B5 Flashcards
Cells divide by two processes which are?
Mitosis and Meiosis
What do similar cells form?
Tissue
What do groups of tissues form?
Organ
What do groups of organs do?
Make up systems within the whole organism
List three reasons why Mitosis occurs?
For growth, repair and to replace old tissues
After Mitosis occurs, what does each new cell have?
Identical sets of chromosomes as the parent cell and the same number of chromosomes as the parent cell and the same genes as the parent cell
To enable Mitosis to take place, what do cells have to go through?
A cycle of growth and then division
What happens when the cell enters the growth phase of the cycle during Mitosis?
The number of organelles increase and the chromosomes are copied - the two strands of each DNA molecule separate and new strands form alongside
What two places does Meiosis only take place in?
Testes and ovaries
What does Meiosis produce?
Gametes for sexual reproduction
How many chromosomes do gametes contain?
Half the number of chromosomes as the parent cell
What happens during fertilisation?
A male gamete and a female gamete fuse together to produce a single boy cell, called a zygote
How many chromosomes does the zygote have?
One whole set of chromosomes because gametes only contain half the number of parent cells, so when both form together it creates a full set
In each new chromosome, how many chromosome come from each parent?
One chromosome from the father and one chromosome from the mother
When the zygote divides, what does it produce?
A cluster of cells called an embryo