UNIT 2: CellsChapter 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 limited by microscopes at the time)

a. __________- cell appeared to be at restb. ________- cell dividing

2. Improved techniques and tools later allowed scientist to identify 4 distinct stages

a. Gap 1 (G1) - cell carries out normal functions1). ______ 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 _______ occurs2). Critical ________ (before cell goes through mitosis cell must be adequate size,

undamaged DNA) 

d. _________ (M) - Includes two processes1). Mitosis - _________ of cell ________ and

its contents2). __________ - Process that ________ the cell __________. Two identical daughter cells produced

B. Cells divide at different rates1. Rates of cell division vary widely

a. ____________ cells typically divide much faster

than____________cellsb. 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 limited1. 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 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 nucleus1). ____ 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 ________ 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

 

Nuclear envelope

Centrioles

chromosomes

Spindle fibers

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. Chromosomes begin to uncoil and spindle fibers fall apart 

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

III. Regulation of Cell Cycle (5.3) 

A. ________ and _______ factors regulate cell division 

1. External factorsa. Include physical and chemical factorsb. Once a cell touches another

cell it ______ dividingc. 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 tumors1). ________ - 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 ___________.(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 functionc. ______ - 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 functions1. 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 types1. ___________- 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. _______)