Lesson 10 Flashcards
The larger a cell becomes there is a
greater demand on the DNA, DNA does not grow, and Information deficit is created.
As a cell becomes larger the
1 volume increases faster than the surface area
2. A cell’s volume cannot exceed its cell membrane (surface area).
3. A larger cell carries out more activities.
4. If it becomes too large the cell membrane can not get rid of wastes or bring in enough materials like food.
Cell Division solves the problem of
getting too big because the cell divides into two daughter cells.
The cell copies
all DNA so each cell has the exact same amount of original DNA.
The cell splits
in half solving the surface area and volume problem.
Asexual Reproduction
It is reproduction without the fusion of reproductive cells.
The offspring is genetically identical to the single parent.
No exchange of DNA information so no genetic diversity.
Sexual Reproduction
It is reproduction with the fusion of reproductive cells.
Offspring inherit half of their information from each parent.
Provides genetic diversity for the continuation of a species.
During the cell cycle the cell
grows, prepares to divide and divides into two daughter cells
Prokaryotes
They use binary fission.
Interphase has ______ phases and then is followed by ________.
three,cell division
G1 Phase:
Cell Growth
Cells increase in size.
Cells make new proteins and organelles.
Centrioles are duplicated.
Intense growth and activity.
S Phase:
DNA Replication
New DNA is synthesized when the chromosomes replicate.
Cells contain twice as much DNA as the beginning of S phase.
This ensures that each daughter cell will get a complete set. Parent =12, daughter cell=12
G2 Phase:
Preparing for Cell Division (Mitosis)
Shortest phase.
Organelles and molecules needed for division are created.
M Phase:
Cell Division
This is the process of mitosis.
Mitosis
Cytokinesis
Mitosis-
divides the nucleus
Cytokinesis-.
Divides the cytoplasm.
Two daughter cells are produced.
Chromosomes are now visible
Prophase-
Longest Phase in mitosis
Chromosomes become condensed.
The nuclear membrane breaks down.
Duplicated strands (sister chromatid) attach at the center (centromere.)
The centrioles begin to move to opposite poles and the spindle (microtubules) connect between them.
In Prophase the centrioles begin to move to _______ poles and the _________ connect between them.
opposite, spindle (microtubules)
Metaphase
The chromatid attach to the middle of the spindle at their centromeres.
Each sister chromatid faces an opposite pole.
Anaphase
The spindle helps the sister chromatids separate at the centromere.
Each chromosome moves along the spindle away from each other.
They begin to arrive at separate poles.
Telophase
The chromosomes unwind and are no longer visible.
The nuclear membrane reforms around the chromosomes.
The spindle breaks down
Stages of Mitosis in order
Prophase, Metaphase, Anaphase, and Telophase.
Cytokinesis in Animal Cells
The cell membrane is drawn inward.
The cytoplasm is pinched in two equal parts.
Each part contains its own nucleus and organelles and DNA.
The two cells are identical and begin interphase
Cytokinesis in Plant Cells
A cell plate forms in between the rigid cell wall.
The cell plate forms a cell membrane that divides the two daughter cells.
A cell wall then forms.
