Cell Division Unit 11 What triggers division? How does division happen? What can happen when division goes wrong?

Division as Reproduction. In your body right now, there are trillions of cells, but you started out from just one cell. Where did all of those cells come from? You know a baby is much smaller than an adult – how does the smaller body of a baby grow into the larger body of an adult

Types of reproduction: Asexual Reproduction Sexual Reproduction

DNA and chromosomes When cells divide, the genetic material inside the nucleus must also divide. Genes are segments of the DNA molecules that function to: 1) Act as a template for formation of mRNA strands used in protein synthesis. 2) Act as a unit of hereditary information to carry the genetic information from parent to offspring. Genome __________________________________

DNA comes in various forms depending on the type of organism: 1) Prokaryotes (bacteria and Cyanobacteria) a) ________________________________________ and _______________________________________ 2) Eukaryotic cells have a larger genome. Genes are distributed on several pieces of DNA called ______________________________.

Prokaryotic Cell Cycle 20 min/cycle! Part 1 - Growth and DNA replication Part 2 - Binary Fission

Eukaryotic cells – 2 types of division Mitosis – asexual reproduction - 1 round of division – identical offspring – somatic cells Meiosis – sexual reproduction – two rounds of division - genetically distinct but similar offspring – gametes – genetic info reduced by half often called a REDUCTION DIVISON

Eukaryotic Cell Cycle differentiation

The form of DNA in Eukaryotic cells depends upon whether the cell is dividing or non-dividing: Note: no matter which FORM – chromatin- chromosomes-

Why would it be an advantage to have the DNA in the form of chromatin in a non-dividing cell? Why does the DNA condense into chromosomes before cell division?

Chromosomes Chromosomes : Telomeres - Centromeres - Two configurations of chromosomes: 1) Single arm chromosomes _________________. 2) Double-arm chromosomes are made up of paired, genetically identical chromatids, called __________. ____________ are joined at the ________________.

Chromosome Pairs: Each of your body cells has ___________ total chromosomes which come in pairs. You have ______ pair. 22 of those pairs are very similar to each, with the same genes, and homologous chromosomes. These are _______________ 1 of those pairs contains sex chromosomes. Female have 2 sex chromosomes that are homologous; or XX Males have X and Y, these are not homologous and contain different genes.

Karyotype Picture of the pairs of chromosomes in a human cell:

Half of your chromosomes came from _____________. The other half is from __________________________. Chromosome pairs are called _____________________ _________________________ (chromosome pairs) are given numbers based on microscopic characteristics. Homologous chromosomes have: _____________________________________________

What is the chromosome pair or _______________ for the #13 chromosome you received from your father? ______________________________ Human body cells contain both homologs of a homologous pair, and are considered to be diploid, or 2n. In humans, the diploid number is ____________. Human sex cells contain only 1 homolog of the homologous pair, and are considered to be haploid. In humans, the haploid number of chromosomes is _________.

Diploid* number of Chromosomes in each cell. Chromosome Number Organism Diploid* number of Chromosomes in each cell. goldfish 94 chimpanzee 48 human _____ brown bat 44

The Cell Cycle: This continual cycle of cell division that produces genetically identical cells (clones) occurs in three phases: interphase: ________________________________ mitosis: ___________________________________ cytokinesis: ________________________________ What form is the genetic material in each phase of the cell cycle?

At this exact moment, what phase of the cell cycle would most of your body cells be in? ____________ Rate of Division: What about skin cells? Nerve cells? Bone cells?

Summary of Events in the Process of Mitosis and Cell Division: Begin with: DNA Condense Split End with: Replication DNA Chromatids ____ of pieces of chromatin ____ replicated chromatin ______ double armed chromosome ______ single armed chromosome _____ of pieces of chromatin per cell

PHASES OF THE CELL CYCLE: I. INTERPHASE _____________________ _____________________________________ What types of processes might be taking place in a cell during interphase? ____________________________________ Is the cell shown below an animal or plant cell?

G1 phase S phase G2 phase

II. MITOSIS Prophase

Metaphase

Anaphase

Telophase

Cytokinesis CYTOKINESIS differs between plants and animals: 1) Furrow-in animal cell ____________________________ 2) Cell plate in plant cells ___________________________

From the inside of the cell: Type/species of organism Factors that affect the rate of division and the progression through the cell cycle. From the inside of the cell: Type/species of organism Type of cell: ex. skin, stomach, embryonic cells frequently divide while mature nerve, blood and muscle cells do not divide Both 1 and 2 are pre-programmed into the DNA of each organism. 3. Size of cell (SA/V ratio), nutrients available, and density of cells.

Check of chromosome status- presence or absence of CYLCIN – Age of Cells:

From the outside: Growth factors:

So what is cancer? It is: causes: