Mitosis, Meiosis, Clones, Stem cells Flashcards
What is meant by mitosis?
Cell division.
What is meant by a diploid cell?
A cell that has 2 sets of chromosomes.
Before the parent cell divides what occurs?
DNA replication.
What happens after DNA replication?
The parent cell divides and forms TWO genetically identical DIPLOID cells.
Name three situations where mitosis is used to produce new cells?
- Growth
- Repair
- Asexual reproduction
Give 2 examples of asexual reproduction.
- Bacteria splitting into two.
- A plant making new plantlet to split off from the parent plant to grow on their own.
True or false:
Asexual reproduction produces genetically identical offspring.
Truuuuuuuuuuuu
What is fertilisation?
When a male gamete combines with a female gamete to produce a zygote.
What’s meant by a haploid cell?
A cell that only has 23 chromosomes (remember HAploid is HAlf).
What is meant by meiosis?
Cell division, that happens when a diploid cell divides to produce haploid gametes.
What is the first thing that happens in the parent cell when meiosis takes place?
DNA replication.
What’s the difference in the steps after DNA replication between mitosis and meiosis?
Mitosis: The parent cell splits into 2 diploid cells with 46 chromosomes per cell.
Meiosis: The parent cell splits into 4 haploid cells with 23 chromosomes each.
True or false:
Meiosis produces 4 identical haploid daughter cells.
False, they are non-identical.
True or false:
Cloning is an example of asexual reproduction.
True.
What are the 6 main steps when cloning animals.
- Nucleus is removed from egg cell.
- The diploid nucleus is removed from an adult body cell.
- The removed diploid nucleus is placed inside the empty egg cell.
- The cell is then stimulated with an electric pulse to start mitotic division.
- The cell divides and grows as an embryo.
- The embryo is placed in a surrogate mothers uterus.
What is one advantage of cloning?
If the animal coned has desirable features then all of its offspring will have the same good features.
Name 3 disadvantages of cloning.
- It’s more difficult to clone a mammal than a plant. Cloning a mammal will take several attempts.
- Cloned mammals may suffer more health problems than usual which can cause them to die early.
- Any genetic defects will be passed on from parent to offspring.
What is a stem cell?
A differentiated cell that can divide to produce many different types of cells.
What are the two main kinds of stem cell?
- Embryonic: taken from embryos that only contain a few cells.
- Adult: found in differentiated tissue e.g. bone and skin for repair.
What are the pros and cons of using embryonic stem cells?
Pros:
- Easy to extract.
- Can produce any type of cell (except gametes).
Cons:
- Unethical.
- Body will reject without drugs.
What are the pros and cons of using adult stem cells?
Pros:
- No ethical issues.
- If taken from the same person they won’t face rejection.
Cons:
- Difficult to find and extract tissue.
- Produce only a few types of cell.
Name one advantage and one disadvantage of stem cells in general.
Advantage: They replace a faulty cell with a healthy cell.
Disadvantage: They can produce cancer cells instead.
