{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

L11_12_Chp8_9_notes - Chapter 8 How Cells Reproduce...

Info icon This preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
Chapter 8 How Cells Reproduce Understanding Cell Division What instructions are necessary for inheritance? How are those instructions duplicated for distribution into daughter cells? By what mechanisms are instructions parceled out to daughter cells? Reproduction Parents produce a new generation of cells or multicelled individuals like themselves Parents must provide daughter cells with hereditary instructions, encoded in DNA, and enough metabolic machinery to start up their own operation Division Mechanisms Eukaryotic organisms ---Mitosis --Meiosis Prokaryotic organisms--Prokaryotic fission Roles of Mitosis Multicelled organisms; some protistans, fungi, plants, animals To promote growth, Cell replacement, Asexual reproduction Meiosis Functions only in sexual reproduction Precedes the formation of gametes (sperm and eggs) or spores Chromosome A DNA molecule & attached proteins Duplicated in preparation for mitosis Sister Chromatids Each chromosome and its copy stay attached to each other as sister chromatids until late in the nuclear division process; attach at the centromere Nucleosome A nucleosome consists of part of a DNA molecule looped twice around a core of histone proteins Organization of Chromosomes Cell Cycle Cycle starts when a new cell forms During cycle, cell increases in mass and duplicates its chromosomes Cycle ends when the new cell divides Interphase Usually longest part of the cycle Cell increases in mass Number of cytoplasmic components doubles DNA is duplicated Stages of Interphase Control of the Cycle Once S begins, the cycle automatically runs through G2 and mitosis The cycle has a built-in molecular brake in G1 Cancer involves a loss of control over the cycle, malfunction of the “brakes” Stopping the Cycle Some cells normally stop in interphase Neurons in human brain Arrested cells do not divide Adverse conditions can stop cycle Nutrient-deprived amoebas get stuck in interphase Chromosome Number Sum total of chromosomes in a cell -For Somatic cells, Chromosome number is diploid (2 n ) Two of each type of chromosome
Image of page 1

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
-For Gametes, Chromosome number is haploid ( n ) One of each chromosome type Human Chromosome Number Diploid chromosome number ( n ) = 46 Two sets of 23 chromosomes each One set from father One set from mother Mitosis produces cells with 46 chromosomes – two of each type Lots of DNA
Image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern