2.6 cell division, cell diversity and cellular organisation definitions Flashcards
Acrosome
An organelle found in the head of sperm cells which is specialised to digest the outer coating of an egg cell during fertilisation
Anaphase (mitosis)
The third stage in mitosis where the chromosomes are pulled apart to the poles of the cell by the spindle fibres.
Anaphase 1 (meiosis)
The third stage of meiosis where the chromosomes that make up the bivalent are pulled apart to the poles of the cell by the spindle fibres
Anaphase 2 (meiosis)
The seventh stage of meiosis where the chromatids are pulled apart to opposite poles of the cell.
Anucleate
A type of cell which does not have a nucleus
Asexual reproduction
The production of genetically identtical offspring from one parent through the process of mitosis.
Bivalent
A pair of homologous chromosomes.
Ciliated epithelium
A type of epithelium which has many fine protrusions known as cilia and is specialised for wafting dirt and debris out of the body.
Crossing over
The exchange of genetic material between two chromosomes in a bivalent
Cytokinesis
The division of the cytoplasm at the end of mitosis to produce two new daughter cells.
Differentiation
The process where a cell develops certain features so that it is specialised to carry out a certain function.
Diploid
Cells with two copies of each chromosome
Erythrocyte
An anucleate cell specialised to carry oxygen from the lungs around the body (commonly referred to as a red blood cell).
G1 (gap 1) checkpoint
The first checkpoint in the cell cycle which occurs just before the end of G1 phase and commits the cell to division under favourable conditions.
G1 (Gap 1) phase
The first growth phase in interphase where the cell synthesises proteins and RNA, duplicates its organelles and increases in size before DNA replication in S phase
G2 (gap 2) checkpoint
The second checkpoint in the cell cycle which occurs at the end of G2 phase and checks that the DNA was correctly replicated during S phase before the cell enters mitosis.
G2 (Gap 2) phase
The second growth phase of interphase where the cell continues to increase in size and synthesize biomolecules
Gametes
Sex cells that have a haploid nucleus and are produced through meioisis
Gene loci
The location of a gene on a chromosome
Guard cells
A type of cell usually found in pairs that is specialised to control the opening and closing of stomata.
Haploid
Cells with only one copy of each chromosome
Homologous chromosomes
Two chromosomes with similar gene loci but different alleles, one inherited from each parent.