name: block: date: unit 4: cell development and...

Honors Biology 2014-2015

Name: ____________________________________ Block:________ Date:________________________ PACKET #8 !

Unit 4: Cell Development and Replication, Part I: The Cell Cycle !Reading: Chapter 8 plus 13.3 and 15.4 !Objectives: By the conclusion of this unit you will be able to explain why the cell cycle is necessary for the growth, maintenance, and repair of multicellular organisms as well as model the major events of the cell cycle (including cell growth, DNA replication, preparation for division, separation of chromosomes, and separation of cell contents). !Topic 1: Introduction to the cell cycle 1. Compare the process of cell division in prokaryotes and eukaryotes (8.1 and 6.3). 2. Explain the importance of the cell cycle. 3. Describe the main events of the cell cycle, including what happens during each stage of interphase – G0, G1,

S, and G2 (8.2). !Topic 2: DNA replication 4. Describe the structure of DNA and explain how it is assembled into the chromosome (8.3, 13.3). 5. Describe the structure of nucleotides and why they are paired up as they are (8.3) 6. Define and relate the following terms: chromatin, chromosomes, DNA, sister chromatids, centromere,

replicated chromosomes, and homologous chromosomes. (8.5, p. 220). 7. Explain the process of DNA synthesis (replication) and evaluate the importance of correcting DNA

replication errors (8.4, 8.5). 8. Define mutation and explain how cells can repair mutations (8.5). !Topic 3:Cell division and control of the cell cycle 9. List the steps of mitosis and both describe and draw what occurs in each step (8.6). 10. Describe how the cell cycle is regulated by cyclin levels and checkpoints (8.8, 8.9). 11. Describe the major differences between cancer cells and normal cells and how the cell cycle may be altered

in cancer (15.4). !Key terms Asexual Reproduction Cell cycle (G0, G1, S, G2, M) Mitosis Interphase M Phase Restriction point Nuclear division Cytokinesis Cleavage Furrow Cell Plate DNA synthesis (replication) !

DNA polymerase Replication origins Daughter Cell Replisome Semi-conservative Chromosome Replicated Chromosome Sister chromatids Centromere Leading Strand Lagging Strand Okazaki Fragment Histone !!

Anti-parallel Ligase Nucleosome Mutation Mutagenic Excision repair Chromosome segregation Aneuploid cells Mitotic spindle Spindle poles Kinetochore Prophase Metaphase !!

Anaphase Telophase Kinase Cyclin Cancer Checkpoints Cell cycle arrest Oncogene Proto-oncogene Apoptosis Tumor Suppressor

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!1. Starting!at!the!starred!cell!(*),!what!is!the!order!of!the!stages!of!a!cell’s!life?!

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2. During!which!phase!does!the!size!of!the!cell!increase?!!!

3. During!which!phase!does!the!number!of!cells!increase?!!!!

4. Considering!your!answers!to!Questions!2!and!3,!identify!two!ways!that!the!growth!of!an!organism!can!be!accomplished!through!the!events!of!the!cell!cycle.!

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The Cell Cycle 1

The Cell CycleWhat controls the life and development of a cell?

Why?An old piece of poetry says “to everything there is a season... a time to be born, a time to die.” For cells, the line might say “a time to divide and a time to grow.” In multicellular organisms, different types of cells have different roles and need to complete specific tasks. For example, a cell that isn’t large enough is not useful for storing nutrients for later, but a cell that is too large will not be useful for transportation through a tiny capillary. In this activity, you will learn about the seasons of a cell’s life, and in turn better understand how organisms function.

Model 1 – The Cell Cycle

S

M

G2

G1

(including cytokinesis)

*

1. How many phases are in the cell cycle as shown in the diagram in Model 1?

2. Starting at the starred cell, what is the order of the stages of a cell’s life?

3. During which phase does the size of the cell increase?

4. During which phase does the number of cells increase?

2 POGIL™ Activities for High School Biology

5. Considering your answer to Questions 3 and 4, identify two ways that the growth of an organ-ism can be accomplished through the events of the cell cycle.

6. Cancer, the uncontrolled growth of cells, often results in a tumor, or mass of abnormal cells. Some cancerous tumors consist of many cells that are much smaller than normal. According to Model 1, what part(s) of the cell cycle is (are) most likely being affected?

7. In Model 1, if the length of the arrow represents time, then for those cancerous cells, what hap-pens to the time that is necessary for the cell cycle? What implication might this have for doctors who are treating cancer patients?

Model 2 – Cell Cycle Data

Phase Key Process Time Interval (hours)

Sets of DNA present in each cell

at end of phase

Number of organelles in each

cell at end of phase

Gap1 11 1 560

Synthesis 8 2 570

Gap2

Protein and organelle synthesis 4 2 600

Mitosis Cell and nuclear splitting 1 1 300

Total time: 24

8. Model 2 presents cell cycle data for a typical human cell in culture. Use the phase names in Model 2 to label the G, M, and S phases in Model 1.

9. Looking at the third column of Model 2, compare the time spent in mitosis with the time spent in gap1 in human cells and describe any difference.

The Cell Cycle 1

The Cell CycleWhat controls the life and development of a cell?

Why?An old piece of poetry says “to everything there is a season... a time to be born, a time to die.” For cells, the line might say “a time to divide and a time to grow.” In multicellular organisms, different types of cells have different roles and need to complete specific tasks. For example, a cell that isn’t large enough is not useful for storing nutrients for later, but a cell that is too large will not be useful for transportation through a tiny capillary. In this activity, you will learn about the seasons of a cell’s life, and in turn better understand how organisms function.

Model 1 – The Cell Cycle

S

M

G2

G1

(including cytokinesis)

*

1. How many phases are in the cell cycle as shown in the diagram in Model 1?

2. Starting at the starred cell, what is the order of the stages of a cell’s life?

3. During which phase does the size of the cell increase?

4. During which phase does the number of cells increase?


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5. Model!2!presents!cell!cycle!data!for!a!typical!human!cell!in!culture.!!!a. Compare!the!time!spent!in!mitosis!with!the!time!spent!in!gap1!in!human!cells!and!

describe!any!difference.!!!!!

b. Imagine!100!cells!were!chosen!randomly!from!a!tissue!sample!and!examined!under!a!microscope.!!In!which!phase!of!the!cell!cycle!would!you!expect!to!find!the!largest!number!of!cells?!Explain.!!

!!!

6. Using!the!information!found!in!Models!1!and!2,!complete!the!“Key!Processes”!column!for!Gap1!and!Synthesis!phases!of!the!cell!cycle.!!

!7. What!do!you!think!takes!place!during!the!mitosis!phase?!Hint:&Consider!the!sets!of!DNA!in!

each!cell.!!!!!

8. Cyto&=!cell,!kinesis!=!cutting.!!What!do!you!think!takes!place!during!cytokinesis?!!!!

9. Cells!will!sometimes!stop!dividing!and!enter!another!phase,!G0.!!Keeping!in!mind!the!events!of!each!part!of!the!cell!cycle,!mark!with!a!double!arrow!on!Model!1!where!those!cells!might!(either!temporarily!or!permanently)!exit!the!cell!cycle!to!G0.!!Why!did!you!choose!this!location!for!G0?!Hint:&Think!of!a!place!in!the!cell!cycle!where!the!cell!is!functioning!normally,!but!not!preparing!to!divide.!!

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10. Liver!and!nerve!cells!are!both!typically!found!in!the!G0!phase!of!the!cell!cycle.!!If!you!damage!your!liver,!new!liver!cells!can!be!produced!to!replace!up!to!75%!of!the!liver.!However,!if!you!sustain!brain!damage,!your!body!does!not!usually!produce!new!brain!cells.!!Explain!this!observation!using!what!you!have!learned!about!the!cell!cycle.!!

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11. Plasmodial!slime!mold!is!an!example!of!a!multinucleated!cell.!!It!can!be!referred!to!as!“one!huge!cytoplasmic!mass!with!many!nuclei”!as!seen!to!the!right.!!What!part!of!Model!1!is!skipped!in!the!formation!of!such!a!cell?!Explain!your!answer.!

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6 POGIL™ Activities for High School Biology

Extension Questions28. For each phase, describe at least one way mistakes during the cell cycle could result in problems.

G1

S

G2

M

G0

29. Some types of cancers are treated with radiation, similar to ultraviolet light. Why might it be beneficial to irradiate cancer cells?

30. Plasmodial slime mold is an example of a multinucleated cell. It can be referred to as “one huge cytoplasmic mass with many nuclei” as seen to the right. What part of Model 1 is skipped in the formation of such a cell? Explain your answer.

31. Chemotherapy utilizes chemicals that disrupt various parts of the cell cycle, targeting rapidly growing cells. Paclitaxel (Taxol®) is one such drug that prevents the mitosis phase from taking place.

a. Explain how this drug is useful as a cancer treatment.

b. How might targeting rapidly growing cells explain common chemotherapy side effects such as hair loss and nausea?


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!!Model!3:!Human!Embryo!Development!!!

!Read!This!!________________________________________________________________________________________________________________!Cell!division!and!the!cell!cycle!are!important!for!many!reasons.!!In!species!that!use!sexual!reproduction,!every!organism!starts!life!as!a!single!cell!called!a!zygote.!In!general,!cell!division!must!occur!for!the!organism!to!grow,!develop,!and!repair!dead!or!damaged!cells.!!12.!!What!is!the!name!of!the!singleacell!stage!of!development?!!!!!!13.!!How!many!cell!divisions!have!occurred!at!the!2acell!stage!of!embryonic!development?!!At!the!4a

cell!stage?!!!!!!!14.!!How!many!cells!would!the!embryo!contain!after!6!cell!divisions?!!!!


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!!!!14.!!During!development,!some!cells!will!undergo!apoptosis,!or!programed!cell!death.!!The!picture!

above!shows!an!example!of!this!occurring.!!With!your!group,!write!one!complete!sentence!explaining!the!purpose!of!apoptosis!illustrated!above.!

!!!!!!!15.!!Summarize:!How!do!mitosis!and!apoptosis!work!together!to!determine!what!we!look!like!as!we!

develop!from!a!single!cell?!!!!!!!!16.!!What!processes!do!you!think!would!take!place!after!an!openaheart!surgery?!Explain.!!


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DNA Structure and Replication 1

DNA Structure and ReplicationHow is genetic information stored and copied?

Why?Deoxyribonucleic acid or DNA is the molecule of heredity. It contains the genetic blueprint for life. For organisms to grow and repair damaged cells, each cell must be capable of accurately copying itself. So how does the structure of DNA allow it to copy itself so accurately?

Model 1 – The Structure of DNA

Nucleotide

Phosphate

Ladder Model of DNA Helix Model of DNA

Deoxyribose sugar

Nitrogen Bases

Adenine

Thymine

Guanine

Cytosine

Nitrogen-containingbase

1. Refer to the diagram in Model 1.

a. What are the three parts of a nucleotide?

b. What kind of sugar is found in a nucleotide?

c. Which nucleotide component contains nitrogen?

d. Name the four nitrogen bases shown in Model 1.

2. DNA is often drawn in a “ladder model.” Locate this drawing in Model 1.

a. Circle a single nucleotide on each side of the ladder model of DNA.

DNA Structure and Replication 1

DNA Structure and ReplicationHow is genetic information stored and copied?

Why?Deoxyribonucleic acid or DNA is the molecule of heredity. It contains the genetic blueprint for life. For organisms to grow and repair damaged cells, each cell must be capable of accurately copying itself. So how does the structure of DNA allow it to copy itself so accurately?

Model 1 – The Structure of DNA

Nucleotide

Phosphate

Ladder Model of DNA Helix Model of DNA

Deoxyribose sugar

Nitrogen Bases

Adenine

Thymine

Guanine

Cytosine

Nitrogen-containingbase

1. Refer to the diagram in Model 1.

a. What are the three parts of a nucleotide?

b. What kind of sugar is found in a nucleotide?

c. Which nucleotide component contains nitrogen?

d. Name the four nitrogen bases shown in Model 1.

2. DNA is often drawn in a “ladder model.” Locate this drawing in Model 1.

a. Circle a single nucleotide on each side of the ladder model of DNA.

1.!!Refer!to!the!diagram!in!Model!1.!!! a.!What!are!the!three!parts!of!a!nucleotide?!!! b.!!What!kind!of!sugar!is!found!in!a!DNA!nucleotide?!!!!! c.!!Name!the!four!nitrogen!bases!shown!in!Model!1.!!!!2.!!DNA!is!often!drawn!in!a!“ladder!model”.!Locate!this!drawing!in!Model!1.!!!! a.!Circle!a!single!nucleotide!on!each!side!of!the!ladder!model!of!DNA.!!! b.!!What!part(s)!of!the!nucleotides!make!up!the!rungs!of!the!“ladder”?!! !!! c.!!What!parts!of!the!nucleotides!make!up!the!sides!(backbone)!of!the!“ladder”?!


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Read%This!%_____________________________________________________________________________________________________________!When!studying!the!structure!of!DNA,!scientists!find!it!useful!to!be!able!to!refer!to!specific!carbons!in!the!deoxyribose!sugar.!By!convention,!we!number!carbons!in!such!a!way!that!we!get!the!longest!unbroken!chain!possible.!Examine!the!diagram!of!deoxyribose!below,!and!notice!that!carbons!are!numbered!1!–!5,!beginning!with!a!carbon!on!the!pentose!ring.!

!_____________________________________________________________________________________________________________!!3.!Number!the!carbons!in!each!nucleotide!you!circled!in!Model!1.!!! a.!!To!which!carbon!is!the!phosphate!group!attached?!!!! b.!!To!which!carbon!does!the!next!nucleotide!in!the!chain!attach?!!!4.!!Look!at!the!bottom!and!top!of!the!“ladder”!in!Model!1.!Are!the!two!sides!parallel!(ends!of!the!strands!match)!or!antiparallel!(the!ends!of!the!strands!are!opposites)?!!!!5.!!Every!DNA!strand!has!2!ends:!a!3’!end!and!a!5’!end.!These!labels!are!given!based!on!which!numbered!carbon!is!closest!to!the!end.!In!model!1,!label!the!3’!and!5’!ends!of!both!DNA!strands.!!!!!6.!!On!the!“ladder”!model!of!DNA!label!each!of!the!nitrogenous!bases!with!the!letter!A,!T,!C,!or!G.!!!!7.!!Refer!to!Model!1.!!When!one!nucleotide!contains!adenine,!what!type!of!base!is!the!adenine!attached!to!on!the!opposite!nucleotide!strand?!!!


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8.!!The!two!strands!of!DNA!are!held!together!with!hydrogen%bonds!between!the!nitrogen!bases.!These!are!weak!bonds!between!polar!molecules.!!How!many!hydrogen!bonds!connect!

the!two!bases!from!Question!7?!

!

!

!

!

!

9.!!Refer!to!Model!1.!!When!one!nucleotide!contains!cytosine,!what!type!of!base!is!the!cytosine!

attached!to!on!the!opposite!nucleotide!strand?!!

! a.!!How!many!hydrogen!bonds!connect!these!two!bases?!!

!

!

!

!

10.!!With!your!group,!use!a!complete!sentence!to!write!a!rule!for!how!the!bases!are!arranged!

in!the!ladder!model!of!DNA.!

!

Read%This!%Erwin!Chargaff!(1905!–!2002),!an!Austrian^American!biochemist,!investigated!the!ratio!of!

nucleotide!bases!found!in!DNA!from!a!variety!of!organisms.!!From!his!research,!as!well!as!

research!by!Rosalind!Franklin!and!Maurice!Wilkins,!Watson!and!Crick!were!able!to!solve!the!

puzzle!of!DNA’s!structure.!!

!

Relative!Proportions!(%)!of!Bases!in!DNA!

Organism% A% T% C% G%Human! 30.9! 29.4! 19.9! 19.8!

Chicken! 28.8! 29.2! 20.5! 21.5!

Grasshopper! 29.3! 29.3! 20.5! 20.7!

Sea!Urchin! 32.8! 32.1! 17.7! 17.3!

Wheat! 27.3! 27.1! 22.7! 22.8!

Yeast! 31.3! 31.9! 18.7! 17.1!

E.!coli! 24.7! 23.6! 26.0! 25.7!

!

11.!Some!data!about!DNA!composition!of!several!species!is!given!in!the!table!above.!Examine!

the!relative!proportions!of!bases.!

A.!!What!percentage!of!bases!in!the!human!genome!is!Adenine?!_______!Thymine?!_______!

Cytosine?!________!!Guanine?!_________!

!

B.!!What!percentage!of!bases!in!the!sea!urchin!genome!is!Adenine?!_______!!

Thymine?!_______!!Cytosine?!________!!Guanine?!_________!

!

C.!!Make!an!observation!about!the!relative!numbers!of!each!nucleotide!base.!

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11.!!Fill!in!the!complementary%bases!on!the!strand!below!according!to!the!base!pair!rule.!!! A! T! C! C! A! G!!!!!!12.!!The!ladder!model!of!DNA!is!a!simplified!representation!of!the!actual!structure!and!shape!of!a!

DNA!molecule.!In!reality,!the!strands!of!DNA!form!a!double%helix.!Refer!to!the!double!helix!diagram!in!Model!1!and!describe!its!shape!using!a!complete!sentence!!

12.!!Based!on!the!data!above,!and!on!similar!data!from!many!other!species,!Chargaff!developed!the!complementary%base<pairing%rules!of!DNA!structure.!!What!do!you!think!this!rule!might!have!been?!Which!bases!appear!to!be!paired!up!with!one!another?!!

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!10DNA Structure and Replication 3

Model 2 – DNA Replication

Direction of DNAhelicase

DNA helicase

Free Nucleotides

11. Examine Model 2. Number the steps below in order to describe the replication of DNA in a cell.

______ Hydrogen bonds between nucleotides form.

______ Hydrogen bonds between nucleotides break.

______ Strands of DNA separate.

______ Free nucleotides are attracted to exposed bases on the loose strands of DNA.

12. Locate the DNA helicase on Model 2.

a. What type of biological molecule is DNA helicase?

b. What is the role of DNA helicase in the replication of DNA?

13. What rule is used to join the free nucleotides to the exposed bases of the DNA?

14. This type of replication is called semi-conservative replication. Considering the meaning of these words (semi—half; conserve—to keep), explain why DNA replication is called semi-conservative.

13.!!Examine!Model!2.!!Number!the!steps!below!in!order!to!describe!the!replication!of!DNA!in!a!cell.!________!!Hydrogen!bonds!between!nucleotides!form.!

________!!Hydrogen!bonds!between!nucleotides!break.!

________!!Strands!of!DNA!separate.!

________!Free!nucleotides!are!aligned!with!exposed!bases!on!the!loose!strands!of!DNA.!

!

14.!!What!rule!is!used!to!join!the!free!nucleotides!to!the!exposed!bases!of!the!DNA?!

!

!

15.!!This!type!of!replication!is!called!semi<conservative%replication.!!Considering!the!

meaning!of!these!words!(semi!–!half;!conserve!–!to!keep),!explain!why!DNA!replication!is!

called!semi^conservative.!


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Model%2A%–%The%Enzymes%of%DNA%Replication%

16.!!Locate!DNA!helicase!and!DNA!polymerase!on!Model!2A.!!!! a.!!To!which!class!of!biological!molecule!do!these!belong?!!!! b.!!What!is!the!role!of!DNA!helicase!in!the!replication!of!DNA?!!!!!! c.!What!is!the!role!of!DNA!polymerase!in!the!replication!of!DNA?!!!!17.!!Use!the!information!in!Model!2A!to!create!a!definition!for!each!of!the!following:!!! a.!!Template!DNA!strand!!!! b.!!Replication!fork!


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! Read%This!%______________________________________________________________________________________________________________!The!formation!of!new!DNA!is!mostly!carried!out!by!an!enzyme!complex!called!DNA%Polymerase%III.!!Specifically,!DNA!Polymerase!III!adds!free!nucleotides!to!the!3’!end!of!a!growing!DNA!strand.!!Recall!that!two!strands!of!a!DNA!molecule!are!anti^parallel.!!Because!of!this,!and!because!DNA!Pol!III!can!only!add!to!the!3’!end,!the!two!new!strands!of!DNA!are!formed!by!slightly!different!processes.!!One!side,!the!leading%strand,!is!assembled!continuously.!The!other!side,!the!lagging%strand,!must!be!assembled!in!short!segments!that!are!later!joined!together.!!These!short!segments!on!the!lagging!strand!are!called!Okazaki%fragments.!!______________________________________________________________________________________________________________!!18.!!Locate!the!“leading!strand”!and!“lagging!strand”!labels!in!Model!2A.!!!!! a.!!Which!strand!is!built!in!the!same!direction!that!helicase!is!unwinding!the!double!helix?!!!!! b.!!Which!strand!is!built!opposite!from!the!direction!that!helicase!is!unwinding!the!double!

helix?!!!!!19.!!DNA!molecules!can!be!tens!of!thousands!of!base!pairs!in!length.!!Mistakes!in!DNA!replication!lead!to!mutations,!which!may!or!may!not!be!harmful!to!an!organism.!!How!does!semi^conservative!replication!help!prevent!mutations!during!DNA!replication?!!!!!!!!20.!The!proportions!of!the!bases!are!consistent!within!a!species;!however!they!do!vary!between!species.!Using!the!base^pair!rules,!complete!the!following!table!to!show!the!percentage!of!each!type!of!base!in!the!five!different!organisms.!!!

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Chromosomes and DNA Packaging Homework (Part of Objective 4): Watch the following animation. Use the video and the pictures below to fill in the blanks. Animation Link: http://www.youtube.com/watch?v=gbSIBhFwQ4s

!1. A DNA double helix has a diameter of ________ and, if stretched out it would have a length of __________. 2. In contrast, a metaphase chromosome has a diameter of _____________, which is approximately ____________ times thicker than the double helix itself. 3. When DNA winds around proteins called ______________________, the resulting tight loop is referred to as a ___________________________. 4. The fiber formed of packed nucelosomes is known as _______________________. It is _________ thick. 5. The many levels of folding allow all _____ feet of DNA in each cell to fit in the nucleus. You could fit __________ cell nuclei on the tip of a needle. 6. The end result is a tightly packed molecule called a _________________. They are not always present in a cell, however. They formed during _________________________.

Label the diagram on the right. Use the following labels:

• Unreplicated chromosome

• Replicated chromosome

• Homologous chromosome pair

• Centromere

• Sister Chromatids

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*A note about homologous chromosome pairs: Everyone has two copies of every chromosome, one from the mother and one from the father. Humans have 23 pairs of chromosomes. The chromosome pairs are considered homologous because they contain the same type of information (genes). The copies of the genes may not be identical, but they code for the same proteins. For example, if the gene for eye color is on chromosome 2, a person has two copies of chromosome 2 and therefore two genes for eye color. Each copy might be different; the person may have a gene for brown eyes and a gene for blue eyes. But the chromosomes are homologous because they both contain the eye color gene.

http://www.youtube.com/watch?v=gbSIBhFwQ4s


DNA Replication HW (Part of Objective 7): Watch the Crash Course video on DNA Structure and Replication: https://www.youtube.com/watch?v=8kK2zwjRV0M

1. What is Hank’s trick to know which direction a DNA strand is facing?

!2. What type of bonds hold the two strands of DNA together? What parts of the nucleotide are connected?

!!3. How many base pairs make up the human genome (all 46 chromosomes)? __________________________

4. What were the two things about DNA that Rosalind Franklin discovered?

!!5. What are the two reasons that Rosalind Franklin didn’t get credit for her work?

!!6. Why is the lagging strand a “pain in the butt to deal with”? What is the solution?

!!7. How often does DNA replication make a mistake? What is the solution?

!!!DNA Repair HW (Part of Objective 8):

Fill in the following table by matching the enzyme to its action

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!!

!!

!!

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Step Action Enzyme

1 mismatch identified (proof reading)

2 short region containing mismatch is excised

3 missing bases are replaced

4 bonds in sugar-phosphate backbone are formed

https://www.youtube.com/watch?v=8kK2zwjRV0M


Mitosis Webquest

Part I: Mitosis Tutorial: http://cellsalive.com/

On the left side of the screen is a navigation bar, click on the link to “MITOSIS”. Read the text on this page and view the animation, you can slow down the video by clicking step-by-step through the phases.

1. During which stage did the following occur?

a. Chromatin condenses into chromosomes. ____________________________________

b. Chromosomes align in center of cell. ____________________________________

c. Movement of centrioles. ____________________________________

d. Nuclear envelope breaks down. ____________________________________

e. Cell is cleaved into two new daughter cells. ____________________________________

f. Daughter chromosomes arrive at the poles. ____________________________________

!2. Watch the video carefully and answer the questions below.

a. Why are the chromosomes in metaphase depicted as replicated chromosomes, comprised of two sister chromatids?

!!

b. How many chromosomes are present during metaphase? Are they replicated or unreplicated?

!!

c. How many chromosomes are present in each daughter cell during telophase? Are they replicated or unreplicated?

!!

d. Describe the appearance and movements of centrioles during each phase of mitosis:

i. Interphase (end of G2)

!!

ii. Prophase

!!

iii. Metaphase

!!

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http://cellsalive.com/


iv. Anaphase

!!

v. Telophase

!!

vi. Interphase (beginning of G1)

!!

e. During which stage is the nuclear membrane visible?

!3. Identify the mitotic stage of each illustration below:

! ! !

4. Go to www.johnkyrk.com/mitosis.html View the animation and sketch the cell in:

Prophase Metaphase Anaphase Telophase

!

!!!

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http://www.johnkyrk.com/mitosis.html


Part III: Onion Root Tip Activity http://biology.arizona.edu/cell_bio/activities/cell_cycle/cell_cycle.html

Read the introduction, then click the “next” button. You wil have 36 cells to classify. When you’re finished, record your data in the chart below.

5. Look back through your webquest. What is the difference between plant and animal cells with regard to cytokinesis?

!Part IV: Final Cell Cycle Review at: http://www.biology.arizona.edu/cell_bio/tutorials/cell_cycle/main.html

1. Look at:

a. DNA Basics (packaging)

b. The Cell Cycle (regulation)

c. Mitosis

2. Test yourself: Fill out the table below as you go.

!

Interphase Prophase Metaphase Anaphse Telophase Total

Number of Cells

!! 36

Percent of Cells (calculate: number of cells divided by total cells x100)

!! 100%

Problem 1 2 3 4 5 6 7 8 9 10 11

My answer

Correct answer

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http://biology.arizona.edu/cell_bio/activities/cell_cycle/cell_cycle.html

http://www.biology.arizona.edu/cell_bio/tutorials/cell_cycle/main.html


Planarian Regeneration Lab

!Introduction: ! Planaria are one of many free-living flat worms that can be found in marine, aquatic, and terrestrial environments. Typical characteristics include an acoelomate (no body cavity) body, a gut with no anus, lack of a blood vascular system, and a simple nervous system. Planaria are carnivorous scavengers. Planaria have been the subject of many studies because of their unusual ability to regenerate. Regeneration is the ability to “re-grow” lost body parts. This is possible because the organism has the ability to form a blastema, which is an accumulation of undifferentiated cells, at the site of the wound. (We saw this in the salamander video!) These undifferentiated cells will eventually differentiate into the missing parts. ! Interesting Fact: Planarian flatworms reproduce by taking advantage of their regeneration capabilities. When conditions are favorable, the organism will attach its tail-end to the ground and pull forward with its head-end until it tears itself in half. Each end will then regenerate its missing half. This is a form of asexual reproduction called fission. The two “new” planaria are clones of each other, both possessing identical genes. ! In this laboratory activity, you will study patterns of regeneration in planaria by conducting your own regeneration experiment. It will be your responsibility to care for your organisms and to keep records of their developmental progress by recording your observations. !!Materials: Planarian, Microscope, Scalpel, Water (preferably pond water), Petri dishes !Procedure: !*When working with Planaria, you can slow its movement by placing the slide on ice for several minutes. 1. Before making any cuts to your planaria, examine it on a slide to try to identify the following anatomical structures.

(An understanding of the Planaria anatomy is essential for determining if there was any regeneration or not!!) a. Catch a Planaria and put it on a microscope slide with a drop of water or place in a Petri dish to observe under

the dissecting scope. b. View the Planaria using a dissecting scope or magnifying glass. Make a detailed drawing of Planaria in your

notebook. 2. There are several classical types of cuts that can be made to your Planaria that should generate good results. You may

research these online if you wish. !3. Slow the Planarian’s movements by chilling the slide on ice. !4. Using a razor blade or scalpel, make the desired cut(s) to your Planaria. !

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Honors Biology 2014-2015 5. Place the pieces obtained from the cut in individual Petri dishes with fresh pond water. !6. Label the Petri dish with your name, the type of cut performed, and which piece is in the dish (i.e. head end, tail end,

left side, right side, etc). !7. Planarian Care: Keep your experimental Planaria in a cool darkened area. Provide your Planaria with fresh stream

water every other day. Remove the old water with a pipette, being careful not to accidentally dispose of your Planaria. Only use fresh pond, spring, or stream water – never tap water or distilled water. Also, do not feed. !

8. Observations: Each time you change the water, observe your Planaria using a scope or magnifying glass and note any changes you see (think about what you need to include: what type of fragments you’re looking at, size, and presence of eyespots). Record observations in your notebook. ** Record the date of your observations. It will take two to three weeks for regeneration to be completed. !!

Lab Questions: - To be completed during Day 0 of lab. !

1. Hypothesize about your planarian. Which dissection cuts do you think will result in new planarian? 2. What environmental variables do you think may influence regeneration? 3. After you cut the planaria, how does the mobility of the tail fragments compare to the mobility of the head

fragments? Do they move the same or differently? If they move differently, why do you think that is? (If you didn’t cut your planaria in a way that gives you a tail and a head, note the mobility of pieces that you did cut).

4. Do you think the head fragments prefer light or shade? How can you test this? !- To be completed on Final Day of regeneration (Probably day 8-10).

!1. As the days went by, what did you notice about the color of the regenerating tissue? 2. Did all the tail fragments regenerate photoreceptors (eyespots)? If not, which fragments did not? 3. Did all the tail fragments regenerate photoreceptors at the same rate? If not, which were slower and which were

faster? 4. What does the relative rate of appearance of photoreceptors in the different tail fragments tell you about the

regeneration ability of different sections of the worm? 5. Did you notice a change in mobility in the tail fragments over time? What about the head fragments? 6. How could you test whether the regenerated photoreceptors are functional? Do you think photoreceptors are

functional before, as soon as, or sometime after they become visible? Why?

!Critical Thinking Question:

1. After learning about the importance of regeneration to planaria, where else might regeneration be important? To what species? Is regeneration related to the study of stem cells? How could the study of regenerative species be of importance to humans? !

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Objective 11:Cancer

Why are tumors harmful?

-

-

-

What are Carcinogens?

-

To be cancerous, a cell must gain the ability to:

Grow in the absence of growth stimulatory signals:

_________________________________________________________________________________

_________________________________________________________________________________

!Grow in the presence of growth inhibitory signals:

_________________________________________________________________________________

_________________________________________________________________________________

!Avoid the process of apoptosis:

_________________________________________________________________________________

_________________________________________________________________________________

!Become angiogenic:

_________________________________________________________________________________

_________________________________________________________________________________

!Proliferate indefinitely:

_________________________________________________________________________________

_________________________________________________________________________________

_________________________________________________________________________________

!Invade and metastasize:

_________________________________________________________________________________

_________________________________________________________________________________

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Angiogenesis: Telomerase:

!!!!!!!

!Metastasis:

!

p53 protein normally acts as a “tumor-suppressor;” when the p53 gene is mutated, a functional p53 protein is no longer produced.

! !21


Practice/Review Questions: DNA Structure and Replication Practice questions !1. Place the following in order, from small to big:

• Nucleus of a cell • Nucleic acid molecule • Neutron • Nitrogen atom

• Nitrogenous base • Nucleotide !

2. __________________ is the type of monomer that is repeated to make a nucleic acid, just as glucose monomers are repeated to make a polysaccharide (or amino acid monomers to make a protein).

3. This monomer is made of a sugar group, a phosphate group, and a __________________ that have been bonded together.

4. In a single strand of DNA, the phosphate group binds to the __________________ of the next group.

5. The 5' end of a single DNA strand contains a free __________________, while the 3' end contains a free __________________________.

6. DNA was not thought to be the genetic blueprint originally; instead many scientists hypothesized that _______________________ contained the genetic code and blueprint of life. (They were later proven wrong.)

7. DNA is a type of ______________ (what type of organic molecule?).

8. In order for DNA to replicate, _____________ (what kind?) bonds are broken. This is catalyzed by an enzyme called _____________. The adding and joining (covalent bonding) of new nucleotides (during the process of replication) is catalyzed by an enzyme called ___________________. This enzyme also catalyzes proofreading as new nucleotides are added (it tries to make sure that C pairs with G and A pairs with T).

9. Number the steps of DNA replication in the correct order (1, 2, 3) ______ Daughter strands are formed using complementary base pairing. ______ DNA unwinds ______ The DNA of the daughter strands winds with together with its parent strand.

10. What enzyme unwinds are unzips the parent strand? ________________

11. What enzyme synthesizes the new DNA strand? _______________________

12. The two sides of the DNA helix are held together by ________________________

13. You are studying a DNA (double helix) molecule that is 1,000 base pairs long and 20% of the molecule consists of thymines.

a. How many total bases are in this double helix? _______

b. What percentage of the bases are guanines? _______

c. How many of the bases are guanines? _______

d. Would you be able to answer this question if the DNA molecule were single-stranded, instead? Explain. ________________________________________________________

14. What makes DNA replication “semiconservative?” !

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Honors Biology 2014-2015 Mitosis Practice: 15. Look at the following pictures and label each one with the appropriate stage of mitosis.

a. �� b. c.

16. Label each of the following statements as being descriptive of interphase, prophase, metaphase, anaphase, or telophase:

a. _____ chromosomes are not yet visible

b. _____ sister chromatids have just broken away from each other at the centromere

c. _____ nuclear membrane is reforming

d. _____ sister chromatids are still attached to each other at the centromere, but chromosomes haven’t lined up yet

e. _____ nuclear membrane is breaking down

f. _____ chromosomes have lined up in a “single file” line

g. _____ the stage that includes cytokinesis

h. _____ organelle replication and protein synthesis occurs

i. _____ in terms of changes in the nuclear membrane, this stage is the opposite of prophase 17. Observe the cell shown below (it has just finished cytokinesis) and make each of the six single

chromosomes below a different color. a. Then, diagram how this cell would appear if it were seen in each of the following stages. Be sure

that each diagram shows the shape of the cell, whether or not the nucleus is visible, and the chromosomal arrangement of the cell.

b. Finally, write a caption for each diagram using words/phrases (where appropriate) such as sister chromatids, homologous chromosomes, centriole, and centromere

a. prophase of mitosis b. anaphase of mitosis !!!!!!23

!!

! !!! !!

Cell

Nuclear

Nucleus


18. Used in chemotherapy treatments, taxol is an anti-cancer drug, which is known to stop cells from dividing. a. Tumors are clusters of cells that are growing and dividing without proper regulation. What is the

difference between a benign tumor (non-cancerous), and a malignant tumor (cancerous)? !

b. How do you think taxol might work? Write about two specific ideas that you have. In other words, what mitotic processes might taxol prevent, and how would stopping these processes prevent effective cell division? (There are many, many possible answers here; the important part is that you apply specific knowledge about the cell cycle.) !!!!!!

19. Cancer is always genetic. This means that cancer is caused by mutations in the DNA. So, a genetic mutation is a mutation (or change) in your DNA molecule. Because your body has evolved to have many back-up systems, cancer is almost always caused by a series of mutations, not just one.

a. Is cancer a genetic disease? ____ Is cancer necessarily an inherited disease? ____

b. Are these “genetic mutations” always “inherited mutations”? ____

c. Is an “inherited mutation” always a “genetic mutation”? ____

d. Are genetic mutations always passed from one generation to another? ____

e. Why do you think that cancer is generally considered a “disease of aging?”

!!

f. Why do you think that some people do have cancer at younger ages?

!

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UNreplicated Chromosome

Replicated Chromosome

UNreplicated Chromosomes

Sister Chromatids


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name: block: date: unit 4: cell development and...

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