Cell Division Flashcards
What do all cells develop from?
Pre-existing cells
What are the steps to form a new cell and how many are there?
3 steps to form a new cell
- Produce materials it will need
- Grow larger
- Reproduce to form a new cell
What are chromosomes?
Structures in Nucleus, made of DNA and Protein
What do we call chromosomes when they are not dividing?
Chromatin forms a number of clearly distinguishable chromosomes
How many chromosomes does each species have?
Each species has a definite no. of Chromosomes, Humans = 46 chromosomes
How many genes does each chromosomes have?
Each chromosomes has 1000s of genes
Draw and label a pair of homologous chromosomes.
.
What is a Haploid?
A Haploid cell has one set of chromosomes, i.e. has only one set of each type of chromosomes in the nucleus.
What is Haploid symbolised by?
the letter n
What is the number of chromosomes in the Haploid cell given as?
n=23
What type of cell are humans eggs and sperm?
haploid n=23
What is a diploid?
A Diploid has two sets of chromosomes, i.e. It has two of each type of chromosome in the nucleus
How are chromosomes organised in a diploid cell?
Chromosomes are in pairs in diploid cell, called homologous pairs.
How is a diploid symbolised as and what is the total no. of chromosomes in a diploid cell given as?
Diploid is symbolised as 2n and total no. of chromosomes in cell is given as 2n = 46
Where do the chromosomes come from in a diploid cell?
In diploid cells, 1 chromosome from the homologous pair comes from the mother and the other comes from the father
What is the cell cycle?
Describes the life of a cell. It includes the period between division when the cell is not dividing, called Interphase.
What is the period when a cell divides called?
Mitosis
What is interphase?
The period between division when the cell is not dividing
How long is interphase?
Longest phase in cell cycle = 90% of a cells life is in interphase
What are chromosomes called in interphase? What is one difference between them and chromosomes?
chromatin
not elongated