The Integumentary The Integumentary SystemSystem

More Than Skin DeepMore Than Skin Deep

Cell CycleCell Cycle

TAKSTAKS

• TAKSTAKS Objective 2Objective 2 – The student will – The student will demonstrate an understanding demonstrate an understanding of living systems and the of living systems and the environment.environment.

TEKSTEKS

• The student knows the structures and The student knows the structures and functions of nucleic acids in the mechanisms functions of nucleic acids in the mechanisms of genetics. The student is expected toof genetics. The student is expected to

(A)(A)describe components of describe components of deoxyribonucleic acid (DNA);deoxyribonucleic acid (DNA); and and illustrate how information fro specifying illustrate how information fro specifying traits of an organism is carried in the DNA;traits of an organism is carried in the DNA;

(B)(B)explain replicationexplain replication, transcription, and , transcription, and translation using models of DNA and translation using models of DNA and ribonucleic acidribonucleic acid

EngageEngage

• Humans shed their Humans shed their entire epidermis entire epidermis every 15 to 30 every 15 to 30 days.days.

• Bloodhounds Bloodhounds detect this upon detect this upon trackingtracking

Explore 1: Cell Cycle Explore 1: Cell Cycle ResearchResearch

• Student will complete a cell cycle Student will complete a cell cycle diagram with detailed description of diagram with detailed description of cellular activity in each of the cell cellular activity in each of the cell cycle phases.cycle phases.

Cell CycleCell Cycle

Explain: Cell CycleExplain: Cell Cycle

• All cells constantly replace All cells constantly replace themselves by a process called themselves by a process called mitosis, which is a small section of mitosis, which is a small section of the cell cycle.the cell cycle.

• New skin cells push the older New skin cells push the older generation of cells toward the generation of cells toward the surface of the skin, where they are surface of the skin, where they are finally shed as a flake-like, lifeless, finally shed as a flake-like, lifeless, residueresidue

includes

is divided into is divided into

What are the two main phases of the cell cycle?

Cell Cycle

M phase (Mitosis)

Interphase

G1 phase S phase ProphaseG2 phase Metaphase TelophaseAnaphase

The Cell Cycle?

Cell cycle - changes a cell goes through during its life span.

contains 2 main steps. 1.Interphase (LONGEST phase of the

cell cycle and has three parts) G1 (Everyday Cellular Activity) S (DNA Synthesis) G2 (Other Organelles Replicated)

2. M-Phase or Mitotic Phase (Shortest phase)

Mitosis (Nuclear Division) Cytokinesis (Cytoplasm Division)

Explore 2: S Phase Berry Full of DNA Lab

Photo 51 Scientific contributions to the discovery

of the DNA structure.

Review: Interphase (G1)

• What is the main purpose of a cell that is in G1?• G1 Phase: During this stage the cell is carrying on its

everyday activities.• If the cell’s surface to volume ratio gets too big then

the cell must get ready to divide.• Do some cells entering a resting state?• What is this phase called?• G0 Phase: Resting State - Some cells leave the cell

cycle and stay here much longer than others ex) brain, nerve, etc…

Purines Pyrimidines

Adenine Guanine Cytosine Thymine

Phosphate group Deoxyribose

Explain: DNASection 12-1

Nucleotides

Hydrogen bonds

Nucleotide

Sugar-phosphate backbone

Key

Adenine (A)

Thymine (T)

Cytosine (C)

Guanine (G)

Structure of DNASection 12-1

DNA Deoxyribose Sugar Base Pairs

A-T G-C

Phosphate

What is a Nucleotide?The basic building block of nucleic acids

containing a sugar, base, and a phosphate.

P B

S

S = Deoxyribose Sugar or Ribose SugarB = Adenine, Guanine, Cytosine, Thymine or UracilP = Phosphate

Sugar

Bases(Nitrogenous Bases)

These chemicals are often called nitrogenous bases because of the high content of nitrogen (N) atoms

Purines

Pyrimidines

1) Cytosine (C) 2) Thymine (T) 3) Uracil (U)

Phosphate

            

Nucleotide

The Sugar and the Phosphate make up the backbone of the structure

The bases make up the rungs of the ladder

Different Types of Nucleotides in DNA

Deoxy---Adenine |

P

Deoxy----Thymine |

P

Deoxy---Cytosine |

P

Deoxy----Guanine |

P

Many Nucleotides Together

Parts of DNA and RNA Have a

Sugar/Phosphate Backbone

Bases make up the steps of the ladder

A-T---DNA A-U---RNA G-C---DNA & RNA

DNA Structure

QuickTime™ and aCinepak decompressor

are needed to see this picture.

Practice On your paper, complete the missing

DNA strand by adding the complementary bases.

A T C G T T G C C A T C T A G C A A C G G T A G

DNA Replication A Closer Look

» DNA before replication: 1 double helix»  »  »

» DNA after replication: 2 identical double helixes

»  

DNA ReplicationSection 12-2

Growth

Growth

Replication fork

DNA polymerase

New strand

Original strand DNA

polymerase

Nitrogenous bases

Replication fork

Original strand

New strand

Getting Ready

Step 1Unwinding and Unzipping

Unwind and UnzipHelicase Enzyme

Step 2Separates

Polymerase Enzyme

Step 3Picking up Complementary Bases

Separation and Adding Bases5’----3’

Step 4Rewind

Two New DNA Molecules

• Each DNA Molecule with a Parent and Daughter Strand

Interphase (G2)

• G2 phase: The rest of the cell’s organelles are reproduced.

Elaborate: DNA Jewelry