1. The Cell Cycle and Control

2. As you know cells are very small
As you know cells are very small. We need __________ to help us see cells to study them. There are reasons that cells are small. Certain limitations keep a cell __________________. Instead of continually growing, when a cell grows to a certain size it _______ (reproduces).
microscopes
from growing too large
divides

3. Cell Size Limitations
________-is fast and efficient over short distances, but becomes slow and inefficient as distances become larger.
For example: A mitochondrion at the center of a hypothetical cell with a diameter of 20 cm would have to wait months before receiving molecules entering the cell!
Diffusion

4. _____- DNA is responsible for coding for proteins in our cells
_____- DNA is responsible for coding for proteins in our cells. The larger the cell the more protein needs it would have. The cell’s DNA could not keep up with the protein needs of a large cell.
DNA
proteins

5. __________________________- As the cell increases, the volume increases much faster than the surface area. As the cell increases it needs more _________ and has more _______ to excrete. This means it needs more plasma membrane in which to release wastes and diffuse nutrients.
Surface area to volume ratio
nutrients
wastes

6. Cell Reproduction-All cells come from ______________. (Cell Theory)
preexisting cells
Scientists discovered that ___________, which contain DNA and proteins become darkly colored when stained, are responsible for passing genetic information from one generation to another. These chromosomes are located inside the _______ and become visible just before the cell divides.
chromosomes
nucleus

7. Before a cell divides, the DNA is unwound into _________ to carry out cell functions.
chromatin

8. The Cell Cycle
The cell cycle is the sequence of _________________ of a cell.
Most of the cell's life is spent in the period of growth called _________.
growth and division
interphase

9. Following interphase, a cell enters its period of division called ______. Mitosis is broken into four phases: ________, _________, _________, and ________. After mitosis, a short period called _________ occurs in order to divide the cytoplasm.
mitosis
prophase
metaphase
anaphase
telophase
cytokinesis

10. During interphase the cell is in a resting phase
During interphase the cell is in a resting phase. It carries out __________, grows, copies its DNA and makes new ________.
cell functions
organelles

11. Interphase is divided into three phases
Interphase is divided into three phases. ___ phase is the first growth period of the cell, __ phase is the time to copy DNA, and ___ phase is the second growth of the cell. G1 S G2

12. Prophase- first phase of mitosis Chromosomes become visible
Chromosomes are made of two sister _________ (B) connected by a __________ (A)
Centrioles move to opposite poles of cell
Spindle starts to form
Nuclear membrane ____________
chromatids
centromere
breaks down

13. Metaphase- Chromosomes line up along ______ of the cell
Spindle attaches to centomeres
equator

14. Anaphase- ____________ divide Chromosomes
Chromatids separate and move to opposite ______ of the cell
Chromosomes
sides

15. Telophase- Chromosomes unwind into _________
Nuclear membrane forms around chromatin
chromatin

16. Cytokinesis- is different in plant and animal cells.
In animal cells, the plasma membrane _______ in separating two new cells. This is called _________ and the fold is called the ______________.
In plant cells, vesicles containing ______________ line up in the center of the cell and fuse together forming a ________. The cell plate then connects with the existing cell wall creating two new cells.
pinches
cleavage
Cleavage furrow
cell wall material
cell plate

18. Label the cell cycle. G1 S G2
Metaphase

19. Results of Mitosis
When mitosis occurs, __________ organisms remain unicellular-they have simply multiplied. In __________ organisms, cell division results in groups of cells that work together as _______.
unicellular
multicellular
tissues

20. Tissues form ______, organs form _____________, and organ systems form __________!
organisms

22. Control of the Cell Cycle
Biologists believe that a series of ________ called cyclins control the cell’s progress during the cell cycle. There are enzymes that tell the cell when to start mitosis as well as controlling it throughout the phases.
enzymes

23. The production of these enzymes is done by _____
The production of these enzymes is done by _____. Genes are a segment of ____ the controls the production of a protein.
genes
DNA

25. Cells can lose control of the cell cycle and start dividing uncontrollably. The results may be ______.
cancer

26. Cancerous cells
Normal cells

27. Meiosis

28. There are two types of cells in your body:
1) ___________—body cells
2) _________—sex cells (germ cells)
Somatic cells
Gametes

29. __________ cells have ½ the number of chromosomes in a species
__________ cells have ½ the number of chromosomes in a species. They are designated by 1N or N. (Sex cells)
What is the haploid number for humans? ___
Haploid cells 23

30. __________ cells have the correct number of (paired) chromosomes for a species. They are designated by 2N. (Body or somatic cells).
What is the diploid number for humans? ___
Diploid cells 46

31. The 2 chromosomes that make up a pair are called __________ chromosomes. Each _____________ in the pair has information about the same ____. The combination they form together results in a particular trait being expressed.
The process that forms new somatic cells is _______.
homologous
sister chromatid
gene
mitosis

32. Human sex cells in the female are the ____ cells
Human sex cells in the female are the ____ cells. In the male, they are the ______ cells. Each has ___ chromosomes or the haploid number for humans.
egg
sperm 23

33. Female sex chromosomes are represented by an ___ and males are represented by a ___. Since chromosomes are paired, _____ results in a female offspring and _____ is male. X Y XX XY

34. The cell division that forms new sex cells is called _______.
Meiosis produces ______ cells.
Meiosis
haploid

35. Meiosis is divided into two distinct parts: ________ and _________.
Each ends with cell division.
Meiosis I
Meiosis II

36. Meiosis I consists of _________I, __________I, _________I, and _________I.
What happens immediately after Telophase I? _________
Prophase
Metaphase
Anaphase
Telophase
Prophase II

38. Meiosis II consists of ________ II, _________ II, _________ II and ________ II. It occurs
immediately after ________. No replication of ______occurs before prophase II.
Prophase
Metaphase
Anaphase
Telophase
Meiosis I
DNA

40. _______ reproduction does not involve the exchange of genetic material (DNA). It can be accomplished by ______ division. This reduces genetic _______ because the resulting daughter cells are _______.
Asexual
cellular
variation
identical

41. Bacteria reproduce by a mitotic division called _______ _______
Bacteria reproduce by a mitotic division called _______ _______. They have circular _______ that copies itself and then a new cell wall forms dividing the cell.
Binary
fission
DNA

42. Other types of asexual reproduction are: _______, which is often used by fungi, and ________ __________, which is used by a lot of plants.
Budding
Vegetative propagation

43. Sexual reproduction increases _______variation within a species because it involves the exchange of _____, which is the genetic material of a species.
genetic
DNA

44. There are ____ sperm produced in meiosis of sperm cells, which is called ______________. Egg cells undergo meiosis that is called _________. It produces ___ egg cell, which receives most of the cytoplasm, and _____ small cells that are called __________.
four
spermatogenesis
oogenesis
one
three
polar bodies

45. ____________ is when chromosomes do not separate correctly and offspring end up with one chromosome too many or one too few. This causes birth defects.
Nondisjunction

46. When a gamete with an extra chromosome is fertilized by a normal gamete the result is called ________. Trisomy zygotes have an extra ______________ and they will develop into a baby with _______________.
trisomy
21st chromosome
Down syndrome

47. If a zygote is ________ a chromosome the result is called _________
If a zygote is ________ a chromosome the result is called _________. This is usually a lethal defect, but one result is called _______________, Females will have only one ___ chromosome instead of two.
missing
monosomy
Turner syndrome X

48. When a whole extra set of ___________ is present in the zygote the condition is called ________. This is lethal to animals, but is desired in plants. Polyploidy leads to ___________________.
chromosomes
polyploidy
larger flowers or fruit.