2.) Topic 2 Cell Division And Stem Cells Flashcards
What are chromosomes
A chromosome is a linear DNA molecule tightly coiled around proteins. It carries genetic information in the form of genes. Genes also exist in pairs, and each gene creates a code that makes a specific protein.
Just before cell division what does the DNA do?
It coils up tightly
How many chromosomes does the human body contain?
46 in total (23 pairs)
W cells divide [3]hen do
When:
An organism grows
Organisms need to replace worn-out cells
Organisms need to repair damaged tissue
What are gametes and what are special about them
Sex cells. They contain half the number of chromosomes of a normal human cell
Where is sperm and egg produced
Sperm is produced in the testes
Egg is produced in the ovaries
What is mitosis
Mitosis is the division of a mother cell to produce two genetically identical daughter cells with a full set of chromosomes (46 chromosomes). It involves one division
Why is mitosis important (4)
It is important because it allows an organism to grow, repair damaged tissues, replace old cells and asexually reproduce
How is a zygote fomed
When a male gamete fuses with a female gamete
In which type of cell division are gametes formed?
By a type of cell division called meiosis
What is meiosis
Meiosis is a type of cell division that creates four genetically different daughter cells known as gametes. Meiosis involves two divisions and produces cells with half the number of chromosomes (23 chromosomes).
Are all gametes genetically different from each other?
Yes
Why is meiosis important
For genetic variation and ensuring that the resultant zygote has a full set of chromosomes
What causes meiosis to take place?
Sexual reproduction
Comparing mitosis and meiosis x6
How many cell divisions are there?
How many cells are produced?
How many chromosomes are present?
What is it used for?
Where in the body does it happen?
Are the cells produced different or the same?
Mitosis The cells divides ONCE 2 daughter cells produced 46 chromosomes present Produce new body cells All parts of the body in non-reproductive cells Genetically identical
Meiosis The cell divides TWICE 4 gamete cells produced 23 chromosomes present How gametes are made Happens in the testes and ovaries Genetically different
What is cancer a result of?
Uncontrolled mitosis