1. 9-1 Cellular growth

2. Déjà vu What are the 3 parts of the Cell Theory?
All living things are made of one or more cells
Cells are the smallest unit of living organisms
Cells arise only from existing cells

3. Why are cells so small?

4. Cells grow until they reach their size limit, then they either stop growing or divide.

5. Cell Size Limitations Ratio of Surface Area to Volume
Transport of Substances
Cellular Communication

6. Cellular Reproduction
As the cell grows, its volume increases much more rapidly than the surface area.
Ratio of Surface Area to Volume
Surface Area = the area covered by the plasma membrane
Volume= the space taken up by the inner contents of the cell (organelles, cytoplasm, nucleus
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7. Transport of Substances
Substances move by diffusion or by motor proteins.
Diffusion over large distances is slow and inefficient.
Small cells maintain more efficient transport systems.

8. Transport of Substances
So…The cell might have difficulty supplying nutrients and expelling enough waste products. (It gets harder to get the good stuff in and the bad stuff out)

9. Think About It…
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10. Cellular Communications
Cellular Reproduction
Cellular Communications
Cell size affects the ability of the cell to communicate instructions for cellular functions.

11. How do cells stay small?

12. Cell Cycle Cells reproduce by a cycle of growing and dividing
Each time a cell goes through one complete cycle, it becomes two cells.

13. Cells go through different types of cell division depending on the organism and the reason for the cell dividing.
Reasons for cell division: -Repair -growth -development -asexual reproduction -gamete formation
About 2 trillion cells are produced by an adult human body every day. This is about 25 million new cells per second!

14. CHROMOSOMES
“packages of DNA”

15. Eukaryotic Chromosomes

16. When genes are being used to make proteins, the DNA is stretched out so it can be easily read. This “relaxed” form of DNA is call chromatin.
As a eukaryotic cell prepares to divide, the DNA associates itself with histone proteins. DNA coils tightly around the proteins and forms a beadlike structure called a nucleosome. Nucleosomes pack together to form thick fibers, forming a chromosome. The “X” chromosome that we are used to seeing is actually two exact copies of one chromosome, each one is called a chromatid. The two chromatids of a chromosome are attached at a point called a centromere.

17. DEMO

18. DNA
Genes
Proteins
YARN =
TAPE =
CLOTHES PIN =

19. Explain the role of chromosomes during cell division.
Journal
Explain the role of chromosomes during cell division.

20. Cell Cycle
Interphase is the stage during which the cell grows, carries out cellular functions, replicates DNA, and prepares for division.
Mitosis is the stage of the cell cycle during which the cell’s nucleus and nuclear material divide.
Cytokinesis is the method by which a cell’s cytoplasm divides, creating a new “daughter” cell with identical nuclei

21. Eukaryotic Cell Cycle

22. Think about it…
How can we tell how much time the cell spends in each phase?

23. Thought Question
How do you think cell division in eukaryotes compares to cell division in bacteria (binary fission)?

24. Prokaryotes vs. eukaryotes
Cell Cycle is the process by which eukaryotic cells reproduce themselves
Reproduce by a method called binary fission

25. Which is not a phase of the cell cycle?
Chapter Diagnostic Questions
Which is not a phase of the cell cycle?
cytokinesis
interphase
apoptosis
mitosis A B C D
CDQ 3

26. Which can more efficiently supply nutrients and expel waste products?
Section 1 Formative Questions
Which can more efficiently supply nutrients and
expel waste products?
larger cells
smaller cells
cells with lower surface area to volume ratio
cells shaped like a cube A B C D
FQ 1

27. At what stage does a cell spend most of its life?
Section 1 Formative Questions
At what stage does a cell spend most of
its life?
cytokinesis
interphase
mitosis
synthesis A B C D
FQ 2

28. What happens in the cell during cytokinesis?
Cellular Reproduction
Section 1 Formative Questions
What happens in the cell during cytokinesis?
The cell grows and carries out normal functions.
The cell copies its DNA and forms chromosomes.
The cell’s nucleus and nuclear material divide.
The cell’s cytoplasm divides. A B C D
FQ 3

29. In what stage of the cell cycle does the
Section 2 Formative Questions
In what stage of the cell cycle does the
cell’s replicated genetic material separate?
cytokinesis
interphase
mitosis
prophase A B C D
FQ 4

30. C B A Which cell has the lowest ratio of surface area to volume?
Standardized Test Practice
Which cell has the lowest ratio of surface area
to volume? A B C A B C
STP 1

31. Standardized Test Practice
At what stage of interphase does the cell take inventory and make sure it is ready for the division of its nucleus? G1 S G2 M A B C D
STP 2

32. The Stages of Interphase
G1 (Gap 1) -The cell is growing, carrying out normal cell functions, and preparing to replicate DNA.
Nerve cells, muscle cells, and some other highly specialized cells do not leave the G1 phase, and therefore do not replicate in the body under normal conditions.

33. The Stages of Interphase
S (Synthesis) -The cell copies its DNA in preparation for cell division.

34. The Stages of Interphase
Cellular Reproduction
The Stages of Interphase
G2 (Gap 2) -The cell prepares for the division of its nucleus.

35. Surface Area : volume activity, page 245

36. Surface area lab
Is the distance of diffusion the same for all blocks? Explain.
List the cubes in order of size, from largest to smallest. Now list them in order of surface area:volume ratio, from largest to smallest. How do these lists compare?
What is the relationship between surface area:volume ratio and diffusion in a cell?
Are large organisms, such as redwood trees and elephants, large because they contain extra-large cells or just more regular sized cells?