Cell Cycle, Mitosis, & Regulation

Chapter 12

Slide 2 of 36

Genome

Slide 3 of 36

Kinetochore – protein attaches to chromosome at centromere + attaches to mitotic spindle

Slide 4 of 36

Haploid –Set of unique chromosomes Only in gametes Sperm + Egg

Diploid – 2 sets of the unique chromosomes 1 set from Mom 1 set from DadALL cells but gametes Somatic Cells

2,700 base pairs OR2.7 kbp (MIT – D. Gifford [7.90J])

What percent of chromosomal DNA = genes?

Slide 5 of 36

Slide 6 of 36

Slide 7 of 36

Slide 8 of 36

“-omes”

Genome – Complete set of genetic information

Transcriptome – set of all the mRNA produced by a cell or an organism

Proteome – entire set of proteins coded for by the genome of a cell or an organism

How many chromosomes in human genome?

Which is larger, genome or transcriptome?

Slide 9 of 36

Central Dogma of Molecular Biology

DNA RNA Protein HIV (Reverse Transcriptase) cDNA (Complementary DNA library) Prions – infectious proteins

Genome Transcriptome Proteome

Slide 10 of 36

Divisions

Prokaryotes = binary fission

Eukaryotes Mitosis

ALL cells arise by mitosis EXCEPT zygote (original cell) Meiosis

ONLY used to produce egg (oocyte) and sperm (spermatocytes)

Slide 11 of 36

This is NOT mitosis!! Proks do NOT do mitosis

Slide 12 of 36

Mitosis

Occurs in which type of cells?

Occurs where in the body?

Genetically identical (Clone)

Produces diploid daughter cells Produces clones

Somatic cells

Slide 13 of 36

Meiosis

Occurs in which type of cells?

Occurs where in the body?

Genetically different

Produces haploid daughter cells Produces eggs or sperm Produces Gametes

Slide 14 of 36

Slide 15 of 36

Questions?

Which is more common mitosis or meiosis?

What is the main way that prokaryote chromosomes differ eukaryotic chromosomes?

Binary fission or mitosis? Fungi E. Coli Plants

What percent of DNA is non-coding in humans?

Slide 16 of 36

Questions? (Page 2)

What is the genome?

What is larger proteome or genome?

Haploid or Diploid? Red Blood Cell Muscle Cell Sperm Neuron Macrophage CD4 T-Cell

Slide 17 of 36

Cell Cycle

“Life of a cell”

From time it is first formed until it divides into 2 daughter cells

Slide 18 of 36

Slide 19 of 36

Slide 20 of 36

Notes on Cell Cycle

G1 – Cell growth Cells do their cell things Vast majority of time in the cell cycle Human cell = 46 chromosomes

S – Chromosomal duplication Human cell = 46*2 = 92 chromosomes Cells still grow during this time

G2 – Second Gap Brief period between S and Mitosis

Mitosis / Cytokinesis

Slide 21 of 36

Watch Videos

Overview.swf

Mitosis.mpg

The_Stages_of_Mitosis_HD.mp4

Slide 22 of 36

Slide 23 of 36

Slide 24 of 36

Slide 25 of 36

Slide 26 of 36

Cytokinesis

Cytokinesis – Cytoplasmic (and contents) division

Cytokinesis Video?

During telophase G1

Animal cells Cleavage furrow divides the cytoplasm into 2 cells

Plant cells Cell plate forms that divides the cytoplasm

Slide 27 of 36

Cell Cycle Control

Some cells divide Continuously (skin cells) Occasionally (liver cells) Never (CNS cells & muscle cells)

Signals to divide are present in cytoplasm These signals control the rate of cell division Result of signal transduction pathways

Slide 28 of 36

Cell Cycle Regulation

Involves checkpoints

There are 3 checkpoints: G1, G2, and M

G1 checkpoint - Most important

G0 – nondividing phase Most body cells Neurons & Muscle cells

Slide 29 of 36

Kinase – protein enzymes that control cell cycle

Cyclins – proteins that bind to kinases and activate them

CdK – cyclin-dependent kinase Activated kinases give the Go-ahead signal at the checkpoints

Slide 30 of 36

Slide 31 of 36

Questions?

What are the phases of the cell cycle?

What are the parts of interphase?

What are the parts of mitosis?

What happens during the S-phase?

Slide 32 of 36

Questions (Page 2)

What is a CdK?

What is the G0 phase?

How is cytokinesis different in animal cells from plant cells?

When does cytokinesis occur in the cell cycle?

How does a kinetochore differ from a centromere?

Slide 33 of 36

Normal Cells Controlled cell cycle

Density-dependent Inhibition - Too many cells = no division - Once a cell contacts another cell, division ceases - Contact Inhibition

Anchorage Dependence - Division only happens when cell is attached to a substrate - If attached to another cell,

no division

Slide 34 of 36

Cancerous Cells

Do NOT adhere to normal cell signals Divide excessively Violate density-dependent inhibition & anchorage

dependency

Considered “immortal cells”

Normal cells undergo a process of genetic alteration that affects cell cycle regulation Called Transformation

Slide 35 of 36

Tumor Terms

Tumor = mass of abnormal cells Abnormal because?

Benign tumor abnormal cells that remain at the original site

Malignant tumor abnormal cells that impair functions of one or more

organs

Slide 36 of 36

Cancer is characterized by …

Malignant tumors are characterized by anaplasia, invasiveness, & metastasis

Anaplasia Cells do not undergo differentiation

Invasiveness Intrusion of cells into and destruction of surrounding

tissues

Metastasis Spread of neoplasms via blood vessels to distant tissues

or organs