Theme 1-

Prokaryotes

Unicellular, no compartmentalised cell structure

Eukaryotes

Can be both unicellular or multicellular with compartmentalised cell structure

What 3 steps need to occur for a cell to replicate successfully?

• genetic information must be copied

• Copies of the genetic information must be separated from each other

• Cells must divide

How do prokaryotic cells reproduce

Binary fission

Are gametes haploid or diploid

Haploid

Centromere

Attachment point for spindle micro tubules

Telomeres

Specific DNA sequence associated with the proteins at the tips of a linear chromosome

Origins of replication

Where the DNA replication starts

Kinetochore

Multiprotein point of attachment for spindle micro tubules

What would happen if kinetochores were not present

The spindle micro tubules wouldn’t attach to the chromosome therefore it wont be drawn into newly formed nucleus therefore daughter cells would be missing a chromosome

Gene

Specific DNA sequence that encodes a product on the chromosome

Locus

Position of a gene on a chromosome

Homologous chromosomes

A pair of chromosomes that are alike in structure and size and that carry genetic information that can differ for the same set of hereditary

Histone

Protein in eukaryotes that associates closely with the DNA to form chromosomes

Chromatin

Material found in the eukaryotic nucleus; consists of DNA and histone proteins

Heterozygous

2 different alleles

Homozygous

2 identical alleles

In eukaryotic cells when does DNA replication occur

S-phase

Centromere is just off centered, looks like it is very close to the middle ( not common)

submetacentric

Centromere is directly in the middle and half-way between the chromosomes

metacentric

Centromere is on the tip of the chromosome

telocentric

Centromere is off-centred ( most common)

acrocentric

What following things must be in place for cellular reproduction to happen effectively?

• genetic info must be copied

• copies of genetic info must be separated from each other

• cells must divide

Purpose of the cell cycle and mitosis

Growth and maintenance of somatic cells ( 2 identical diploid daughter cells)

Purpose of meiosis

`produces gametes for sexual reproduction from germline cells ( 4 genetically unique haploid daughter cells)

Major features in the G₀ phase

Stable, non-dividing period

Major features in the G₁ phase ?

Growth and development of cells

Major features in the S-phase?

Synthesis of DNA

Major features in the G₂ phase?

Preparation for division