Cell Division & Genetics Flashcards
What is the name given to a genetically identical cell?
A clone.
What is mitosis?
The exact duplication of chromosomes producing daughter cells that are genetically identical to parent cells, known as clones.
What does it mean if all the cells are the exact same?
This means that every cell in the growing organism has the same genes and chromosomes and that these are the same as the very first cell, the zygote.
What does mitosis allow?
- Organisms to grow
- To replace worn out cells
- Repair damaged tissue
What happens to the two new daughter cells?
They grow to ‘normal’ cell size before dividing again.
The circular process of growth, DNA replication and cell division?
The cell cycle.
In what organs does meiosis take place?
The sex organs (e.g. ovaries and testes) during the production of gametes - sperm and egg cells.
What is the purpose of meiosis?
To produce gametes with half the number of chromosomes of all the other (non-gamete) cells in the body.
What is another name for meiosis? Why?
Reduction division.
Becuase it halves the number of chromosomes in the daughter cells.
How many chromosomes do the sperm and egg cells have?
23 chromosomes, one from each pair.
Most human cells have how many chromosomes?
46, arranged in 23 pairs.
Can it be just any 23 chromosomes from the 46 that. Pass into the gamete?
NO! It must be ONE FROM EACH PAIR. It could be either chromosome of a particular par that passes into a particular gamete.
The random INDEPENDENT ASSORTMENT of chromosomes in meiosis causes the production of UNIQUE GAMETES and so helps to produce VARIATION, why is that a good thing?
It is good for NATURAL SELECTION.
What two important roles does fertilisation have?
- Restoring the diploid number (46)
- Combining the different arrangements of chromosomes produced during the process of meiosis.
What key things happen for the daughter cells in MITOSIS?
-They are identical to each other
-They are identical to the parent cell
-Produce TWO cells in ONE division
What key things happen for the daughter cells in MEIOSIS?
-They have half the number of chromones of the parent cell
-Are different form each other
-Produce FOUR cells in TWO divisions.
How many chromosomes are in each daughter cell in MITOSIS?
4!
How many chromosomes are in each daughter cell in MEIOSIS?
2!
How many divisions are there in MEIOSIS?
Two!
Name the process in MEIOSIS which causes genetic variation:
Independent assortment.
Give three functions of mitosis in living organisms:
- Growth
- Repair
- Asexual reproduction
