The Cell Cycle & Cellular DivisionName:___________________________________________________Period:_______Date:___________

I. Cell Division: All _______________ are derived from preexisting cells (Cell Theory) ________________________________________ is the process by which cells produce new cells Cells grow in number, NOT in ____________________

o Smaller cells more ______________________(cellular transport, cellular communication/signaling)

o _____________________________to take in nutrients & get rid of wastes

How Often Do Cells Divide? o Some cells must be repaired often such as cells lining the___________________, _____________________,

_________________with a short lifespan 

o Other cells DO NOT divide at all after birth such as__________________________, nerve cells, ______________________, _____________________________

II. Reasons for Cell Division: Cell _________________________

__________________& ___________________________of damaged cell parts

Growth and development of an __________________

IV. Chromosomes & Their Structure: The plans for making cells are coded in __________

DNA, deoxyribose nucleic acid, is a long thin molecule that stores ____________________________

DNA is organized into giant molecules called __________________________

________________________are made of protein & a long, single, tightly-coiled DNA molecule visible only when the cell divides

When a cell is NOT dividing the chromosome (DNA) is less visible & is called ____________________

______________________hold duplicated chromosomes together before they are separated in mitosis

When DNA makes copies of itself before cell division, each half of the chromosome is called a ___________________________________

o Each sister chromatid contains the ____________genetic information

VI. Cell Cycle & Cell Division:

Eukaryotes (nucleus & membrane-bound organelles) must be copied exactly so the 2 new cells formed from division will be ____________________

o The original parent cell & 2 new __________________________must have IDENTICAL chromosomes o Ex: Humans have 46 chromosomes in our _____________________(body cells). After one of these somatic

cells goes through mitosis, 2 daughter cells are produced each having 46 chromosomes (genetically identical).

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Both the nucleus (_______________) and the cytoplasm (______________________) must be divided during cell division in eukaryotes

Cells go through phases or a cell cycle during their life before they divide to form new cells o Cell cycle is about ________________ hrs. for most animal cellso Cell cycle is controlled by proteins and _________________________

The cell cycle includes 3 main parts ---________________________, ____________________, and _______________________________________

o ________________________= nuclear divisiono __________________________________________= division of the cytoplasm

A. Interphase:

Interphase is the ___________________________________part of a cell's life cycle and is called the "resting stage" because the cell isn't dividing

Divided into 3 stages:

1) _________ (Gap 1) = cell is growing, carrying out normal cell functions, preparing to replicate DNA

Cells mature & increase in size by making more _____________________________ & _______________________________

2) ________ (synthesis) = DNA is copied or ___________________

DNA is in the form of ______________________________(uncoiled DNA) and is NOT ________________________________

3) ________ (Gap 2) =cell prepares for nuclear division (mitosis)

cells makes all the structures needed to ________________________

B. 4 Stages of Mitosis:

Division of the nucleus or _______________________occurs first

Mitosis is an _____________________________method of reproduction

o Only_________ parent cell

o Daughter cells have SAME number of _____________________(genetic info.)

Mitosis consists of 4 stages --- prophase, metaphase, anaphase, & telophase

1. Prophase:

______________________ phase of MITOSIS

Chromatin (__________________) condenses and coils into the form of chromosomes

chromosomes are visible (shaped like a “X”)

______________________ (half of a “X”) attach to each other by the _________________

Centrioles in animal cells move to opposite ends of cell

Spindle forms from each centriole (ONLY in _____________________ cells)

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__________cells ___________have centrioles (spindle forms from a microtubule)

_____________________dissolves (disappears)

_____________________disintegrates

2. Metaphase:

__________________________phase of MITOSIS

Chromosomes line up in center or ________________________of the cell

the centromere of each chromosome attaches to spindle fibers

3. Anaphase:

Spindle fibers attached to the centriole pull the _________________________ apart at their centromere

Separated chromosomes travel along the _________________________ to the two poles (ends) of the cell.

4. Telophase:

____________________________ forms at each end of the cell around the chromosomes

______________________________reforms

Spindle fibers begin to break down

Chromosomes become less tightly coiled & appear as _________________________again

Cytokinesis begins

C. Cytokinesis:

Animal Cell

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__________________________________= division of the cytoplasm of the cell and its organelles separate into 2 new daughter cells

In_____________________, a groove called the _______________________forms pinching the parent cell in two

In_______________________, a ___________________ forms down the middle of the cell where the new ______________________will be

VI. Cancer:

Cell division must be controlled, otherwise cell growth will occur without limit (cancer) o _____________mutations lead to changes in the proteins/enzymes that regulate the cell cycle

_____________________= a cell or group of cells that grow out of control and create a tumoro Crowds out normal cells and results in the loss of tissue function o ___________________= mass of growing, unregulated cells

2 types of tumors:

1. _____________________________- tumor that does not spread

2. _____________________________- tumor that spreads and destroys healthy tissue

Causes of cancer:

o _____________________(family history)o ______________________o ________________________(cancer-causing chemicals)o _________________:

HPV can lead to cancer of reproductive organs

o _____________________:

Sunlight- skin cancer

VOCABULARY: o _________________________= a cell containing TWO sets of

chromosomes. one set inherited from each parent 2n (number of chromosomes) ___________ (somatic cells)

o _________________________= a cell with only ONE set of chromosomes. 1n (number of chromosomes) _____________ (gametes)

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o ________________________= sex cells ___________= male gamete ____________= female gamete

o ____________________________________= paired chromosomes that have genes for the same traits arranged in the same order.

One homologous chromosome is inherited from the organism’s father, the other from the mother.

o ______________________= a two stage type of cell division that results in gametes with HALF the number of chromosome number as the body cells.

o ____________________________= when nonsister chromatids of homologous chromosomes exchange genetic information, results in a new combination of genes.

o _________________________= the process of joining gametes.

o ____________________= when sperm (haploid) fertilizes the egg (haploid), the resulting cell is the zygote (diploid).

I. GENES, CHROMOSOMES, AND NUMBERS:

In humans, each ________________(any cell other than a sperm or egg, has ___ chromosomes)

46 chromosomes __________(humans get ___________from each parent)

____________________________- determine the sex of an individual

last pair of chromosomes—23rd pair for humansXX = ______________XY = ______________

The ______________________for an organism is NOT related to the _______________________of that organism!!

Ex: A dog has 78 body chromosomes and humans have 46 body chromosomes

A thousand or more genes are lined up on a chromosomes at one time

Diploid & Haploid Numbers: Each ________________of an organism contains __________chromosomes. o Half of each pair came from each parent. These cells are said to have 2n

chromosomes, or a full set. They are DIPLOID.

Ex: Humans have 46 body chromosomes

Each ____________of an organism contains only ____________a chromosome set. o These cells are HAPLOID and have 1n chromosomes

Ex: Humans have 23 chromosomes in their gametes (egg or sperm cell)o Sex cells will fuse with another sex cell during fertilization to create a

_______________________________.

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So if human sperm and egg both have 23 chromosomes, after fertilization an embryo would have 46 chromosomes.

2 Reasons Why MEIOSIS Is Significant: 1. ______________is another form of cell division that _______________ ___________to be used

for reproduction. If mitosis was the only form of cell division, then new offspring would always

have ___________ as many ____________________ as their parents. Eventually, there would be so many chromosomes, the organism

would ________________or be severely_______________. 2. Meiosis provides __________________________- the reshuffling of genes carried by the

individual members of a populatioII. MEIOSIS vs. MITOSIS:

Remember: ________________= asexual division of diploid body cells MEIOSIS MITOSIS

Cell type of parent

Number of daughter cells produced

Number of cell divisions

Genetic relationship of daughter cells to parent cell

Genetic relationship of daughter cells to one another

MEIOSIS I: Separates ____________________________of chromosomes, NOT sister chromatids of individual chromosomes.

1. Interphase Io Metabolic activities & replicate chromosomes

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2. Prophase Io ______________occurs- the pairing of homologous chromosomeso Each pair of ________________chromosomes come together to form a _________________(4 part

structure)o Genetic material is exchanged in a process called ____________________(swapping portions of

adjacent DNA) Must be done with great precision so that neither chromatid gains or loses any

genes!

3. Metaphase Io __________________________line up at the _______________in pairs

4. Anaphase Io Homologous chromosomes separate and move to opposite ends of the cell.

This occurs because the ___________________do NOT split like in mitosiso This ensures that each ___________will receive only ___________________ for each homologous

pair.

5. Telophase Io The new cells are _____________so another division is required to create ________________cells

MEIOSIS II: The mechanisms of _____________is almost the same as ____________

o However, the chromosomes DO NOT replicate between meiosis I and meiosis II, the final outcome of meiosis is ___________the number of chromosomes per cell.

1. Interphase IIo ________________________________________o Allows the new cells to become ____________________

2. Prophase IIo Same as Prophase I except NO _______________are formed

3. Metaphase IIo Chromosomes line up at the ______________________.

4. Anaphase IIo ______________________________move to the opposite ends of the cell

5. Telophase IIo Creates 4 __________________cells (gametes)

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Meiosis Provides for Genetic Variation in 2 Ways: 1. _______________________________of homologous chromosomes during meiosis I

o The amount of different chromosomes that can be produced increases greatly as the number of chromosomes an organism has.

o A pea plant has 7 pairs of chromosomes. Each pair can line up 2 different ways. Therefore, each gamete can have 27= 128 possibilities!!

o Humans: n=23; so the number of different kinds of eggs or sperms a person can produce is more than 8 million (223)

When fertilization occurs, 223 X 223 zygotes are possible or 70 trillion!! No wonder brothers and sisters can be so different.

2. ____________________________between homologous chromosomes during prophase of meiosis I

o Increases the number of genetic variations

Stages of Cellular Division

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Directions: Number the following six stages of cell division in animal cells in the proper order. Then label each stage (interphase, prophase, metaphase, anaphase, telophase, cytokinesis).

Directions: Do the same for the plant cell below. Also label the cell plate!

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The Cell Cycle Review Worksheet1. List the 3 main parts of the cell cycle.

a. ______________________________b. ______________________________c. ______________________________

2. When do cell go through the cell cycle and/or mitosis?

3. What is the difference between chromatin and chromosomes?

4. The division of the nucleus is called? ____________________5. The division of the cytoplasm is called? ____________________6. What happens to the cell during interphase?

7. What are the stages of mitosis?________________________________________8. What is the longest phase of mitosis?___________________9. What is the shortest phase of mitosis?__________________10. During what phase does the nucleolus and nuclear membrane disappear?

____________11. In what form is the DNA in during interphase? ____________________12. What happens to the DNA during interphase?

13. What happens to the chromosomes during prophase?

14. What happens to the chromosomes during metaphase?

15. What happens to the chromosomes during anaphase?

16. What happens to the chromosomes during telophase?17. What is the difference between cytokinesis in plant and animal cells?

18. Is mitosis a form of sexual or asexual reproduction? Provide 2 reasons for you choice.

19. What is the difference between a malignant tumor and a benign tumor?10

20. Define cancer.

21. What are several causes of cancer?

22. Explain what happens during each of the 3 stages of interphase (G1, S, G2)a. G1 = _________________________________________________________b. S = _________________________________________________________c. G2 = ________________________________________________________

23. Label the following parts.

Meiosis Review WorksheetPart 1: VOCABULARY: Answer the following question using the best vocabulary word.

1) A cell with two of each kind of chromosome is called a(n) __________________ cell.

2) A cell with one of each kind of chromosome is a(n) ________________________ cell.

3) _______________________ are sperm or egg cells.

4) ___________________________ chromosomes have genes for the same traits in the same order on both chromosomes.

5) Parent cells make gametes in a process called ____________________.

B. _______________________A. _________________________

C. ______________________________

E. ______________________________

F. ______________________________

D. ______________________________

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6) A _______________ is the cell created when a sperm enters an egg.

7) When nonsister chromatids exchange genes, it is called ____________________________________.

8) All cells, other than sperm or egg cells are called________________________________________.

9) The process of joining a sperm cell with an egg cell is called ________________________________.

Part 2: SHORT ANSWER: Answer the following questions in a clear and concise manner.

1) What is the diploid number of chromosomes in humans?________________

2) What is the haploid number of chromosomes in humans?________________

3) Would egg and/or sperm cells be considered haploid or diploid? __________________

4) Would somatic cells (skin, hair, muscle cells, etc.) be considered haploid or diploid? _____________

5) Is the chromosome number related to the complexity of the organism? Explain.

6) When does the process of crossing over occur?____________________________________________

7) How many daughter cells are created at the end of meiosis I?________

8) How many daughter cells are created at the end of meiosis II?________Are these cells considered haploid or diploid?_____________

9) In humans, how many chromosomes are present in each cell at the end of meiosis I?_____________

10) In humans, how many chromosomes are present in each cell at the end of meiosis II?_____________

11) What is the important outcome of meiosis I?

12) What is the important outcome of meiosis II?

13) Why is meiosis important? List 2 reasons.

14) In what 2 ways does meiosis provide genetic variation? Explain how each provides genetic variety.

COMPARING MITOSIS & MEIOSIS

MITOSIS MEIOSIS1. no pairing of homologs occurs

2. two divisions

3. four daughter cells produced

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4. associated with growth and asexual reproduction

5. associated with sexual reproduction

6. one division

7. two daughter cells produced

8. involves duplication of chromosomes

9. chromosome number is maintained

10. chromosome number is halved

11. crossing over between homologous chromosomes may occur

12. daughter cells are identical to parent cell

13. daughter cells are not identical to parent cell

14. produces gametes

15. a synapsis occurs in prophaseDetermine whether the following characteristics apply to mitosis, meiosis or both by putting a check in the appropriate column

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