Chapter 11: Cell Division

What is sexual reproduction? List its characteristics.

• The fusion of two reproductive cells formed by each of the two parents 

• offspring inherits some of the genetic information from each parent 

• Fewer offspring growth takes more time

• Need to find a mate

• Changing environments 

• genetic diversity can be beneficial

• Offspring may be less well adapted to current conditions

What is asexual reproduction? List its characteristics.

• The production of genetically identical offspring from a single-parent

• Simple, effective, efficient, and quick

• Two cells that are genetically identical to the cell that produces them are produced. 

• Produce many offspring in a short period

• Don't need to find a mate 

• In stable environments, genetically identical Offspring thrive 

• If conditions change, Offspring not well-adapted

What are the advantages and disadvantages of both asexual and sexual reproduction?

Asexual

• Advantage: quick and efficient, creates many offspring, and simple

• Disadvantage: no genetic diversity, offspring not adapted to new environments 

Sexual:

• Advantage: offspring adapt better to new environments, and genetic diversity 

• Disadvantage: takes longer, creates less offspring 

Why is the surface area-to-volume ratio an important concept? How does it relate to cell growth/size? As a cell’s size increases, what happens to the ratio of its surface area to its volume?

As a cell grows, the surface area and volume increase; the larger the cell, the less efficient it becomes. If a cell has a smaller surface area to volume ratio, then it will be more efficient

In what type of cells does the cell cycle occur? (prokaryotes or eukaryotes

• Prokaryotes: binary fission

• Eukaryotes: cell cycle

What are the stages (phases) of interphase? What happens in each phase of interphase

G1: cells increase in size and synthesize (make) new organelles

S: DNA replication

G2: organelles and molecules required for cell division are produced

Chromosomes:

Threadlike structure within the nucleus that contains genetic information

sister chromatids (chromatids):

Single strand of DNA

Centromere:

The point at which two strands of chromosomes connect

spindle fibers:

a network of filaments that are formed during the cell division process

Centrioles:

a type of microtubules that helps form the mitotic spindle

Chromatin:

DNA tightly coiled around histone proteins

In what phase do cells duplicate their DNA?

Interphase (s Phase)

What is cytokinesis? How does this process differ in animal cells vs. plant cells?

Cytokinesis is the splitting of the cytoplasm into two. In plant cells, a cell plate forms halfway between divided nuclei, and then the cell plate joins the membrane, splitting the cell. In animal cells, microfilament rings form and pinch the cytoplasm, creating two cells.

How many chromosomes will the cell have after the S phase?

46

How many sister chromatids are present during prophase?

92

How many chromosomes will each new daughter cell have following mitosis?

23

What moves the chromatids during mitosis?

• Miotic Spindle fibers

How does the DNA structure differ in each phase of the cell cycle? Why is this important?

• In g1, it's not condensed

• 2 phase is replicated

• G2 its xs

• Prophase condensing full-on xs

• Metaphase- condensed xs

• Anaphase- chromatids are pulled apart  

• Telaphase- condescend and on opposite sides of the cell

• Mitosis- entangled together 

• Cytoskensies- retangle within each other still

stages of mitosis

• prophase

• metaphase

• anaphase

• telophase

prophase

nucleus condenses and chromosomes become visible

centrioles go to side of the cell

spindle starts to form

metaphase

shorterst phase

chromosomes line up in the center of cell

nucleus and its membrane dissasembles

miotic spindle attaches to centrioles

anaphase

sister chromatids are pulled apart and move along the spindle fibers in opposite ends in the cell

the spindel fibers are getting disasembles until chromosomes are esch on one side of the cell

in anapahse when do the the spindle fibers stop dissasembleing

chromosomes are completely seperted and movement stopped

telaphase

nuclear envolope reforms

chromosomes retangle tmeselves with chromatin

nucleus becomes visible

when mitosis is complete what continues

cell divison

cytokeneisis in animal cells

microfilimant ring forms

pinchs the cytoplams

2 cells created

cytokenesis in plant cells

1. cell plate forms hald way between divided nuclei

2. cell plate joins membrane, splitting the cell