Flashcards in Meiosis Deck (104)
What is the control centre for all cellular activities?
What happens just before cell division?
The chromatin network contracts and becomes visible as individual chromosomes
What does each chromosome consist of?
DNA molecules wrapped around proteins
What makes up genes?
Do all organisms have the same number of chromosomes?
How many chromosomes do humans have?
What happens during DNA replication?
single-stranded chromosomes replicate to become double stranded
What does a double-stranded chromosome consist of?
two chromatids joined by a centromere
What joins chromatids?
What does replication ensure?
that all daughter cells contain the same hereditary information as the parent cells
When are chromosomes arrached in pairs called homologous chromosomes?
just before cell division
What is similar between each chromosome of the homologous pair?
They are the same length and contain the same genes
How many chromatids does one pair of homologous chromosomes contain?
What are autosomes?
The are chromosomes that control features in males and females
What are gonosomes?
They are sex chromosomes that determine the sex of the organism.
How many types of gonosomes are there?
2 (X & Y)
What are some features that could be controlled by autosomes?
What is meiosis?
A special type of cell division necessary for sexual reproduction
What type of cell does the process of meiosis begin with?
one diploid (2n) cell
What does diploid imply?
That it is a cell containing two copies of each chromosome
One copy from the organism's father; one copy from the organism's mother
The number and appearance of chromosomes in the nucleus of a cell
What does the process of meiosis produce?
four haploid cells
These are all genetically different from each other
When one of the haploid male gametes fuses with one of the haploid female gametes
What does fertilisation produce?
a diploid zygote
What describes the complete set of chromosomes in a species or in an individual organism?
Where does meiosis occur?
In the gonads
What are the gonads?
Reproductive organs (testes and ovaries)
What are the cells produced by meiosis called?
What can the process of meiosis also be called?