Chapter 10-1 Notes Cell Growth. Key Concept: What problems does growth cause for cells?

Transcription

1 Chapter 10-1 Notes Cell Growth Key Concept: What problems does growth cause for cells?

2 I. Does an animal get larger because each cell increases in size or because it produces more cells?

3 A. Living Things Grow by: 1. Producing more cells. a. For example: cells of an adult animal are the same size as those of a young animal

4 All of the following are problems that growth causes for cells EXCEPT A. DNA overload. B. excess oxygen. C. obtaining enough food. D. expelling wastes. 0% 0% 0% 0% Answer Now DNA overload. excess oxygen. obtaining enough food. expelling wastes. 18

5 B. Why not just keep growing in size? 2 reasons: 1. First reason: More demands placed on the cell s DNA a. Ex: a small town library has enough books for people to borrow but if a lot of people move into the town not enough books so, some people may have to wait for popular books.

6 b. Larger cells would have to make greater demands on its small genetic library i. In time, the cell s DNA is no longer able to serve the needs of a growing cell!

7 2. Second Reason: More trouble moving enough nutrients & wastes across the cell membrane

8 a. The rate that materials enter and exit the membrane depends on surface area and cell volume

9 i. The rate of exchange for food, H 2 O, and oxygen across a cell's membrane depends upon the cell s SURFACE AREA ii. How quickly these materials are used by the cell depends upon the VOLUME of the cell

10 The rate at which wastes are produced by a cell depends on the cell s A. ratio of surface area to volume. B. environment. C. volume. D. surface area. 0% 0% 0% 0% Answer Now ratio of surface area to volume. environment. volume. surface area. 18

11 As a cell grows, it A. places more demands on its DNA. B. uses up food and oxygen more quickly. C. has more trouble moving enough materials across its cell membrane. D. all of the above Answer Now places more demands on its... 0% 0% 0% 0% uses up food and oxygen mo.. has more trouble moving e... all of the above 25

12 C. Understanding these surface area and volume concepts will help us understand why cells must divide in order to grow

13 As a cell becomes larger, its A. volume increases faster than its surface area. B. surface area increases faster than its volume. C. volume increases, but its surface area stays the same. D. surface area stays the same, but its volume increases. Answer Now volume increases faster than... 0% 0% 0% 0% surface area increases faster... volume increases, but its sur surface area stays the same,...

14 1. Example: 1 cm 2 cm SA= length x width x # of sides Volume= length x width x height SA: Volume ratio= SA/Volume : 1 SA= 6 cm 2 SA= 24 cm 2 Volume= 1 cm 3 Volume= 8 cm 3 SA/Volume ratio= 6:1 SA/Volume ratio= 3:1

15 2. Example: 3 cm 4 cm SA= length x width x # of sides Volume= length x width x height SA: Volume ratio= SA/Volume : 1 SA= 54 cm 2 SA= 96 cm 2 Volume= 27 cm 3 Volume= 64 cm 3 SA/Volume ratio= 2:1 SA/Volume ratio= 1.5:1

16 3. What does the SA/Volume ratio tell us? a. The lower the SA/Volume ratio, the harder it is to get materials into/out of the cell

17 b. What does this mean? i. The 4 cm cube is too large to efficiently move nutrients and waste in and out of the cell... c. Small cells = BIG Ratios = Good!!!

18 II. Why Does the Rate of Exchange Become Difficult? A. SURFACE AREA & VOLUME DO NOT INCREASE AT THE SAME RATE. THIS IS A PROBLEM FOR THE CELL!

19 If the surface area of a cell increases 100 times, its volume increases about A. 5 times. B. 10 times. C. 100 times. D times. 0% 0% 0% 0% Answer Now 5 times. 10 times. 100 times times. 17

20 1. The volume of the cell increases faster than the surface area.thus, it is much more difficult for cells to move materials in and out of the membrane fast enough when it is bigger in size. a. Example: traffic increases as size of city increases, but the roads stay the same (two lanes) causing traffic congestion.

21 b. A cell that continues to grow will encounter similar problems; to solve this: Watch Video:

22 Compared to small cells, large cells have more trouble A. dividing. B. producing daughter cells. C. moving needed materials in and waste products out. D. making cyclin proteins. Answer Now dividing. 0% 0% 0% 0% producing daughter cells. moving needed materials i... making cyclin proteins. 18

23 The process by which a cell divides into two daughter cells is called A. cell division. B. metaphase. C. interphase. D. mitosis. 0% 0% 0% 0% Answer Now cell division. metaphase. interphase. mitosis. 15

24 B. To solve this problem cells divide in a process is called Cell Division 1. The process by which a cell divides into 2 daughter cells

25 Which of the following happens when a cell divides? A. The cell s volume increases. B. It becomes more difficult for the cell to get enough oxygen and nutrients. C. The cell has DNA overload. D. Each daughter cell receives its own copy of the parent cell s DNA. Answer Now The cell s volume increases. 0% 0% 0% 0% It becomes more difficult for... The cell has DNA overload. Each daughter cell receives i.. 25

26 2. Cell replicates (copies) all of its DNA each cell will get a copy of the DNA

27 By the time a normal cell divides, you can assume that A. the cell s surface area has become larger than its volume. B. the cell s volume has become larger than its surface area. C. the cell has replicated all of its DNA. D. the cell s mitochondria have been destroyed. Answer Now the cell s surface area has... 0% 0% 0% 0% the cell s volume has beco.. the cell has replicated all of i.. 25 the cell s mitochondria hav...

28 3. This solves the DNA problem, as well as, reducing the cells volume so that materials can be exchanged across the membrane efficiently.

29 Add to Notes: Reasons for cell division: 1. Growth of an organism 2. Replace damaged cells/tissues 3. Can then differentiate to create different cell types

30 Which of the following is NOT a way that cell division solves the problems of cell growth? A. Cell division provides each daughter cell with its own copy of DNA. B. Cell division increases the mass of the original cell. C. Cell division increases the surface area of the original cell. D. Cell division reduces the original cell s volume. Answer Now Cell division provides each... 0% 0% 0% 0% Cell division increases the m... Cell division increases the su Cell division reduces the ori...

31 After cell division, each daughter cell A. has a lower surface area/volume ratio than the parent cell. B. has a higher surface area/volume ratio than the parent cell. C. has more DNA in its nucleus than the parent cell. D. has less DNA in its nucleus than the parent cell. Answer Now has a lower surface area/vo... 0% 0% 0% 0% has a higher surface area/v... has more DNA in its nucleus has less DNA in its nucleus t...