Lecture Notes for General Biology BI 101 - Cell Division


I Cancer - Practical Applications and Cellular Reproduction

	A) Definition of Cancer
		1) neoplasm of proliferating cells, cell division out of control, cells
			produced are useless, compete with healthy cells for nutrients
			and oxygen
		2) Benign versus malignant
			a) benign is a sedentary mass of cancerous cells
			b) malignant is a moving mass of cancerous cells
				metastasis
		3) Basic types
			a) carcinoma - arises from body's outer coverings and inner linings
			b) sarcoma - arises from body's supporting structures
			c) lymphoma - arises from lymph system
			d) leukemia - arises from blood marrow in bone, spleen
	B) Causes of Cancer
		1) Carcinogenic chemicals
		2) UV Light
		3) Viruses
		4) Mechanism - mutations and oncogenes
			a) cell growth is no longer under control, mutagenic agents
				cause mutations in proto-oncogenes (genes that encode for
				proteins that stimulate cell division and growth), these genes become
				oncogenes that cause cancer
Problem Effect
Mutation in proto-oncogene creates hyperactive protein
Multiple copies of a gene produces excess amount of protein
Movement of gene locus no longer under control from original locus, produces excess amount of protein
		5) Mechanism - mutations to tumor-suppressing genes
			a) mutation in a gene that inhibits cell division, produces
				a faulty protein that can not stop cell division
	C) Consequences
		1) alteration of DNA
		2) Cancerous growth - tumor or polyp
	D) Diagnosis
		1) Radiology (x-rays and dyes)
		2) Ultrasound imaging
		3) Endoscopy - fiber optics (example - colonoscopy, inside the esophagus)
		4) Biopsy
		5) Monitoring chemical levels in the blood (blood testing)
		6) Mammogram for breast cancer
			Click here to donate a mammogram for free
	E) Treatments
		1) Surgery (physical removal)
		2) Radiation Therapy (Radiation - high energy particle beams)
		3) Chemotherapy (cytotoxic drugs - chemotherapeutic agents)
			disrupts DNA synthesis or  mitosis, affects normal cells also
			some bad side-effects
		4) Hormone therapy - used for cancers associated with sex hormones
			tamoxifen suppresses estrogen used to treat breast cancer
			anti-androgens used to treat prostate cancer (reduce androgen levels)
		5) Boosting the immune system (stimulate the production of cells that
			recognize healthy versus unhealthy or cancerous cells)
		6) Diet
		7) Monoclonal antibodies - silver bullets, respond to protein on cancer cell
			surface and deliver cytotoxic drug
	F) Types of Cancers - some examples of virus related cancers
		1) Leukemia - associated with bone marrow cancer
		2) HIV - associated with cancers in blood vessels (Kaposi's Sarcoma)
		3) Hepatitis B, C virus - associated with liver cancer
		4) Papilloma virus - causes genital warts and benign cancers, associated with cervical cancer
	G) Types of Cancers - some examples of Carcinogen related cancers
		1) Lung cancer - tobacco
		2) oral cancer - chewing tobacco
		3) Bladder and rectal cancer
	H) Types of Cancers - some examples of Light related Cancers
		1) UV light - lesions and melanomas
	I) Other cancers
		Breast cancer in females and males
		Prostate cancer in males
	J) Summary - types and incidence

II Cellular Reproduction

	A) Two types of cell division
		1) Mitosis and Fission- results in exact duplication of parent cell (2N to 2N)
				Binary Fission - special cell division in bacteria
		2) Meiosis - results in production of gametes (2N to 1N)
	B) Mitosis
		1) Functions
			a) cell reproduction
			b) replacement of cells
			c) healing
			d) growth
			e) regeneration (in some organisms)
		2) Phases
			a) Cell cycle (cell division, G1, S - duplication phase, G2)
			b) S phase - duplication of chromosomes, sister
				chromatids bound by centromere
			c) Prophase (appearance of chromosomes)
			d) Metaphase (lining up along the equator)
			e) Anaphase (splitting of the chromosomes)
			f) Telophase (segregation, cell plate appears in plants)
			g) Differs between plants and animals
				animals (see whitefish blastula above)
				plants (onion root tip you will observe in lab)
			h) Cytokinesis (splitting of cytoplasm) not part of mitosis
				in animals
	C) Meiosis - characteristics
		1) Function - sexual reproduction
			a) diploid (2N) adult produce gametes (sperm, eggs = haploid - 1N)
		2) two cell divisions in order to produce haploid gametes
		3) restricted to gonads
	D) Meiosis - mechanics of the phases
		1) Meiosis I: prophase I, metaphase I, anaphase I, telophase I
			a) metaphase I - homologous pairs line up across the equator
				from each other
			b) anaphase I - homologous pairs are split (reduction of
				chromosomes = 2N - 1N condition)
		2) Meiosis II: prophase II, metaphase II, anaphase II, telophase II
			a) metaphase II - chromosomes line up along the equator
				like they were going through a mitotic division
			b) anaphase II - chromatids are split by breaking the
				centromere (in animal cells)
	E) From Meiosis to gamete production
		1) Making sperm
Cell Type Cell Division Product
Spermatagonium (2N) Undergoes Mitosis Primary Spermatocyte (2N)
Primary Spermatocyte (2N) Undergoes Meiosis I 2 Secondary Spermatocytes (1N)
Secondary Spermatocyte (1N) Undergoes Meiosis II Spermatid (1N)
Spermatid (1N) Maturation - no cell division Sperm cell (1N)

		2) Making eggs
Cell Type Cell Division Product
Oogonium (2N) development - no cell division Primary Oocyte (2N)
Primary Oocyte (2N) Undergoes Meiosis I Secondary Oocyte (1N) and First Polar Body (1N)
Secondary Oocyte (1N) Undergoes Meiosis II (stimulated by fertilization from sperm) Ovum (1N) and Second Polar Body (1N)

			
	F) Maintaining Genetic Variation
		1) Genetic Recombination
		2) Crossing Over 
 

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Copyright © 2001 Jay Pitocchelli. All rights reserved. The contents of this page are the intellectual property of Dr. Jay Pitocchelli for distribution to students enrolled in General Biology BI 01 at Saint Anselm College. These pages may not be copied, photocopied, reproduced, translated, or published in any electronic or machine-readable form in whole or in part without prior written approval of Jay Pitocchelli. Students enrolled in General Biology BI 01 at Saint Anselm College have permission to print this material for their lecture notes. The images linked to this web page are the sole property of Addison Wesley/ Benjamin Cummings Publishers™.