Cyclins and packaging DNA (week 2)

How do prokaryotic cells divide their nuclear material?

process called binary fission

How do eukaryotic cells divide?

through a process called mitosis

What does the creation of new cells allow?

growth, asexual reproduction, tissue repair and embryonic development.

What is chromatin made of and where is it found?

DNA, histones and other proteins and found inside the nuclear envelope eukaryotic cells

What are the forms of chromatin?

heterochromatin (condensed) and euchromatin extended

What are the functions of chromatin?

to package DNA into smaller volumes, to strengthen DNA for mitosis/meiosis, to control gene expression and DNA replication

How is Chromatin fibre organised?

chromatin fibre is

organized by H1 into

looped domains. The looped

domains are attached to a

scaffold non-histone protein. Looped domains fold repeatedly which then produces condensed chromos

What happens in G1 of the cell cycle?

cellular contents are duplicated - excluding chromosomes

What happens in the S phase of the cell cycle

Each of the 46 chromosomes are duplicated by the cell

What happens in the G2 phase of the cell cycle

the cell double checks the duplicated chromosomes for error making any needed repairs

What are cyclins and what do they bind to?

A group of proteins called cyclins that control the cell cycle. They bind to enzymes called cylin-dependent kinases that become active and attach

phosphate groups to other proteins in the cell which trigger other proteins to become active and carry out tasks specific to phases of the cell cycle.

Why are cyclins important?

more errors would occur as threshold amounts are needed to go to the next phase. Without cyclins the cell growth could become cancerous.

What are the three main cycles of the cell?

interphase, mitosis and cytokenesis.