Name:________________________

Unit 4: DNA, Replication, Mitosis, &Meiosis

Mastery Quiz #1: 10/3Mastery Quiz #2: 10/9

Unit 4 Test: 10/11

(organelle)

Where in the cell is DNA?!

*CHROMOSOMES ARE

_____________________*DNA

Answer the following questions while you read the passages on the structure of DNA! (starting on pg. 291)

1. DNA is made of what units? What are the 3 components of each unit?

2. How many types of nitrogenous bases are there? What are they?

3. What are the 2 components of the DNA “backbone”?

Pg. 294:4. What does a “double helix” look like?

5. What type of bonds hold the two strands of DNA together?

6. Which base pairs will have hydrogen bonds between them?

Pg. 295:7. Where is DNA located in prokaryotes? WHY!?

Label the following in the picture:

DNA Cell Nucleus Chromosome Gene

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8. Where is DNA located in eukaryotes?

9. How many chromosomes do humans have in every nuclei of every cell in their body?

10.How long is the DNA in a human cell nucleus? (pg 296)

DeoxyribonucleicAcid(_____) is a _____________ ________ (so it is made of _________________!)

Found in the ___________ of eukaryotes, _____________ of prokaryotes You are ______% identical to the person next to you In ___________________, DNA gets compacted into _________________

Complementary Base PairingThe same nitrogenous bases will always pair together

Adenine (A) pairs with _______________ (___)Cytosine (C) pairs with _______________ (___)

Two bases are held together by _________________ bonds

IMPORTANT: Hydrogen bonds are very _______________!

Try It!:A T T A T C G T A___________________

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You try it!1. The strands below are missing their complementary strands! Write the complementary DNA strand

below each DNA strand given. Example: DNA strand: ATGGC

Complementary DNA strand: TACCG

a) A G T TT A C G G C A T

b) A G C CC G A T T A G C

2. How do we know that A always pairs with T and G pairs with C? A scientist named Erwin Chargaff performed experiments which showed that the ratio of A to T is always 1:1, and the ratio of G:C is always 1:1. Look at the data below and answer questions about it so that you can prove this to yourself!

Source of Sample

Amount of A

Amount of G

Amount of C

Amount of T

Human liver cell 30 19 19 30Human lung cell 31 20 20 31

Fish cell 28 22 22 28Bacteria cell 32 18 18 32

Questions about the chart:1. Compare the amounts of A, G, C & T in human liver cells. Which nucleotides have the same

amount?

2. Compare the amounts of A, G, C & T in human lung cells. Which nucleotides have the same amount?

3. Compare the amounts of A, G, C & T in fish cells. Which nucleotides have the same amount?

4. Compare the amounts of A, G, C & T in bacteria cells. Which nucleotides have the same amount?

5. Look at your answers to #’s 1-4. What pattern are you starting to see?

6. In human lung cells A=31 and T=31. Is the ratio of A:T 1:1, 1:2, 1:3 or 1:4?

7. Which of the four types of cells have about the same amounts of A, G, C and T, and why do you think they have similar DNA?

8. The ratio of A:T is always 1:1 and the ratio of G:C is always 1:1. This means that the amount of A always equals T and the amount of G always equals C. Why does this prove that A pairs with T and G pairs with C?

3. What are A, T, G and C? Adenine (A), Guanine (G), Thymine (T), and Cytosine (C) are ring shaped nitrogen bases. Adenine and Guanine are purines. Thymine and Cytosine are pyrimidines.

Questions:1. What are A, T, G and C?

a. hydrogen bonds b. nitrogen bases c. nitrogen bonds d. hydrogen bases

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2. What is the shape of a nitrogen base?a. straight line b. ring-shape c. spiral-shape d. gladiator-shape

3. How are two nitrogen bases in DNA connected? a. phosphate bond b. carbon bond c. nitrogen bond d. hydrogen bond

4. How do we use nitrogen bases (A, T, G and C) to store genetic information? We store genetic information in our DNA. Our DNA is made up of 4 different nucleotides. The nucleotides are different because they contain different nitrogen bases (A, T, G and C). We store genetic information as patterns of nucleotides in our DNA.The more alike two organisms are, the more alike their DNA is. For example, the DNA of a tiger and a cat is more alike than the DNA of a cat and a flower.

Questions:1. How do we store genetic information in our DNA?

2. True or False. The more alike two organisms are, the more alike their DNA is.

3. The more alike two organisms are, the more alike their DNA is. Based on this statement, look at the DNA of the animals below, and put them on a timeline based on how alike their DNA is.

Example: Tiger(ACT)___________Mouse(ACC)_______________Flower (CCC)

Put these Animals on the timeline: Frog: ATGGTTT Jellyfish: ATTAGGT Butterfly: ATTAGTTFish: ATTGTTT Elephant: GGGGTTT Starfish: ATTATTTBird: AGGGTTT Bacteria: ATTAGGC

Bacteria____________________________________________________________________________________ElephantATTAGGC GGGGTTT

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What does “replication” mean?!

DNA Replication

WHAT is it?

WHERE does it happen?

WHY does DNA need to make a copy of itself?

Cells divide for an organism to _______ or ______________. Every ______ cell needs a _______ of the DNA to know how to be a cell. DNA makes an exact _______ of itself _________ the cell ___________.

HOW does it occur?

1. UNZIP: An enzyme “__________” the 2 strands of DNA by breaking the weak ______________bonds

2. ADD: New nucleotides are added to the old strands (REVIEW: A= ____; C= ____)

3. ZIPUP: Another _______________ zips the strands back up4. PROOFREAD: DNA polymerase “______________” the strands to make

sure there are no mistakes

DNA replication is ___________________________ = when the DNA copies itself, it always has ____ parental strand, ___ daughter strand

Semi: _______________________Conservative: _______________

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Original Strand Step 1: ______________

Step 2: ______________ Step 3&4: ______________ _______________

Have your DNA and eat it too!Background Information:

When isolated from a cell and stretched out, DNA looks like a twisted ladder. This shape is called a double helix. The sides of the DNA ladder are called the backbone and the steps (also called rungs) of the ladder are pairs of small chemicals called bases. There are four types of chemical bases in DNA: Adenine (A), Cytosine (C), Guanine (G), and Thymine (T). They form pairs in very specific ways: Adenine (A) always pairs with Thymine (T) and Cytosine (C) always pairs with Guanine (G).

Your task is to use the following materials and procedure to construct an edible model of DNA with your partner.

Pre-Lab Questions:1. What are the 4 different bases and their single letter abbreviations?

2. Write the pair for the following bases:A:___ C: ___G:___ T: ___

Procedure:Step 1: Give the complementary strand for your sequence below:

Sequence: T A C G C A T G Complementary strand: _____________________

Step 2: Assemble one side of your DNA molecule. A piece of licorice will form the backbone and marshmallows will be the nitrogenous bases. Place a marshmallow on the end of a toothpick so that the point of the toothpick goes all the way through. Anchor the toothpick into the licorice backbone. Refer to the table to choose the correct color marshmallow to represent the nitrogenous bases in your sequence.

Step 3: Match the nitrogenous base pairs. Place the color marshmallow for the matching nitrogenous base on the other end of each toothpick. Remember that A always pairs with T and C always pairs with G!

Step 4: Complete your DNA model. Attach the other backbone so your model looks like a ladder.

Step 5: Twist your DNA model. Carefully twist your DNA molecule so that it looks like a double helix.

Step 6: Label the DNA model. Label (and color!) the drawing to the right according to your model. Use the following words:

Sugar phosphate backbone Adenine Guanine Cytosine Thymine Hydrogen bond

Adenine (A) = GreenThymine (T) = PinkCytosine (C) = YellowGuanine (G) = Orange

Materials:2 pieces of licorice10 toothpickspink marshmallowsyellow marshmallowsgreen marshmallowsorange marshmallows

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Step 7: Simulate DNA replication.One partner will break the toothpicks in the center to separate the two strands. Use another stick of licorice, more marshmallows, and toothpick halves to form the new DNA strand!

Post-Lab Questions:1. Which color marshmallow was always paired with green? Why?

2. Which color marshmallow was always paired with yellow? Why?

3. What did the licorice represent? What are the two components called?

4. What represented the hydrogen bonds in your model? What happened to them when you replicated your DNA?

5. After you replicated your single strand of DNA, how many strands of DNA did you have? Were they complete? Were they identical?

5. Which nitrogen bases are needed to complete the DNA strand pictured below? Give your answer in order from top to bottom.

A. T,A,G,CB. A, T, G,CC. A,T,C,GD. C,G,T,A

6. What is the role of enzymes in the DNA replication process?A. Enzymes read the DNA code and build a new

DNA molecule from scratchB. Enzymes link together to form a template for a

new DNA molecule to be builtC. Enzymes split the DNA molecule in half, then

transport matching nitrogen bases to each railD. Enzymes link adjacent nucleotides together,

becoming an integral structure of the DNA

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7. When one DNA molecule is replicated, the result is two DNA molecules. What is true of the second DNA molecule?

A. It is identical to the first DNA moleculeB. The sequence of bases, from top to

bottom, is opposite the first DNA molecule sequence

C. It is half the size of the first DNA molecule

D. It is twice the size of the first DNA molecule

EOC questions:8. Color the DNA molecule according to the code that you create.

Coloring Codes:Example: phosphates (P): purple

Phosphates (P): __________Deoxyribose (D): ________________Thymine (T): ____________Adenine (A): ______________Guanine (G): _____________Cytosine (C): _______________Hydrogen Bonds: _________________

2 Types of ReproductionReproduction! Sex or Not?Use Page 17—3rd paragraph “Reproduction” to answer the following questions.

1. What process do organisms use to make more of themselves (new organisms)?

2. What are the two types of reproduction?

3. Use your book to write the definition of SEXUAL REPRODUCTION in your notes (page 17).

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4. How many parents are required during sexual reproduction?

5. Use your book to write the definition of ASEXUAL REPRODUCTION in your notes (page 17).

6. How many parents are required during asexual reproduction?

WHO are we even talking about?! What organisms even participate in this asexual reproduction that only requires ONE parent? Do

humans or other complex or simple animals make babies this way? No! We all know that it “takes two to tango” for animals like humans and lions and dogs and birds. So which types of organisms can make babies that are identical to themselves without the help of a mate? There are a few types of organisms that usually do ASEXUAL REPRODUCTION, make identical copies of themselves: bacteria and fungi. But wait! Plants can too! So each of these three types of organisms: bacteria, fungi and plants can make identical copies (clones) of themselves.

1. What three types of organisms can undergo asexual reproduction?

2. How many parent cells are involved in asexual reproduction that does NOT require a mate?

3. Describe how the organism (baby) produced during asexual reproduction compares to the parent in one sentence.

Compare and contrast sexual and asexual reproduction below:

Check it out!: Reproduction StationsAt each station, circle whether it is sexual or asexual reproduction and record the organism that you are observing.

STATION 1 STATION 2 STATION 3

Organism:______________

Sexual or Asexual

Organism:______________

Sexual or Asexual

Organism:______________

Sexual or Asexual

Put the following words into the appropriate part of the venn diagram:

1parent 2 parents Identical (clones) Variation (differences) Humans Bacteria Plants

Sexual Asexual

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Sexual Life Cycle

Process: Process:

STATION 4 STATION 5 STATION 6

Organism:______________

Sexual or Asexual

Organism:______________

Sexual or Asexual

Organism:______________

Sexual or Asexual

Let’s talk about SEX!Purpose: to create genetically _________________ offspring!Gametes:sex cells that come together to make a ________________(fertilized egg)

2 types!:

Haploid vs. DiploidDiploid (2N): all of your “____________” cells aka: body cells; ____ chromosomes Haploid cells (N): ____________ & ________ ; ___ chromosomes (**think haploid means half**)

haploid diploidClassify the following as haploid or diploid.

N 2n Sperm Egg Zygote (fertilized egg) Liver cell Heart cell Nerve cell Muscle cell Embryo

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Egg SpermFemales Males

Cell Cycle

Two main stages:1. ______________________2. ______________________

It takes ___ to ___ hours ____% of a cell’s time is spent in INTERPHASE

Mitosis & Meiosis(1 cell 2 cells) (1 cell 4 gametes)

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Stage What happens?!Growth 1 (G1)

Synthesis (S)

Growth 2 (G2)

Mitosis (M)

Cytokinesis

A Closer Look at Mitosis!Use the micro-viewer and the insert to help you complete these notes.The slides show mitosis in an animal cell.

Forwarda. How does an animal begin to develop from single cell?

b. What is the equatorial plate?

Slide 1 – The Zygote1. Define Zygote:2. Draw the slide and label structures.3. Where did the two masses of chromatin come from?

Slide 2 – Pro-Metaphase1. Draw the slide and label the structures2. What is happening to the chromosomes?

Slide 1

Slide 2

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MITOSIS MEIOSISType of

Reproduction asexualUsed for? sexual reproduction

Starts with? 1 diploid cell (____) 1 diploid cell (2n)Makes? 2 __________ diploid cells 4 haploid (n) ___________

# of Divisions? 2Variation(genetic

differences)?NO

Picture

4 _______________

Slide 7

3. Where are the chromosome pairs moving to?

Slide 3 – Metaphase1. What is the star-like structure?2. Where do the star-like structures come from?

3. What structures hold the chromosomes together in the middle?

Slide 4 – Metaphase-Polar view1. How many chromosomes are seen on the equatorial plate?2. Look back at slide 3, where are the centromeres located?

Slide 5 – Early Anaphase1. Draw the slide2. How many groups are the duplicated chromosomes forming?

3. Chromosomes are pulled by what structure?4. Where do the spindle fibers attach?

Slide 6 – Anaphase1. What type of microscope is used to see the chromosomes?2. What are microtubules?

3. When do Chromosomes look beaded?

Slide 7 – Telophase1. Draw this slide2. What is happening to the chromosomes?

3. What is happening to the cell membrane?

Slide 8 – Late Telophase1. Is the separation complete? yes no2. What will soon happen to the chromosomes?

3. Is the process of mitosis the same in humans? yes no4. How many chromosomes did scientists think humans had up until 1958?5. What enabled scientists to determine humans only have 46 chromosomes?

Practice: Mitosis & Meiosis Part 1:Use the following chart to compare and contrast mitosis and meiosis:

MITOSIS MEIOSISChromosome number stays the sameChromosome number divides in half

DNA must first replicateTakes place in somatic (body) cells

Takes place in sex cellsDivides onceDivides twiceMakes 2 cellsMakes 4 cells

Used for sexual reproductionUsed for asexual reproduction

Slide 5

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Cells made are different from their parent cellsCells made are identical to their parent cells

Used for growthUsed only for reproduction

If you start with 40 chromosomes, you end with 20 chromosomesIf you start with 40 chromosomes, you end with 40 chromosomes

Makes gametesMakes daughter cellsMakes haploid cellsMakes diploid cells

Part 2: A human has 46 chromosomes in its skin cells.

If one skin cell makes a copy of itself…

1. Is this mitosis or meiosis?

2. How many daughter cells are created?

3. How many chromosomes are in each daughter cell?

Sketch a picture of the process:

If the human needs to create sex cells…

1. Is this mitosis or meiosis?

2. How many daughter cells are created?

3. How many chromosomes are in each gamete?

Sketch a picture of the process:

Part 3: Fill in the blanks.Mitosis happens in __________ (sex/body cells). In mitosis, one cell divides to form _____ cells. In mitosis, each new cell has ____________________ (the same/a different) number and type of chromosomes as the original cell. Meiosis happens in ___________________ (sex/body cells). In meiosis, one cell divides to form ______ cells. In meiosis, each new cell has _________________ (twice/half/the same) the number of chromosomes as the original cell.

Part 4: Complete the graphic organizer:

SexualAsexualMitosisMeiosis

Word bank:PlantBacteriaFungi1224

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1. During normal meiotic division of a diploid cell, the change in chromosome number that occurs is represented asA. 4n n C. 2n4nB. 2n n D. n½ n

2. A cell with a diploid chromosome number of 12 divided two times, producing 4 cells with 6 chromosomes in each. The process that produced these four cells was most likely

A. Internal fertilizationB. Asexual reproductionC. Mitotic cell divisionD. Meiotic cell division

4. Uncontrolled cell division is characteristic ofA. Cleavage C. RegenerationB. Cancer D. Crossing over

5. Warts result when certain viruses cause skin cells to reproduce at a high rate. This rapid reproduction of skin cells is due to the viruses causing

A. Cellular digestionB. Mitotic cell divisionC. Synthesis processesD. Meiotic cell division

3. What process is represented in the diagram below?

A. Asexual reproductionB. Sexual reproductionC. MeiosisD. DNA Replication

6. Which is a true statement about normal diploid cells?

A. They contain only one chromosome of each homologous pair

B. They contain only half the number of chromosomes as a gamete

C. They contain homologous pairs of chromosomes

D. They contain chromosomes that are all of equal length

7. Which process is represented by the diagram below?

A. FertilizationB. MeiosisC. Binary fissionD. Vegetative

propagation

8. The diagram below represents chromosomes in a zygote. Which diagram best illustrates the daughter cells that result from normal mitotic division of this zygote?

9. Radiation has caused a mutation in the DNA of a bird. This change will most likely be passed on to its offspring if the mutation occurs in its: A. Sperm cell C. Feather cellB. Skin cell D. Nerve cell

10. Which process is represented by the series of diagrams below?

Part 5: EOC practice

AKA: why you don’t look

exactly like your mom or

exactly like your dad!

A. C.

B. D.

A. Gametogenesis C. Meiotic cell division

B. Fertilization D. Mitotic cell division

12. Presence of a cancerous mass in a lung is the result ofA. Prolonged exposure to very dry airB. The introduction of chemicals through the

skinC. Uncontrolled mitotic division and growth of

cellsD. Meiotic cell division

14. Mitosis and meiosis are similar because both processes

A. Produce diploid gametes from haploid cells

B. Involve the formation of chromosomes

C. Make 4 cellsD. Involve the replication of DNA

before division

15. Which sequence represents the correct order of processes that result in the formation and development of an embryo?

A. fertilization meiosis mitosisB. fertilization mitosis meiosisC. meiosis fertilization mitosisD. mitosis fertilization meiosis

Genetic VariationGenetic = having to do with the ______.Variation = __________.

Sources of Genetic Variation Definition Example/

Picture

How does this cause

greater geneticvariety?

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Crossing over

Only in MEIOSIS!

Gene Mutations

ATC GCA TTA TAT

ATC CCA TTA TAT

Nondisjunction

Fertilization(animals)

sperm + egg

Pollination(plants)

female gamete + pollen

change

Unit 4 Study GuideSexual vs. Asexual

Distinguishing the differences between asexual and sexual reproductionType of Reproduction Summarizing Word/PhraseAsexual ReproductionSexual Reproduction

Mitosis vs. MeiosisMITOSIS MEIOSIS

What must happen before the cell divides? What must happen before the cell divides?

How many cells does this process start with? How many cells does this process start with?

How many cells does this process produce? How many cells does this process produce?

What is this process used for? What is the process used for?

What types of cells are produced? What types of cells are produced?

Explain each part of the process below: Explain each part of the process below:

What type of reproduction uses this type of cell division? EXPLAIN.

What type of reproduction uses this type of cell division? EXPLAIN.

Compare the original cell with the TWO cells produced during the process.

Compare the original cell with the FOUR cells produced during the process.

There are haploid cells with one set of chromosomes and diploid cells with two sets of chromosomes. Which type of cells are produced? EXPLAIN

There are haploid cells with one set of chromosomes and diploid cells with two sets of chromosomes. Which type of cells are produced? EXPLAIN

Does this type of cell division produce variation in the offspring?

Does this type of cell division produce variation in the offspring?

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2n

MitosisUsing the mitosis cards, draw each of the six steps of mitosis and describe what is happening in each step:

1st 2nd 3rd 4th 5th 6th

Dra

win

gW

hat

is

happ

enin

g?

ChromosomesSketch the following: This is a cell with a 2 chromosomes:

ORIGINAL CELL

Draw the products of MITOSIS:

How many cells? Are they n or 2n? Are they diploid or

haploid?

Draw the products of MEIOSIS:

How many cells? Are they n or 2n? Are they diploid or

haploid?

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DUE ON TEST DAY (10/11/13)Name: ____________________________

What would 1 daughter cell look like after mitosis & meiosis?

After MITOSIS: After MEIOSIS:

1 chromosome 1 pair of homologous chromosomes

1 chromosome after DNA replication

1 pair of homologous chromosomes after DNA

replication

Genetic Variation1. What are the sources of genetic variation?

2. What does genetic variation mean?

3. A baby with Down syndrome has too many chromosomes because the chromosomes were NOT correctly separated. What type of genetic variation is this?

4. How does a mutation (change) in the DNA of a cell cause genetic variation?

5. The scientist who is studying meiosis cannot figure out why the chromosomes have switched parts of their sequences with one another. Can you help explain to him what occurred?

DNA1. Label the three parts of the nucleotide to the right:

2. WHY does a cell replicate its DNA?

3. Draw & name the four steps of DNA replication in the chart below:Original DNA Step 1:

_________________Step 2:

_________________Step 3&4:

______________

4. What are the four nitrogenous bases? 1)2)3)4)

5. Give the complementary strand of this DNA molecule.A T G C CC G T A AA T A T A

____________________________________

6. Label the following on the picture of DNA to the right: Phosphate Hydrogen bond Nitrogenous base Deoxyribose

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