in pairs of 23 per body cell, so 46 in total
Name the process in which cells divide
Cell Cycle
What is the cell cycle?
The cell cycle is a series of stages in which a cell divides
Explain the 1st stage of the cell cycle
The 1st stage of the cell cycle is cell growth
- The number of sub-cellular structures, such as the mitochondria and ribosomes increase
- The cell itself grows in size
- The DNA replicates to form 2 copies of each other
Explain the 2nd stage of the cell cycle
Mitosis is when one set of chromosome is pulled to each end of the cell, and the nucleus divides into two
Explain the 3rd stage of the cell cycle
The 3rd stage of the cell cycle is Cell Divison where:
- The cytoplasm and cell membrane divide to form 2 identical daughter cells
What are the names of the three stages of when a cell divides?
Stage 1- Growth
Stage 2- Mitosis
Stage 3- Cell division
Give 3 functions of mitosis
Functions of mitosis:
- Growth and development of multicellular organisms
- Healing and repairing of organisms
- Mitosis occurs during asexual reproduction
What are stem cells?
Stem cells are undifferentiated cells that have not yet become specialised, and can create more stem cells, from which they can differentiate to form other types of cells
What is special about stem cells inside an embryo (embryonic stem cells)?
Stem cells inside the embryo are unspecialised so they can differentiate to produce a wide range of cells
Embryo
An embryo develops from a fertilised egg
What is the function of stem cells inside an embryo
Stem cells inside the embryo is to differentiate to produce many different cell types
What is the nature of stem cells in adult animals
They can only differentitate into a limited range of cell types
What is the function of stem cells in adult animals
To replace cells that are worn out or damaged
Where can adult stem cells be found
Adult stem cells can be found in bone marrow
What is special about adult bone marrow?
Stem cells from adult bone marrow can form many types of cells, including blood cells
What conditions can stem cells be used to treat?
Treatment with stem cells can be used to help conditions such as diabetes and paralysis
What are meristems?
Meristems are specialised tissues that produce plant stem cells
What is special about plant stem cells?
Plant stem cells can differentiate into any type of plant cell throughout the life of the plant
What is therapeutic cloning?
Process that produces an embryo with the same genes as the patient, so that it can be used for medical treatment and will not be rejected by the patient’s body
Explain the process of therapeutic cloning
- The nucleus of a donated egg cell is removed and replaced with the nucleus of a patient’s cell
- The egg cell develops into an embryo that has the same genes as the patient
- The stem cells from the embryo are removed to treat the patient
Why are stem cells not rejected by the patient’s body in therapeutic cloning?
They have the same genes as the patient’s body
List 2 benefits of therapeutic cloning
- Stem cells can help treat many conditions such as diabities and paralysis
- The cells produced can be used for research
- Not rejected by the body
- Produces wider range of cells
List 3 issues of therapeutic cloning
- Ethical objections - Should an embryo be treated as a person?
- Stem cells have potential to transfer viral infections
- There is a risk of stem cells mutating and behaving like cancer cells
List 3 benefits of using stem cells from meristems
- Plants can be cloned quickly
- Rare species of plants can be cloned to protect from extinction
- Plants with useful features (like disease resistance) can be cloned to produce large numbers for farmers