Producing new cells Flashcards
What is the importance of cell division?
Single cell organisms use cell division as a means of reproduction. In multicellular organisms, cell division makes new cells for growth or to repair damage (cuts, broken bones)
What do chromosomes do in cell division?
Chromosomes carry the instructions for making all of our proteins.
One gene is…
The instruction for 1 protein
What do genes do?
Genes determine our characteristics.
When do we see chromosomes?
During cell division (only)
How many sets of chromosomes do sex cells have?
1 set (23 chromosomes)
How many sets of chromosomes do cells (not sex cells) have?
2 sets- 1 set from mum and 1 set from dad (46 chromosomes)
What is a diploid cell?
A cell with 2 sets of chromosomes.
What is a diploid number?
The number of chromosomes in total in the two sets combined (eg, 46-humans).
When a cell divides, why must the diploid number be maintained?
So that each new cell receives a full set of genetic information which is vital as it controls cell development and all cell activities.
In cell division, what: carry the instructions for making all of our proteins?
Chromosomes.
What determines our characteristics?
Genes.
What is: MITOSIS?
The division of the nucleus which ensures that each of the two daughter cells will contain the same number of chromosomes as the original parent cell, and be genetically identical to it.
Explain the stages of mitosis.
The chromosomes are replicated and become visible.
Each consists of two strands called chromotids, joined at a point: centromere.
Nuclear membrane starts to break down and spindle forms.
The chromosomes line up along the equator of the cell, attatched to the spindle by their centromeres.
The spindle contracts, which pulls the chromosomes apart to opposite ends of the cell.
The chromosomes reach opposite end of the cell and new nuclear membrane forms round each set of chromosomes.
The cell divides into two daughter cells when the cytoplasm divides.
(then different things in animal and plant cells)
What happens at the end of division in a: PLANT CELL?
A new cell wall forms, separating cytoplasm.
What happens at the end of division in a: ANIMAL CELL?
Divison occurs when cytoplasm constricts.
In division of a cell, what cell type does this happen in: Divison occurs when cytoplasm constricts?
An animal cell.
In division of a cell, what cell type does this happen in: A new cell wall forms, separating cytoplasm?
A plant cell.
In cell culture, what are 3 requirements?
A sterile environment, free from contaminants that might act as competitors.
An appropriate growth medium.
A controlled environment to provide optimum conditions.
In cell culture, what are 3 optimums that are required?
Optimum level of oxygen.
Optimum pH of the medium
Optimum temperature
What must the culture medium contain?
An energy source such as glucose, and nutrients for building new cells.
What are: ASEPTIC TECHNIQUES?
Laboratory procedures designed to prevent contamination when working with micro-organisms or other cell cultures.
