6 highlights

8/14/2019 6 Highlights

1/14

6 Highlights

chromosome (P.101) compact structure oftightly coiled DNA that forms prior to meiosis

or mitosis.

chromatin (p. 101) thread-like complex of

DNA and proteins in the nucleus of a non-

dividing cell.

karyotype (p. 103) an array of the

chromosomes found in the cells of anindividual, arranged in order of size and

shape.

6-1 Chromosomes


2/14

6 Highlights

diploid (p. 103)- cells that have two sets of

chromosomes.

haploid (p. 103) cells that have one set of

chromosomes.

sex chromosome (P.103) either of a pair

of chromosomes responsible for determining

sex.

6-1 Chromosomes


3/14

6 Highlights

Chromosomes are

composed of DNAand associated

proteins.

Chromosomes carry

genetic information

from parent to

offspring.


4/14

6 Highlights

A eukaryotic

chromosome is made ofDNA wrapped around

protein.

A prokaryotic

chromosome is a singlecircle of DNA.

Before a eukaryotic cell

divides, a chromosomecondenses into a

compact rod-shaped

body that can be easily

moved around the cell.


5/14

6 Highlights

mitosis (p. 105) nuclear division involvingthe copying and separation of chromosomes

into two nuclei.

cytokinesis (P.105) division of the

cytoplasm following mitosis.

cell cycle (p. 107) the five (5) phase

sequence of eukaryotic growth and division.

6-2 Mitosis and Cell Division


6/14

6 Highlights

tumor (p. 108) the formation of a mass ofcells as the result of abnormally rapid cell

division.

cancer(p. 109) - a condition in which normal

constraints on cell reproduction break down,

resulting in rapid uncontrolled cell division.

mutation (p. 109) the abrupt change in

genotype of an organism.

6-2 Mitosis and Cell Division


7/14

6 Highlights

Before it can divide,

a cell must make a

copy of its DNA.

Bacteria divide bysplitting in half.

Eukaryotic cellsdivide through

mitosis (division ofthe nucleus) followedby cytokinesis(division of the

cytoplasm).


8/14

6 Highlights

In cytokinesis, thecytoplasm forms two

distinct cells.

In mitosis, the

nucleus of a cell isdivided into two

nuclei, each with the

same number of

chromosomes as theparent cell.


9/14

6 Highlights

A cell undergoes an

interval of growthand division called

the cell cycle.

Cancer is a life-

threatening disease

that results from

unregulated cell

growth.


10/14

6 Highlights

gamete (p. 110)- a haploid reproductive cell

such as an egg or sperm.

meiosis (p. 110) a form of cell division that

reduces the number of chromosomes in a cell

by half.

crossing-over (P.112) the exchange of

genetic material between paired homologous

pairs of chromosomes.

6-3 How Gametes Form: - Meiosis


11/14

6 Highlights

A gamete is a haploid

reproductive cell,such as an egg or a

sperm cell.

Meiosis is a type of

nuclear division that

reduces the numberof chromosomes in a

cell by half.


12/14

6 Highlights

Crossing-over is the exchange of segments of

DNA between homologous chromosomes. It isa source of genetic variation.


13/14

References & Acknowledgements

Johnson, George B.: Biology, Visualizing Life,HOLT, RINEHART & WINSTON; Austin,1998.

Miller, Kenneth R. & Levine, Joseph: Biology,

Prentice Hall; Upper Saddle River, New Jersey,

2004.

Campbell, Neil A., Williamson, Brad & Heyden,Robin J. BIOLOGY, Exploring Life, Prentice Hall;

Needham, Massachusetts, 2004.

Biggs, Alton, Hagins; Whitney Crispen; Kapica,

Chris; Lundgren, Linda; Rillero, Peter; Tallman,

Kathleen G.; Zike, Dinah; National GeographicSociety; Biology, The Dynamics of Life, McGraw

Hill, Glencoe, New York, New York, 2004.


14/14

Photo Credits

Aaron Haupt

Corbis

Digital Stock

Elaine Shay

Mark Thayer

PhotoDisc

Alton Biggs

6 highlights

Documents