Chapter 5: Cell Growth and Division Unit 2: Cells Chapter 5: Cell Growth and Division

Chapter 4: Cell Growth and Division UNIT 2: Cells Chapter 4: Cell Growth and Division I. The Cell Cycle has four main stages (5.1)   A. The _____ ______is a regular pattern of ______, _____________, and ___ ________ in ___________ cells

1. Originally divided into two stages (observations were  1. Originally divided into two stages (observations were limited by microscopes at the time) a. __________- cell appeared to be at rest b. ________- cell dividing 2. Improved techniques and tools later allowed scientist to identify 4 distinct stages

a. Gap 1 (G1) - cell carries out normal functions 1). ______ increases in ______ 2). _________ increase in numbers  

b. ___________ (S) - Cell makes copy of its nuclear ______. 1). __________ means “the combining of parts to make a whole. 2). By end of S stage, cell nucleus contains _____complete sets of ______  

c. Gap 2 (G2) - Cells continue to carry out normal functions 1).Additional _______ occurs 2). Critical ________ (before cell goes through mitosis cell must be adequate size, undamaged DNA)  

d. _________ (M) - Includes two processes 1). Mitosis - _________ of cell ________ and its contents 2). __________ - Process that ________ the cell __________. Two identical daughter cells produced

B. Cells divide at different rates 1. Rates of cell division vary widely a. ____________ cells typically divide much faster than____________cells b. Rate at which cells divide linked to body’s _______ for those cells.  

2. In human cells, S, G2, and M stages together usually take about ____________ a. Length of G1 stage differs most for different cell types b. Rate of cell division greater in _________ and _________  

C. Cell size is limited 1. Cells have upper and lower size limits a. Must be ______ enough to “hold” everything b. Upper limit due to ratio of cell ___________to _________  

1). Oxygen, nutrients, and wastes move 1).Oxygen, nutrients, and wastes move across the __________________(surface of cell) 2). As cell grows, its surface area (cell membrane) does not grow as fast as volume- too small for adequate ____________________  

2. To maintain suitable cell size, growth and cell division must be ____________.  

II. Mitosis and Cytokinesis (5.2) A. Chromosomes condense at start of mitosis 1. _____________ - one long continuous thread of _______ a. Consists of numerous ________ b. You have ____ chromosomes

c. Must be ___________ to fit into cell nucleus 1). ____ wraps around proteins called _______ 2). When loosely condensed called _________  

d. Chromosome looks like “___” (each half is identical DNA- called a __________) e. ______chromatids held together by _________

f. ________ - found at ends of DNA molecules and prevent DNA from coming apart  

B. Mitosis and cytokinesis produce two genetically ________ B. Mitosis and cytokinesis produce two genetically ________ daughter cells 1. ________ - important role in preparing cell to divide (2 sets of _____ and are ______ enough)   2. Mitosis - divides cell’s ________ into two genetically ________ nuclei, each with its own single, full set of _______ Two genetically identical nuclei

3. 4 main phases of Mitosis   a. _________ - DNA condenses into tightly coiled _____________. Nuclear envelope breaks down. _________ move to poles and ________ fibers form Centrioles chromosomes Nuclear envelope Spindle fibers

b. ___________ - Spindle fibers attach to each __________ b. ___________ - Spindle fibers attach to each __________. Chromosomes align along cell _______ (middle)   centromere What is the name of this structure?

c. _________ - Chromatids ________ to opposite sides of cell   chromotids

d. _________ - Nuclear _________ starts to. form d. _________ - Nuclear _________ starts to form. Chromosomes begin to uncoil and spindle fibers fall apart  

4. ___________ - division of cytoplasm 4. ___________ - division of cytoplasm. Different in ______ and _______cells.  

III. Regulation of Cell Cycle (5.3)   A. ________ and _______ factors regulate cell division 1. External factors a. Include physical and chemical factors b. Once a cell touches another cell it ______ dividing c. Many cells release chemical signals (_____________) that trigger cell growth.

2. Internal factors   a. External factors trigger internal factors that affect cell cycle b. Two of the most important internal factors are kinases and cyclins

3. __________ - programmed cell ______ (signals activate genes producing self-destructive _______

B. Cell division is uncontrolled in _______.   1. Cancer - common name for class or diseases characterized by ____________ cell division a. Form from disorganized clumps called________

b. Two types of tumors 1). ________ - cancer cells typically remain __________ together.  

2). _________ - Some cell break away (or ____________) from the tumor and spread through body  

2. Cancer cells come from normal cells that have suffered damage to ________ that make ________ involved in _____________   Brain cancer cells

a. damage from _________,________, _________, _________ radiation   b. _____________ - Substances know to cause cancer

c. Cancer can be treated with both ____________ and ___________ c. Cancer can be treated with both ____________ and ___________.(these typically kill both cancerous and healthy cells)  

IV. Asexual Reproduction (5.4) A. _______________is similar in function to mitosis   1. Reproduction occurs in two ways (______ and ______ reproduction)

a. ______ reproduction - joining of two specialized cells (_________ - egg and sperm), one from each parent   1). Offspring are genetically _________   2). Mixture of _______ from both parents

b. __________ reproduction - creation of offspring from a single parent. Offspring genetically ____________  

2. Binary fission - asexual reproduction of single-celled organism a. Occurs in _____________ b. binary fission and _________ have similar results

B. Advantages and Disadvantages of Asexual reproduction   1.In environments that don’t change, _________ may be better. If they are well suited to environment may be more efficient   2. In changing environments __________ reproduction produces genetic ______ which raises chances for survival

V. Multicellular Life (5.5) A. Multicellular organisms depend on _____________ among different cell types. 1. Cells ____________ and ______________ in groups that form increasingly large, more complex structures  

a. CELLS → _______ → ________ → ________ __________

b. ________ - group or cells that _____ _______to perform a particular function c. ______ - group of _______ that work together to perform specific function or related functions  

d. Organ system - _______ that carry out similar ___________   1). Organ systems work together to maintain ________________ 2). Occurs in ______ and ________

B. Specialized cells perform specific functions 1. Cell _____________ - process by which unspecialized cells develop into their mature _____ and __________ a. Every cell in body has full set of ____ b. Cells only use certain ______ and become________(ie. bone cells, mucscle cells, nerver cells, etc.)  

C. Stem cells can develop into different cell types 1. ___________- unique type of body cell   a. Can divide and renew themselves for long periods of time   b. Remain ___________ in form c. Develop into a variety of specialized cell types

2. Stem cells can be catorgorized by their ability or potential to develop into differentiated cell types and different tissues.  

3. _______ Stem Cells - partially _____________ cells located among the specialized cells or many organs and tissues   4. _________ Stem Cells - come from donated embryos grown in a clinic

5. Research and Treatment Hope   a. Stem cells have long been used to treat ________ and _______   b. Might be used to repair damaged ______ c. Used to cure diseases (i.e. _______)