The Integumentary System More Than Skin Deep Cell Cycle

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

TEKS The student knows the structures and functions of nucleic acids in the mechanisms of genetics. The student is expected to The student knows the structures and functions of nucleic acids in the mechanisms of genetics. The student is expected to (A) describe components of deoxyribonucleic acid (DNA); and illustrate how information fro specifying traits of an organism is carried in the DNA; (B) explain replication, transcription, and translation using models of DNA and ribonucleic acid

Engage Humans shed their entire epidermis every 15 to 30 days. Humans shed their entire epidermis every 15 to 30 days. Humans Bloodhounds detect this upon tracking Bloodhounds detect this upon tracking

Explore 1: Cell Cycle Research Student will complete a cell cycle diagram with detailed description of cellular activity in each of the cell cycle phases. Student will complete a cell cycle diagram with detailed description of cellular activity in each of the cell cycle phases.

Cell Cycle

Explain: Cell Cycle All cells constantly replace themselves by a process called mitosis, which is a small section of the cell cycle. All cells constantly replace themselves by a process called mitosis, which is a small section of the cell cycle. New skin cells push the older generation of cells toward the surface of the skin, where they are finally shed as a flake-like, lifeless, residue New skin cells push the older generation of cells toward the surface of the skin, where they are finally shed as a flake-like, lifeless, residue

includes is divided into What are the two main phases of the cell cycle? Cell Cycle M phase (Mitosis) Interphase G 1 phaseS phaseProphaseG 2 phaseMetaphaseTelophaseAnaphase

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? G 1 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? G 0 Phase: Resting State - Some cells leave the cell cycle and stay here much longer than others ex) brain, nerve, etc…

PurinesPyrimidines AdenineGuanine CytosineThymine Phosphate group Deoxyribose Explain: DNA Section 12-1 Nucleotides

Hydrogen bonds Nucleotide Sugar-phosphate backbone Key Adenine (A) Thymine (T) Cytosine (C) Guanine (G) Structure of DNA Section 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 Sugar B = Adenine, Guanine, Cytosine, Thymine or Uracil P = 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

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 Replication Section 12-2 Growth Replication fork DNA polymerase New strand Original strand DNA polymerase Nitrogenous bases Replication fork Original strand New strand

Getting Ready

Step 1 Unwinding and Unzipping

Unwind and Unzip Helicase Enzyme

Step 2 Separates Polymerase Enzyme

Step 3 Picking up Complementary Bases

Separation and Adding Bases 5’----3’

Step 4 Rewind

Two New DNA Molecules Each DNA Molecule with a Parent and Daughter Strand

Interphase (G2) G 2 phase: The rest of the cell’s organelles are reproduced.

Elaborate: DNA Jewelry